achievements and results annual report 2000

Achievements and Results Annual Report 2000

The Fraunhofer Institute for Solar Energy SystemsISE conducts research on the technology neededto supply energy efficiently and on an environ-mentally sound basis in industrialised, thresholdand developing countries. To this purpose, theInstitute develops systems, components, materialsand processes in the areas of thermal use of solarenergy, photovoltaics, solar building, electricpower supplies, micro-energy technology, chemi-cal energy conversion, energy storage and ratio-nal use of energy.

The institute's work ranges from investigation ofscientific fundamentals for solar energy applica-tion, through the development of production technology and prototypes, to the constructionof demonstration systems. The institute plans,advises and provides know-how and technicalfacilities as services.

Foreword 4

The Institute in Brief- Institute Profile 6- Organigram 6- Research and

Services Spectrum 6- Highlights of 2000 7- Examples of Innovation 8

The Institute in Figures 9

Board of Trustees 10

Clients 11

International Co-operation 12

The Departments of the Institute 14

Research Trends in 2001 18

Table of Contents

2 Fraunhofer ISE 2000

Reports from the Departments

Research and Development in Thermal Solar Energy and Optics 22- Large-Area 3D Nanostructures and

Microstructures – "Nanofab" 24- Photoelectrochromic Windows 25- Concept for a Multiple-Stage

Adsorption Heat Pump 26- Micro-Encapsulated Phase Change

Materials in Integrated Wall Systems for Heat Storage 27

- Thermotropically Controlled Façade Components 28

- Building Simulation Improved by Higher-Frequency Modelling of Radiation Data 29

- Simulation-Supported Controls Development to Optimise the Integration of Fuel-Cell Cogeneration Plants into Hybrid Solar Energy Supply Systems 30

- Earth-to-Air Heat Exchangers 30- Ray-Tracing to Analyse and Optimise

Optical Reflectors 31

Measurement and Testing in Thermal Solar Energy and Optics 32- Compact Ventilation Units – Efficiency

for Passive Solar Houses 34- Test Facility for Solar Desiccant

Cooling Systems 35- Experimental Investigations of the

Stagnation Behaviour of Thermal Solar Systems 36

- Collector with a Corrosion-Free Absorber for Desalination of Seawater 37

- IR Thermography as a Tool to Develop and Analyse Modern Façade Elements 38

- User Reactions to Sun-Shades and Glare Control 39

Solar Engineering – Advising, Planning, Implementing 40- Solar Building – Residential Buildings 42- Solar Building – Commercial Buildings 43- Solar Building – Cross-Sectional Analyses 45

Energy Technology 46- Natural Gas Reformer for a Fuel-Cell

Cogeneration Plant to Supply Energy for Buildings 48

- Innovative Energy Supply for Houses with a Fuel-Cell Cogeneration Plant 50

- Miniature Photovoltaic Modules for Small Appliances and Sensors 51

- Fuel Cells in the Low Power Range as Power Supplies for Portable Electronic Appliances 52

- Thermophotovoltaic Energy Conversion with Micro-Structured Emitters 53

Fraunhofer ISE 1999 3

Solar Cells – Materials and Technology 54- Monocrystalline Solar Cells with Highest

Efficiency and Innovative Manufacturing Technology 56

- Rapid Thermal Processing of Solar Cells 58- The SIR Process for Energy-Saving

Production of Crystalline Silicon Thin-Film Solar Cells 59

- Front-Surface Contacting for Crystalline Silicon Thin-Film Solar Cells with Screen-Printing Processes 60

- III-V Solar Cells 61- Laboratory and Service Centre in

Gelsenkirchen 63

ISE CalLab – Precision Measurements for Photovoltaics 64- An Overview of the Photovoltaic

Calibration Laboratory 66- Calibration Reduces Costs for

Photovoltaic Electricity 67

Electricity for Areas Remote from the Grid 68- Strategies for Grid-Independent Village

Electricity Supply – The Example of Rambla del Agua 70

- Village Power Systems in Indonesia 71- Purification of Drinking Water with

Photovoltaics for Remote Areas 72- Monitoring by Fraunhofer ISE Maintains

High Quality Standards for Solar Systems on Mountain Lodges 73

- Electromagnetic Compatibility of Photovoltaic Systems and Components 74

- Batteries – Core Components for all Stand-Alone Power Supplies 75

Development of Products and Components 76- Photovoltaics for Appliances and

Small Systems 78- Photovoltaic Information Centre for

Shell Solar Deutschland GmbH 79- Customised Measurement Units for

the Photovoltaic Industry 80- Stand-Alone Power Supplies for

Telecommunications, based on Photovoltaics, Fuel Cells and a Hydrogen Seasonal Storage Unit 81

Grid-Connected Photovoltaics 82- The 120 kWp Photovoltaic Training

System of the Cologne Trades Corporation – Butzweilerhof 84

- Towards the Electricity Grid of the Future 85

- Building Integration of Photovoltaic Systems: The New Premises of Fraunhofer ISE as an Example 86

Facts and Figures

Visiting Scientists 88

Participation in National and International Associations 88

Congresses, Conferences and Seminars organised by the Institute 89

Lectures and Seminars 89

Trade Fairs and Exhibitions 89

Patents 90

Doctoral Theses 90

Press Information 91

Lectures 92

Publications 94

Abbreviations 104

2000 was an extremely successful year forFraunhofer ISE. Significant progress in the scientific-technological sector, a gratifyingly highlevel of commissions from industry and growthof about 7 % are indicators of this success.

As examples for the technological area, I wouldlike to highlight our successes in achieving cost-efficient, solar "1-litre houses", the progress onminiature fuel cells and the peak values achievedfor highly efficient tandem solar cells for spaceand terrestrial applications.

The new premises for the Institute in Freiburg,which are being financially supported by theState of Baden-Württemberg and the FederalGovernment with 35 million DM each, are rapidly approaching completion. We will bemoving into the new building from July 2001onwards. The official opening, which will becombined with celebrations for the 20th anni-versary of Fraunhofer ISE, is planned forNovember 2001. At this point, I would like to express our sincere gratitude to the Federal and State governments for their high level ofsupport.

The State of North Rhine-Westphalia and thephotovoltaic industry enabled us to open a newLaboratory and Service Centre in 2000. A highlyflexible production line for silicon wafer solarcells was installed in our centre in Gelsenkirchen.With these unique facilities, we are able toproduce cells under similar conditions to a factory and carry out experiments as in a labo-ratory. Dr Dietmar Borchert and his team inGelsenkirchen as well as their associates inFreiburg deserve hearty thanks for their im-pressive work in establishing the centre.

4–Fraunhofer ISE 2000

Since Fraunhofer ISE was founded, its work hasbeen actively accompanied by its Board ofTrustees. In 2001, the long-standing trusteesProf. Hans Albrecht, Ulf Hecksteden, JürgenMalsch and Dr Gerhard Paul ended their serviceto this valuable advisory board due to retirementor professional reorientation. On behalf of thewhole Institute, I wish to thank them for theircontributions. In future, five new trustees willaccompany the Institute with their advice andcriticism: Jürgen Berger, VDI/VDE; Martin Bitzer,Fresnel Optics; Dr Holger Jürgenson, Aixtron; Dr Thomas Pflüger, Ministry of Science, Researchand the Arts of the State of Baden-Württem-berg; Gerhard Warnke, MAICO.

During the past year, there was a change in theleadership of our Department for Solar Cells -Materials and Technology. I did not succeed inconvincing Prof. Wolfram Wettling to remain atFraunhofer ISE until his 65th birthday, so he leftfor early retirement on 31st March. Dear Prof.Wettling, may I again thank you most sincerely -also on behalf of the entire Institute and parti-cularly your department - for your outstandingachievements. Dr Gerhard Willeke, formerly at the University of Constance, assumed the leadership of our Solar Cell Department on 1st April.

In the autumn of 2000, Dr Angelika Heinzel, leader of the Department for Energy Technology,was invited to accept a professorship at theUniversity of Duisburg. The Institute will exert all powers available to persuade her to stay inFreiburg.

Fraunhofer ISE 2000–5

My thanks also go to all members of theInstitute for their creative, highly motivated and successful work. Above all, I am grateful to those representatives of industry, ministriesand the European Union, whose commissionsindicated their interest and trust, and ultimatelymade our work possible.

Prof. Joachim Luther

Organigram

Institute Profile

The Fraunhofer Institute for Solar EnergySystems ISE conducts research on the technologyneeded to supply energy efficiently and on anenvironmentally sound basis in industrialised,threshold and developing countries. To this purpose, the Institute develops systems, com-ponents, materials and processes in the areas of thermal use of solar energy, solar building,photovoltaics, electrical power supplies, micro-energy technology, chemical energy conversion,energy storage and rational use of energy.

The institute's work ranges from investigation of scientific fundamentals for solar energy appli-cation, through the development of productiontechnology and prototypes, to the constructionof demonstration systems. The institute plans,advises and provides know-how and technicalfacilities as services.

The Institute is integrated into a network ofnational and international co-operation. Amongothers, it is a member of the Solar EnergyResearch Association (ForschungsverbundSonnenenergie) and the European RenewableEnergy Centres (EUREC) Agency. There is partic-ularly close co-operation with the Albert LudwigUniversity in Freiburg.

Research and Services Spectrum

The Fraunhofer Institute for Solar EnergySystems ISE is a member of the FraunhoferSociety, a non-profit organisation, which occupies a mediating position between the basic research of universities and industrial practice. The Institute finances itself withapplied research projects and services on thetechnical application of renewable energy sources. Whether it concerns a major project orbrief consultancy work, the working method ischaracterised by its clear relevance to practiceand orientation toward the wishes of the client.


The Institute in Brief

Institute Director Prof. Joachim Luther

Departments Thermal and Optical Systems +49 (0) 7 61/45 88-1 43Dr Volker WittwerEnergy Technology +49 (0) 7 61/45 88-1 94Dr Angelika HeinzelSolar Cells – Materials and Technology* +49 (0) 7 61/45 88-2 66Dr Gerhard WillekeElectrical Energy Systems +49 (0) 7 61/45 88-2 16Klaus Preiser

Administration, Technical Wolfgang Wissler +49 (0) 7 61/45 88-3 50Infrastructure and ServicesPress and Public Relations Karin Schneider M.A. +49 (0) 7 61/45 88-1 47

Strategic Planning Dr Tim Meyer +49 (0) 7 61/45 88-3 46

+49(0)761/45 88-*Prof. Wolfram Wettling until 31.3.2000


Research and Development

- solar passive houses in Neuenburg consume only 10 kWh/(m2a) (1-litre house)

- gasochromic windows with a large switching range prove themselves in the practice

- micro-encapsulated phase change materials in plasters enable new heating and cooling concepts for buildings

- major project on "New Integrated Energy Supply Concepts for Buildings (NEGEV)" started; development of modular components for energy systems, e.g. compact ventilation units for passive solar houses, fuel cell systemsand heat storage units

- monitoring and quality assurance of 100 passive buildings started for the utility, Energie Baden-Württemberg

- test stand for solar air-conditioning commissioned

- procedure developed for inexpensive, scratch-resistant, anti-reflective treatment of transparent injection moulding components

- numerical simulation model for small fuel cells validated

- Fraunhofer consortium to develop miniature fuel cells founded

- first tandem solar cell of Ga0.35In0.65P/Ga0.83In0.17As produced in the world, and an efficiency record > 30 % achieved with it for 1000-fold concentration of solar radiation (AM1.5d)

- concentrator module with monolithic tandem cells reached an efficiency value of 24.8 % outdoors

- tandem cell for space applications attains an efficiency value of 24.1 % (AM0)

- Si solar cells, with back surface contacts based on plasma etching and laser technology, and more simply processed, reach an efficiency value of 21.6 % over an area of 2 x 2 cm2

- Si solar cell produced by Rapid Thermal Processing achieves an efficiency value of 18.7 % on 5 x 5 cm2 float zone Si

Highlights of 2000

- Si solar cell with an efficiency value of 17.2 %over 10 x 10 cm2 produced for the first time with new in-line RTP equipment

- 100 cm2 block-cast Si solar cell produced for the first time in the world applying industriallyrelevant pad-printing

- industrial screen-printing process for single-sided contacting developed

- crystalline Si thin-film solar cell on industrial silicon nitride ceramic reaches an efficiency value of 9.4 %

- Laboratory and Service Centre for production-orientated research, with in-line solar cell processing lines, opened in Gelsenkirchen

- measurement technology for concentrator solar cells with an optical concentration of 1200 suns developed

- highly efficient solar cell modules extend operating lifetimes for portable electronic devices

- largest PV system in Europe for testing, demonstration and training purposes taken into operation for the Trades Corporation in Cologne

- unique solar exhibits and models developed for Shell Solar Photovoltaic Information Centrein Gelsenkirchen

- photovoltaically powered system developed for water purification in remote regions

- photovoltaically powered water treatment systems developed for pumping and purification

University Appointments

Dr Angelika Heinzel was invited to accept a professorship at the University of Duisburg,Chair of Energy Technology.

Dr Roland Schindler was appointed as a profes-sor at the University of Hagen.


Examples of Innovation

The institute is looking for partners for develop-ment, production or marketing of these productsand services, depending on the stage of devel-opment. None of the products is restricted byan exclusive licence.

Product Market/Sector Fraunhofer ISE contact person, phone, email

micro-structured light-redirecting sun-shading devices Christopher Bühlerand sun-shading elements +49 (0) 7 61-45 88-2 96

[email protected] Werner Platzer+49 (0) 7 61-45 88-1 [email protected]

full-year simulation of lighting design for buildings Jan Wienolddaylighting autonomy +49 (0) 7 61-45 88-1 33

[email protected]

testing and measurement of manufacturers of compact Andreas Bühringcompact ventilation units ventilation units with +49 (0) 7 61-45 88-2 88

heat pumps [email protected]

stochastic anti-reflective structures polymer optics Dr Andreas Gombert+49 (0) 761-4 01 [email protected]

micro-energy technology manufacturers of portable Dr Christopher Heblingelectronic devices +49 (0) 7 61-45 88-1 95

[email protected]

thermophotovoltaic PV industry, gas industry Dr Christopher Heblingsystems technology +49 (0) 7 61-45 88-1 95

[email protected]

reformer systems car industry, gas suppliers, Dr Peter Hübnerfor hydrogen generation oil industry +49 (0) 7 61-45 88-2 10

[email protected]

fuel cells in the battery manufacturers and Mario Zeddalow power range users +49 (0) 7 61-45 88-2 07

[email protected].

optical concentrator systems photovoltaic industry Dr Andreas Bett+49 (0) 7 61-45 88-2 [email protected]

yield guarantee for grid- utilities, contractors for Klaus Kieferconnected PV systems large photovoltaic systems +49 (0) 7 61-45 88-2 18

[email protected]

water purification processes water purification industry Orlando Parodi+49 (0) 7 61-45 88-2 [email protected]

socio-technological analyses energy utilities, PV industry, Dr Petra Schweizer-Riesof village power supplies governmental and non- +49 (0) 7 61/45 88-2 28

governmental organisations [email protected]

active compensation for manufacturers of energy- Georg Bopp interference from electronic saving lamps, PV industry, +49 (0) 7 61/45 88-2 40ballasts energy utilities [email protected]

state-of-charge meter photovoltaics, electric Dirk Uwe Sauerfor batteries vehicles, electric +49 (0) 7 61/45 88-2 19

power supplies [email protected] Heribert Schmidt+49 (0) 7 61/45 88-2 [email protected]

Expenditure

Income

The Institute in Figures

Institutionelle Förderu

Sonstige

Industrie

1997 1998 1999 2000(vor.)

200(pla

0

2

4

6

8

10

12

14

16

0

Mio Euro

■ Bund/Länder ■ Industrie■ Sonstige■ Institutionelle Förderung

Institutionelle Förde

Sonstige

1997 1998 1999 2000(vorl.)

0

2

4

6

8

10

12

14

16

0

Mio Euro

■ Sachkosten ■ Sonstiges Personal■ Eigenes Personal

Neue Reihe Nr. 14

Neue Reihe Nr. 15

1997 1998 1999 2000 20(pla

0

40

80

120

160

200

240

280

320

0

■ Sonstige■ Befristete Stellen ■ Unbefristete Stellen

Personnel development

The "other" staff members are an important pillar of the institute, who support the work inthe research projects and thus contribute signi-ficantly to the scientific results obtained. InDecember 2000, 25 doctoral candidates, 40 undergraduate students, 77 scientific and 20 other assistants were employed at theInstitute. In this way, Fraunhofer ISE providesessential support to the education system.

In addition to the expenditure documented inthe graph, the Institute made investments of 3.1 million € in 2000.


(prov.)

(prov.)

(prov.)others

non-tenured staff members

tenured staff members

federal/stateindustryotherinstitute funding

in millions of €

in millions of €

materials expenditureother personnelinstitute staff

Board of Trustees


The board of trustees assesses the research projects and advises the Institute directorate and the Fraunhofer Society Executive with regardto the working programme of Fraunhofer ISE.January, 2001

Chairman

Prof. Peter WoditschDeutsche Solar GmbH, Freiberg

Deputy Chairman

Dr Rolf BlessingInterpane Entwicklungs- undBeratungsgesellschaft mbH & Co., Lauenförde

Trustees

Dr Hubert AulichPV Silicon, Erfurt

Jürgen BergerVDI/VDE TechnologiezentrumInformationstechnik GmbH, Teltow

Hans Martin BitzerFresnel Optics GmbH, Apolda

Prof. Michael BohnetBundesministerium für wirtschaftlicheZusammenarbeit und Entwicklung BMZ, Bonn

Dr Richard EinzingerSiemens Solar GmbH, Munich

Dr Gerd EisenbeißDeutsche Forschungsanstalt für Luft- und Raumfahrt e.V. DLR, Cologne

Dr Klaus HassmannSiemens AG, Erlangen

Prof. Thomas HerzogTechnische Universität Munich

Dr Winfried HoffmannAngewandte Solarenergie GmbH ASE, Alzenau

Helmut JägerSolvis Energiesysteme GmbH & Co. KG,Braunschweig

Dr Holger JürgensenAixtron AG, Aachen

Prof. Werner KleinkaufGesamthochschule Kassel, Kassel

Dr Thomas PflügerMinisterium für Wissenschaft, Forschung und Kunst Baden-Württemberg, Stuttgart

Dr. Thomas SchottZentrum für Sonnenenergie- und Wasserstoff-Forschung ZSW, Stuttgart

Prof. Paul SiffertLaboratoire de Physique et Applicationsdes Semiconducteurs CNRS, Straßburg, France

Dr Wolfhart von StackelbergBundesministerium für Wirtschaft und Technologie BMWi, Bonn

Gerhard WarnkeMAICO - Ventilatoren, Villingen-Schwenningen

Clients

The Fraunhofer Institute for Solar EnergySystems has co-operated successfully for yearswith clients from all sectors and company sizes.

Clients, who have agreed to publication of theirnames:

- Abac GmbH, Eningen- ACR GmbH, Niedereschbach- Adam Opel AG- AEG MIS GmbH, Ulm- Aixtron GmbH, Aachen- Akkumulatorenfabrik Sonnenschein GmbH

(Exide German Group), Büdingen- Angewandte Solarenergie GmbH ASE,

Alzenau und Heilbronn- BASF AG, Ludwigshafen- Bayer AG, Krefeld-Uerdingen- British Petroleum BP Solar International,

Sunbury, Great Britain- Bundesministerium für Bildung und Forschung

BMBF, Berlin (German Federal Ministry of Education and Research)

- Bundesministerium für Wirtschaft und Technologie BMWi, Berlin (German Federal Ministry of Economics and Technology)

- Caparol Farben, Lacke, Bautenschutz, Ober-Ramstadt

- Centrotherm GmbH, Blaubeuren- Compagnie Européenne d'Accumulateurs

CEAC, Gennevielliers, France- Creavis GmbH, Marl- Daimler-Chrysler AG, Stuttgart- Degussa-Hüls AG, Hanau- DETA Batterien, Bad Lauterberg- Deutsche Bundesstiftung Umwelt, Osnabrück

(German National Foundation for the Environment)

- Deutsche Everlite GmbH, Wertheim (Main)- Deutsche Gesellschaft für Technische

Zusammenarbeit GmbH GTZ (German Society for Technical Co-operation), Eschborn

- Deutscher Alpenverein DAV (German Mountaineering Club), Munich

- Deutsche Solar GmbH, Freiberg- Dmc2 AG, Hanau- ECN, Petten, Netherlands- EKRA Maschinenfabrik GmbH, Bönnigheim- Energie Baden-Württemberg AG, EnBW,

Karlsruhe

- E.ON Energie AG, Munich- European Union EU, Brussels, Belgium- Flabeg Holding GmbH, Gelsenkirchen- Freiburger Energie- und Wasserversorgungs-

AG FEW, Freiburg- Fresnel Optics GmbH, Apolda- G+H Isover, Ladenburg- Gaia Kapital-Beteiligungsgesellschaft mbH,

Cologne- Gebäudemanagement Schleswig-Holstein

(GMSH),Kiel- Gebr. Märklin & Cie. GmbH, Göppingen- Grammer KG, Amberg- Grundwert Verwaltungs- und Projektent-

wicklungs- GmbH (GVP), Frankfurt- H.C. Stark GmbH & Co. KG, Goslar- Haas-Laser-GmbH & Co. KG, Schramberg- Hagen Batterie, (Exide German Group), Soest- Handwerkskammer zu Köln, Cologne- Heraeus Quarzglas GmbH / Co. KG,

Kleinstheim- Hochbauamt der Stadt Mannheim- Hüppe Form, Oldenburg- Institut für Mikrosystemtechnik IMTEK,

Freiburg- Institut für Angewandte Photovoltaik INAP

GmbH, Gelsenkirchen- Instituto Nacional de Tecnologia Agropecuaria,

San Juan, Argentina- Interpane E & BmbH, Lauenförde- Ist EnergieCom GmbH, Augsburg- Karl Süss KG-GmbH & Co., Garching- Labor für Bildschirmtechnik, University of

Stuttgart- Landis & Steafa, Stuttgart- M + W Zander GmbH, Stuttgart- Maico Haustechnik, Villingen-Schwenningen- Maxit Baustoff- und Kalkwerk Mathis GmbH,

Merdingen- Merck KGaA, Darmstadt- Ministerium für Wissenschaft, Forschung und

Kunst, Baden-Württemberg, Stuttgart- Okalux Kapillarglas GmbH, Marktheidenfeld


- Prokuwa Kunststoff GmbH, Dortmund- PV Silicon, Erfurt- RENA Sondermaschinen GmbH, Gütenbach- Robert Bosch GmbH, Stuttgart- RWE Energie AG, Essen- RWTH Aachen, Aachen- S. Siedle & Söhne Stiftung & Co., Furtwangen- S. E. del Acumulador Tudor, S.A., Madrid,

Spain- Saint Gobain Glass, Herzogenrath- Schott Rohrglas GmbH, Mitterteich- Shell Solar Deutschland GmbH, Gelsenkirchen- Siemens Solar GmbH, Munich- Solar World, Bonn- Solar-Application GmbH, Freiburg- Solar-Fabrik GmbH, Freiburg- Solarwatt GmbH, Dresden- Stadtwerke Karlsruhe, Karlsruhe- Stadtwerke Aachen AG STAWAG, Aachen- Steca GmbH, Memmingen- Stiftung Energieforschung Land Baden-

Württemberg (State Energy Research Foundation)

- Sto AG, Stühlingen- Süd-Chemie AG, Munich- Sunlight Power Maroc, Rabat, Morocco- Suptina Grieshaber, Schapbach- TeCe, Selb- Trama Tecno Ambiental, Barcelona, Spain- Transénergie, Lyon, France- TÜV Rheinland Sicherheit und Umweltschutz

GmbH, Cologne- Unaxis, Hanau- Vegla GmbH, Aachen- Velux A/S, Vedbaek, Denmark- Warema Renkhoff GmbH, Marktheidenfeld- Wirtschaftsministerium NRW- World Bank, Washington, USA- Würth Elektronik Systemtechnik, Marbach am

Neckar- Zentrum für Sonnenenergie- und Wasserstoff-

Forschung ZSW, Stuttgart/Ulm


International Co-operation

An increasing number of our projects involveco-operation with international partners.

- Agricultural University of Athens, Greece- Air Liquide S.A., Sassenage, France- Alcatel Standard Electricia S.A., Madrid, Spain- Altai Centre for Non-Traditional Energy and

Energy Saving, Barnaul, Russia- APEX Ingénierie, Laverune, France- A.S. Joffe Institute, St. Petersburg, Russia- Arge Erneuerbare Energie, Gleisdorf, Austria- Australian National University - ANU,

Canberra, Australia- Berner Fachhochschule, Hochschule für

Technik und Architektur, Burgdorf, Switzerland- BPP Teknologi LSDE, Technical Implementation

Unit, Energy Technology Laboratory, Serpong Tangerang, Indonesia

- British Petroleum BP Solar International, Sunbury, Great Britain

- CEA-GENEC – Centre de Caderache, Saint-Paul-Lez-Durance, France

- Centre National de la Recherche Scientifique CNRS, Palaiseau/Meudon/Strasbourg/Marseille/Montpellier, France

- Centre Scientifique et Technique du Bâtiment CSTB, Grenoble, France

- Centro de Investigación en Energía y Agua, CIEA, Las Palmas de Gran Canaria, Spain

- CIEMAT Instituto de Energías Renovables IER, Madrid, Spain

- Compagnie Européenne d'Accumulateurs CEAC, Gennevielliers, France

- Consejo Superior de Investigaciones Cientificas CSIC, Madrid, Spain

- Council on Renewable Energy CORE in the Mekong Riparian Countries

- Curtin University of Technology, Perth, Australia

- De Nora s.p.a., Milan, Italy- Det Norske Meteorologisk Institutt, Bergen,

Norway- Ecole des Mines, Paris (Centre d'Energétique,

Sophia Antipolis), France- Ecole Nationale des Travaux Publics de l'Etat

ENTPE, Lyon, France


- Elkem, Kjeller, Norway- ENECOLO, Mönchaltorf, Switzerland- Esbensen Consulting Engineers, Virum,

Denmark- Georgia Institute of Technology, Atlanta, USA- Hebrew University, Jerusalem, Israel- Hydrogen Systems, Sint-Truiden, Belgium- Instituto Catalan de Energía ICAEN, Barcelona,

Spain- Instituto de Energía Solar IES, Madrid, Spain- Instituto de Investigaciones Electricas,

Cuernavaca, Morelos, Mexico- Instituto Nacional de Tecnica Aerospacial

"Esteban Terradas" INTA, Madrid, Spain- Instituto Nacional de Engenharia e Tecnologia

Industrial INETI, Lisbon, Portugal- International Energy Agency IEA, Paris, France

Photovoltaic Power Systems Programme PVPS- Task 5: Grid Interconnection of Building-

Integrated and Other Dispersed PV Power Systems

- Task 7: Photovoltaic Power Systems in the Built Environment

- Task 9: PV Deployment in Developing CountriesSolar Heating & Cooling Programme SHCP- Task 21: Daylight in Buildings- Task 25: Solar Assisted Air Conditioning of

Buildings- Task 27: Building Envelope Components- Task 28: Solar Sustainable Housing

- Interuniversity Microelectronics Centre IMEC, Leuven, Belgium

- Joint Research Centre ISPRA, ESTI Group, Ispra, Italy

- Kema Nederland B. V., Arnhem, The Netherlands

- Microelectronic Centre - MIC; Copenhagen, Denmark

- National and Kapodistrian University of Athens, Athens, Greece

- National Institute for Chemistry, Ljubljana, Slovenia

- National Renewable Energy Laboratory NREL, Golden, USA

- National Testing and Research Institute, Boras, Sweden

- Naval Research Laboratory, Washington, USA- Netherlands Energy Research Foundation ECN,

Petten, Netherlands- Reusselaer Polytechnic Institute, Troy, USA- Rutherford Appleton Laboratory CCLRC,

Chilton, Great Britain- Solar Energy Research Training Centre SERT,

Naresuan University, Phitsanulok, Thailand- Solarenergie Prüf- und Forschungsstelle,

Rapperswil, Switzerland- TNO Building and Construction Research,

Delft, The Netherlands- Tokyo University of Agriculture and Technology,

Tokyo, Japan- Toyota Technological Institute, Nagoya, Japan- Trama Tecno Ambiental, Barcelona, Spain- University Center of Excellence for Photovoltaic

Research, Atlanta, USA- University of Indonesia, Jakarta, Indonesia- University of New South Wales UNSW, Sydney,

Australia- University of San Juan UNSJ, San Juan,

Argentina- University of Uppsala, Uppsala, Sweden- University of Utrecht, Utrecht, Netherlands- Vergnet S.A. Ingré, France- World Bank, Washington, USA

International Co-operation

Research Areas- optically selective coatings, anti-reflective

coatings- transparent insulation- optically switching windows and façades- systems with automatic protection against

overheating- light-redirecting components- thermal collectors for domestic hot water

and process heat- thermo-chemical storage and solar cooling- optical and thermal measurement of complex

window and daylighting systems- improved simulation programmes to model

optical and thermal systems- controls for energy supply systems- visualisation of the light distribution in

buildings- energy efficiency in buildings- compact heat pumps, ventilation equipment,

earth-to-air heat exchangers- integrated energy concepts for buildings

Services- spectral measurements for quality assurance- optical coatings as desired- durability (accelerated ageing) tests- fluid dynamics simulations- thermal and optical test laboratory (TOPLAB):

determination of optical and thermal system characteristics

- characterisation of sorption systems- performance measurements of domestic hot

water and high-temperature collectors (DIN testing centre)

- ray-tracing simulation for designing optical systems (e.g. solar control systems)

- measurement of energy flows and lighting characteristics for façades in an outdoor measurement facility, FASTEST

- energy concepts and energy planning- lighting design- dynamic building and system simulation:

TRNSYS, ESPr, SMILE, ColSim- lighting simulation including video animation

of the results: RADIANCE- software development to model thermal and

optical systems- integrated energy concepts for buildings and

settlements- conception and energy analysis of

demonstration buildings- tests and measurement of residential

ventilation equipment

Equipment- optical characterisation laboratories- PVD coater (1 m2 area)- field emission scanning electron microscope- thermo-chemical analytical laboratory- laser exposure stand to produce large-area

sub-micron structures- climatic chambers for accelerated ageing tests- outdoor test area (collectors)- two rotatable daylighting measurement rooms- apparatus for 3D-visualisation of lighting

simulation results- facade test stand- storage tank and system test stand for solar

collector systems and solar air conditioning- test stand for compact ventilation units


The Departments of the Institute

Thermal and Optical SystemsDr. Volker Wittwer

Energy TechnologyDr Angelika Heinzel

Research Areas- electrochemical, chemical and thermal energy

converters- polymer electrolyte membrane fuel cell- micro-energy technology- hydrogen production by electrolysis, reforming

of carbonaceous fuels and treatment of gas from biomass

- catalytic burners for natural gas, oil and hydrogen

- safety and storage technology for hydrogen

Services- advice and supervision in the implementation

of hydrogen systems- conception of energy supply systems with

fuel cells- characterisation of fuel cells and fuel cell

components- simulation of fuel cell processes- development of components for fuel cell

systems- development of low-emission burners- scientific studies, studies on market potential

relating to micro-systems technology

Equipment- prototype laboratory for hydrogen technology- fuel cell laboratory for electrochemical

characterisation procedures, spatially resolved measurements, impedance spectroscopy and production of membrane/electrode units

- burner laboratory with exhaust gas analysis and characterisation of catalysts

- measurement and analysis laboratory: mercury porosimetry, gas chromatography, differential scanning calorimetry DSC

- scanning electron microscope with energy-dispersive X-ray micro-analysis

- Fourier Transform Infrared FTIR spectrometer- micro-milling- test stands for kinetic and integral characteri-

sation of catalysts for reforming and gas purification

- IR thermography to determine heat distri-bution in fuel cells

- test stand for thermophotovoltaic systems





Solar Cells - Materials and TechnologyDr Gerhard Willeke

Research Areas - high-efficiency silicon solar cells- multicrystalline silicon solar cells with high

efficiency values- thin-film solar cells of crystalline silicon- development of solar cell materials from

Si and III-V semiconductors- III-V concentrator solar cells- III-V epitaxy- gas-phase deposition of silicon for crystalline

thin-film cells- recrystallisation of silicon films with optical

heating- characterisation procedures for silicon- plasma technologies for photovoltaics- innovative metallisation techniques for solar

cells- industrially relevant solar cell technology- texturing, structuring and passivation of silicon

surfaces

- development of production equipment for Si ribbons (SSP), Si deposition (CVD) and Si recrystallisation (ZMR)

- production of Si CVD layers- recrystallisation of Si layers

Services- technology optimisation for solar cells- development of semiconductor characteri-

sation procedures- small series of high-efficiency solar cells- optimisation of manufacturing processes for

solar cell materials- characterisation of semiconductor materials- studies on photovoltaics- calibration and characterisation of solar cells- evaluation of novel processing sequences

Equipment- clean-room laboratory- standard solar cell technology- industrially relevant production line (screen-

printing, pad-printing, in-line RTP oven, in-lineRTP diffusion oven)

- characterisation of solar cells: I-V characteristiccurve measurement, SR, LBIC, PCVD, MSC, diffusion length mapping

- characterisation of materials: MW-PCD, MFCA, DLTS, CV, SPV

- chemical vapour deposition of Si: RTCVD- plasma etching system- liquid phase epitaxy for GaAs: LPE- MOVPE for III-V epitaxy- optical heating systems for silicon production

and processing- thin-film technology: plasma deposition,

evaporation, galvanisation, contacting- characterisation: X-ray diffraction, charge

carrier lifetime measurements, photoluminescence, ellipsometer, IR Fourier spectro-meter, glow discharge mass spectrometer, scanning electron microscope with EBIC, ECV profiling

- screen-printing and pad-printing for solar cells- calibration laboratory for solar cells- solar simulator for continuous exposure- filter monochromator- grating monochromator- RTP equipment

Electrical Energy SystemsKlaus Preiser

Research Areas - products with integrated photovoltaic power

supplies- electronic components for batteries and

photovoltaic systems- charging strategies for storage batteries- stand-alone photovoltaic power supplies- operation management for stand-alone

systems- rural electrification in areas remote from the

grid- rural water supply and treatment- grid-connected photovoltaics- photovoltaics in buildings- computer simulation and energy flow analyses- development of precision measurement

technology for photovoltaics

Services- planning, construction and evaluation of

photovoltaic systems- prototype development and accrediting of

photovoltaically powered products- measurement data acquisition and analysis of

photovoltaic systems- off-grid power supplies for telecommuni-

cations and information systems- calibration and characterisation of solar

modules and solar generators- visualisation and optimisation of photovoltaics

in buildings- training and consultancy in the solar energy

sector- electromagnetic compatibility (EMC)

measurements of components and systems

Equipment- calibration laboratory for solar modules- pulsed solar simulator- DC laboratory for testing and development of

PV system components and consumer appliances

- lighting measurement laboratory- development laboratory for photovoltaically

powered industrial products- test stands for multiple-cell batteries, hybrid

storage units and power-conditioning devices- outdoor test area for solar components- AC laboratory with an inverter test stand and

instruments to characterise electromagnetic compatibility EMC

- EMC measurement chamber- pump measurement stand- test stand for drinking water purification

systems




Research Trends in 2001

In many economic sectors, renewable energyand energy efficiency already belong to the standard technological repertoire. The marketshare is growing strongly, penetration of massmarkets is starting. The best example is the building sector: Low-energy solar houses areproving to be increasingly competitive in the private market.

Research which aims to support this diversifi-cation of applications must cover a wide spec-trum: Bringing forth new materials, components,technology and application ideas is one con-stantly recurring aspect. The other aspect is orientation towards products and customers,which is determined by the market and respondsto the needs of commercial enterprises. Thistype of research facilitates application, improvesthe economic viability, polishes up the final product, and guarantees quality and user satis-faction. The approaches encompass efficientcalculation and simulation tools for professionalplanning and consultancy, rational productiontechnology, quality control of components anddissemination of "lessons learned" from demon-stration projects, without losing sight of theoverall effect - the object is to optimise the com-plete system, taking all technical, ecological,economic and social factors into account.

Fraunhofer ISE demonstrates this comprehensivephilosophy particularly clearly in the integratedsystems approach: Psychologists and sociologistshelp to introduce Solar Home Systems in devel-oping countries, the local users are involved indetermining the introduction process and areable to service the technology themselves at theend of the project.

Simultaneously, research still depends on the existence of an unrestricted space for creativethoughts and strokes of genius. Some examplescan be found in the report in your hands:Converting solar heat to air-conditioning cool-ness, keeping surfaces clean for a lifetime bymicrostructuring, approaching efficiency valuesof 40 % with tandem cells.

Solar research in 2001 will consist more thanever of interdisciplinary teamwork. From thehigh-flying visionary through the systematic calculator to the pragmatic engineer, all teammembers must be actively involved, so that goodideas are converted to successful products quick-ly and effectively. Applied research means supplying not only the basic idea but also thetools for production and marketing.


Thermal and optical systems

The buildings of the future will be largely self-sufficient with regard to energy. Fraunhofer ISEwill combine with almost a dozen industrial partners in a major strategic project to establishthe technical, planning and organisational basisneeded for a fundamentally new approach tobuilding, which regards buildings as completeenergy systems.

Simulations make the complex interactions transparent and thus allow targets to be defined, also with regard to economic factors:Exact predictions mean that expensive tolerancefactors can be avoided during planning, pavingthe way to "lean buildings". The accuracy isconstantly being improved. At present, we workwith one-minute averages for daylight, meteoro-logical data and energy flows in buildings.Stochastic models will soon be able to representindividual user behaviour.

Integrated planning of the total energy supplygives the designer maximum freedom: The building owner can select from short-term economic viability as the highest priority,through additional solar options, to a buildingwhich supplies more energy than it consumes.Technical elements supporting this developmentin residential buildings include e.g. compact heating units with miniature heat pumps to supply solar passive buildings with heat, andsorption storage units for seasonal thermal storage.

The more a building profits from solar gains, themore significant solar control also becomes. Theresearch trend for clerestory and overhead gla-zing is moving away from mechanical elements:Switchable glazing changes the transmittance ofwindows and skylights as desired, withoutmoving parts. Microstructured surfaces deflectdirect light in pre-determined directions.

Multifunctionality represents a general trend, notonly for buildings. Whereas protective pro-perties or aesthetics were the most importantfunctions for a building envelope up to now, the

surfaces of the future will also collect energy orbe easy to clean - as with the "lotus effect"®.

Commercial solar collectors for domestic hotwater represent the technological state of theart. Research is now concentrating on twotopics:- Large systems: Optimised control strategies

guarantee efficient operation e.g. when generating process heat.

- New application areas: Non-corroding collectors can be used for seawater desali-nation to obtain drinking water, and desiccant cooling processes offer an environmentally acceptable method of air-conditioning, with water as the cooling agent and the sun as the driving power. Low-energy buildings shift solar space heating back into focus, with new materials and storage options.

Energy technology

The focus on "micro-energy technology" reflectsa general trend: smaller and more powerful.Fuel cells, which act as miniature power stationsin battery format, could reflect a qualitative leapin electricity storage. Highly efficient, device-integrated solar modules guarantee power forrecharging. Thermoelectrics and thermophoto-voltaics convert heat into electricity withoutmechanical movement - with 100 % reliabilityeven under the harshest environmental condi-tions, at remote locations.

The fuel cell has become a topic of major in-terest. Like a solar cell, it is modular, can beadapted as required to the demand and doesnot contain any moving parts. It supplies en-vironmentally acceptable electricity from hydro-gen with a high efficiency value. In the future,the generation of hydrogen by reforminggaseous or liquid fuels will play a central role,particularly for transport. Reforming is also thekey needed to use natural gas in fuel-cell coge-neration plants, to provide energy for buildings.



Solar Cells - Materials and Technology

The common denominators for cells of crystal-line silicon and III-V compound semiconductorsare industrial relevance, improvement of effi-ciency and cost reduction. The Institute is following three approaches in these directions:

- Further developing well-proven materials: There is still considerable potential to reduce the cost of the dominating market leader, crystalline silicon. The standard workhorses, block-cast and Czochralski silicon, can still win some races if spurred on by new production procedures. The aims of further work include rapid processing, the application of thin and extremely thin wafers and the industrial implementation of 10 x 10 cm2 cells with an efficiency of 20 %, which has already been achieved in the laboratory.

- Researching the technology of the next and the following generation: This includes the crystalline silicon thin-film cell, with its efficiency value of just on 20 %. The goals of further work are inexpensive substrates and large-area, continuous deposition processes. A different strategy is adopted with III-V high-performance cells, which are conquering the space market due to their superior perfor-mance characteristics. For terrestrial applications, it makes sense to use them in con-centrating systems, where significant cost advantages are achieved. The cell efficiency value of 31 % can be further improved to 40 %, but the primary focus must be on the system components.

- Narrowing the gap between research and production: The production capacity is becoming larger, innovation cycles shorter, and the competition keener. Thus, research will include a growing component which accom- panies production. Fraunhofer ISE acted vigorously to convert this trend into focussed development. This included the major extension of our production technology laboratory in Gelsenkirchen


Electrical Energy Systems

Photovoltaics is overtaking a multimillion marketin giant steps. The new Federal 100,000 RoofsProgramme and the renewable energy law haveopened wide the door to the market for grid-connected photovoltaics in Germany. Portableappliances and telecommunications are boomingand Solar Home Systems have become a massproduct. At the instant when the market finallybegins to "pull", it is important that the marketdevelopment be actively accompanied, so thatthe positive image of photovoltaics is preservedin its broad application. Examples include:

- Monitoring: ensuring energy gains; certifying "green" electricity rates

- Energy distribution: preparing the reorgani- sation of grids to intelligent, customer-friendly,decentralised circuit structures in co-operation with electric utilities and industrial partners

- Rural electrification: involving local users, removing economic barriers with micro-finance, guaranteeing project sustainability with national testing laboratories

- Measurement technology: developing procedures and instruments for production-relevant quality control

- International standards: guaranteeing com-parability, quality standards and planning certainty

Hybrid systems are becoming increasingly pop-ular for applications such as telecommunicationsequipment with stringent demands on reliability.In addition to PV systems for individual houses,power supplies for complete villages are growingin importance. In developing countries, the pro-vision of clean drinking water is an increasinglysignificant application.

As has already been found in Solar HomeSystems, it is becoming evident in all otherstand-alone applications that batteries representthe weak link in the chain with regard to reli-ability and costs. Research is responding to thischallenge with battery management conceptsand the development of specifically tailored batteries.

Rep

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Research and Development in Thermal Solar Energy and Optics

Solar Engineering – Advising, Planning, Implementing

Measurement and Testing in Thermal Solar Energy and Optics

Energy Technology

Solar Cells – Materials and Technology

ISE CalLab – Precision Measurements for Photovoltaics

Electricity for Areas Remote from the Grid

Development of Products and Components

Grid-Connected Photovoltaics


Research and Development in Thermal Solar Energy and Optics

Dispersion of white light by diffraction with a periodic surfacestructure (optical grating). Large areas of periodic and stochasticstructures are employed in anti-reflective, light-scattering, dirt-repellent and other functional surfaces.


Two examples:Surfaces possessing extremely finestructures, on the order of 100 nano-metres to several micrometres, havespecial properties. With their opticallyfunctional properties, they transformconventional products into innova-tions with special features, e.g. anti-reflective covers for displays, or façadefinishes which are self-cleaning in therain.

Interconnected controls optimise thecomplete supply of electricity andthermal energy in buildings. As thebuildings of the future will often bedecentralised miniature powerstations, these control strategies alsotake the requirements of theelectricity grid into account andinclude weather forecasts andelectricity tariffs among the inputs.

The common denominator of ouractivities is that we use thecompetence gained in research onrenewable energy to prepareattractive products in a rapidlyexpanding and sustainable market.

Research and Development inThermal Solar Energy and Optics

Building construction and residentialapplications represent major marketsfor the future from both an ecologicaland an economic perspective. On theone hand, about a third of the endenergy consumed in Germany is forheating and hot water. An enormouspotential to reduce CO2 emissionscould be tapped with energyefficiency and solar energy. On theother hand, many of these measuresare already economic today; risingenergy prices open the market to anincreasing number of concepts whichonly recently were still confined toresearch and demonstration.

This is our starting point: We co-operate closely with manufacturers todevelop materials and processes, sothat we can always be well ahead ofthe established market with newideas. This applies not only for theclassic fields of thermal solar systemsand solar building, such as domestichot water, space heating, cooling,energy storage and lighting, but alsofor integrated energy concepts, inwhich buildings take on an active rolewithin the public electricity grid.

Contact partners:

Coatings Wolfgang Graf Tel.: +49 (0) 7 61/4 01 66-85E-Mail: [email protected]

Analysis and energy Dr Werner Platzer Tel.: +49 (0) 7 61/45 88-1 31optimisation of E-Mail: [email protected]çades

Earth-to-air heat Christian Reise Tel.: +49 (0) 7 61/45 88-2 82exchangers E-Mail: [email protected]

Light scattering and Dr Werner Platzer Tel.: +49 (0) 7 61/45 88-1 31thermotropic layers E-Mail: [email protected]

Nanostructured and Dr Andreas Gombert Tel.: +49 (0) 7 61/4 01 66-83 microstructured materials E-Mail: [email protected]

New collector concepts Matthias Rommel Tel.: +49 (0) 7 61/45 88-1 41E-Mail: [email protected]

Control systems Dr Christof Wittwer Tel.: +49 (0) 7 61/45 88-1 15E-Mail: [email protected]

Sorptive materials Dr Hans-Martin Henning Tel.: +49 (0) 7 61/45 88-1 34E-Mail: [email protected]



Large-Area 3D Nanostructures andMicrostructures - "Nanofab"

Microstructured surfaces can functionas light-guiding or self-cleaningelements. A consortium of tenpartners is developing procedures toproduce homogeneously structuredsurfaces with an area of 800 x 1000 mm2.

Benedikt Bläsi, Christopher Bühler,Andreas Gombert, Volker Kübler*,Michael Niggemann, Christine Wellens, Armin Zastrow

Microstructured surfaces can disperselight and guide it in the directiondesired. In this way, a double glazedunit can become a daylightingelement. Tiny retro-reflectors make iteasier to see road markings or trafficsigns. Self-cleaning surfaces, artificialshark skin, sanding papers, micro-reactors - these are all applications ofsurfaces structured with nanometreaccuracy.

Production is economic, due tomicroreplication of the originalstructure in polymers with galvanicand forming processes, such as hotembossing, UV curing and injectionmoulding. The sophisticated originalstructure costs only a few pennies inthe moulded part.

The demand is high, but until now,there was a lack of masters with both continuous structure profiles (3D structures) and relatively large,homogeneously structured areas forproduction.

The "Nanofab" joint project, which is supported by the German FederalMinistry for Education and ResearchBMBF, is thus developing tools toproduce structures with contours on a nanometre scale over a large area.The vital condition which must be methere is the seamless, adjacent posi-tioning of small, microstructured areaswith embossing technology (fig. 1).This technology is called recom-bination. The state of the art is toproduce seams with a width ofaround 100 µm. The "Nanofab"project is aiming for seam widths on the order of 1 µm.

The Fraunhofer Institutes forProduction Technology IPT, for SiliconTechnology ISIT and for Solar EnergySystems ISE are developing newstructures and the recombinationtechnology. The Kugler company isconstructing the necessary positioningsystems, Scana and Fresnel Opticsreplicate the structures, Creavis isdeveloping self-cleaning surfaces,

Nanofocus and FRT (Fries Researchand Technology GmbH) are providingthe measurement technology andBeiersdorf is responsible for the self-adhesive coating on the microstruc-tured polymer films. The main em-phasis at Fraunhofer ISE is on micro-structures for daylighting purposesand a holographic structuring processfor large areas.

For daylighting, we predominantly useprismatic arrays. The faces of theprisms serve to refract or totally reflectthe light. We are also investigatingparabolic elements. They offer opticaladvantages, but are more difficult toproduce. The critical question con-cerns the dimensions of the struc-tures: From what size on do diffrac-tion effects destroy the functionswhich were obtained with geometric-optical methods?

Holographic exposure of photoresistallows certain structures to beproduced over large areas in a singlestep. In the project, we intend toproduce homogeneous embossingtools with anti-reflective moth-eyestructures over an area of 600 x 800 mm2, three times larger than the areas which have been structuredto date. To achieve this, we cannotsimply scale up existing processes, buthave to redesign many of the com-ponents in the optical system -including an automated, extremelystable sample holder for the holo-graphic exposure.

* PSE Projektgesellschaft Solare EnergiesystemembH, Freiburg

Fig. 1: Recombination process, in which small, microstructuredareas are "stamped" next to each other without perceptibleseams.



Photoelectrochromic Windows

The transmission of photoelectro-chromic windows can be switched.The energy for colouring is providedby sunlight, so that a voltage supply isnot required. Applications includeprotection against overheating andglare, e.g. in buildings or cars.

Andreas Georg, Anneke Hauch*,Wolfgang Graf, Volker Wittwer

Photoelectrochromic systems consistof a combination of an electrochromiccell and an electrochemical solar cell.The configuration illustrated in fig. 1originated at Fraunhofer ISE, and is aparticularly advantageous combi-nation of the dye-sensitised solar celland an electrochromic element. Thecolouring time is independent of thearea, the transmittance can be variedalso in the illuminated state, and thesystem can also be switched by anauxiliary external voltage. Initialsamples reduce their transmittanceduring illumination within threeminutes from 61 % to 15 %. Theytake about 2 minutes to bleach.

ConfigurationA glass substrate is coated with atransparent electrode (TE) and anelectrochromic WO3 film. This iscovered with a nanoporous TiO2 layer.The porosity leads to a large surfacearea of the TiO2, which is coated witha monolayer of a dye. The pores andthe space between the TiO2 and thecounter-electrode are filled with anelectrolyte, in which lithium iodide (LiI)is dissolved. The counter-electrode isa second glass substrate, which iscovered with a TE film and coatedwith a thin, transparent Pt film. Thetwo transparent electrodes are con-nected with each other via an externalswitch. In principle, the order of the

TiO2 layer and the WO3 film could bereversed, or they could be combinedin a single layer.

Principle of the colouring processThe dye is excited by illumination(upper half of fig. 1). It donates anelectron to the TiO2, which transfers itto the WO3. There, it reduces thetungsten and colours it from trans-parent to blue. The dye regains itselectron from an I- ion from theelectrolyte, which is oxidised to I3-.The excess Li+ ions diffuse throughthe porous TiO2 into the WO3 layer,maintaining charge equilibrium. TheTE coating does not play any role inthe colouring process, the systemoperates as a passive photochromicelement. As a result, in particular theswitching time for colouring isindependent of the TE layer andindependent of the area of theelement. This an advantage com-pared to previous electrochromic

windows, in which the switching timeis limited by the conductivity of the TElayer and depends strongly on thearea.

Principle of the bleaching processIf the external switch is closed (lowerhalf of fig. 1), the electrons from theWO3 can flow via the switch to thecounter-electrode. Here, the platinumcatalyses the reverse reaction of I3- to I-. At the same time, the Li+

ions return through the electrolyte.This process can also happen duringillumination, i.e. the transmittance canbe increased by switching both duringillumination or in the dark.

* University of Freiburg, Freiburger Materialforschungszentrum FMF, Freiburg

Fig. 1: Schematic diagram of the configuration and operating principles of the photoelectrochromic element (TE: transparent electrode). Upper half: Colouring duringillumination, lower half: bleaching.

glass

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Concept for a Multiple-StageAdsorption Heat Pump

Adsorption heat pumps can reducethe consumption of natural gas forheating appreciably. Simulation of atwo-stage adsorption heat pumpdemonstrated the potential and theefficiency value which can beexpected from this technology inseasonal applications.

Hans-Martin Henning, FrankLuginsland*, Tomas Núñez

In the novel process, we use twodifferent adsorbents, in order to bringlarge amounts of ambient heat to auseful temperature level, using a smallamount of heat at a high tempe-rature. The high-temperature heat isgenerated with natural gas. The heat-ing coefficient of performance (COP)is the ratio of useful heat to the ap-plied energy from natural gas. If it isequal e.g. to 2, then the natural gas isused twice as efficiently as if it wereburnt directly for space heating.

We were able to prove the funda-mental feasibility of both the solidadsorption process for heat trans-formation and also the specific,multiple-stage cycle.

We determined the heating COP as afunction of the average heat transfermedium temperature from simulationcalculations. In addition, we used asingle-chamber prototype adsorber todetermine the parameters for massand heat transfer experimentally, andused them in dynamic simulations ofthe multiple-stage process.

A simple simulation of the completesystem, consisting of an adsorptionheat pump, a building and its heatingsystem, gave the following annualaverages for the heating COP's, for adriving temperature of 280 °C and anambient heat source, which providesheat at an average temperature of 7 °C:

Adsorption heat pump and low-temperature heating (maximumtemperature of heat transfer medium= 45 °C): average heating COP of 2 ormore.

Adsorption heat pump andstandard heating (maximum tempe-rature of heat transfer medium = 65 °C): average heating COP of 1.7.

This results in fuel savings of 50 % or40 %, respectively, compared to useof a modern heating boiler alone.

The project, which was funded by theEnergy Research Foundation of Baden-Württemberg, has been completed.Further investigations are concen-trating on single-stage heat pumps for heating and cooling.

* PSE Projektgesellschaft Solare Energiesysteme mbH, Freiburg

Fig. 1: Calculated characteristic curve for themultiple-stage adsorption heat pump (heatingCOP versus the average temperature of theheat transfer fluid). The material in the high-temperature adsorber is "Zeolith 13X", and a"Selective Water Sorbent" is used in the low-temperature adsorber. The driving temperatureis 280 °C, the evaporator temperature is 7 °C.

30 35 40 45 50 55 60average temperature of heattransfer medium [°C]

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Micro-Encapsulated Phase ChangeMaterials in Integrated WallSystems for Heat Storage

The heat capacity of a wall can beraised in a certain temperature rangeby incorporating phase change mate-rials (PCM) in the wall construction.This is often desirable, in order toflatten out load peaks and release thestored energy at a more favourabletime. Especially for light-constructionbuildings, this technology results notonly in energy savings but also in aconsiderable increase in comfort.

Hans-Martin Henning, Peter Schossig,Guido Weingarten, Alexandra Raicu*

Internal wall systems, e.g. plaster-board panels, are conceivable withintegrated PCM's such as paraffins.They can prevent over-heating ofoffice buildings in summer by shiftingthe peak loads into the night.Applying the same principle, theheating energy demand can bereduced by shifting superfluousenergy gains to the times whenheating is needed.

The PCM must be encapsulated sothat it does not adversely affect thefunction of the construction material,e.g. plaster. Previous experimentswith large-volume (or macro-)encapsulation failed due to the poorconductivity of the PCM. When itwas time to regain the heat from theliquid phase, the PCM solidifiedaround the edges and preventedeffective heat transfer. With micro-encapsulation, the dimensions are sosmall that this effect does not occur.

Micro-encapsulation also allows thePCM to be incorporated simply andeconomically into conventionalconstruction materials.

In co-operation with our industrialpartners, BASF, DAW, Maxit and Sto,we identified suitable applicationfields and are developing systems.

We simulate the thermal behaviour ofbuilding components in order tocompare the dynamic performance ofdifferent types of wall constructionsincluding PCM. The basis is anempirically validated model for thephase transition. The model is beingexperimentally validated with ameasurement facility for wall sampleswith an area of 0.5 x 0.5 m2.Building energy simulations help toestimate the potential for applications.We investigate the effect as a functionof the temperature range of the phasetransition, the proportion of PCM, andthe structure and usage of a building.

The following thermographs illustratequalitatively the effect of the PCM inconstruction materials: Fig. 2 showsfour wall samples with differingamounts of PCM, which had beenheated in an oven and were thenmonitored during cooling. Thevariation of temperature with time infig. 3 clearly indicates the effect of thePCM. The larger the proportion ofPCM, the longer the cooling processlasts.

Thus, in a certain temperature range,the thermal mass of a buildingcomponent can be significantlyincreased due to the phase changeprocess, so that the thermal comfortassociated with massive buildings canbe approached with light constructionmaterials.

The project is supported by theGerman Federal Ministry of Economicsand Technology BMWi.

* Sto AG, Stühlingen

Fig. 1: Schematic diagram of micro-encapsulated PCM in interior plaster.

Fig. 2: Thermograph of 4 samples withdiffering proportions of PCM. The grey scaleand the height of the profiles to the right andat the bottom indicate the temperature.

Fig. 3: Cooling behaviour of the four samples.The PCM content increases from left to right.The time scale runs from the back to the front,with 30 seconds between consecutive contourlines. The temperature is indicated by theheight.

micro-capsules

masonryinterior finish



Thermotropically Controlled Façade Components

Thermotropic layers, integrated intofaçades and windows, reduce theinput of undesired light and solarheat. Thermotropic overheatingprotection operates automatically anddoes not require a power supply.

Peter Nitz*, Werner Platzer,Alexandra Raicu**, Helen RoseWilson***, Volker Wittwer

Thermotropic LayersThe optical properties of thermotropicmaterials vary with temperature. Atlow temperatures, they are clear, likewindow glass. If the material tempe-rature exceeds a certain limit, athermotropic layer becomes milkywhite and reflects a large proportionof the incident light. This propertypredestines thermotropic layers foruse in automatically operating facadecomponents. Integrated as thin layersinto modern glazing units or trans-parent insulating systems, they allowsolar light and heat to penetrate undi-minished into the building duringwinter. In summer, in the switchedstate, they protect against excessivesunlight and the associatedoverheating and glare.

There are various concepts andmaterials for thermotropic layers. In co-operation with BASF AG(materials development), Sto AG(thermal insulation systems), andInterpane E&BmbH and Okalux GmbH(glazing), we have optimised theintegration of thermotropic polymerblends into facades over the pastyears. Here, we present someexamples of the project results. Inparallel, we are investigating alter-native thermotropic materials, layersand systems in other projects.

Work at Fraunhofer ISE We characterise the optical andthermal properties of thermotropiclayers and system prototypes, supportthe materials and prototype develop-ment by simulating the light-scattering characteristics and the

effect on building energyconsumption, test the long-termstability of layers and systems andmonitor prototypes under real meteo-rological and installation conditions inour façade test stand.

Thermotropically controlled,transparent exterior insulation andfinish system (TEIFS)The transparent finish was modifiedfor a TEIFS variant with integrated,thermotropic overheating protection.It now provides effective protectionagainst UV radiation for the thermo-tropic layer. The system is currentlybeing tested on a demonstrationbuilding in Stühlingen (fig. 1). It ischaracterised by good switchingperformance and a high transmittancein the clear state.

Thermotropic glazingWe used our calorimeter to determinethe total solar energy transmittance gof heat-mirror glazing with an inte-grated thermotropic layer. Theswitching range is good, even for thelarge incident angles typical ofsummer. The measurement agreeswith the values from simulation,which were based on the physicalproperties of the components (fig. 2).Measurements from the façade teststand confirmed similarly good valuesfor the solar transmittance.

OutlookThe publicly funded project describedhas now been completed. The aim offurther work is to achieve a durable,commercially marketable facadeelement with thermotropic properties.

Fig. 1: System demonstration in the façade of aresidential building: thermotropically controlledTEIFS variant (upper centre, clear state) and aTEIFS standard system (lower panels).

Fig. 2: Comparison of measured and simulatedtotal solar energy transmittance g forthermotropic, heat-mirror glazing.

0 30 60 90angle of incidence / degrees

total solar energy transmittance g

measurement; clearmeasurement; scatteringsimulation; clearsimulation; scattering

* PSE Projektgesellschaft Solare Energiesysteme mbH, Freiburg

** Sto AG, Stühlingen*** Interpane E&BmbH, Lauenförde

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Building Simulation Improved byHigher-Frequency Modelling ofRadiation Data

We improved a stochastic model forsolar radiation in order to generate60-second averages from hourlyaverages. This increases thesimulation accuracy for thermal anddaylighting performance of buildings.

Oliver Walkenhorst, Christoph Reinhart*

Many thermal and daylightingsimulation programs to model thevariation with time of heat flows ordaylighting conditions require timeseries of the solar radiation. These areavailable for representative sitesthroughout Germany with a timeresolution of one hour. However,information on short-term variation inthe solar radiation - for example, thatcaused by passing clouds - is lostwhen these hourly averages are used(fig. 1).

In particular, when the daylightingpotential in buildings is simulated, theuse of hourly averages can lead tosignificant errors: After all, a short-term radiation excess cannot compen-sate for a subsequent deficit.

For this reason, we improved astochastic model which generateshigher-frequency data with a 1-minuteresolution from hourly radiation data.We were able to improve the reliabilityof daylighting simulation e.g. topredict the annual demand for arti-ficial lighting (fig. 2).

Fig. 2: Predicted annual artificial lightingdemand for two office desks, 2 m and 4 mfrom the window. Simulation for a modeloffice in Freiburg for 1998, with the artificiallighting automatically controlled to guarantee anominal illuminance of 500 lux. When hourlyradiation data are used (light grey), the artificiallighting demand is underestimated by about 25 % compared to a simulation with measured1-minute averages (dark grey). This moreaccurate value for the artificial lightingdemand, based on 1-minute measured data, isreproduced well by simulation based on themodelled 1-minute averages.

Fig. 1: Daily profile of the global radiationmeasured in Freiburg on 17th May, 1998: The sky was clear until about 9 o'clock andthe 1-minute averages (dashed line) agreewell with the hourly averages (solid line).Afterwards, cloud movement resulted in rapid variation of the 1-minute averages,which is not registered in the hourly averages.

time of day [h]

glob

al r

adia

tion

[W/m

2 ]

2 m position 4 m positionartif

icia

l lig

htin

g de

man

d [k

Wh/

m2 a

]

20

16

12

8

4

0




Simulation-Supported ControlsDevelopment to Optimise theIntegration of Fuel-CellCogeneration Plants into HybridSolar Energy Supply Systems

The ColSim software developed atFraunhofer ISE simulates both theindividual components of an energysupply system and the control of theentire system. At present, work isconcentrating on the integratedcontrol of a fuel-cell heat/electricitycogeneration plant, which is operatedwith natural gas. The predictivecontrol strategy takes account ofweather forecasts, energy prices anduser behaviour.

Matthias Vetter, Christof Wittwer

Heat/electricity cogeneration plantsreduce the emission of pollutants andCO2 from energy supply systems (seepage 48). If several energy sources(fossil and solar) are to be combined,higher-level system controls are

Earth-to-Air Heat Exchangers

Earth-to-air heat exchangers areintended for installation in theground. They make use of thestorage capacity and thermal inertia ofthe ground. In summer, they can coolthe inlet air for buildings, whereas inwinter they pre-heat it, such thatunder favourable conditions, a con-ventional air-conditioning unit maybecome unnecessary.

Christian Reise

In non-residential buildings, earth-to-air heat exchangers are particularlyattractive if the cooling load can beremoved by air change alone. Inthese cases, the earth-to-air heatexchanger can replace an activecooling system. Precise simulationtools are needed to determine theeconomically optimal dimensions foran earth-to-air heat exchanger. Wedevelop such tools and quantify theremaining uncertainties. To thispurpose, we monitor the interactionbetween earth-to-air heat exchangersand ventilation systems in detail inmeasurement projects involvingsystems of all dimensions.

Our clients, whom we advise indivi-dually during the planning phase oftheir projects, profit directly fromthese measurements, as well as fromthe resulting improvements we maketo our calculation tools.

needed. In the electricity grid of the future, decentralised electricitygenerators will need to be cross-linked with the utilities.

At present, we are developing controlconcepts for a grid-connected fuel-cellcogeneration plant, which is operatedwith natural gas in combination witha thermal solar system. We analysethe complete systems on the basis ofyearly simulations made with theColSim simulation software. Thesystem is linked to the Internet, sothat weather forecasts and dynamicelectricity or gas tariffs can beintegrated for predictive strategies.The control algorithm "learns" cyclicuser behaviour during operation.

After development with ColSim andimplementation in ANSI C, the controlalgorithms are ported directly to thecontrol hardware of the cogenerationplant. At present, this is achieved asan "embedded system" in the multi-tasking Linux operating system.

0 1460 2920 4380 5840 7300 8760time [h]

temperature [°C]25

20

15

10

5

0

Fig. 1: Comparison of measurement (solid line)and simulation calculation (dotted line) for anearth-to-air heat exchanger. The lines showmoving averages for calculated and measuredoutlet temperatures. The results calculated bythe program used here are still too optimistic.

Fig. 1: Simulation of a building energy supply in ColSim. The individual units correspond to thecomponents, gas connection, reforming, fuel cell as a cogeneration plant, inverter, grid electricityconnection, solar collector, heat storage unit, meteorological data, the house as a "load", and thecentral controls. ColSim simulates both the individual components and their interaction in theoverall system.



Ray-Tracing to Analyse andOptimise Optical Reflectors

We improve the optical yield of reflectors, e.g. those used inevacuated collectors for thermal solar systems.

Matthias Rommel, Andreas Häberle*, Arim Schäfer

We use 3-dimensional forward ray-tracing to calculate the total amountof radiative power absorbed and theray density distribution on the absor-ber, taking the material parameters ofreflectors and transparent componentsinto account. This allows us not onlyto optimise the reflector geometry,but also to apply sensitivity analysisand determine the effect of inac-curacies in the geometry or thesurface quality resulting from pro-duction. The aim is the economicallyoptimal compromise between pro-duction costs for the reflectors andtheir solar energy yield.

Fig. 2: Detail of an evacuated tubular collector with an external reflector.

Fig. 1: The diagram shows the ray paths in anevacuated tubular collector with an externalreflector, for an incident angle of 10° (cross-hatched area). Only a few rays miss theabsorber (circle) and are re-directed upwards or sidewards.

incident rays

outer glass tube

absorber

reflector

* PSE GmbH Forschung Entwicklung Marketing, Freiburg


Measurement and Testing in Thermal Solar Energy and Optics

Thermography of a segmented facade element,viewed from the building interior. The surfacetemperatures of the various components, e.g.glazing, frame, spacer, ventilation element andspandrel, are represented in a colour code.Prototypes are tested under real climatic andinstallation conditions with the facade teststand at Fraunhofer ISE, and the long-termperformance is monitored if required.


Our clients benefit in three ways:

Tests under defined conditions allowthe user to compare products andenable manufacturers to assess newtechnology.

As globalisation expands, stand-ardisation becomes increasinglyimportant. By participating ininternational projects (EU, IEA) and standardisation committees,Fraunhofer ISE is involved in definingnew testing and standardisationprocedures, and can represent theinterests of the German economy.

The refinement of measurementtechnology and the development ofaccelerated ageing tests shortens theroute from a prototype to the finalproduct and provides the certaintyneeded for guarantees.

Measurement and Testing inThermal Solar Energy and Optics

A young market is like a young plant.It needs greater attention and care -in this case, quality assurance. Solarenergy affects many aspects ofeveryday life and competes withtechnology which was new 100 yearsago and has had time to maturesince. If a new product does notbring the performance or lifetimewhich the user expects, the wide-spread friendly attitude towardrenewable energy can quickly turninto general scepticism.

We thus co-operate with the industryand standardisation bodies in drawingattention to high quality. We developmeasurement procedures for newproducts, and conduct extensive long-term measurements to check whetherthe technology will still perform aswell after 20 years of usage as itoriginally did in the laboratory.

Contact persons:

Window and Dr Werner Platzer Tel.: +49 (0) 7 61/45 88-1 31façade testing E-Mail: [email protected]

Collector and Matthias Rommel Tel.: +49 (0) 7 61/45 88-1 41storage tank tests E-Mail: [email protected]

Lifetime testing Michael Köhl Tel.: +49 (0) 7 61/4 01 66-82of materials E-Mail: [email protected]

Lighting measurement Jan Wienold Tel.: +49 (0) 7 61/45 88-1 33room E-Mail: [email protected]

Solar air-conditioning Carsten Hindenburg Tel.: +49 (0) 7 61/45 88-3 53E-Mail: [email protected]

Thermal optical testing Tilmann Kuhn Tel.: +49 (0) 7 61/45 88-2 97laboratory TOPLAB E-Mail: [email protected]

Compact heat pumps Andreas Bühring Tel.: +49 (0) 7 61/45 88-2 88E-Mail: [email protected]



Compact Ventilation Units –Efficiency for Passive Solar Houses

We support our clients in thedevelopment of compact ventilationunits with an integrated exhaust airheat pump. In combination with asolar collector, the units can supplypassive solar houses completely withheat and fresh air.

Andreas Bühring, Sebastian BundyCarsten Dittmar, Bastian Greuel,Wolfgang Guter, Christel Russ,Tim Schmid, Bernhard Seigel

DevelopmentWe have developed new modules forsimulation: component models forexhaust air heat pumps, air-to-air heatexchangers with condensation andvariable air flows, and gas heaters forauxiliary heating. These are used toinvestigate new concepts for buildingservices technology. We simulate theinteraction with other buildingservices components and the buildingitself for varying user behaviour andclimatic conditions.

Laboratory testingWe have considerably extended ourtest stand to measure the energyefficiency of ventilation equipmentand its components: We can nowchoose stationary test conditions froma wide spectrum. In addition, theautomation of the test stand meansthat we can choose dynamicallyvarying conditions. The measure-ments form the basis for our recom-mendations to the manufacturer foroptimising the components and theirinteraction. Thanks to remote moni-toring of the test stand, we will beable to visualise the laboratorymeasurements on-line, directly in theclient's office: You are welcome tolook over our shoulders!

ApplicationThe performance of compact venti-lation units from different manu-facturers is tested practically withmeasurements in various occupiedpassive solar houses (see page 42).On the basis of daily data analysis, wemake suggestions to optimise theoperating mode, the equipment andits controls. Any possible defects arequickly identified and remedied.

InnovationAs our contribution within a majorproject supported by the GermanFederal Ministry of Economics andTechnology BMWi (see page 48), wedevelop new concepts for heat pumpsand their operating modes in co-operation with industrial partners.Additional modules extend theapplication field for compact venti-lation units e.g. for operation with afuel cell.

Fig. 1: Automated test stand with room fortwo separate ventilation devices with exhaustair heat pumps.

Fig. 2: Outlet air conditions behind the heat pump during heating operation in a fieldtest. The exhaust air from the rooms is the heat source here. The higher thehumidity, the more efficient is the heat pump operation. It accepts condensation heatwhen the exhaust air is cooled - and thus dehumidified - and does not have to coolthe outlet air (to the surroundings) as much in order to gain the same amount ofheat. For example: Let the air temperature at the evaporator inlet be 10 °C. Thenthe outlet air must be cooled to -1.5 °C, if the exhaust air humidity is 35 %. If thehumidity is 50 %, cooling to +0.5 °C is sufficient.

8 9 10 11 12 13 14air temperature at the evaporator inlet [in °C]

outle

t ai

r te

mpe

raru

re [

in °

C]

2.5

1.5

0.5

-0.5

-1.5

-2.5

45%

40%

50%

35%

exhaust air humidity



Test Facility for Solar DesiccantCooling Systems

Solar desiccant cooling systems (SDCS)present an environmentally friendlyalternative to conventional air-conditioning systems. Integration ofthermal solar systems is particularlypromising due to the low operatingtemperature of SDCS. We have beenworking intensively on this topic forseveral years and set up a new testfacility last year.

Carsten Hindenburg,Volker Kallwellis, Barbara Fuchsberger,Mario Motta, Sascha Backes

The main components of the testfacility are:- sorption-assisted air-conditioning

system with a nominal volume current of 4000 m3/h. A system of these dimensions can provide air conditioning for seminar rooms with40 - 80 persons.

- 20 m2 solar collectors with a liquid heat transfer medium, 20 m2 solar air collectors, 2 m3 buffer storage tank

With the test facility (fig. 1), we canconfigure sophisticated hydrauliccircuits and thus investigate 4 to 5very different SDCS simultaneously.As specified by our clients, weinvestigate both the performance ofthe complete system and that ofindividual components under real,non-stationary solar operatingconditions. Optional conditioning ofthe ambient air makes us practicallyindependent of the prevailing ambientconditions.

We offer the following services to ourclients:

- development and analysis of energy-optimised control strategies for SDCS

- measurement and further development of sorption wheels; close co-operation with the thermo-analytical laboratory of Fraunhofer ISE means that we can develop and directly test new sorption materials

- measurement and further development of thermal solar collectors specifically for air-conditioning applications

Fig. 1: Test facility. The following companies provided financial support for its construction: SolvisSolarsysteme GmbH, GREENoneTEC Solarindustrie GmbH, Sonnenkraft GmbH Deutschland,Grammer KG Solar-Luft-Technik, Landis&Staefa GmbH Region München, Viega, robatherm GmbH.

- development of cost-optimised combinations of thermal solar energy with SDCS

- system investigations and comparison with accompanying system simulations

- development of controllers for solar and non-solar SAAC systems

- development of customised software solutions to simulate SDCS



Experimental Investigations of theStagnation Behaviour of ThermalSolar Systems

Solar systems for space heatingsupport are often subject to extremestagnation temperatures in summer.The aim of our investigations is toimprove the operation and lifetime ofthese systems.

Matthias Rommel, Konrad Lustig,Dirk Stankowski, Arim Schäfer

Increasing numbers of collectorsystems are being installed inGermany, which not only heatdomestic hot water, but also meetpart of the energy demand for spaceheating. Austria has led the way inthis development, where already 40 % of the recently installedcollector area provides solar supportfor space heating. In these systems,the ratio of collector area to tankstorage volume is considerably largerthan in systems purely for domestichot water. As a result, the systemsoften go "into stagnation" duringsummer. The collector rapidly heatsup to its stagnation temperature. Thisis in the range between 180 and 200 °C for flat-plate collectors, and

between 220 and 300 °C for evacu-ated tubular collectors. The water/glycol mixture in the collector loopthen evaporates at the usual systempressures of 2 to 4 bar and latercondenses again when the systemcools down. During this process,pressure pulses with pro-nouncedpressure peaks arise, and at the sametime, all of the components in thecollector loop experience a highthermal load. Together with partnersfrom Austria and Germany, we areinvestigating the stagnation behaviourof thermal collectors in a project sup-ported by the European Commission.Manufacturers of collectors, pumps,control systems and heat transfermedia are represented in the project.

At the beginning of 2000, weinstalled two tubular collector systemswith different internal piping configu-rations in the system test stand ofFraunhofer ISE. Since then, we havebeen measuring them continuouslyunder various operating conditions,and monitor the evaporation of thefluid during stagnation in detail. Wewere able to gain significant insight

into the energy and steam transportprocesses, as well as the load on the components, with our event-triggered, high-frequency pressuremeasurements. Measurements aremade every 4 milliseconds and theresult is stored temporarily. If one ofthe measured values exceeds a certainlimit, all of the measurement data forthe evaporation process are storedpermanently. In this way, we wereable to trace very rapid variations inthe pressure. They occurred when theliquid heat transfer medium reachedoverheated areas of the collector.

The load on the heat transfer mediummust be known for long-termoperation of a thermal solar system.Thus, we set up one of the twocollector systems as a reduced systemwithout a storage tank, so that thefluid was subjected to the maximumstagnation load. Statistical analysis ofthe frequency distribution fortemperatures and evaporationprocesses indicated the direction forimprovement of the heat transfermedium.

storagetank

storagetank

expansionvessel

collector

expansionvessel

collector

storagetank

expansionvessel

collector

50 temperature in °C 200

liquid vapour

Fig. 1: Visualisation of the processes during stagnation in a solar system with a collector area of 40 m2, prepared with the "Dview" visualisation tooldeveloped at Fraunhofer ISE. It shows how the steam areas progress from left to right into the collector inlet and outlet.



Collector with a Corrosion-FreeAbsorber for Desalination ofSeawater

We have developed a collector inwhich hot seawater (90 °C) can flowdirectly through the absorber.

Matthias Rommel,Joachim Koschikowski*,Michael Hermann, Arim Schäfer

The absorber consists of glass tubes(16 mm external diameter) with aselective absorber coating and feederpipes of reinforced silicone. A zigzagpleated reflector is mounted underthe absorber so that the aperture areaof the collector is used efficiently.Figure 1 shows a sketch of thecollector configuration, fig. 2 a photoof the collector. The absorber con-struction is such that a large-areamodule with external dimensions of1.5 m x 4.8 m can be built.

We produced eight collector modulesin our own workshop as a pilot plantfor the SODESA seawater desalinationproject on Gran Canaria, which issupported by the European Union.The system (fig. 3) was installed onGran Canaria in May, 2000 and taken

into operation. It applies the Multi-Effect Humidification (MEH) processfor distillation. The collector field withthe 8 collectors has an aperture areaof 47.2 m2. A building can be seenbehind the collectors. It houses the6.3 m3 storage tank for 90 °C hotseawater, the distillation unit and aphotovoltaically powered waterpurification unit with mineralisationand UV sterilisation. The system isdimensioned for a daily production of600 l drinking water in very goodquality.

The new collectors with the corrosion-free absorbers have proven themselveswell. They can be used universally inall thermally powered seawaterdesalination processes or to heat theinlet water in desalination units basedon reverse osmosis.

Fig. 1: Construction of the SODESA collector. A zigzag pleated reflector is located below theabsorber tubes (circles).

Fig. 2: The reflections from the folded edges ofthe reflector can be seen as bright lines parallelto the collector tube axes.


Fig. 3: SODESA collector system on Gran Canaria.



IR Thermography as a Tool toDevelop and Analyse ModernFaçade Elements

Infrared thermography visualises thetemperature distribution of a surface.It is an important, non-invasiveinvestigation method, which we useprimarily to characterise innovativeelements in buildings and to localisebuilding defects.

Alexandra Raicu*, Werner Platzer,Werner Hube, Volker Wittwer

Transparent insulation for solarheating of buildingsFaçade elements with transparentinsulation (TI) have been installed e.g. in the demonstration project,"Solarhaus Gundelfingen". IRthermography helps us to investigatetheir performance when integratedinto the building.

During a fine weather period inMarch, we investigated the façade,which is insulated with TI elements. A thermogram was recorded every 15 minutes, so that the dynamic vari-ation of the inside wall temperaturecould be visualised. Figure 1 showsthe interior thermogram of a cornerof the building. The image was rec-orded on 21st March, 2000 at 6.30p.m., and documents the highesttemperature difference between thetwo surfaces recorded on that day:The TI wall was up to 15 °C warmerthan the conventionally insulated wall.

The delayed release of heat from thesolar heated, transparently insulatedwall during the evening and the nightis evident in fig. 2: The inside walltemperature is significantly higherthan the room air temperature

between 6.30 p.m. and midnight,although the sun had already set.

Visualisation of concealed defectsand damage in a buildingFor the first time, we systematicallyinvestigated the use of IR thermo-graphy to reveal concealed defectsand damage in a building, also undernon-stationary temperature con-ditions.

A set of guidelines for users is theresult of the investigations, which wasfunded by the German FederalMinistry for Transport, Building andHousing BMBau. It explains how themeasured results are affected by theambient conditions, controlled heatingof the façade or the choice ofmeasurement equipment. Up to now,it was accepted that IR thermographyto detect defects was best doneduring cold winter nights. Wedemonstrated how good results canbe obtained also under non-stationaryconditions during the day and insummer. The boundary conditions areclassified according to the radiationon the façade and the temperaturedifference between inside and outsideinto representative categories (e.g.overcast winter day, clear summer day,etc.). Recommendations forthermographic measurements weremade for the different categories.Advantages and disadvantages,favourable and unfavourablesituations were presented andexplained.

OutlookIR thermography is simple to applyand allows temperature fields to bepresented accurately, with goodtemporal and spatial resolution. Weintend to use it more intensively as atool for the development and qualitycontrol of façade elements.

* Sto AG, Stühlingen

Fig. 2: Qualitative representation of thevariation with time of temperature values alonga horizontal straight line, as marked in Fig. 1.The baseline corresponds to 19 °C, the peaksto 35 °C. The temperature variation is shownbetween 6.30 p.m. (back) and 12.00 p.m.(front), measured at 15-minute intervals.

Fig. 1: Temperature distribution on the inside ofan outer wall, which is insulated with 2 TIelements (right, 35 °C), compared to an outerwall with opaque insulation (left, 20 °C).

Fig. 3: Thermographically visualiseddefects in the insulation of a test façade(e.g. two joints, upper right and centreright). The element dimensions are 1.8 m x 2.3 m.

1 2 3position [m]

35

30

25

20

time [

h]

temperature [°C]




User Reactions to Sun-Shades andGlare Control

Daylighting and thermal simulationsare becoming increasingly accurate.When the daylighting potential inbuildings is being estimated, one ofthe main sources of uncertainty isinformation on everyday use ofartificial lighting and variable sun-shading elements. Within a pilotstudy, which is running for a year, weare documenting how the users in anoffice building manually switch on thelights and adjust the blinds.

Christoph Reinhart*

Improved simulation tools allowphysically accurate descriptions of thelighting and thermal conditions inrooms with complex facade confi-gurations and for a growing selectionof light-guiding elements (fig. 1). Inaddition, we can now simulate theinternal room illuminance in 1-minutesteps for the whole year, allowingqualified analysis of different planningoptions (see page 29).

As a result of these improvements, the greatest uncertainty in buildingsimulation is now the user behaviour.For this reason, we have been investi-gating the behaviour of 20 users in anew office building in Weilheim (fig. 2). The users can manually adjustboth the blinds and the artificiallighting, which is automatically dimmed in response to the daylightlevel, according to their ownpreferences.

Based on the information gained, weare developing a model which predicts

the user reactions as a function of theclimatic conditions (outside and in the office). We can then use themodel as a reference case for coupledlighting and thermal simulations,allowing a general evaluation ofautomatic controls for artificiallighting and sun-shading devices.

Initial analysis indicates that:- The presence of the users in their

offices can be described satis-factorily by a stochastic model based on several specific user parameters.

- The blinds are retracted during those periods when artificial lightingis needed in the investigated office, which was optimised for daylighting(fig. 3). This statement indicates that the use of blinds and artificial lighting can be modelled separately for the investigated office type, and that artificial lighting is switched on only when there is insufficient daylight.

- There is a clear correlation between the nominal illuminance at the desk and the probability that artificial lighting will be switched on when the user enters the office.

The collated results will be integratedinto building simulation programs andwill be validated and refined bycomparison with further buildings infuture.

The investigation is supported by theDeutsche Forschungsgemeinschaft.

Fig. 2: The pilot study was carried out in the 10south-facing offices of the new building for theengineering and measurement office belongingto Hans Lamparter GBR (architects: Werkge-meinschaft Maier, Weinbrenner, Single).

Fig. 1: Measured and simulated daylightingautonomy in the measurement container onthe roof of Fraunhofer ISE, for more than10000 sky situations and three different blindsettings. The daylighting autonomy describesthe proportion of working time for which atask-dependent nominal illuminance limit isexceeded.

Fig. 3: Blind position in the investigated officesduring the periods when artificial lighting wasswitched on. The high correlation betweenretracted blinds and artificial lighting demon-strates that in the investigated building, artificiallighting was switched on only when there wasinsufficient daylight.

dayl

ight

ing

auto

nom

y [%

]

60

50

40

30

20

10

00 200 400 600 800 1000

nominal illuminance [lux]

measuredsimulated

blind down

1 2 3 4 5 6 7 8 9 10office

100 %

80 %

60 %

40%

20 %

0 %

blind retracted


Solar Engineering - Advising, Planning, Implementing

These solar passive terrace houses in Neuenburg/Rhein consumeonly 8 kWh per m2 and year. The integrated energy concept hasfive essential components: very good thermal insulation, solarcollectors for domestic hot water, controlled inward and outwardventilation with heat recovery, pre-heating the inlet air in an earth-to-air heat exchanger and an innovative, compact unit with a smallelectric heat pump to supply the remaining heating energy. Theelectricity for the entire building services technology can besupplied to 100 % by solar energy with 10 m2 of photovoltaicmodules.


Appropriate solar concepts for officebuildings are based on extending theuse of daylighting and passive cooling,so that the electricity consumption fortechnical building services can bereduced, while maintaining high usercomfort. Greater use of daylightingand passive cooling are goals whichalready have a large effect on buildingplanning during the design phase.Success depends greatly on dedicatedapplication of simulation tools forlighting and indoor thermal con-ditions. The savings in technicalbuilding services (lean building) re-quire additional investment in theplanning phase.

The following articles report onconcepts, technology and projects forbuildings designed for sustainableliving and working in the future.

Solar Engineering - Advising,Planning, Implementing

Sustainable buildings for the futuredemand that the energy consumptionbe clearly reduced. The revisedenergy-saving regulation expected in2001 will stimulate a continueddecrease in the heating consumptionof new buildings. Beyond this,already constructed buildingsdemonstrate that buildings up to thestandard of a zero-emission house canbe built today with the availablestrategies and technology. Increasedenergy efficiency is the basis for amajor contribution by solar energy tothe building energy balance.

Whereas the energy demand forresidential buildings is still dominatedby the heating demand for spaceheating and hot water, electricity isalready the major form of energyconsumed in office buildings today.

Contact persons:

Building renovation Dr Christel Russ Tel.: +49 (0) 7 61/45 88-1 30E-Mail: [email protected]

Demonstration Dr Karsten Voss Tel.: +49 (0) 7 61/45 88-1 35projects and E-Mail: [email protected] analyses

Building simulation Sebastian Herkel Tel.: +49 (0) 7 61/45 88-1 17E-Mail: Sebastian [email protected]

Solar air-conditioning Carsten Hindenburg Tel.: +49 (0) 7 61/45 88-3 53E-Mail: [email protected]

Solar shading devices Tilmann Kuhn Tel.: +49 (0) 7 61/45 88-2 97E-Mail: [email protected]

Daylighting Jan Wienold Tel.: +49 (0) 7 61/45 88-1 33E-Mail: [email protected]

Transparent Dr Werner Platzer Tel.: +49 (0) 7 61/45 88-1 31insulation E-Mail: [email protected]

kWh/m2a

hot water

system losses

district heating

internal sources

solar collectorheat pump

windows and TI

-120

100

80

60

40

20

0

-20

-40

-60

-80

-100

-120

dem

and

-><

- su

pply

ventilation

transmission

tota

l hea

t de

man

d:10

9 kW

h/m

2 a

41 % solar fraction



Solar Building - Residential Buildings

The complete project development forsolar passive buildings, as well as thedevelopment and assessment ofsystems and components for buildingservices technology, are servicesoffered by the Institute (see page 14).

Andreas Bühring, Christel Russ,Karsten Voss, Christof Wittwer,Werner Hube

In a monitoring programme, weevaluate the energy efficiency inoccupied houses of novel energyconcepts for so-called "solar passivebuildings", on commission to industryand with financial support from theFoundation for Energy Research inBaden-Württemberg. At present, weare evaluating further systems in thefunding programme for 100 solarpassive houses throughout Baden-Württemberg for the utility, EnBW

Energie Baden-Württemberg AG. Theterrace houses in Neuenburg and thefree-standing house in Büchenau weresupported within this programme.

In general, solar passive buildings arecharacterised by a major reduction inheat losses through the buildingenvelope or due to ventilation. Thesolar energy gained through windowsis then sufficient to keep the annualdemand for conventional heatingenergy to less than 1.5 l heating oilper square metre (=15 kWh/m2) underCentral European climatic conditions.The pre-requisite is not only a veryhigh standard of thermal insulation,but also controlled room ventilationwith heat recovery.

Fig. 1: View of the solar passive houses in Neuenburg.

Fig. 2: Heating energy consumption andprimary energy demand for the buildingservices in the solar passive houses inNeuenburg during the heating season fromOctober 1999 to April 2000.

Fig. 3: Two examples of buildings supported within the "Passive House Funding Programme",sponsored by the utility, Energie Baden-Württemberg AG. The energy consumption of all buildingsinvolved is recorded and analysed as part of a monitoring programme.

Fig. 5: Annual heat balance for the solarapartment building in Gundelfingen. Thebalance is based on measured data from oneyear. The aim of achieving a 3-litre building in the practice was reached, with a heatingenergy demand of 28.5 kWh/(m2a). More thanone third of the energy demand for spaceheating and domestic hot water is met withsolar energy. TI: transparent insulation

Fig. 4: Annual heat balance for the solarpassive house in Büchenau. The balance isbased on measured data for one year. Thetotal heating demand of 110 kWh/(m2a),including around 20 kWh/(m2a) for spaceheating, is met by consuming 13 kWh/(m2a)electricity. Major contributions are provided bysolar energy gains through windows and withcollectors. HR: heat recovery, ETA: earth-to-airheat exchanger

40 % solar fraction

kWh/m2a

specific heating energy (average: 8.1 kWh/m2)

primary energy consumption for building services

50

40

30

20

10

0

spec

ific

heat

ing

ener

gy/p

rimar

yene

rgy

cons

umpt

ion

for

build

ing

serv

ices

[kW

h/m

2 ]

125

100

75

50

25

0

-25

-50

-75

-100

-125

dem

and

-><

- su

pply

hot water

windows and TI

internal sources

solar collectorheat pump

electric heating

ventilation

transmission

HR, ETA

tota

l hea

t de

man

d:11

0 kW

h/m

2 a

13 kWh/m2aelectricityconsumption

houseD houseF houseG houseC houseE houseB houseA

distribution losses

(average: 25.6 kWh/m2)



BWe have improved this standard stillfurther in the 1-litre solar houses inNeuenburg: The newly developed,compact ventilation unit from theMaico HaustechnikSysteme companycombines ventilation, heating anddomestic hot water. The favourablypriced, system-integrated model usesthe spent air as a heat source to pre-heat the incoming air (heat recovery)and as the heat source for a heatpump.

A further practical test with thecompact ventilation unit ran success-fully in a free-standing house inBüchenau, near Bruchsal, althoughthe heating energy demand was 2 lheating oil per square metre. Thisdemonstrated that innovative buildingservices technology opens up newpossibilities for sustainable living infuture, with major savings in CO2emissions. The implemented conceptfor building services indicated anefficient and ecologically responsibleway to use electricity for heating, incontrast to direct electric heating (fig. 4).

The measurement results from oneyear were also summarised as anannual balance for the "SolarhausGundelfingen", an apartment building(fig. 5). With its heating energydemand of 28 kWh/(m2a), it reachedthe aim of a 3-litre building. Solarenergy meets 40 % of the total heatdemand for the building. The projectwill be continued with extensivedetailed analyses, in co-operation withthe University of Karlsruhe and withsupport from the German FederalMinistry of Economics and TechnologyBMWi.

Solar Building - Commercial Buildings

The costs associated with energysupply usually represent only afraction of the total costs in abuilding: In office buildings, thesalaries of the employees are thedominating cost factor, whereas theimmediate energy costs total onlyabout 1 %. Due to the highpersonnel costs, optimal workingconditions have a high priority in theplanning process, so that theemployees feel motivated to workefficiently. Thermal and visual comfortare decisive aspects of the workingenvironment, and are closelyassociated with the planning conceptfor ventilation, cooling and lighting.

Sebastian Herkel, Jan Wienold,Tilmann Kuhn, Karsten Voss

New building for the headquartersof the Fraunhofer SocietyA double envelope is planned for the16-storey building in Munich. It willprovide natural ventilation and plentyof daylight within the offices, whileoffering acoustic insulation against thenearby railway line at the same time.The potential users are at the centreof this planning process: Sophist-icated control of ventilation flaps inthe facade will ensure that the cavityis well ventilated, and will reduce thewind pressure on the windows in theupper storeys. The user can open thewindow for ventilation at any time,without any danger of overheating ordraughts. We are supporting theoptimisation with simulationcalculations and measurements with aprototype facade (fig. 6). As part of

the measurement programme, weanalysed the effect of differentoptions for the facade and sun-shading devices on summer comfort.In addition to the qualitative assess-ment of the various options, thesimulation results were also con-firmed.

Fig. 6: Test cell from a high-rise building with adouble envelope, for the new headquarters ofthe Fraunhofer Society in Munich.



The new premises for FraunhoferISE will be completed in the middle of2001. In comparison to conventionalbuildings, we reduced the primaryenergy demand for the office areas by50 % with improved thermal insu-lation, passive cooling, daylightingand photovoltaic electricity gene-ration. An energy supply based on acombined heating, power and coolingsystem was the logical answer to thehigh energy demand created by theuse of laboratories and clean rooms.The building will be monitored fortwo years and intensively analysed.Further information in text and illu-strations can be found in the Internetat: www.solarbau.de (in German).

Collini CentreThe Collini Centre in Mannheim is atypical office complex from thebeginning of the seventies. Wedetermined the energy-saving poten-tial offered by renovation of thefacade in preparing a concept report.We used combined daylighting andthermal simulations to evaluate vari-ous renovation options with regard tothe internal air quality and lightingconditions in the offices.

GalileoWe are supporting the planning teamfor the "Galileo" skyscraper of theDresdner Bank in Frankfurt withmodel calculations, calori-metric gvalue measurements and tests ofelements to prevent glare.

Fig. 7: New premises for Fraunhofer ISE, in autumn 2000.

Fig. 8: Comparison with a conventionalbuilding of the primary energy demand for the office areas in the new premises forFraunhofer ISE.

Fig. 9: Electricity demand for artificial lightingaccording to various lighting strategies, for therenovation of the Collini Centre in Mannheim.

build

ing

conc

ept

ther

mal

sim

ulat

ion

light

ing

sim

ulat

ion

cons

ulta

ncy

prod

uct

test

ing

mon

itorin

g

DB Hamm • • •

Fraunhofer ISE • • • • • •

Collini Centre • • • •

Fraunhofer • • •Headquarters

Pollmeier •

Mensa, Kiel • • • •

Galileo • •

Sapfina • • • •

Lamparter • • •

Tab. 1: Selected projects from the year 2000.

150

125

100

75

50

25

0convent.building

demand supply(new premises forFraunhofer ISE)

lightingventilationcoolingheating

-50 %

PV

fossilfuels

40

30

20

10

0

elec

tric

ity d

eman

d fo

rar

tific

ial l

ight

ing

[kW

h/m

2 a]

lights always on

0 2 4 6 8 room depth [m]

lights on/off

lightsdimmed

primary energy[kWh/m2a]

http://www.solarbau.de



Solar Building - Cross-Sectional Analyses

We document and evaluate conceptsand results in cross-sectional projectsfor national and internationaldemonstration programmes on thebasis of a common analytical platform.

Karsten Voss

The subject of marketable residentialbuildings, with a primary energyconsumption which is only a quarterof the current standard, is beingaddressed by a group of expertswithin the International EnergyAgency IEA. We are participating inthe Task on "Sustainable SolarHousing" within the IEA Solar Heatingand Cooling Programme with researchon energy supplies (see chapter onMeasurement and Testing for ThermalSolar Energy and Optics) and areleading the working group on"Monitoring and Evaluation". We areable to include many of our owndemonstration projects in this work.The aim is to define an internationallyaccepted platform, which allowscomparable documentation andanalysis of buildings. The GermanFederal Ministry of Economics andTechnology BMWi is supporting thiswork.

Solar concepts for office buildings arebased primarily on improved use ofdaylight and replacement of active air-conditioning by "passive cooling".These buildings are characterised bylow investment and maintenancecosts for the technical buildingservices, coupled with a higher budgetfor the building construction. The aimis comparable or lower total buildingscosts for high-quality working

conditions and a low energyconsumption. Integrated buildingplanning, using modern simulationtools, can reproduce the multi-facetted effects of the building on the lighting conditions and the indoorsummer air quality in detail, andprovide planning certainty early in the process. The necessary furtherdevelopment of programs, userinterfaces and program links willfacilitate use in everyday planningprocesses.

Examples of such "lean buildings" are currently being supported, withfunding for the additional planningeffort and measurement-basedevaluation during operation, withinthe "SolarBau" programme of theGerman Federal Ministry of Economicsand Technology BMWi. Compre-hensive documentation, which wehave prepared with BMWi fundingtogether with the Faculty for BuildingScience and Technical BuildingServices from the University ofKarlsruhe and the architectural office,sol°id°ar, from Berlin, is available onthe Internet: www.solarbau.de. Atthe end of the year, an 80-pagejournal was published with the topicsstudied in individual projects and thefirst results of the analysis. Thejournal can be obtained for a smallfee from BINE Bürger-InformationNeue Energietechniken Tel: +49 (0)2 28 / 92 37 90, Fax: +49 (0)2 28 / 92 37 20http://bine.fiz-karlsruhe.de.

Fig. 10: Characterisation of building envelopesfrom various projects as a function of thetransmission heat loss coefficient (HT) and thepassive use of solar energy (relative aperturearea). The demonstration projects ofFraunhofer ISE which were discussed earlier are highlighted.

Fig. 11: Statistics on visits to the Internet site: www.solarbau.de.

Fig. 12: Part 1 of the scientific evaluation ofthe SolarBau Funding Programme appeared atthe end of 2000 as the "SolarBau:MONITORJournal 2000". It can be obtained from BINEBürger-Information Neue Energietechniken,Internet: bine.fiz-karlsruhe.de.

heat

ing

tran

smis

sion

loss

coef

ficie

nt H

T[W

/m2 N

FAK

] [

W/m

NFA

2 K]

5 10 15 20 solar aperture area as %

of net floor area

1.0

0.8

0.6

0.4

0.2

0.0

March 1998 to September 2000

10000

8000

6000

4000

2000

Number of visits per month

Büchenau

Gundelfingen

Neuenburg

http://bine.fiz-karlsruhe.de


Energy Technology

Test stand for a 3.3 kWel fuel cell stack. The PEM fuel cell supplied by SIEMENS is part of a heat/electricity co-generation plant,which is powered by natural gas and wasdeveloped and constructed as part of a project commissioned by E.ON Energie AG on "Innovative Domestic Energy Supply".


The application in buildings is typicalfor the trend to use fuel cells in lowerand lower power ranges. Our micro-energy technology group is workingon systems with 0.1 - 5 W. Replacingrechargeable batteries with fuel cellsopens up a new dimension inoperating times for appliances, bethey notebooks or camcorders, andallows customised design: Theelectricity supply and the operatingtime are independent parameters.The fuel cell determines the former,the storage unit the latter.

A completely new technology alsobenefits from our technology in themicrometre range: thermophotovoltaicenergy conversion. A thermophoto-voltaic converter functions like a solarcell for infrared radiation and canconvert heat with a power densityexceeding 1 W/cm2 into electricity.As it does not have any movableparts, it requires very little main-tenance and is predestined forapplications in remote areas, e.g. fortelecommunication repeaters.

The common aim of all our work is toprovide efficient and low-maintenanceenergy converters which make thesustainable use of energy still moreconvenient and economicallyattractive.

Energy Technology

A fuel cell instead of oil heating?New building concepts need a newtype of energy supply. In energy-saving solar houses, only a minimalheating demand still needs to be met.A conventional heating system is notwarranted and is also not desirableecologically. Low-temperature heat isproduced during electricity generationas a "waste product". Polymermembrane fuel cells now generateelectricity from hydrogen with anefficiency value of around 50 %.Thus, with a power rating of severalkilowatts, they could provide all theelectricity and heat that a buildingneeds. Surplus electricity is fed intothe grid. In this way, a house willbecome part of the decentralisedenergy economy of tomorrow. If areformer is used, conventional naturalgas can be used as the fuel.

Reforming is a chemical process whichextracts hydrogen from gases oralcohols. It offers two advantages: Onthe one hand, it enables fuels such asnatural gas to be used, which arealready widely available, so that con-sumers do not have to wait for solarhydrogen. On the other hand, fuelswith a high storage density such asmethanol can be applied, e.g. in thetransport sector.

Contact persons:

Fuel cells Mario Zedda Tel.: +49 (0) 7 61/45 88-2 07E-Mail: [email protected]

Hydrogen generation Peter Hübner Tel.: +49 (0) 7 61/45 88-2 10E-Mail: [email protected]

Systems technology Dieter Schlegel Tel.: +49 (0) 7 61/45 88-2 09and low-pollution E-Mail: [email protected]

Micro-Energy Dr Christopher Hebling Tel.: +49 (0) 7 61/45 88-1 95technology E-Mail: [email protected]

Energy Technology


Natural Gas Reformer for a Fuel-Cell Cogeneration Plant to SupplyEnergy for Buildings

Fuel cells can generate electricity withhigh efficiency from hydrogen, andthe associated thermal energy canheat buildings. We are developing areformer which prepares hydrogenfrom natural gas. This technologysupplies energy to buildings withpractically no emission of pollutants,with the exception of CO2.

Peter Hübner, Angelika Heinzel,Christof Wittwer, Matthias Vetter,Walter Mittelbach, Andreas Bühring,Tim Schmid, Bernhard Seigel

Building services technology mustmeet specifications which cannot befulfilled by the reformer for a fuel cellwithout further development. Thecriteria include flexible operation, ashort start-up phase, low maintenancedemand, long lifetime, compactconstruction and at least the oper-ating reliability of a conventionalenergy supply system. We haveconceived a system based on naturalgas and intended for the power rangeof 1 - 2 kWel. The main componentsof a fuel-cell cogneration plant areshown in fig. 1.

In the first process step, the reformingreactor generates a hydrogen-rich gasmixture by the reaction of natural gasand water vapour. Two subsequentcatalytic converters convert theremaining fraction of carbon mono-xide, about 10 vol %, into carbondioxide and hydrogen. Finally, the COfine purification step removes thecarbon monoxide until only ppmconcentrations remain. The gas thenhas the quality required for use inmembrane fuel cells.

Important criteria for the reformingreactor include the thermal lossesthrough the outer wall, the load-dependent reaction yield in thereactor, the pressure loss through andthe heat input into the catalystsystem, and the (inner) heat exchangewith the initial reactants. All of theseeffects must be taken into accountwhen the efficiency of the reformerand the complete system is optimised.

We are aiming for high flexibility ofthe reformer with respect to therelationship between hydrogen andheat generation. The CO conversionis intended to guarantee stable values

for the CO content, even when theload varies. It is performed accordingto the current state of the art in twosteps, a high-temperature step atabout 400 °C and a low-temperaturestep at about 200 °C.

The subsequent CO fine purificationprocess must reduce the CO contentfor a membrane fuel cell to well under100 ppm to avoid poisoning theanodic catalyst. For the present, weare achieving this with selectiveoxidation, but membrane separationprocedures are also conceivable in thefuture.

Catalysts are tested for the variousprocessing steps (project partner: Süd-Chemie AG, Munich), which ensurethat the fuels used react efficiently. To this purpose, we have set up a newcatalyst test stand with gas chroma-tography.

Depending on the flexibility achievedwith the reformer and the user speci-fications, a heating boiler can beforeseen in the household energysupply system as a reserve heatsource, and its integration into the

Fig. 1: Schematic diagram of a fuel-cellcogeneration plant. HTS and LTS are catalytichigh-temperature and low-temperature COshift steps.

natural gas + water

air

air

hydrogen

reformingreactor

HTS

LTS

CO fine purification

heat

fuel cell

product gas water, airCO2

CO shift

electricity


Energy Technology

hot water circulation system can betaken into account.

After selecting the peripheralcomponents, such as heat exchangers,mixing valves, pumps and ventilators,we integrate the reformer and all thegas purification steps. We developcontrol strategies, investigate the gasquality which can be achieved in thelaboratory for various operatingconditions, and optimise the reformersystem. Finally, the complete gassupply is combined with the fuel cell(Proton Motor, Starnberg) in a singlesystem, and tested.

The natural gas reformer is acomponent in the major project on"New Integrated Energy SupplyConcepts for Buildings (NEGEV)",which is co-ordinated by the Instituteand funded by the German FederalMinistry of Economics and TechnologyBMWi. The main topics are a tech-nologically orientated demandanalysis, the development ofcomponents for building energysupply systems as modular elements,and their integration into completesystems, including the connection to

the existing grids of public utilities.Together with industrial partners (fig. 2), technologies are being furtherdeveloped, which can meet the lowenergy demand of modern buildingswith high efficiency. These includesolar systems, fuel cells, heat pumpsand low-loss storage systems. At theInstitute, we co-operate closely withthe Department for "Thermal andOptical Systems" (see page 30).

Fig. 2: Partners in the major project, "NEGEV".

Energy Technology


Innovative Energy Supply forHouses with a Fuel-CellCogeneration Plant

A fuel-cell cogeneration plant is beingdeveloped at Fraunhofer ISE, con-structed, and installed in the Tech-nology Pavilion of the Building Centreat the Munich Showground, as part ofthe "Innovative Energy Supply forHouses" project for E.ON Energie AG.

Dieter Schlegel, Sylvain Darou,Tobias Wartha, Robert Szolak,Christoph Strobel, Maurizio Palmisano, Angelika Heinzel

Progressive energy supply conceptsconcentrate on environmentalacceptability and the best possible useof the fuel. Fuel cells, with theirextremely efficient and environ-mentally friendly energy conversionprocess and low emission ofpollutants, meet these requirements.The Fraunhofer Institute for Solar

Energy Systems ISE has been devel-oping natural gas reformers togenerate hydrogen for heat/electricitycogeneration plants for several years.Two reformer systems were con-structed during this period, in 1997 atthe Technological Centre in Riesa,Saxony, and in 1999 at the TechnicalCollege in Ulm.

If natural gas is to be used in a fuel-cell cogeneration plant, furthercomponents are needed in addition tothe PEM fuel cell block (polymerelectrolyte membrane). Figure 2shows a schematic diagram of a fuel-cell cogeneration plant.

The fuel, natural gas, is converted in a reformer to hydrogen-rich syntheticgas. After further gas treatment(carbon monoxide conversion) andfine purification (e.g. selectiveoxidation of carbon monoxide), thereforming product, which contains 75 % hydrogen, is supplied to thePEM fuel cell for electricity generation.The resulting heat is used both in theprocess itself and also externally asheating energy. At present, there areno inverters commercially available forthe DC voltage output from the fuelcell (12 V, 275 A under full load).Thus, the voltage must first be raisedwith a DC/DC converter to 350 V.The electricity is fed into thehousehold circuit via an inverter. The

Fig. 2: Schematic diagram of a fuel cell system to run on natural gas(source: E.ON Energie AG).

mg/

m3

exha

ust

gas

300

250

200

150

100

50

0

S02

NOx

CO

NMVOC

dust

natu

ral g

as-

pow

ered

, fu

el-c

ell

coge

nera

tion

plan

t

natu

ral g

as-

pow

ered

, co

m-

bust

ion

engi

neco

gene

ratio

n pl

ant

mod

ern

blac

k co

alpo

wer

sta

tion

mod

ern

brow

nco

al p

ower

stat

ion

250

200 200

200200

100

102

100

50

50

300

115

5 10,10 7 20 3-5 0 3-8 0

com

bine

dna

tura

l gas

and

stea

m p

ower

stat

ion

air

air

naturalgas

naturalgas

exhaust air

exhaust gas

refo

rmer inverter

fuelcellblockCO

conversion

fine purification

burn

erhydrogencarbon dioxidewater vapour

reformate

AC electricity

heat

Fig. 1: Specific air pollutant emissions fromdifferent stationary technological approaches togenerating electricity (source: VDEW).


Energy Technology

Miniature Photovoltaic Modules forSmall Appliances and Sensors

At Fraunhofer ISE, highly efficient,miniature photovoltaic modules arebeing developed as solar powersupplies for small, high-qualityappliances such as mobile phones,organisers or sensors. The photo-voltaic units extend the stand-by timeor even allow complete independencefrom external power sources.

Christopher Hebling, Helge Schmidhuber, Stefan Glunz,Heribert Schmidt, Werner Roth

Solar cells convert the light from thesun or a lamp into electricity. Theyare electrically connected to formmodules, allowing easy handling.They need to have special properties,if they are to supply power toappliances indoors (fig 1).

The cells which we use include thehigh-efficiency solar cells produced atFraunhofer ISE, which are distin-guished by very good performance atlow lighting intensities. Modulesmade of these solar cells achieve highefficiency values and high voltages,even under indoor lighting conditions.

Space is in short supply in smallappliances. For this reason, the solarcells are connected to form high-performance modules and encap-sulated. We contact the cells in theshingle configuration with a con-ductive adhesive, and then encap-sulate them in a highly transparentsilicone resin (fig 2). This reduces thearea obstructed by contacts andmeans that our modules can achievean efficiency value of 20 %.

The energy-saving circuits to rechargebatteries, which were also developed

DC/DC converter is being developedtogether with the inverter by the Kacocompany.

The total efficiency value for thesystem, without electric loads and theinverter, should be at least 60 %. Thefuel cell block, which consists of 20individual cells, operates with 0.6 VDCper cell and 275 A at the nominaloperating point. This operating pointdepends on the composition of thereformer and other operatingparameters such as pressure andtemperature.

The electric power of the systemamounts to 3.3 kW, the thermalpower is 4.5 kW. The fuel cell blockwas supplied by the Siemenscompany. The fuel cell system isautomated with an SPS unit(programmable storage control) andcan be remotely maintained via ISDNand a software tool. Authorised staffcan modify the process data with aspecial access code, and carry outmaintenance work. The process dataare visualised on a PC, so that visitorscan observe the data on-line.

The project is funded by the BavarianState Ministry of Economics, Transportand Technology.

at Fraunhofer ISE, adapt the moduleelectronically to the appliance re-quired. They ensure that the gener-ated electricity is used optimally tooperate the device.

The performance of the miniaturephotovoltaic modules has alreadybeen demonstrated with operationalprototypes for telecom-munications,portable computers and wire-lesssensors. PV modules are the long-term power supply for these sensors.This significantly reduces the demandfor service and maintenance.

Fig. 1: Prototype of a solar-powered organiser.The rechargeable batteries, which areintegrated into the device, are charged by thephotovoltaic module. (Co-operation betweenFraunhofer ISE, Casio Computer and AccuCell).

Fig. 2: Schematic configuration of a photo-voltaic module with a curved cover. Moduleswith a minimum thickness of 1.5 mm can beproduced.

PMMA / PC

silicone

solar cell

insulating film

Energy Technology


Fuel Cells in the Low Power Range as Power Supplies forPortable Electronic Appliances

Miniature fuel cell systems are beingdeveloped to complement or replacerechargeable batteries within a jointproject involving five FraunhoferInstitutes. All aspects needed for amass-producible fuel cell system, frommaterials development to theevaluation of structure replicationmethods and micro-mountingtechnology, are being investigated.

Christopher Hebling, Mario Zedda,Andreas Schmitz, Ulf Groos,Alexander Hakenjos, Jürgen Schumacher, Klaus Tüber

Fuel cells are considered to be apromising technology of the future foroff-grid power supply, with their highelectrical efficiency value, unrestrictedmodular construction and pollutant-free energy conversion. Operational,durable systems have been achievedonly in the past few decades. Morerecently, fuel cells have also beeninvestigated for low-cost applicationsin mass markets such as portableelectronic appliances.

Fuel cells in the power range between0.1 and 5 W are being developedwithin a economically orientated,strategic alliance (WISA), which is ledby Fraunhofer ISE and supported bythe Fraunhofer Society. TheFraunhofer Institutes for ChemicalTechnology (ICT), for Reliability andMicro-Integration (IZM), and forProduction Technology (IPT), and theCentre for Manufacturing Innovation(CMI) are each contributing with theirspecific competence toward thecomplete system. The combination ofthe individual competences is resultingin additional synergetic value, not onlyin the technical development of the

fuel cell components, but also insetting up the manufacturingtechnology.

The reference product is a widelyavailable camcorder, in which therechargeable battery is replaced by afuel cell system. All the relevantsystem aspects are being investigatedon a prototype: fluid-mechanicalsimulations of the channel structure,material variations of the bipolarplate, integration of peripheral micro-elements, development of a specialpower management strategy and theevaluation of suitable manufacturingand mounting technology.

Parallel to the so-called "stackdesign", the series connection of fuelcells stacked on top of each other, anextremely flat configuration of series-connected cells is being implemented,which is mounted on the back of anMP3 player as its power supply.

Fraunhofer ISE is contributing to theproject with its long-term experiencein dimensioning, constructing andcharacterising fuel cell systems. As a supporting measure, we haveintensified our efforts in the fluid-mechanical, thermodynamic and

electrochemical simulation of the masstransport and conversion. Forexample, we can now calculate theposition-dependent production ofheat and water as a function of thegeometry of the gas channels and thevolume current. In parallel, we haveset up a measurement stand with a 5 x 5 cm2 test cell, which is dividedinto 49 individual segments andallows spatially resolved measurementof the following parameters:

- temperature (highly sensitive IR camera with a macro-lens)

- current density (measurement of theI-V characteristic for each individual segment)

- water content of the membrane (impedance spectroscopy)

- pressure difference (manometers at the inlet and outlet of the gas channels)

- air humidity (hygrometers at the inlet and outlet of the cell)

- hydrogen humidity (hygrometers at the inlet and outlet of the cell)

The measurement results help us toimprove the model definition forsimulation and thus lead to a growingunderstanding of the processes in afuel cell.

Fig. 1: Photo of the teststand for spatially resolvedmeasurement of thecurrent density, theimpedance and thetemperature.


Energy Technology

Thermophotovoltaic EnergyConversion with Micro-StructuredEmitters

Thermophotovoltaics (TPV) is theconversion of thermal radiation intoelectricity with photovoltaic cells. TPVoffers the potential for thermal-electric converters with high efficiencyand reliability, particularly in the lowpower range. Further fundamentaladvantages of thermophotovoltaicsinclude the possibility for cogener-ation of electricity and heat, highpower densities (> 1 W/cm2) and alow maintenance demand due to thelack of moving parts.

Christopher Hebling, Jörg Ferber*,Johannes Aschaber*, Christian Schlemmer, Rolf Wiehle,Volkmar Börner, Andreas Heinzel,Andreas Gombert

A TPV market study conducted byFraunhofer ISE identified attractiveapplications in the fields of off-gridpower supply, camping/leisure(cogeneration of electricity and heat),telecommunications (PV hybridsystems) and grid-independent gasheaters, among others. A marketpotential could also arise from the useof industrial waste heat (e.g. fromglass, aluminium or steel production).

We are pursuing a novel concept,which includes a micro-structuredemitter heated by a burner, a vacuumsystem and photovoltaic cells of IR-sensitive GaSb (see page 61). Thestructuring of the emitter surfaceserves to adapt the spectrum of theheated material to the spectralresponse of the GaSb cells. Atpresent we are investigating tungstenas the emitter material, as it ischaracterised by a natural radiative

selectivity, which can be reinforcedand optimised by the micro-structuring. The use of a selectiveemitter means that an additional filterto tune the radiation is not required.In addition, tungsten is suitable foruse at the operating temperatures dueto its high melting point.

Operating the system in vacuumoffers the advantage of eliminatingconvective heat transfer, which acts toreduce the efficiency of the photo-voltaic cells. The tungsten plates canbe heated by any method, providedthat temperatures of around 1250 °Ccan be reached. It is conceivable thatbio-fuels could be used to thispurpose.

Figure 1 shows the simulated emissionspectrum of a micro-structured tung-sten surface with a grating period of1.45 µm and a depth of 0.3 µm, as afunction of various angles of emission.As the angle of emission increases,the emission maximum shifts tolonger wavelengths - an undesiredeffect, as GaSb cells can only convertradiation of wavelengths shorter than1.7 µm into electricity. Simulationcalculations show that deeper struc-tures, on the order of micrometres,could prevent this angular selectivity.Initial measurements confirm this. Figure 2 shows the scanning electronmicrograph of a deeper surfacestructure on a tungsten sample, witha grating period of 1.4 µm and astructure depth exceeding 1 µm. Atpresent, we are working on optimisingthe structure and achieving long-termstability for the radiation emitter.

Fig. 1: Simulated emission spectrum at 1400 °Cof a two-dimensional tungsten grating with aperiod of 1.45 µm, plotted for different anglesof emission. GaSb cells can only convertphotons corresponding to a wavelength shorterthan 1.7 µm. The plotted spectrum has beencalculated. At present we are preparing theequipment for measurements at the requiredhigh temperatures.

Fig. 2: Scanning electron micrograph of amicro-structured tungsten surface with agrating period of 1.4 µm and a structure depth of 1 µm.


1.0

0.8

0.6

0.4

0.2

01.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

wavelength [µm]

emitt

ance

– ■ – 30°– x – 30°– ▲ – 60°



Monolithic tandem concentrator cells,which achieve an efficiency value of31.1 %, installed in a test module.Tandem solar cells consist of two ormore spectrally adapted componentsolar cells, which convert differentspectral ranges of the solar radiationinto electricity with particularly highefficiency. Lenses concentrate thesunlight by a factor of 100 to 1000.


We can now produce highly efficientsolar cells, e.g. for portable applian-ces, in small series with a pilot pro-duction line in Freiburg.

The crystalline silicon thin-film solarcell combines the classic advantagesof silicon with the advantages of thin-film technology. As well as investi-gating the physical fundamentals, we also develop the manufacturingtechnology: The energy-saving SIRprocess results in flexible films with a noteworthy efficiency value.

With respect to III-V solar cells, we areworking on radiation-resistant tandemcells for space applications. For ter-restrial applications, we are develop-ing an economically attractive proce-dure to produce the Fresnel lenses inconcentrator modules and constructcomplete modules for outdoorapplications.

We also develop special III-V cells forlaser power transmission and forthermophotovoltaic applications,which are optimised for the relevantradiation spectra.


More than 80 % of the solar cellsmanufactured throughout the worldare of crystalline silicon. The cost/performance ratio, their long-termstability and reliable potential forfurther cost reduction indicate thatthese mainstays of terrestrial photo-voltaics will continue to dominate themarket for the next 10 years.

III-V semiconductors such as galliumarsenide form the second materialclass which we are investigating. Atpresent it is associated with a nichemarket, which can be summarised bythe concepts of space and specialapplications, and optical concen-trators. The common trend for us inboth areas: Research is approachingthe commercial application yet moreclosely.

Some examples demonstrate this:In October, we commissioned ourLaboratory and Service Centre inGelsenkirchen. Here, we can workunder production conditions in thelaboratory. Industry can transfer theresults directly to production, withoutinterruptions for the investigations.

Contact persons:

Silicon material Dr Achim Eyer Tel.: +49 (0) 7 61/45 88-2 61development E-Mail: [email protected]

Crystalline silicon Dr Albert Hurrle Tel.: +49 (0) 7 61/45 88-2 65thin-film cells E-Mail: [email protected]

Multicrystalline Prof. Roland Schindler Tel.: +49 (0) 7 61/45 88-2 52silicon solar cells E-Mail: [email protected]

Highly efficient Dr Stefan Glunz Tel.: +49 (0) 7 61/45 88-1 91silicon solar cells E-Mail: [email protected]

III-V photovoltaic cells Dr Andreas Bett Tel.: +49 (0) 7 61/45 88-2 57and layered structures E-Mail: [email protected]

Dielectric and Dr Friedrich Lutz Tel.: +49 (0) 7 61/45 88-2 67metallic coatings E-Mail: [email protected]

Characterisation of Dr Wilhelm Warta Tel.: +49 (0) 7 61/45 88-1 92PV materials E-Mail: [email protected]

Innovative production Dr Ralf Lüdemann Tel.: +49 (0) 7 61/45 88-1 99technology E-Mail: [email protected]



Monocrystalline Solar Cells withHighest Efficiency and InnovativeManufacturing Technology

About half of all the solar cellsmanufactured around the world aremade of monocrystalline silicon. Over the last few years, a clear trendtoward higher efficiency values andthinner wafers can be observed inter-nationally. For that reason, some ofour research activities concentrated on the processing of thin wafers withnew, cost-saving production pro-cesses. In addition, we set up a pilot line to produce highly efficientsolar cells and took it into operation.

Stefan Glunz, Jochen Dicker,Franz J. Kamerewerd, Joachim Knobloch, Bettina Köster*,Antonio Leimenstoll, Ralf Lüdemann,Ralf Preu, Stefan Rein**,Sebastian Schaefer, Elisabeth Schäffer,Eric Schneiderlöchner,Jürgen Schumacher, Wilhelm Warta,Wolfram Wettling, Gerhard Willeke

If high efficiency values are also to beachieved with thin wafers, new cellstructures are needed for industrialproduction. The efficiency value ofsolar cells with an aluminium back-surface field decreases very stronglywhen the cell thickness is reduced. Byapplying appropriate measures, suchas improved surface passivation andan internal reflector on the backsurface, the efficiency value can begreatly increased, particularly for smallcell thicknesses. Solar cell concepts,with which efficiency values wellabove 20 % can be achieved (see fig.1), have been known for quite sometime. Nevertheless, these conceptshave not yet been introduced intoindustrial production, as they arecomplex and thus too expensive.Recently we have intensified ourinvestigations of ways to simplify theirimplementation.

The most important feature of highlyefficient silicon solar cells is that thesurface is well passivated. This can beachieved by coating it with silicondioxide or silicon nitride. However,when the contacts are applied, thisinsulating layer must be removed atsome points (fig. 1). This was donewith relatively sophisticated photo-lithographic steps up to now. Wehave now succeeded in piercing theinsulating layer by laser ablation,which reduces the number of pro-cessing steps to produce the backsurface point contacts by a factor offive. We tested the suitability of twolaser systems:

Fig. 2: Contact point pierced by an excimerlaser in the dielectric passivation layer on theback surface of a highly efficient silicon solarcell.

Fig. 1: Highly efficient solar cell (Passivated Emitter andRear Cell PERC concept). The surface passivation isachieved either with thermally grown SiO2 or a depositedSiNx coating.


**University of Freiburg, Freiburger Materialforschungszentrum FMF, Freiburg

thin contact bars⇒ minimal shading

surface texturing⇒ reduction of reflection +oblique light path

surface layer⇒ surface passivation +internal light trapping

small contact areas⇒ reduced recombination



a KrF excimer laser with a very shortwavelength (248 nm) and a Nd:YAGlaser with a long wavelength (1064 nm). Figure 2 shows a backsurface contact point which wasprepared with an excimer laser.

As silicon nitride absorbs radiation ofthis wavelength very strongly, thepassivation layer is ablated veryselectively. By contrast, the laser rayfrom the Nd:YAG laser, with its longwavelength, penetrates deeply intothe underlying silicon and creates atype of crater in the silicon (fig. 3).

Despite the difference in the ablationresults, the solar cells treated withboth laser systems achieved efficiencyvalues exceeding 20 %. The resultsare only slightly lower than the valuesfor conventionally processed, high-efficiency solar cells.

These high-efficiency cell conceptsallow the wafer thickness to bedrastically reduced without decreasingthe efficiency significantly. Thus, weachieved an efficiency value of 20 %with a 115 µm "thin" wafer ofindustrially relevant Czochralski silicon. An 85 µm thin, highlyefficient Czochralski silicon solar cellis illustrated on the title page. In

addition to the savings in material,another prominent feature of the cells is evident in the picture: they areflexible. This opens up completelynew application fields.

Up to now, we were able to verifynew, high-efficiency cell concepts onlyon a laboratory scale. On the one

hand, this had the disadvantage ofsmall production volumes, whichmeant that the potential costs ofhighly efficient solar cells could onlybe estimated approximately. On theother hand, we were not able tointroduce any automated processingsteps in this context, which in turnwould contribute to cost reduction.

Therefore, we set up a pilot line forhighly efficient solar cells this year andtook it into operation. We identifiedthose processing steps in laboratoryoperation which were particularlytime-consuming, and automatedthem. We developed some of thenew equipment for this ourselves.

An equally important goal for thispilot line is to provide sufficientquantities of highly efficient solar cellsfor the prototype development ofsolar-powered small appliances.Figure 4 shows a silicon wafer with 14highly efficient solar cells. These cellshave been optimised for seriesconnection by shingle mounting, inwhich the solar cells overlap slightly:The main contact bus (horizontalmetal strip in fig. 4) is covered by theadjacent cell. This appreciably reducesshading and wasted area due toempty spaces in the module. Themodule which is illustrated in fig. 4(upper right) was manufactured withthis technology. Whereas this modulealready brings about 60 % morepower than a conventional module infull sunlight, the difference is stillgreater at lower intensities. Withconventional cells, the voltage falls offso rapidly for lower radiation intensity

that significantly more cells arerequired to guarantee the voltagerequired for a specific application.This effect does not occur with ourhigh-efficiency cells. This is decisive inpower supplies for electronic devicessuch as mobile phones, palmtops,etc., which are almost alwaysoperated indoors (see page 51).

Fig. 3: Contact point pierced by a Nd:YAGlaser in the dielectric passivation layer on theback surface of a highly efficient silicon solarcell.

Fig. 4: Highly efficient solar cells on a waferand after shingled connection to form amodule (upper right).



Rapid Thermal Processing of SolarCells

Solar cell production is currentlyaiming to further shorten processingtimes. A clear reduction can beachieved e.g. with the help of RapidThermal Processing (RTP). Extendedprocesses at present can be completedwithin a few seconds when RTP isapplied.

Harald Lautenschlager, Stefan Peters,Volker Radt, Christian Schetter,Roland Schindler

In comparison to monocrystalline cells,the efficiency value of multicrystallinecells is 2 - 3 percentage points lower,depending on the quality of theoriginal wafers. This is true both forlaboratory cells and for industriallymanufactured cells. The lowerefficiency value is attributed to thehigh density of dislocations and grainboundaries, and an inherently higherdegree of contamination with metallicimpurities.

Optimal processing can improvemulticrystalline material, in some casesto the point that it closely approachesmonocrystalline material. This can beachieved e.g. by so-called getteringsteps, in which impurities are removed

from the interior of the solar cell andare thus rendered harmless. However,this is usually associated with longprocessing times, which are difficult tointegrate into industrial production.The simple, conventional solar cellprocess developed in the past atFraunhofer ISE, which includes anintegrated gettering step, had thesame characteristics. In general, thistype of high-temperature processingwith resistance-heated ovens isdescribed as "conventionalprocessing".

Rapid Thermal Processing (RTP)represents a new direction forprocessing. In this technology, thesilicon wafers are heated with light ofshort wavelengths. As thesurroundings of the wafer remaincold, steep heating and cooling rampscan be applied with this method. Incontrast to conventional processing,RTP thus allows very short processingtimes on the order of several seconds.Figure 1 shows the construction of acommercial RTP oven, such as is usedfor microelectronic production. Werecently developed an in-line RTP ovento meet the requirements of thephotovoltaic industry.

Our work has demonstrated thatmonocrystalline solar cells can be

produced with RTP, which are just asefficient as those produced with theslower, conventional process. Forexample, we can produce a solar cellfrom industrial Cz Si with an efficiencyvalue of 17.5 %, applying RTP toachieve an extremely short diffusiontime. The RTP processes applied forthe emitter diffusion and oxidepassivation last less than one minutein total. Further, we succeeded inproducing a solar cell from high-quality float zone silicon with anefficiency value of 18.7 %. In thiscell, a screen-printed aluminium back-surface field for back surfacepassivation was formed by a speciallyadapted RTP process.

For block-cast multicrystalline silicon,however, the efficiency of RTP solarcells is somewhat lower. Surprisingly,this does not apply for ribbon materialsuch as EFG (edge-defined, film-fedgrowth) or RGS (ribbon growth onsubstrate). The cell efficiency valuesfor RGS and EFG silicon are shown infig. 2. In each case, we were able toachieve higher efficiency values withRTP than with the conventionalprocess. The cause is probably theactivation and segregation kinetics ofthe impurities: When the temperatureload is increased, clusters orprecipitates of impurities and otherdefects form. This is indicated in EFGmaterial e.g. by a higher short-circuitcurrent, together with a lower open-circuit voltage. Altogether, shorterprocessing times result in higherefficiency values. These effectsdepend strongly on the particularmaterial and the drawing processapplied in its production.

Fig. 1: Schematic diagram of the RTP oven usedat Fraunhofer ISE.

Fig. 2: Improvement in the efficiency value oflaboratory samples of silicon sheet materialssuch as RGS (ribbon growth on substrate) andEFG (edge-defined film-fed growth) due to theapplication of RTP rather than conventionalprocessing.

wafer

door

N2,O2

reactor block- water-cooled- highly reflective

pyrometer

tungsten halogen lamps

quartz tube

conv. RTP conv. RTP

RGS

effic

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]

EFG14

12

10

8

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2

0



The SIR Process for Energy-SavingProduction of Crystalline SiliconThin-Film Solar Cells

The energy consumption is asignificant cost factor in theproduction of crystalline silicon thin-film solar cells. Fraunhofer ISEcontributed to the invention of thenew SIR process, which can reducethe energy costs considerably.

Achim Eyer, Stefan Reber,Daniela Oßwald*, Albert Hurrle,Norbert Schillinger, Sandra Bau**,Andreas Roosen***,Christiane Lutz***, Hans-Jürgen Pohlmann****

In the production of crystalline siliconthin-film solar cells, not only thematerial costs but also the energycosts play an important role. In theso-called "high-temperature ap-proach", there are two energy-intensive production steps withtemperatures of 1400 °C and higher:firing the ceramic substrate andmelting for recrystallisation.

In the SIR process - SimultaneousInfiltration and Recrystallisation - thefiring and recrystallisation are com-bined in a single step. This makessignificant energy and thus costsavings possible.

The basic idea underlying the SIRprocess is shown in more detail in fig. 1: A ceramic "green tape" of

silicon, silicon carbide and carbon withan intermediate layer serves as thesubstrate. Next, the substrate iscoated with silicon, either as siliconpowder or by a deposition process.Then follows the decisive SIR processstep: A narrow strip of the compoundlayer structure is heated to above themelting temperature of silicon in azone-melting oven, and is simul-taneously "scanned" along thesample. The single melting step hastwo effects: On the one hand, thefine-grained silicon is recrystallisedabove the intermediate layer and acoarse-grained silicon film results. Onthe other hand, the liquid silicon inthe green tape reacts with the inte-grated carbon to form silicon carbide,converting the green tape to ceramicand thus hardening it. A "waferequivalent" is formed by epitaxialdeposition of silicon onto the recrys-tallised silicon. It can then be pro-cessed to a solar cell with conven-tional manufacturing procedures.

In co-operation with the University ofErlangen-Nürnberg and with supportfrom TeCe Technical Ceramics GmbHand Shell Solar, we applied the idea ofSIR processing in practice. TheUniversity of Erlangen-Nürnbergdeveloped a procedure to produce theceramic green tapes. The tape-castingmethod used allows large areas oftape to be produced quickly andinexpensively. The largest tapes whichwere produced there had a length of2 m and a width of 25 cm (fig. 2).

The tape composition was successivelyoptimised in Erlangen in co-operationwith Fraunhofer ISE.

We carried out all the subsequentprocessing steps up to solar cellprocessing and characterisation. Weproduced solar cells with areasbetween 1 cm2 and 25 cm2. As anexample, fig. 3 shows an SIR solar cellwith an area of 5 x 5 cm2. After onlya short period of development, thebest efficiency values for the solarcells were already about 6.4 %.

Fig. 2: Green tape of Si-SiC-C, which was produced by tape-casting.

Fig. 3: SIR solar cell with an area of 5 x 5 cm2.

Fig. 1: Schematic presentation of the processing steps (from left to right) for production of acrystalline silicon thin-film solar cell according to the SIR process.


** PSE Projektgesellschaft Solare Energiesysteme mbH, Freiburg

*** University of Erlangen-Nürnberg**** TeCe Technical Ceramics GmbH

Intermediatelayer- separates green

film and nucleation layer

Silicon- on the inter-

mediate layer- in the green film

for reactive binding

SIR process- to recrystallise

the Si layer- for reactive

binding

Solar cell process- deposition of the photo-

voltaically active layer- p/n-junction production

and metallisation

Si-SiC-C green film- produced by

“tape-casting”- coked



Front-Surface Contacting forCrystalline Silicon Thin-Film SolarCells with Screen-Printing Processes

If crystalline silicon thin-film solar cellsare produced on electrically insulatingsubstrates, the contacts must all bemade from one side. Screen printingis the appropriate, industrially relevantstandard technology.

Dominik Huljic, Ralf Lüdemann,Gernot Emanuel*, Sebastian Schaefer,Daniel Biro, Stefan Reber

The films for crystalline silicon thin-film solar cells are usually depositedon inexpensive substrates. Thesubstrate material is often electricallyinsulating. This can be a major advan-tage: by integrating the series connec-tion of individual solar cells of stripform on the substrate, the productionof strings of large, series-connectedcells can be avoided. However, thisproperty can also be a disadvantage:the electrically insulating substratemeans that the solar cell cannot becontacted in the conventional waywith a base contact on the back sur-face and a metal grid for the emittercontact on the front surface. Bothcontacts have to be made on theilluminated front surface.

The best-known concept is that of the"interdigitated grid" (fig. 1). Themost obvious difference to conven-tional cells is the selective emitterstructure: The emitter regions on thesurface do not cover the whole area,but alternate with base regions.

We implemented this type of selectiveemitter structure with interdigitated-grid contacts several years ago verysuccessfully with the help of photo-lithographic and masked diffusionsteps. Excellent efficiency values of19.2 % proved the high potential forcrystalline silicon thin-film solar cells.

However, the process used then wastoo expensive for industrial massproduction. Thus, we wanted toimplement the interdigitated-gridconcept with the quick and inexpen-sive screen-printing process.

We tested three approaches (fig. 2):Buried Base Contact (BBC), GridAligned Trenching (GAT) and Patter-ned Emitter (PE). None of the pro-cesses require expensive photo-lithographic or masked diffusion steps.The screen printing replaces thecomplex evaporation technology withits need for masks. The PE conceptdiffers from the others in that the

emitter is structured simultaneouslyduring the emitter diffusion process.It is thus the concept requiring thefewest processing steps. However,substantial short circuits can formbetween the emitter and base regionsif masking steps are not applied. TheGAT concept also includes processingsteps which can result in similarshunts. By contrast, the BBC conceptis much less sensitive to processingtolerances. This was demonstratedclearly by the electrical properties ofthe solar cell samples producedaccording to the three differentconcepts (fig. 3).

In the first tests with multicrystallinesilicon wafers, the BBC conceptresulted in efficiency values of up to7.6 %. The aluminium paste used forthe base metallisation, which had notyet been optimised, caused relativelylow fill factors of around 50 %. Byfurther optimising the processes app-lied, in particular the screen printingof the base grid, we intend to explorethe efficiency potential of the BBCconcept, which certainly has not beenexhausted yet.


Fig. 1: Schematic diagram of a thin-film solarcell with front-surface, "interdigitated grid"contacts.

Fig. 2: Processing schemes for the threedifferent concepts to implement a screen-printed interdigitated grid.

Fig. 3: Test solar cell with screen-printed, front-surface contacts on a multicrystalline siliconwafer.

emitter emittergrid

basegrid

baseinsulatingintermediatelayer

anti-reflec-tivecoating

BBC GAT PEhomogeneous emitter diffusion

etching clear thebase regions

screen-printing of emitter and base metallisation

rapid thermal firing

selective emitter diffusion

etching of in-sulating grooves

deposition of silicon nitride anti-reflective coating

optional: insulationby etching theemitter

hydrogen passivation

insulating substrate



III-V Solar Cells

We apply MOVPE, LPE and gas phasediffusion technology to form pnjunctions in different combinations ofmaterials. The aim is to make solarcells with efficiency values > 30 %and photovoltaic cells for specialapplications such as laser powertransmission, thermophotovoltaics orspace.

Carsten Agert, Rolf Beckert,Andreas W. Bett, Frank Dimroth,Mathias Hein, Vladimir Hinkov,Gerrit Lange, Peter Lanyi, Gergö Létay,Matthias Meusel, Sascha van Riesen,Ute Schubert, Oleg Sulima

Development of monolithic tandemcells using MOVPEWe use an industrially compatibleMOVPE system from the AIXTRON AGcompany to produce monolithictandem cells. We develop processeson the AIX2600G3 which ourindustrial partners can apply directly inproduction.

The standard combination formonolithic tandem cells isGa0.51In0.49P/GaAs on a Ge substrate.We suggested the use of GaInAsinstead of the GaAs material, as thetheory indicated that higher efficiencyvalues could be achieved. Wesuccessfully developed this conceptfurther this year. For space appli-cations, we achieved an efficiencyvalue of 24.1 % (AM0 spectrum) witha Ga0.35In0.65P/Ga0.83In0.17As tandemcell. Initial investigations with protonradiation demonstrated very goodstability. Using our concentrator cellsof the same material, we achie-ved aworld record: an efficiency value ex-ceeding 31 % at around 300-foldconcentration of solar intensity. Evenwith 1300 suns, the efficiency value is

still above 29 % (fig. 1). We havealready constructed the first testmodules with these concentrator cells.

Construction of concentratormodulesIn order to test our tandem solar cellsalso in their foreseen applications, weconstructed modules including Fresnellenses and concentrators (see also thetitle page). The aim is to test the in-stalled concentrator cells over a longerperiod of time under outdoor con-ditions. The modules have a concen-tration factor of 120 at present. Weapply technology for the productionwhich was developed jointly with theIoffe Institute in St. Petersburg, Russia.To produce the lenses, we use PMMAmatrices, with which the Fresnel lensstructure is embossed in a 2 mm thinsilicone coating on glass. It hasbecome evident that the quality of thelenses prepared in this way dependsalmost entirely on the quality of theindividually diamond-cut matrices.

We mounted the III-V concentratorcells, which we had developed, insmall test modules with an aperturearea of 64 cm2 for the outdoormeasurements. A test module withfour Ga0.35In0.65P/Ga0.83In0.17Astandem solar cells achieved anefficiency value of 24.8 % (fig. 2).

Development of PV cells for laserpower transmission"Laser power transmission" meanswireless power supply with laser light.Laser light is sent to a consumer e.g.through an optical fibre and is thenconverted there to electricity with a PVcell. This makes a safe power supplyfeasible e.g. in explosive atmospheres.It is also possible to transmit data froma sensor via an optical fibre. We have

developed photovoltaic cells speciallyfor this application, which have adiameter of only 1 mm and can beintegrated into commercially availabletransistor housings. The mono-chromatic radiation means that veryhigh cell efficiency values can beattained. The cells we producedachieved an efficiency value exceeding50 % for a radiation intensity of 6W/cm2 (fig. 3). Better cells for this

Fig. 1: Efficiency value of aGa0.35In0.65P/Ga0.83In0.17As tandem cell underconcentrated sunlight. Measurements fromFraunhofer ISE and NREL, Golden, USA arecompared. The measurements differ essentiallyonly in the short-circuit current under 1xAM1.5d. The concentration value is obtained,assuming a linear short-circuit current response,from Isc(C)/Isc (at 1 sun).

Fig. 2: Characteristic curve of a test moduleconsisting of a Fresnel lens and fourGa0.35In0.65P/Ga0.83In0.17As tandem solar cells.Specifications: η = 24.8 %, Voc = 4.25 V, Isc = 347 mA, FF = 84.4 %; Pin = 825 W/m2 ,Tamb = 15.6 °C. The aperture area is 64 cm2.

η = 30.0–31.3 %for C = 300

concentration ISC/ISC (C= 1*AM1.5d)

currentpower

voltage [V]

effic

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]cu

rren

t [m

A]

time:

pow

er [

mW

]

flash simulator (NREL)continous light sim. with lens (ISE)



power range have not been reportedin the literature. In the incident laserpower range above 10 W/cm2, sig-nificant improvements can still beexpected.

Development of "low band-gap"photovoltaic cellsGas phase diffusion process toproduce pn junctions: Materials withsmall band gaps (e.g. GaSb, GaInAsSb,GaInSb) are used in thermophoto-voltaic generators (see page 53). We apply Zn gas phase diffusiontechno-logy to create pn junctions inthese materials. This year, we contin-ued our co-operation with theAstroPower company, USA and theResselaer Polytechnic Institute, USA.We succeeded in developing

photovoltaic cells with a spectralresponse up to an IR wavelength of 3µm. Figure 4 shows the externalquantum efficiencies of the followinglayer sequences:- p-InAsSbP (Zn diffused) / n-InAsSbP

(LPE) / n-InAs (substrate) epitaxial layer from AstroPower

- p-GaInSb (Zn diffused) / n-GaInSb (substrate); substrate from Resselaer Polytechnic Institute

- p-InGaAsSb (Zn diffused) / n-InGaAsSb (LPE) / n-GaSb (substrate) epitaxial layer from AstroPower

- p-GaSb (Zn diffused) / n-GaSb (substrate)

Fig. 3: Efficiency value of a PV cell withmonochromatic radiation at 810 nm as afunction of the incident radiation density.

Fig. 4: External quantum efficiency of PV cells without an anti-reflective coating (ARC),produced from different low band-gapsemiconductor materials. Only the GaSb cell had an ARC.

Fig. 5: Oxygen concentration as a function ofthe aluminium concentration for various sourcematerials for MOVPE.

Fig. 6: External quantum efficiency of GaSband (AlGa)(AsSb) photovoltaic cells without ananti-reflective coating, in which the pnjunctions had been grown with MOVPE.

MOVPE of group III antimonidesIII/V semiconductors containingantimony on GaSb substrates allowlattice-matched growth of crystals inthe direct band-gap range between0.5 eV and 1.1 eV. This means thatsolar cells of these materials areinteresting both for thermophoto-voltaic applications (see page 53) andalso for stacked systems of the highestefficiency. The specific properties ofcrystals containing antimony present aparticular challenge for the MOVPEprocess. The selection of suitablemetal-organic source materials is acritical point for compounds con-taining aluminium. We investigatedthe suitability of tri-tertiary butylaluminium (TTBAl) and dimethylethylamine alane (DMEAA) fordepositing antimonides containingaluminium in our AIX2600G3 MOVPEsystem. The introduction of oxygenimpurities into the material is of greatinterest. We were able to demon-strate that the purity achieved withDMEAA was clearly superior to thatwith TTBAl (fig. 5).

Drawing on the results from MOVPEfor bulk crystals, we have begun todevelop electronic componentstructures. We have already devel-oped solar cells from binary GaSb,which function very well (fig. 6).Similarly, we were able to produce thefirst solar cells from a material with a1 eV band gap, the system(AlGa)(AsSb), also shown in fig. 6.The development of a material withthis band gap is of greatest interest inother areas of III/V MOVPE (e.g.semiconductor lasers).

cident laser power density [W/cm2] Al concentration xAl

effic

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]

O c

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tion

[ato

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cm3 ]

wavelength [µm]

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triteritiary batyl aluminiumdimethyl ethylamine alane

GaSb solar cell

(AlGa)(AsSb) solar cell

InAsSbPInGaAsSb

InGaSbGaSb (with ARC)



Laboratory and Service Centre inGelsenkirchen

The need to use increasingly largesubstrates and in-line processes with a high throughput in photovoltaicproduction makes it more difficult totransfer laboratory results into produc-tion steps. As a response to thisdevelopment, Fraunhofer ISE hasestablished an industrially relevantlaboratory and service centre inGelsenkirchen.

Christophe Ballif, Dietmar Borchert,Marco Gräßel, Stefan Peters,Alexander Poddey, Roland Schindler,Wilhelm Warta, Gerhard Willeke,Thomas Zerres

In the newly founded Laboratory andService Centre in Gelsenkirchen, wecarry out our research underconditions similar to those in industry.Almost a complete processing line isavailable, where production as in afactory and experimentation as in alaboratory can be carried out. Highlyflexible, state-of-the-art, in-lineprocessing equipment allows solar cellmanufacturers to reproduce andimprove their processes in the"laboratory", without having tointerrupt industrial production. Newprocesses can also be tested andoptimised there, without the dangerof disturbing production.

To this purpose, the "clean room" isequipped with a wet-chemistry bench,an in-line diffusion furnace with arapid thermal processing module (seepage 58), an in-line sintering furnaceand an in-line PECVD unit. Substrateswith dimensions up to 150 mm x 150mm can be processed withoutdifficulty.

Measurement technology, whichenables the characterisation of theraw material, the individual processing

steps and the final solar cell, is avail-able to support the process develop-ment or optimisation.This measure-ment technology can also be used forfast trouble-shooting while productionis running. The many different typesof measurement technology, togetherwith comprehensive know-how andfurther special procedures atFraunhofer ISE in Freiburg, ensurequick response times if problems arise.

It is not only the photovoltaic industrywhich can benefit from the processingand measurement technology. Othersemiconductor manufacturers can beassisted in particular aspects of semi-conductor production or characteri-sation. Extensively automated, large-area measurement technology forsubstrates up to 6", or in some cases8", means that very specific processmonitoring of small series is possible.

Facilities:Material characterisation:- research microscope- microwave reflection- spectrometer- ellipsometer- film resistance mapping

Cell characterisation:- solar simulator- dark characteristic measurement

stand- filter monochromator- stripping Hall- SR-LBIC (spectrally resolved light

beam induced current)- thermography

ModuleTechnology:- permanent outdoor test stand

Processing technology:- 100 m2 clean room- wet-chemistry bench

- spin coater- evaporating unit- in-line sintering furnace- in-line diffusion furnace with RTP

module- in-line PECVD system with a

deposition area of 450 mm x 450 mm

Services- substrate characterisation- contamination control- process monitoring- determination of diffusion

profiles- characterisation of solar cells- processing of large-area silicon

substrates, also as an in-line process

- reproduction and optimisation of in-line processes

- support to semiconductor manufacturers, in particular on questions concerning semiconductor production or characterisation

- deposition of silicon nitride and silicon oxide on commission to clients

- etching of silicon, silicon nitride and silicon oxide on commission to clients

- direct access to know-how at Fraunhofer ISE, Freiburg

- fast response times

Fig. 1: Characterisation of anti-reflectivecoatings with the ellipsometer.


ISE CalLab - Precision Measurement for Photovoltaics

Module measurement stand of "ISE CalLab", the photovoltaiccalibration laboratory at Fraunhofer ISE, which is one of theinternationally leading centres offering these services. High-quality facilities allow photovoltaic cells and modules of all types to be measured.


The scientific know-how is constantlykept up-to-date by research and in-strument development at FraunhoferISE, and almost 20 years of experiencewith photovoltaic systems brings inthe practical side. The orientation ofISE CalLab towards application is also demonstrated by its home page,http://www.callab.de. It providesinformation on technical details, gives prices and allows orders to be placed on-line.

One special feature of ISE CalLab isits bandwidth: The samples can be

commercial silicon solar cells, dye-sensitised solar cells, thin-film tech-nology or multiple-junction cells for1000-fold concentration or evencomplete photovoltaic modules - ISECalLab can measure any object whichconverts light to electricity via thephotovoltaic effect. Researchers fromall over the world come to Freiburgwith their new developments, for ameasurement result from ISE CalLab isinternationally recognised at con-ferences and in the scientific journals.

ISE CalLab - PrecisionMeasurement for Photovoltaics

The characterisation of solar cells andphotovoltaic modules plays a decisiverole not only in research and develop-ment but also for production. It isequally indispensable for the compari-son of products from different manu-facturers as for the dimensioning andauthorisation of photovoltaic systems.

The Photovoltaic CalibrationLaboratory at Fraunhofer ISE (ISECalLab) is one of the internationallyleading laboratories in measurementtechnology for photovoltaics - withcontinuing quality assurance guaran-teed by measurement comparisonsand harmonisation with the Physi-kalisch-Technische Bundesanstalt(National Standards Laboratory) inBraunschweig. Not only internation-ally renowned manufacturers, but also the TÜV Rheinland have theirreference cells measured by ISECalLab.

The success of the calibrationlaboratory results from the funda-mental aim of the Fraunhofer Societyto combine research and applications:

Contact persons:

Cell calibration Dr Wilhelm Warta Tel.: +49 (0) 7 61/45 88-1 92E-Mail: [email protected]

Jürgen Weber Tel.: +49 (0) 7 61/45 88-1 08E-Mail: [email protected]

Module Georg Bopp Tel.: +49 (0) 7 61/45 88-2 40measurement E-Mail: [email protected]

Instrument Dr Heribert Schmidt Tel.: +49 (0) 7 61/45 88-2 26development E-Mail: [email protected]

Stefan Brachmann Tel.: +49 (0) 7 61/45 88- 1 44E-Mail: [email protected]

Marketing Ulf Groos Tel.: +49 (0) 7 61/45 88-2 02E-Mail: [email protected]

http://www.callab.de.



An Overview of the PhotovoltaicCalibration Laboratory

The organisation of the PhotovoltaicCalibration Laboratory “ISE CalLab”has been restructured to makes itsservices more efficient and transpar-ent. In this contribution, an overviewwill be given of the three main areas,solar cell calibration, module measure-ment and instrument development.

Georg Bopp, Ulf Groos,Heribert Schmidt, Wilhelm Warta

Our expertiseThanks to our long years of practicalexperience in PV measurementtechnology, we can offer completesolutions to problems. In providingthese services, our primary goal is toprovide our clients with the solutionwhich is most useful to them:

- reliable results, which are guaranteed by regular participation in round-robin tests with other internationally recognised measurement laboratories

- compliance with international standards in all calibration steps andin the use of reference elements andmeasurement facilities

- continuous further development of the measurement procedures in accordance with research activities at Fraunhofer ISE

Our services- measurements for production

control, testing of development results, preparation of product comparisons and ensuring guaranteed specifications

- intensive and competent advice on individual measurement requirements

- rapid, non-bureaucratic processing- strict confidentiality guaranteed- regular maintenance and testing of

our measurement equipment

Cell calibrationWe undertake extensive measurementseries for characterising solar cells,detectors and PV mini-modules:- calibration of standard solar cells

(c-Si, a-Si, CIS, CdTe)- calibration of dye-sensitised solar

cells and IR solar cells- calibration of concentrator cells and

tandem cells- calibration of reference cells- spectral response measurement- determination of the annual

efficiency value of solar cells

Module measurementWe characterise PV modules of allconstructions up to dimensions of 2 x 2 m2:- module measurement with a pulsed

solar simulator- outdoor module measurements

- determination of the NOCT temperature and power output

- measurement of the angular and temperature dependence of the module parameters

- determination of the annual efficiency value of PV modules

Instrument developmentWe develop and construct highlyaccurate measurement equipment tocharacterise solar cells and PVmodules.- steady-state radiation facility for cell

and module calibration- outdoor measurement stands- pulsed solar simulator for cell and

module calibration- spectral measurement facility for

cells and mini-modules- WPVS reference cells- instruments for quality assurance in

module production- software development for

measurement data analysis

Our measurement facilitiesISE CalLab is equipped with high-quality measurement facilities to meetdemanding measurement challenges.- class A steady-state solar simulator(AM 1.5; AM 0)- simulator with three light sources- concentrating solar simulator

(up to 1200 suns)- pulsed solar simulator (AM 1.5)- outdoor measurement stand- filter monochromator

(300 nm to 1400 nm)- grating monochromator

(300 nm to 1800 nm)- various spectroradiometers- measurement facility for dye-

sensitised solar cells

InternetFor more detailed information, simplyconsult our Internet site athttp://www.callab.de. From there,you can also place measurementorders simply by e-mail.

Fig. 1: Solar module and reference cellmounted for measurement with the pulsedsolar simulator.

http://www.callab.de.



Calibration Reduces Costs forPhotovoltaic Electricity

The work in ISE CalLab spans a widerange from fundamental to appli-cations-orientated measurements. We present the characterisation ofsolar cells with highest efficiencyvalues and the measurement ofmodules as examples.

Georg Bopp, Wilhelm Warta,Rolf Beckert, Matthias Meusel,Tomislav Paradzik*, Gerald Siefer,Jürgen Weber

Multiple-junction solar cellsare currently overtaking the powersupply field in space. With efficiencyvalues exceeding 30 % and concen-tration of the sunlight by more than afactor of 1000, these cells will alsobecome extremely interesting for ter-restrial applications in future.Fraunhofer ISE is at the internationalforefront in developing new structuresfor these cells (see page 61).

ISE CalLab is one of the fewlaboratories around the world which isable to determine the efficiency ofthese cells. Internationalcomparability is important not only forresearch: A difference of only a fewpercentage points in the efficiencyvalues, if multiplied by highproduction volumes and highefficiency values, can have drasticeffects on the costs of solargenerators.

Solar cells with several pn junctionsare very sensitive to details of theradiation spectrum. This makes itdifficult to determine the efficiencyvalue correctly under standard

measurement conditions. Slight shiftsbetween the red and blue portions ofthe spectrum can strongly affect theperformance of the complete cell ifone sub-cell is limiting the totalcurrent, which must flow through allcells due to the monolithic seriesconnection.

To date, manufacturers of solarsimulators have not succeeded ingenerating the standard spectrum soexactly ("close match" simulator) thatmeasurement errors due to spectraleffects are practically eliminated. Theonly accurate measurement methodknown consists of first measuring thespectral response of all the sub-cells,so that the operating state of the testcell under the standard spectrum andthe simulator spectrum can be com-pared. The internationally practised,iterative procedure to match theoperating state under the simulatorspectrum to that under standard testconditions is very time-consuming.

We have developed a much shortermethod, which replaces the wholeiterative procedure by the solution ofa system of equations. It provides thesettings needed for our multiple-source simulator in a single step.

To check the reliability of ourcalibration, we compared ourmeasurements with those from NREL,USA - beside ISE CalLab, one of thefew laboratories around the worldwhich can calibrate tandem solar cells.The values for not only the spectralresponse but also the efficiency valueagreed very well.

Measurement of high-efficiency,large-area solar modulesSolar modules which are constructedof high-efficiency silicon, copperindium diselenide (CIS) or cadmiumtelluride (CdTe) cells, are difficult tomeasure correctly due to their highbarrier layer capacity. In addition,large-area facade modules demandhomogeneous illumination. Solarmodules with an area of 2 x 2 m2 canbe illuminated homogeneously withthe Class A pulsed solar simulator atFraunhofer ISE. By applying themultiple-flash technique, also solarmodules with a high barrier layercapacity can be measured accurately.

The standard measurement, with anaccuracy of ±5 %, costs less than astandard 50 Wp module today. Thus,even for a 1 kW system, an initialmeasurement costs appreciably lessthan e.g. a ten-percent safety margin,which planners and installers oftenadd to ensure "guaranteed yields"when they dimension their photo-voltaic systems.

Fig. 1: Comparison of the measured values forthe external quantum efficiency of the sub-cellsof a triple solar cell from ISE CalLab and NREL.The high spectral resolution of the ISE CalLabmeasurement allows interferences to be seenfor the lowest cell.


upper middle lower cell

EQE

[%]

100

80

60

40

20

0400 600 800 1000 1200 1400 1600 1800

wavelength [nm]

solid lines: ISEmeasurementssymbols: NRELmeasurements



Off-grid power with solar energy. Fraunhofer ISE is participating in numerous international projects on rural electrification. Thework concentrates on optimising system components and qualityassurance on site. The users are also involved in the project workwith training sessions and initiation of micro-financing concepts.The photo shows a man in Indonesia transporting his Solar HomeSystem before installation.


The conventional lead-acid battery isstill the workhorse of photovoltaicsystems technology. We develop newproducts for the battery industry andoptimised charging procedures forsolar applications. This results notonly in higher usable storagecapacities and efficiency values, butalso extended lifetimes and thusreduced costs.

Clean drinking water is becoming anincreasingly high priority. It affectsnot only the well-being of theconsumers, but also the economicstrength of a country. Often surfacewater is drunk without furthertreatment, with two thousand millioncases of illness annually being theresult. Photovoltaics can providecheap and reliable electricity fordisinfection with UV lamps, which donot alter the natural taste of thewater.

When thousands of millions of peopleare affected, it means that there isalso a potential market of severalthousand million US dollars. We areinvolved nationally and internationallyin promoting quality assurance andsustainable market development. Inthis capacity, we advise governmentsaround the world and accompanymarket introduction programmes withour technical, sociological andeconomic expertise.


Whether power is needed for atelecommunications repeater inGerman mountains or for light in amud hut in Morocco: Photovoltaics isoften the cheapest alternative if therenot a grid nearby. This is equally validfor the two thousand million peoplein threshold and developing countriesand for the 400,000 houses inEuropean mountainous regions.

In addition to Solar Home Systems,which with their rated power of 50 Wp represent the smallest "ray ofhope" for rural areas in developingcountries, we have been investigatingphotovoltaic systems of 1 - 20 kWpwith increasing intensity for off-gridpower supply. They make additionalcommercial activities or the operationof a clinic feasible. With regard toenergy economics, they are interestingas the smallest unit in a decentralised,inter-connected grid. In grid-independent village power supplies,distribution of the electricity is acontentious issue. Our approach ofdeveloping the technology togetherwith the local users has proven to bebeneficial here. This is equally true formountaineering lodges, where wehave provided advice on planning,energy concepts and monitoring, insome cases for more than a decadenow.

Contact persons:

Systems technology Georg Bopp Tel.: +49 (0) 7 61/45 88-2 40 E-Mail: [email protected]

Sociology Dr Petra Schweizer-Ries Tel.: +49 (0) 7 61/45 88-2 28 E-Mail: [email protected]

Economics Rana Adib Tel.: +49 (0) 7 61/45 88-2 81 E-Mail: [email protected]

Supply and purification Orlando Parodi Tel.: +49 (0) 7 61/45 88-2 81 of drinking water E-Mail: [email protected]

Storage systems Dirk Uwe Sauer Tel.: +49 (0) 7 61/45 88-2 19 E-Mail: [email protected]



Strategies for Grid-IndependentVillage Electricity Supply - TheExample of Rambla del Agua

At present, we are co-ordinating theinstallation of 17 photovoltaic villagepower supplies. Engineers andpsychologists are working withtechnical and social concepts on theoptimised use of community facilities,and are implementing these togetherwith local enterprises.

Georg Bopp, Claudia Casper*,Johannes Koops, Petra Schweizer-Ries, Gisela Vogt

Since January 2000, we have been co-operating with partner institutionsfrom Spain, France, Portugal andSwitzerland on the construction andfurther development of community-based, off-grid village power suppliesin Spain.

In addition to the co-ordination, weare responsible for the followingtasks:- technical further development of

information transfer and energy distribution; an infobus transmits

data on the energy consumption of the individual households

- organisational and social support of the systems and their users to facilitate permanent operation

We are implementing research resultsfrom the engineering and socialsciences directly in the demonstrationproject. While we are concernedprimarily with the scientific aspects,the Spanish company, TTA, and theUniversity of Vigo are constructing thedemonstration systems in Spain andLatin America.

The work up to now has concentratedon socio-technological measures inthe village of Rambla del Agua inAndalusia. There, 38 households havebeen supplied since 1997 with 230 VAC electricity from a system com-prising a 10 kWp PV generator, a3660 Ah/48 V battery and a 10 kVAback-up diesel generator.

We conducted 15 interviews withusers of photovoltaic electricity, 3 withnon-users and a further 6 interviewswith key persons involved in theoperation of the PV system at variouslevels.

The interviews indicated:- The users are basically very satisfied

with the power supply, but would welcome further technical improvements.

- There is great interest in more information on the system and its use.

- The household displays on "electricity distribution" and demand adaptation are not often used.

- Identification with the system is verystrong in the village; the residents accept complete responsibility for service and maintenance.

We improved the automatic transferof information on the status of thephotovoltaic system. The statusinformation determines the currentelectricity tariff via an energymonitoring instrument, and thusinfluences the user behaviour. Errorsin the data transfer caused faults inthe energy monitoring instruments;they were no longer able to fulfil theirpurpose. We introduced signalamplifiers, which rectified the errors.

In addition, we supported theorganisation of a solar festival (fig. 1).The "Fiesta del Sol" was important tothe whole process: It drew theattention of neighbours andpoliticians to the new technology,reinforced the identification of thevillagers with their PV system andraised awareness about its sustainableuse.

Further research work within thisproject, which is supported by the EU,will concentrate on another village.New technical and organisationalmeasures are intended to guaranteepermanent operation and anoptimised distribution of energy there.

Fig. 1: Solar festival in Rambla del Agua,Andalusia. * free-lance



Village Power Systems in Indonesia

We conducted sociological andtechnical investigations in threeIndonesian villages with centralphotovoltaic village power supplies.After staying in each village for severaldays, the investigation team, withGerman, French and Indonesianmembers, introduced technical andorganisational improvements.

Michael Müller*, Klaus Preiser,Petra Schweizer-Ries, Sebastian Will,Birgit Uenze

We investigated the functionality andacceptance of three central photo-voltaic village power supplies inIndonesia. Two of them had beeninstalled by a French consortium in co-operation with the Ministry for Trans-migration in Kalimantan and Sulawesi.They are operated according to thepre-payment scheme, which limits thesupply of power to individual house-holds and is based on the sales ofenergy units. The third system, whichwas equipped with Australian com-ponents, had been constructed by theIndonesian Ministry for TechnologyBPPT in Java. It did not include a pre-payment scheme.

We investigated the technical oper-ation of all systems and interviewedusers as well as those persons respon-sible for the maintenance, operationand electricity distribution in thevillage (figures 1 and 2). We came tothe following conclusions:- The French village power systems

operate well. Only the satellite datatransfer, allowing remote monitoringfor research purposes, occasionally causes problems.

- The pre-payment scheme has the effect that much less electricity is

used than originally planned. The users pay for their energy units in advance.

- The distribution of electricity was regarded as being fair in principle.

- Several inhabitants did not understand how the pre-payment scheme worked and wired bypasses to the meters.

- Operating weaknesses in "charging" the pre-payment systems additionally reduced the acceptance.

- Both the users and the Indonesian project managers would like to be more involved in the French project.

- The system on Java, with unrestricted access of the users to power and energy, is hopelessly overloaded and often has to be repaired.

- Measures to control the electricity consumption, such as subsequently installed power limiters, led to acceptance problems.

- Technical staff to operate the systemand a village committee to organise the consumption were present in each village. Rules for usage are being prepared.

Together with the Indonesianpartners, we implemented thefollowing measures for one of theFrench systems:- correction of minor technical faults- raising awareness of usage and

energy consumption with the aim ofcontrolling the increase in demand and discouraging bypasses to the meters

- involving the local government to assume responsibility for the technology at the end of the project

- preparation of a strategy for permanent use of the system, together with the future Indonesian owners

The conclusion to this project, whichwas supported by the EuropeanUnion, is the evaluation of thesemeasures and the preparation ofrecommendations for the introductionof future PV hybrid systems in ruralareas of Indonesia.


Fig. 1: Investigation of a technical system: The photo shows on-site measurement ofphotovoltaic strings in operation. Themeasurements are made by an Indonesian staff member.

Fig. 2: Interview with a village inhabitant: With the help of staff from the University ofIndonesia, we were able to conductstandardised and open interviews with 50people from each village. The analysis wasbased on written records and tape recordings.



Purification of Drinking Water withPhotovoltaics for Remote Areas

Systems and methods to purifydrinking water are available all overthe world. Despite this, about 5million people die every year fromdiseases which are transmitted viadrinking water. Together withpartners from Latin America andSpain, we have developed approachesfor purifying drinking water andimplemented them in five pilotvillages.

Orlando Parodi, Klaus Preiser,Petra Schweizer-Ries

Why, when water treatment withchlorine, ozone and UV radiation iswidely known, are there still abouttwo thousand million cases ofdiarrhoea each year caused bydrinking water? We started the EUproject on "Clean Water with CleanEnergy" with this question. Surveys in Morocco and 10 LatinAmerican countries revealed thefollowing information:- In rural regions of developing

countries, drinking water is often drawn from surface sources which are anthropogenically polluted.

- This water is usually not disinfected before consumption. From the consumers' perspective, the hygienicaspects of drinking water are secondary to taste, supply reliability and convenience.

- Rural regions often lack not only intact drinking water and sewage systems, but also electricity.

- Regulations on drinking water quality exist in almost every country of the world, but they are seldom enforced in rural areas.

Commercially available chlorinationsystems, UV devices and systemsbased on the principles of anodicoxidation or microfiltration were alldeemed to be fundamentally suitablefor the boundary conditions listedabove, but none of the tested systemscould meet all the necessaryspecifications. Thus, we developednew, appropriate, PV poweredsystems. Finally, five different, energy-optimised systems were installed infive villages: Different dosing systems

for sodium hypochloride, anelectrolysis cell to produce chlorinegas and a UV system.

The fact that the inhabitants of mostof the pilot villages now actuallyconsume hygienically acceptabledrinking water results from theinteraction between the newtechnology and non-technical factors:- At the beginning of the project,

there was already a desire for clean drinking water or it was aroused by health education.

- Negative effects of disinfection, such as a change in taste, were largely avoided.

- The introduced technology was robust, easy to handle, largely automated and required little maintenance. Responsible persons were involved at the village level and within the appropriate government bodies.

After two years of operation, all ofthe systems are functioning reliably,without any breakdowns.

The results of the project on "CleanWater with Clean Energy" demon-strate that photovoltaically poweredsystems can make an importantcontribution towards supplying ruralareas of developing countries withhygienically acceptable drinking water,if the technology and the introductionmethods are chosen appropriately.We will therefore continue to developsuch systems and methods to intro-duce them.

Fig. 1: Clean drinking water cannot be takenfor granted in developing countries.

Fig. 2: San Antonio de Agua Bendita inMexico: Disinfection of drinking water usinga PV powered electrolysis cell.



Monitoring by Fraunhofer ISEMaintains High Quality Standardsfor Solar Systems on MountainLodges

Fraunhofer ISE has already been co-operating with the GermanMountaineering Club (DAV) for ten years in the application of solarenergy to mountain lodges. Initially,there were only a few technicallymature charge controllers and inver-ters on the market, so that theemphasis was on technologicaldevelopment and practical tests.Today, system optimisation, standard-isation and quality assurance are theprimary aspects. The Institute nowsupports about 30 lodges with itsmonitoring programme.

Klaus Kiefer, Georg Bopp,Martin Schulz*, Petra Schweizer-Ries,Eberhard Rössler*

In the "EURALP" joint project, whichis funded by the Commission of theEuropean Union, 17 off-gridphotovoltaic systems on mountainlodges belonging to the DAV arebeing monitored and the measure-ment results analysed. This projectallows valuable knowledge to begained on the optimal interactionbetween system components such as the solar generator, storage unitand electric appliances.

On commission to the DAV, we areco-ordinating the technical aspects ofthe project with our European part-ners, the Austrian MountaineeringClub (OEAV) and the Spanishconsumer association SEBA. Theprojects which have already beencompleted are located in the Austrianand German Alps and the SpanishPyrenées.

All of the mountain lodges whichwere equipped as part of the projectare electrically autonomous systems,as they are not connected to thepublic grid. The photovoltaicgenerator supplies most of theelectricity in almost all of the systems.Diesel generators or wind generatorsincrease the supply reliability duringextreme demand peaks or overcastweather periods. These hybridsystems can often meet the severedemands on electricity quality andsystem reliability for a lower cost thanpurely photovoltaic systems.

A solar power supply does not simplyimply that one source of energy isreplaced by another, but also includesoptimising the consumer side: Forinstance, the electricity consumptionin the Tölzer Lodge was halved byinstalling compact fluorescent lampsand energy-saving appliances. Sincethe installation of the 3 kWpphotovoltaic system, about 1200 litresof diesel oil have been saved eachseason.

We have summarised the experienceand results from EURALP in a 16-pagebrochure (in German). This isavailable from the Munich office ofthe DAV, www.alpenverein.de.

* free-lance

Fig. 1: Photovoltaic modules and collector fieldon the south-facing roof of the BrandenburgerLodge, the highest lodge of the DAV at analtitude of 3277 metres above sea-level.

Fig. 3: Monthly electricity consumption of the Tölzer Lodge in kWh per day, from July to October. Solar energy provides 85 % and wind energy 15 % of the demand.

Fig. 4: Information brochure published by theDAV on the EURALP project.

Jul Aug Sep Octsolar contribution per day [kWh/d] windenergy contribution per day [kWh/d]

aver

age

tota

l con

sum

ptio

n [k

Wh/

d] 9.0

7.0

5.0

3.0

1.0

Fig. 2: Tölzer Lodge, at an altitude of 1825metres above sea-level. The entire electricitydemand is met by 35 m2 of solar cells with arated power of 3.5 kWp and a 750 W windgenerator.

www.alpenverein.de



Electromagnetic Compatibility of Photovoltaic Systems andComponents

We help to ensure the electro-magnetic compatibility (EMC) of newequipment under development andalready installed systems, with ourstationary and mobile EMC measure-ment technology and our experiencein standardisation.

Georg Bopp, Thomas Erge,Steffen Schattner

The increasing density and interfer-ence potential of electric components,devices and systems means that theirelectromagnetic compatibility isbecoming an increasingly importantquality aspect. "Electromagneticcompatibility" of a device means thatit does not disturb its electromagneticenvironment by more than amoderate amount. On the otherhand, it should be sufficiently resistantto disturbing influences in its ownenvironment. The limiting values aredefined in extensive standardisationliterature.

Of course, photovoltaic systems arenot immune to electromagneticincompatibility. On the contrary:Television and radio reception wasdisturbed by some of the photovoltaicsystems in the 1000 Roofs Pro-gramme. Interference with telephoneand radio systems was also reported.In Solar Home Systems, it is oftenimpossible to receive medium-waveradio transmissions after lights withtheir electronic ballasts have beenswitched on.

In larger PV systems, it is primarily theextensive DC side with its - unfortu-nately - excellent antenna propertieswhich is responsible for the distur-bances. Awareness of this aspect ofEMC has only developed graduallyamong the manufacturers of potentialsources of interference, such asinverters and charge controllers. The boundary conditions are notconducive either: The technicalstandards are still being written.Nevertheless, the law obliges themanufacturer to ensure EMC. This is unsettling for the manufacturers.

Often they do not know how toproceed or which standard isapplicable.

We are able to help here: Within anEU research project together with theDutch partner, KEMA and the Swisspartner, HTA Burgdorf, we haveprepared an up-to-date overview ofstandards, measurement configu-rations and recommendations, andapplicable limiting values. Specificallyfor the DC side, a line impedancestabilisation network (LISN) wasdefined for simple and reproduciblemeasurements and limiting valueswere recommended for the inter-national standardisation process. This limit must be observed whenevera new device is developed. Up to 500 kHz, the DC limit of EN 55014-1is applicable; at higher frequencies itis about halfway between the AC and DC limits of this standard.

We advise our clients with respect tolimits, accompany developments withmeasurements in our shielded EMCmeasurement chamber or certifyproducts within the Fraunhofer EMCconsortium. Improvement of aproduct to meet the standards at anearly stage in its development isgenerally much less expensive thansubsequent measures. However, weare also able to help with our mobileEMC measurement technology ifdisturbance from PV systems arises on site (this also applies to protectivemeasures against lightning orovervoltage). For Solar HomeSystems, we have developed a reliableand inexpensive recommendedprocedure for measurements in thelaboratory and on site.

Fig. 1: View into the EMC measurementchamber at Fraunhofer ISE.



Batteries - Core Components for allStand-Alone Power Supplies

The operating conditions for batteriesin stand-alone power supplies differappreciably from classical applications.We characterise various storagetechnologies in the laboratory and infield tests. We develop chargingstrategies, charging electronics andalgorithms to give reliable indicationsof the state of charge and the ageingcondition of the batteries.

Oliver Bohlen, Edward Gareis,Rudi Kaiser, Jérôme Kuhmann,Dirk Uwe Sauer, Heribert Schmidt,Birgit Thoben, Gerrit Volck

Battery storage units are needed in allstand-alone power supplies with acontinuous energy demand. Thisapplies for mobile devices (e.g. mobilephones, laptops), stationary technicaldevices (e.g. timetable displays, signalsystems) and for household powersupplies (e.g. Solar Home Systems,mountain lodges, village powersupplies). Profound knowledge of thestorage unit is an essential basis forsuccessful system development. Theprimary aim of our activities is tooptimise the complete system andminimise the costs of the storagesystem.

We investigate small batteries forapplications in appliances. Currentlywe are studying lithium ion batteriesand rechargeable alkali manganese(RAM) cells. We concentrate ontypical stresses found in stand-alonepower supplies, such as very lowcurrents during charging anddischarging, high and lowtemperatures, infrequent completecharging and long periods in thepartly discharged state. We test thebatteries both under controlled

conditions in the laboratory and alsounder real operating conditionsoutdoors with detailed measurements.

Today, larger systems still use lead-acidbatteries almost exclusively. In recentyears, increased use has been made ofclosed, maintenance-free batteries.However, appropriate chargingstrategies are still being sought foruse in photovoltaic power supplysystems, which adequately meet thedemands of both the batteries andthe system with its users. Togetherwith battery manufacturers, weinvestigate charging strategies incomparative field tests and analysethe results with respect to lifetime andsystem performance. The knowledgegained is applied in improvements tocharge controllers or device andsystem controls.

In order to gain more insight into theageing behaviour of batteries, we alsodevelop detailed models. Suggestionsto improve operation and the batterydesign are based on these. In future,we aim to determine the lifetime oflead-acid batteries after only a shorttesting period, using a combination ofelectrochemical tests and modelling.Simplified models are also used in oursimulation programs for systemdesign.

Modern power electronics and thegeneral avoidance of current-smoothing elements like capacitorsand inductors mean that batteriestoday are subjected to an increasingproportion of AC current components.The effects are still largely unknownor are the subject of considerablecontroversy. Within a project fundedby the European Union, we are

investigating the effect of pulsedcurrents on the electric performanceand the ageing of lead-acid batteries.We were able to demonstrate that thereal charge transfer in the batteries isappreciably higher than is measuredwith standard measurement tech-nology. The reason is that chargingand discharging currents occursimultaneously. The resulting batterycurrent can reverse its polarity with afrequency between 1 and 300 Hz,which can result in a charge transferwhich is up to 20 % higher thanassumed, depending on the system.

In order to supply high systemvoltages, many individual lead-acidbatteries must be connected in series.The weakest link (e.g. a damaged cell)determines the performance of theentire system. In order to guaranteemaximal system performance evenwhen individual cells are defective, wedevelop charge-equalising systems(CHargeEQualizer). They are nowequipped with an integrated batterymonitoring system with monitoringand analysis of the individual cells.

To enable integration of the storageunit into devices and systems, thesystem management requirescontinuous information on its state.This includes not only the state ofcharge but also the instantaneouscapacity, an indicator for the ageingstatus of the battery. To this purpose,we are developing algorithms whichdo not require sophisticatedmeasurement technology and whichcan be easily integrated into themicrocontrollers of charge controllers,device controls and energymanagement systems.



Fraunhofer ISE co-operates with industry to develop products with photovoltaic powersupplies. Shown here is an information boardfor bus and tram stops, which displays the nextconnections and informs about delays. Anenergy management system monitors andcontrols all components involved.


extremely low input voltages.Another example is our energymanagement system, which efficientlycombines very diverse electricity gen-erators, loads and storage units. It"learns" from the user behaviour andcan be adapted to very different app-lications. The future belongs tolithium ion rechargeable batteries formany applications. We determinetheir suitability with long-term inves-tigations, both in the laboratory andoutdoors, and define optimal areas ofusage.

In addition to scientific competence,our second asset is the practicalexperience we have gained over 19years of co-operation with manu-facturers and users. After all, it is notthe concept but the market successwhich is decisive. Thus, we observewhat the market needs and ensurethat we can provide it. As a conse-quence, we promote comprehensivequality assurance - not only at theInstitute, but in national and inter-national bodies - to ensure high-quality components and systems.

We also develop interactive exhibitsfor information and training purposes,which are not only unique but arealso fun to encounter. Apart fromtheir teaching value, also an attractivemarketing idea!


Products which are powered by thesun are more convenient, save batterycosts or replace expensive grid con-nections. Already in 2001, there willbe more than four thousand millionportable electronic appliances such asradios, mobile phones, camcorders orpalmtops. Industrial applications ofphotovoltaics include decentralisedfacilities for telecommunications,information technology and trafficdirection.

Each application has its own specifi-cations for the power supply. Fortelecommunications, it is 100 %availability, which we can guaranteewith hybrid systems. In the consumersector, the trend is towards smallerand more powerful devices. Ouranswer to that is miniaturisation andefficiency, for good appliances de-mand excellent components: High-efficiency solar cells, sophisticatedenergy management, low-powerelectronic components, surface moun-ted devices (SMD), optimised batteryperiphery.

Solar power supplies are characterisedby high flexibility and efficiency, so weadapt the electronics to each specificapplication. For instance, we havepaved the way to a completely newfamily of products with our DC/DCconverter for very high currents and

Contact persons:

Appliances and Werner Roth Tel.: +49 (0) 7 61/45 88-2 27 small systems E-Mail: [email protected]

Component development Dr Heribert Schmidt Tel.: +49 (0) 7 61/45 88-2 26and instrument design E-Mail: [email protected]

Storage systems Dirk Uwe Sauer Tel.: +49 (0) 7 61/45 88-2 19E-Mail: [email protected]



Photovoltaics for Appliances and Small Systems

The aim of our activities is to developmarketable appliances and smallsystems with photovoltaic powersupplies. We specialise in supportingsmall and medium-sized enterprises toexploit the potential offered byphotovoltaics for diverse, innovativeproducts.

Sergej Aingorn, Jochen Benz,Jérôme Kuhmann, Werner Roth,Wolfgang Schulz, Andreas Steinhüser,Gerrit Volck

Photovoltaically powered products are the main focus of the programmeon "Photovoltaics for Appliances andSmall Systems", which is funded bythe German Federal Ministry of Economics and Technology BMWi.Further, the development of compo-nents and measurement instrumentsfor use in small photovoltaic systemscan also be supported. Small andmedium-sized enterprises, as definedby EU subsidy guidelines, are eligibleto apply. They can choose betweentwo different forms of support:

Co-operation between anenterprise and Fraunhofer ISE

This form is directed mainly towardenterprises which do not have muchexperience with photovoltaics, do nothave suitable laboratory equipment orwish to draw on the experience ofFraunhofer ISE. We support the enter-prise within the framework of a co-operation agreement. The spectrumranges from consultancy to jointdevelopment of marketable products.We concentrate on system design,photovoltaic electricity generation,energy conditioning, energy storage,reduction of consumption and energymanagement.

Development work carried by the enterprise

Here, the enterprise is completelyresponsible for making the develo-pment. It receives a grant of maxi-mally 35 % of the costs which areeligible for the subsidy.

This year, we co-operated withindustrial partners to develop photo-voltaically powered products forlighting technology, water purifi-cation, public transport, measure-ment technology and informationtechnology.

Fig. 1: Photovoltaicallypowered roller blinds:Maintenance-free andconvenient to operate withremote control (photo:WAREMA).



Photovoltaic Information Centrefor Shell Solar Deutschland GmbH

Solar energy is considered to besimple technology. But how manypeople really know how a solar celloperates? Who is well informedabout the sun's path or theinteractions between the componentsof a solar system? Who still has anoverview of the current state ofresearch? We have answered theseand other questions posed byinterested laypeople by setting upinteractive high-tech exhibits.

Stefan Glunz, Andreas Häberle*,Jürgen Ketterer, Hans-Georg Puls,Bernhard Schmidt**,Heribert Schmidt,Andreas Steinhüser

On commission to Shell SolarDeutschland GmbH, Fraunhofer ISEdesigned and constructed interactiveexhibits for the PhotovoltaicInformation Centre in Gelsenkirchen.The existing exhibits cover thefollowing topics:

From sand to silicon wafersAmong other items, a sand pillar twometres high demonstrates the highsilicon purity required formanufacturing solar cells(1:1,000,000,000). An original wiresaw demonstrates how individual solarcells are sawn out of silicon blocks.

Production of silicon solar cellsAn animated video illustrates absor-ption of light, generation of freecharge carriers and recombination inan intrinsic (undoped) semiconductor.Active displays explain concepts suchas "doping" and "p and n conduc-tion". A unique mechanical modelwith liquids of different colours - likethe popular "Lava Lamps" - demon-strates the operation of a solar cell.

Overview of a wide range of solar cell technologyTwelve different types of solar celltechnology are exhibited in ashowcase. The spectrum ranges fromthe monocrystalline silicon solar cell,through the dye-sensitised cell, to themonolithic tandem solar cell ofGaInP/GaAs for space applications.Each exhibited solar cell is describedbriefly on an information board. Thisincludes the graphical representationof the usable portion of the AM 1.5spectrum. In addition, the physicallypossible efficiency value, the highestvalue achieved in the laboratory andtypical efficiency values of commercialsolar cells are specified.

From the cell to a systemA 50x magnified cross-section showsthe construction of a solar module.The mechanical robustness of solarmodules is impressively demonstratedby regularly dropping a steel ball froma tower onto a module. An electronicsystem construction kit combined witha professional simulation programallows visitors to become acquaintedwith different photovoltaic systemsand their design.

Laboratory bench for photovoltaic systems technologyThree experimental set-ups demon-strate all aspects of series and parallelconnection of solar cells, MPP trackingand the effect of orientation, tilt andshading on the energy yield of solarmodules.

The demonstration of complexphenomena, e.g. of connecting solarcells, by the exhibits is physicallycorrect, yet also entertaining. Factswhich an engineer carefully clarifiesfor himself with formulae and func-tions can be appreciated immediatelyby the visitor by looking or touching:Partial shading with a hand results ina clearly visible downturn in thecharacteristic curve. A lower yield, i.e.less energy, becomes evident as asmaller amount of water pumped intoa reservoir. Less power transforms ajet of water to a tired trickle. Evenexperienced technicians and scientistsgain a new feeling for the interactionspresented. Not to mention the plea-sure of simply playing, which capti-vates visitors of all ages and educa-tional levels.

Fig. 1: Visitors to the Photovoltaic InformationCentre in Gelsenkirchen.


**Ingenieurbüro Schmidt, Neunkirchen



Customised Measurement Units forthe Photovoltaic Industry

Our spectrum of solar cell and modulecalibration services calls for compre-hensive measurement units tailored tothe various solar cell technologies.These measurement units are gener-ally not commercially available. Eachone is individually developed in theCalibration Labor-atory of FraunhoferISE (ISE CalLab) according to thespecific requirements of the relevantsolar cell technology. We now offerthis know-how to the photovoltaicindustry and supply complete mea-surement units as specified by ourclients.

Sybille Baumann, Stefan Brachmann,Heribert Schmidt

One particular feature of our offer isits diversity. Whether for thin-filmtechnology, dye-sensitised solar cells,multiple-junction cells, cells for 1000xconcentration or crystalline siliconsolar cells - we develop customisedmeasurements units distinguished byhigh accuracy and convenientoperation.

These measurement units are used inthe photovoltaic industry and inresearch institutions. The followinghave been constructed to date:

- spectral measurement unit for dye-sensitised solar cells. This equipment allows the reference andtest solar cells to be measured simultaneously, thus reducing the calibration time considerably.

- combined measurement unit for the spectral response and I/V characteristic of solar cells. The special feature here is that the mechanically sensitive solar cell can be completely characterised at one position.

- filter monochromator measurement unit for large-area silicon solar cells.This equipment to determine the relative and absolute spectral response allows the sample to be illuminated very homogeneously with monochromatic light over a large area.

- spectral measurement unit with a grating monochromator for thin-filmtechnology. In addition to the spectral response of solar cells, the transmittance of coated glass can bedetermined over a large spectral range with this facility.

- measurement unit to determine degradation effects in solar modulesunder outdoor conditions. With this set-up, the module is operated at the maximum power point (MPP) and I/V characteristics are measured and saved at freely programmable intervals.

- solar simulator to characterise solar cells and small modules up to 30 x 30 cm2. Here, the sample holder can be moved out of the radiation plane to be contacted under better working conditions (fig. 1).

Fig. 1: Solar simulator to characterise CISmodules, developed and constructed for theSiemens Solar company, Munich.



Stand-Alone Power Supplies forTelecommunications, based onPhotovoltaics, Fuel Cells and aHydrogen Seasonal Storage Unit

We develop stand-alone powersupplies for telecommunicationssystems. They are based on photo-voltaic generators with hydrogen-fuelled fuel cells as the back-up powersupply. In a second step, an electro-lyser makes complete autonomyfeasible.

Jochen Benz, Beatrice Hacker,Angelika Heinzel, Hans-Georg Puls,Dirk Uwe Sauer

Repeaters for telecommunications areoften located in remote areas. Acombination of a photovoltaic gene-rator, a fuel cell and a conventionalbattery can make them independentof logistically complicated fuel de-liveries. For the first developmentstage, the hydrogen is still delivered ingas cylinders. In the second stage, wewill integrate an electrolyser togetherwith a hydrogen storage unit into thesystem. This will result in a com-pletely autonomous system withseasonal energy storage. Minimisedmaintenance and 100% availability ofelectricity is given the highest priority.

At present, we are developingprototypes under the leadership ofAlcatel, Spain, drawing on theexperience gained with the self-sufficient solar house in Freiburg(commissioned in 1992). We are now further developing the systemconcept, which was demonstrated forthe first time then, for broad technicalapplication. In addition to developingconcepts, we are involved in theproject with planning tools andsystem components.

System designIn order to achieve continuous systemavailability at low cost, we areoptimising the system design on thebasis of lifetime costs. To thispurpose, we are using and extendingour TALCO simulation program(technical and least cost optimisation).The program optimises the completesystem after all the technical andeconomic parameters describing thecomponents have been entered. Theoutput is the system cost and thedimensions of the individualcomponents.

For the system to be implemented inthe first stage, with a fuel cell andexternally supplied hydrogen, theprice of the hydrogen cylinders turnedout to be the most critical parameterfor the system dimensioning. Thecosts for generating a kWh electricityfrom hydrogen are two to three timeshigher than for photovoltaicgeneration. Thus the system designvaries considerably, depending on theprice development assumed forhydrogen.

Energy management systemThe central control unit of the systemis an energy management system(EMS), based on a microprocessor unitwith an extremely low electricityconsumption. The EMS controls andmonitors all the energy flows and thesystem state. It calculates the battery

state-of-charge, connects in the elec-trolyser and fuel cell at the optimaltimes and make automatic tests of allcomponents, including the battery.Remote monitoring is possible via theEMS.

ElektrolyserAs illustrated in fig. 1, the stand-alonepower supply will also become inde-pendent of hydrogen deliveries in thesecond stage. Hydrogen will be pro-duced in summer with the excesselectricity from the photovoltaicgenerator, and stored in a metalhydride unit. The hydrogen is

produced in a pressure electrolyserwith a polymer electrolyte membrane,which was developed at FraunhoferISE. The result is a system withseasonal energy storage (electrolyser -hydrogen storage unit - fuel cell). Thepower will be about 1 kW. Outdooroperation of the electrolyser attemperatures below the freezing pointpresents a particular challenge, ifmaintenance is to be kept minimal.At present we are working onmeasures to allow the electrolyser to"survive" the winter.

The PV fuel cell system will be takeninto operation under real outdoorconditions in Madrid in the firstquarter of 2001, and the system withseasonal storage will follow in thesecond quarter of 2002. The EU isfunding the project.

Fig. 1: Schematic repre-sentation of the stand-alonepower system with seasonalhydrogen storage. Thissystem will be implementedin the second project step, inco-operation with manu-facturers of photovoltaics,fuel cells and telecommu-nications.electrolyser

fuel cell

photovoltaicgenerator

energy management

Seasonal Energy Storage System

telecommunicationequipment

H2 storage

battery


Grid-ConnectedPhotovoltaics

Photovoltaics is becoming increasingly popular as an element of solar building. Fraunhofer ISE is incorporating functionalelements in its new premises. A view into the saw-toothed roof construction of the atrium: The photovoltaic modulesintegrated there are installed within the double glazed units. In addition to providing thermal insulation in winter, they alsoserve as sun-shading elements in summer.


element of solar building. PVmodules fulfil many differentfunctions in buildings, includingaesthetic purposes, daylighting andshading, as well as electricity gene-ration. We identify the desiredsolution with simulation programs.

In co-operation with industrialpartners, we are working toward theintelligent electricity grid of the future,which will allow a growing proportionof renewable energy to be incor-porated. The most obvious newfeature is the communication channel,which e.g. can switch decentralisedpower plants or storage units in orout as needed. Many complementarygenerators drawing on PV, wind,water and biomass, together withstorage and control elements, willensure that the electricity customerdoes not notice the transition to asustainable energy economy, becausethe convenience and reliability of thegrid will remained unchanged.


The 100,000 Roofs Programme andthe Renewable Energy Law havestimulated a rapid upswing for photo-voltaics in Germany. We accompanymarket introduction programmes ofthis type and accept responsibility forplanning, dimensioning, authorisationand monitoring of the systems. Withpayments of 0.99 DM/kWh for elec-tricity supplied to the grid, carefulplanning for an optimal yield iscertainly warranted. Ten years ofmonitoring have taught us whereweaknesses can be expected and how they can be remedied quickly.

Not only operators, but also manu-facturers profit from our experience.The best example is given by inverters,which are now characterised by anoperating availability of 99 %, andhave become an export success.A strong increase in the number ofenquiries from architects and civilengineers indicates that photovoltaicsis developing swiftly in its role as an

Contact persons:

PV monitoring Klaus Kiefer Tel.: +49 (0) 7 61/45 88-2 18 E-Mail: [email protected]

Systems analysis Dr Thomas Erge Tel.: +49 (0) 7 61/45 88-3 37and design E-Mail: [email protected]

Systems components Dr Heribert Schmidt Tel.: +49 (0) 7 61/45 88-2 26E-Mail: [email protected]

Photovoltaics in Hermann Laukamp Tel.: +49 (0) 7 61/45 88-2 75buildings E-Mail: [email protected]

Dr Karsten Voss Tel.: +49 (0) 7 61/45 88-1 35E-Mail: [email protected]

Energy storage Dirk Uwe Sauer Tel.: +49 (0) 7 61/45 88-2 19in electricity grids E-Mail: [email protected]



The 120 kWp Photovoltaic TrainingSystem of the Cologne TradesCorporation - Butzweilerhof

We designed the technical part of thisdemonstration project for differenttypes of photovoltaic technology andprovide scientific support to theproject.

Thomas Erge, Alfons Armbruster*,Klaus Kiefer, Eberhard Rössler**,Edo Wiemken

The photovoltaic system on the"Butzweilerhof" building of theCologne Trades Corporation(Handwerkskammer) was installed in1999 and 2000. In addition to thephotovoltaic generation of electricity,the aim of this project is to demon-strate technical, architectural and

economic aspects of photovoltaics,and to integrate these into thetraining programmes of the TradesCorporation.

The complete system consists of about1400 modules with a total power ofabout 120 kWp. They are distributedamong three subsystems:

- 103.5 kWp flat-roof system, consisting of one system section with a central inverter (50 kWp), another system section with string inverters (44 kWp) and a third system section with module-integrated inverters (9.5 kWp).

- 9.0 kWp façade system consisting ofvertical and tilted facade elements. The tilted modules are mounted above the windows and shade the associated rooms from the high-standing summer sun.

- 7.5 kWp training systems, which were installed as three separate small systems to illustrate different roof installation procedures on a specially constructed training roof. The demonstrated technologies are roof integration, stand-off installation and installation of photovoltaic roofing tiles. The installation here includes a small stand-alone battery system with special energy management.

We planned all the photovoltaicgenerators on commission to theCologne Trades Corporation, takingnot only the electrical concept butalso the specific building and archi-tectural requirements into account.

We are monitoring the systemoperation in a scientific monitoringand analysis programme. This pro-vides us with extensive data series,which serve both in the trainingcourses offered by the Trades Corp-oration and for scientific analysis atFraunhofer ISE. One of our goals is tocompare the different system con-cepts with respect to their operatingperformance, reliability and efficiency.

We are designing and programmingInternet pages with on-line access toselected measurement data for thepublic presentation of the project.This will be found at the Internet siteof the Cologne Trades Corporation:http://www.handwerkskammer-koeln.de.

The photovoltaic system complex wasfunded by the European Union andthe State of North-Rhine Westphalia.


** free-lance

Fig. 3: Shortly before the systems wereinstalled, the Calibration Laboratory atFraunhofer ISE (ISE CalLab) characterisedselected modules in detail.

Fig. 1: PV façade system as shading for theassociated training rooms.

Fig. 2: Integration of PV roofing tiles into theroof of the "Butzweilerhof" Training Centre.



Towards the Electricity Grid of the Future

We are working in a consortium of 17partners from industry and researchon a decentralised grid structure withan integrated communication system.The aim is a high-quality power supplyand the greatest possible flexibility fortechnical and economic options.

Heribert Schmidt, Thomas Erge,Angelika Heinzel, Dirk Uwe Sauer,Dieter Schlegel

The Karlsruhe Stadtwerke (city utility),Fraunhofer ISE in Freiburg, EUS GmbHin Gelsenkirchen and Siemens AG inErlangen are managing the consor-tium, which calls itself "EDISON".The consortium has set itself twotasks to be completed by 2003:adaptation of the energy distributiongrids to the liberalised electricitymarket, and preparation for moderntechnology such as renewable energy.

EDISON combines energy distributionwith information processing and isdeveloping decentralised componentsfor the new grid structure. Examplesof components include:

- power quality equipment, which e.g. compensates for voltage breakdowns

- local electricity storage units, which ensure a homogeneous energy flow

- decentralised electricity generators such as photovoltaic and wind energy systems, or heat/electricity cogeneration plants with fuel cells.

Together with decentralised energymanagement systems, thesecomponents open up new options fordemand-relevant control of energyflows in extended electricitydistribution networks.

This applies, for instance, whencogeneration plants based on fuelcells are introduced, which can bothmeet peak electric loads and supplyheating energy. The energy utility canuse cogeneration plants particularlyefficiently if their electric output canbe controlled according to thedemand. The decentralisedcommunication structure allowsaccess to the electricity generator atany time. This means that expensivegrid extensions can be avoided.

Another application is to meet atemporarily raised demand forelectricity in an environmentallyfriendly way in grid segments whichwere not designed for this load, e.g.the power supply for building sites orfolk festivals. Mobile storage batterieswith an energy management systemcan eliminate the need for large dieselaggregates or costly expansion of gridstructures.

Thus, the introduction of additionaldecentralised generators and storageunits may not be measuredeconomically, purely on the basis ofthe electricity production costs or thesavings in electricity trading whichresult from reducing the peak load.The essential savings for the utilityarise from the avoided investments forextending the grid with power linesand transformers.

We are primarily responsible for twoscientific sub-projects for EDISON:

- sub-project 2, "Energy storage and conversion units"

- sub-project 7, "Monitoring and analysis of results"

In sub-project 2, we co-operated withpartners to initially document thestate of the art concerning energystorage and conversion units. We aretesting components in the laboratoryto investigate their operating charac-teristics and to determine technicalparameters. Based on this, we deve-lop new hardware and software tooptimise their operation.

In sub-project 7, we are comparingthe currently used, decentralisedenergy conversion and storage unitsby analysing the system data onenergy and power. The data aretransferred on-line from the decen-tralised operation managementsystem to the process managementsystem and then stored in our databank. In addition, we install mea-surement sensors and data loggers inselected systems or components.

The EDISON project is supported bythe German Federal Ministry ofEconomics and Technology BMWi.

access tractfaçade

central wingroof

south wing roof

south wingspandrels



Building Integration ofPhotovoltaic Systems: The New Premises of FraunhoferISE as an Example

Five photovoltaic systems with a totalrated power of 20 kWp will beinstalled on the new premises forFraunhofer ISE. The planning isexemplary for the comprehensiveapproach applied by Fraunhofer ISE to solar building: optimisation ofarchitecture, user comfort, thermaland electric use of energy in anintegrated concept.

Sören Andersen*, Sebastian Herkel,Klaus Kiefer, Hermann Laukamp,Karsten Voss

The five photovoltaic systems (fig. 1and table 1) will serve mainly as elec-tricity generators, but some of themcan also be used as test generators.The planning team placed great valueon the balance between buildingaspects and electricity generation.The PV generators demonstrate dif-ferent aspects of building integration:

In the southern façade and the saw-toothed roof, the solar cells areencapsulated within double glazing.They reduce the heat gains to thebuilding and support the efforts todispense largely with conventional airconditioning. The generator on thefaçade of the southern wing willdemonstrate the application ofphotovoltaic modules as spandrelelements in vertical and tiltedconfigurations. The generators on the

roofs of the southern and centralwings serve as cladding for theventilation shafts behind them.

The example of the saw-toothed roofover the atrium indicates how wedeveloped the construction: The tablein fig. 2 illustrates the optimisation ofthe saw-toothed roof geometry aspart of the building concept.

Good daylighting conditions areessential for the use and the aestheticeffect of an atrium. On the otherhand, enormous overheating loadsarise in summer if transparency is highand there are no shading elements.We carried out simulations for theindoor thermal and daylightingconditions to take account of bothaspects mentioned, in combinationwith the energy yield of thephotovoltaic system.

Conclusion: The photovoltaic systems,with an annual yield of around 16 MWh, will meet the entire demandfor office lighting in the new building.

The European Union is supporting theconstruction of the photovoltaicsystems.

* Dissing+Weitling, CopenhagenTable 1: Position and rated power of the PV systems.

Fig. 1: The five photovoltaic systems on thenew premises for Fraunhofer ISE.

Fig. 3: A view up to the top of the atrium. The photovoltaic generator projects a shadowpattern onto the curved wall of the atrium.

Façade of the access tract 2.5 kWp

Saw-toothed roof over the atrium 4.9 kWp

Spandrels of the southern wing 2.9 kWp

Roof of the southern wing 4.5 kWp

Roof of the central wing 5.3 kWp

PVGlassElectricity + 0 –

Daylight – 0 +

Temperature + 0 –

Fig. 2: The slope of the photovoltaic generatorson the saw-toothed roof is adapted to theenergy concept for the building. Electricitygeneration, daylighting and reduction of heatgains to the atrium in summer were all takeninto account when optimising the design.

Construction N

+ = favourable, - = unfavourable, 0 = neutral

saw-toothedroof


Facts and Figures

Visiting Scientists

Participation in National andInternational Associations

Congresses, Conferences andSeminars organised by the Institute

Lecture Courses and Seminars

Trade Fairs and Exhibitions

Patents

Doctoral Theses

Press Information

Lectures

Publications

Facts and Figures


Visiting Scientists

Claudia CasperUniversidad BarcelonaBarcelona, Spain1.2.2000 - 30.5.2001Research area: sociological studies on rural electrification

Dr Andres CuevasAustralian National UniversityCanberra, Australia16.7 - 31.8.2000Research area: high-efficiency silicon solar cells

Mario MottaPolitecnico di MilanoMilan, Italy1.7.1999-30.6.2000Research area: solar air-conditioning

Maryam Kharrazi OlssonUniversity of UppsalaUppsala, Sweden1.3.1998 - 29.2.2000Research area: coating technology

Anders ØdegårdNorwegian University for Science andTechnology (NTNU)Trondheim, Norway21.8.2000 - 21.2.2001Research area: micro-energy technology

Prof. Valeri RumyantsevIoffe InstituteSt Petersburg, Russia1.6. - 30.9.2000Research area: III-V concentrator modules

Dr Oleg V. SulimaIoffe InstituteSt. Petersburg, Russia1.1.1997 - 31.12.2000Research area: III-V epitaxy and technology

Participation in National andInternational Associations

Bundesministerium für Wirtschaft undTechnologie BMWi- Lenkungsausschuss “Solar optimiertes

Bauen”

Deutsche Elektrotechnische Kommission DKE- Komitee 373: Photovoltaische

Solarenergiesysteme- Komitee 221: Elektrische Anlagen

von Gebäuden

Deutsche Elektrotechnische Kommission DKE- Komitee 384: Brennstoffzellen

Deutsche Gesellschaft für ChemischesApparatewesen, Chemische Technik undBiotechnologie Dechema e.V.- Arbeitsausschuss “Elektrochemische Prozesse”

Deutsche Gesellschaft für Galvano- undOberflächentechnik DGO- Fachausschuss “Mikrosysteme und

Oberflächentechnik”

Deutsche Gesellschaft für Psychologie- Fachausschuss “Umweltpsychologie”

Deutsche Gesellschaft für Sonnenenergie DGS- Vorstand der Sektion Südbaden

Deutsche Physikalische Gesellschaft DPG- Arbeitskreis “Energie”

Deutscher Wasserstoff-Verein DWV

Deutsches Flachdisplay-Forum

European Committee for Standardisation CEN / TC33 / WG3 / TG5 - Member

European Co-operation for SpaceStandardisation ECSS- “Solar Cell Standard” Working Group

European Fuel Cell Group

European Renewable Energy Centres (EUREC)Agency- President

Fachverband Transparente Wärmedämmung e.v.- Arbeitskreis “Normung”

Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. FhG- Hauptkommission

German Advisory Council on Global Change- Member

Hahn-Meitner-Institut HMI- Wissenschaftlicher Beirat

Institut für Solare EnergieversorgungstechnikISET- Wissenschaftlicher Beirat

International Solar Energy Society Europe (ISES-Europe)- Governing Board

International Solar Energy Society ISES- Board of Directors

ISO/TC 197 Hydrogen Technologies - “Gas technology” Subcommittee

“Solar Energy”, Pergamon Press/Elsevier- Editor-in-Chief

Verein Deutscher Elektrotechniker- ETG-Fachausschuss “Brennstoffzellen”

Verein Deutscher Ingenieure VDI- Fachausschuss “Brennstoffzellen”

Verein Deutscher Ingenieure, VDI-GesellschaftEnergietechnik- Fachausschuss “Regenerative Energien”

VMPA- Verband der Materialprüfämter e.V.- Sektorgruppe “Türen, Fenster und

Glasprodukte”

Zentrum für Solarenergie und Wasserstoff ZSW- Kuratorium

Lecture Courses and Seminars

Prof. Joachim LutherPhotovoltaische Energiewandlung, Vorlesung SS 00Solarthermische Energiewandlung, Vorlesung WS 00/01Solare Energiekonversion, Oberseminar SS 00, WS 00/01Universität Freiburg, Fakultät für Physik

Prof. Roland SchindlerPhotovoltaik Teil I und II, Vorlesung WS 99/00, SS 00FernUniversität Hagen

Dr.-Ing. Heribert SchmidtPhotovoltaik-Systemtechnik, Vorlesung SS 00Universität Karlsruhe

Dr. Petra Schweizer-RiesGemeinschaftliche Nutzung von Ressourcen:Von sozial-ökologischer Dilemma-Forschung bis hin zur Gemeingutforschung, Seminar SS 00Universität Zürich, Umweltpsychologie

Prof. Wolfram WettlingHalbleiter-Technologie und -Bauelemente, Vorlesung WS 00/01Universität Freiburg, Fakultät für Physik

Priv. Doz. Dr. Gerhard WillekeFundamentals of Semiconductor Technology, WS 99/00,University of Constance, Faculty of Physics

Priv. Doz. Dr. Volker WittwerInnovative Energiesysteme, Vorlesung SS 00 und Seminar WS 00/01 Universität Freiburg, Fakultät für AngewandteWissenschaften, Institut für MikrosystemtechnikIMTEK


Facts and Figures

Trade Fairs and Exhibitions

Industrieausstellung im Rahmen des15. Symposiums Photovoltaische SolarenergieStaffelsteinStaffelstein, Kloster Banz, 15.-17.3.2000

light+buildingFrankfurt, 19.-23.3.2000

Hanover Trade Fair 2000Participation in the joint stand of the FraunhoferGesellschaft on “Surface Technology” Participation in the joint stand on “Hydrogenand Fuel Cell Technology”Hanover, 20.-25.3.2000

Sustainable Building 2000Maastricht, The Netherlands, 22.-25.5.2000

Intersolar 2000Freiburg, 7.-9.7.2000

GlasstecDüsseldorf, 24.-28.10.2000

Intelligent Building DesignStuttgart, 10/11.11.2000

MegaWattGelsenkirchen, 24./25.11.2000

Congresses, Conferences andSeminars organised by the Institute

OTTI Technologie-Kolleg Regensburg6. Symposium LichtStaffelstein, Kloster Banz, 27./28.1.2000

OTTI Energie-Kolleg RegensburgFachseminar “Photovoltaisch versorgte Geräteund Kleinsysteme”Freiburg, 2./3.2.2000

OTTI-Energie-Kolleg Regensburg15. Symposium Photovoltaische SolarenergieStaffelstein, Kloster Banz, 15.-17.3.2000

2nd Workshop on Light Degradation of CarrierLifetime in Cz-Si Solar CellsGlasgow, United Kingdom, 3.5.2000

OTTI Technologie-Kolleg Regensburg10. Symposium Thermische SolarenergieStaffelstein, Kloster Banz, 10.-12.5.2000

OTTI Energie-Kolleg RegensburgFachseminar “Photovoltaik-Anlagen”Freiburg, 23./24.5.2000

MonitoringHamm, 16./17.11.2000

BMWi Projekt “SolarBau: MONITOR”Integrale Planung und ArchitekturSeminareBonn, St. Augustin, 17/18.11.2000

Materialien in SolarkollektorenSymposiumSalzburg, Österreich, 24.11.2000

Arbeitsgemeinschaft Erneuerbare Energien AEEInstitut für Solartechnik SPFFraunhofer-Institut für Solare Energiesysteme ISEMaterialien und Komponenten in SolaranlagenTagungSalzburg, Österreich, 24.11.2000

Facts and Figures


Doctoral Theses

Benedikt BläsiHolographisch hergestellte Antireflexoberflächenfür solare und visuelle Anwendungen(Holographically produced anti-reflective surfacesfor solar and visual applications)Doctoral thesis, University of FreiburgFreiburg, 2000

Frank DimrothMetallorganische Gasphasenepitaxie zurHerstellung von hocheffizienten Solarzellen ausIII-V Halbleitern(Metal-organic vapour phase epitaxy to producehighly efficient solar cells from III-V semicon-ductors)Doctoral thesis, University of ConstanceConstance, 2000

Peter HahneInnovative Druck- und Metallisierungsverfahrenfür die Solarzellentechnologie(Innovative printing and metallisation proceduresfor solar cell technology)Doctoral thesis, University of HagenHagen, 2000

Ralf PreuInnovative Produktionstechnologien fürkristalline Silicium-Solarzellen(Innovative production technology for crystallinesilicon solar cells)Doctoral thesis, University of HagenHagen, 2000

Sebastian SchaeferPlasmaätzen für die Photovoltaik - Plasma-systeme und -prozesse für die Herstellung vonkristallinen Siliciumsolarzellen(Plasma-etching for photovoltaics - plasma systems and processes for the production ofcrystalline silicon solar cells)Doctoral thesis, University of ConstanceConstance, 2000

Stefan ReberElectrical Confinement for the Crystalline SiliconThin-Film Solar Cell on Foreign SubstrateDoctoral thesis, University of MainzMainz, 2000

Tim MeyerDC/DC-Wandler mit kleiner Eingangsspannungfür photovoltaische, elektrochemische und thermoelektrische Zellen(DC/DC converter with low input voltage forphotovoltaic, electrochemical and thermoelectriccells)Doctoral thesis, University of KarlsruheKarlsruhe, 2000

Prof. Adolf Goetzberger, Thomas Kuckelkorn“Daylighting element based on a CPC”

Michael Köhl, Klaus Rose, Matthias Heinrich,Karl-Heinz Haas“Multifunctional superphobic coatings”

Orlando Parodi, Ulrike Seibert, Konstanze Fleige“WATER Pumping and Purification System”(WATERpps)

Daniel Biró“Low-contamination transport through a high-temperature zone with a lifting-arm procedurewith a flexible arm”

Dr Gerhard Willeke, Daniel Kray“Damage-free wafer production”

Ralf Preu, Eric Schneiderlöchner,Dr Stefan Glunz, Dr Ralf Lüdemann“Procedure to produce a semiconductor-metalcontact through a dielectric layer”

Michael Köhl, Franz Brucker, Volker Lieske“Procedure to improve biocatalytic reaction”

Dirk Uwe Sauer, Rudi Kaiser“Concept for parallel operation of different storage technologies in autonomous power sup-plies”

Volkmar Boerner, Dr Andreas Gombert,Dr Benedikt Bläsi“Procedure to produce light-scattering elementswith non-gaussian scattering profiles”

Dr Andreas Gombert, Michael Niggemann,Hansjörg Lerchenmüller“Procedure and device to produce coupling gridsfor integrated optical components”

Patents

Patents Granted

Klaus Preiser, Jérôme Kuhmann“Device to test stand-alone solar systems”

Dr Heribert Schmidt, Dirk Uwe Sauer“Device to determine the density of an electrolyte”

Prof. Adolf Goetzberger“Solar control glazing”

Prof. Adolf Goetzberger“Configuration for light-guiding systems”

Dr Peter Apian-Bennewitz“Projection system”

Dr Wilhelm Warta, Daniel Biró“Semiconductor configuration and procedure to passivate the surface of a semiconductormaterial”

Konrad Lustig“Heat exchanger unit and procedure to produce a heat exchanger unit”

Patent Applications

Dr Peter Nitz, Wolfgang Graf, Michael Wagner,Wolfgang Schnell, Rainer Lebacher,Clemens Roch“Application of condensate-sensitive, low-emit-ting films and device to prevent condensation incavities of double or multiple-walled envelopesof heatable rooms”

Michael Hermann, Peter Schossig,Carsten Hindenburg“Active thermal building component with phasechange material”

Uli Röltgen, Norbert Wiesheu, Dr Andreas Docter“Autothermal reforming reactor”

Dr Andreas Georg, Anneke Hauch, Dr EliasStathatos, Prof. Panagiotis Lianos, NavaGroselj, Dr. Urska Lavrencic, Prof. Boris Orel, “Ion conductor for dye-sensitised solar cells”

Dr Andreas Bett, Dr Siegbart Kunz,Dr Jochen Buschmann, Christian Braun,Harald Humpfer, Volker Geneiß“Implanted field and temperature probe forEMC measurements”

^ ^ ^^


Facts and Figures

Press Information

Press Releases

http://www.ise.fhg.de/Public_Relations/pi.html

7.2.2000Moth-Eyes and Lotus Petals:Micro-Structuring for Functional SurfacesHanover Trade Fair, March 20-25, 2000

7.2.2000Miniature Fuel Cells for Portable ElectronicAppliancesHanover Trade Fair, March 20-25, 2000

26.7.2000Small Devices - Large MarketsFraunhofer Institute develops new photovoltaicproducts

7.8.2000Solar Power Supply Remote from the GridPractical Tips for a Market of Millions

1.9.2000Solar Cell Record at Fraunhofer ISEEfficiency Value of Monolithic TandemConcentrator Cells Exceeds 30 %

9.10.2000Lifestyle for the Future in Neuenburg1-litre solar houses with an innovative, compact,building services unit

20.10.2000Photovoltaic Scientists at the Conveyor BeltThe Fraunhofer ISE Laboratory and ServiceCentre in Gelsenkirchen

8.12.2000Calibration reduces costs for photovoltaic electricityFraunhofer ISE measurement technology forwidespread application

http://www.ise.fhg.de/Public_Relations/ pi_german.html

Facts and Figures


Lectures

Lectures with publishedmanuscripts are listed under“Publications”

Adib, R.“The Vision: Financial SustainableRural Electrification. ThePerformance: MicrofinanceInstitutions and their Technology”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, Poster

Agert, C.“MOVPE GaSb-basierender HL undphotovoltaische Anwendungen”,Seminar, Universität Erlangen,Erlangen, 19.11.1999

Agert, C.“MOVPE of GaSb, (AlGa)Sb and(AlGa)(AsSb) in a MultiwaferPlanetary Reactor”, LincolnLaboratory, MIT, Boston, USA,10.8.2000; BandwidthSemiconductor LLC, Boston, USA,11.8.2000; NREL, Golden, USA,21.8.2000; Sandia National Lab.,Albuquerque, USA, 23.8.2000;EMCORE Photovoltaics Division,Albuquerque, USA, 24.8.2000

Agert, C.“MOVPE von GaSb-basierendenIII-V-Halbleitern im Planeten-reaktor”, Seminar Materialfor-schungszentrum FMF Freiburg,Freiburg, 17.11.2000

Bett, A.W.; Sulima, O.; Dimroth, F.; Wettling, W.; Willeke, G.“Tandem- und Tripel-Solarzellenaus III-V-Verbindungen für An-wendungen in Konzentrator- undThermophotovoltaik-Systemen”, 9.Kolloquium Materialforschungs-zentrum FMF Freiburg, Breisach,3.-4.11.2000

Bopp, G.“Netzferne PV-Versorgung amWatzmannhaus”, Technologie-börse Bau, Congress Center,Nürnberg, 27.1.2000

Hoffmann, V.U.“Erfahrungen mit PV-Schul-projekten – SONNEonline undSonne in der Schule”, 12. Inter-nationales Sonnenforum, Freiburg,7.7.2000

Hoffmann, V.U.“Freier Strommarkt – was nun?”,öffentliche Podiumsdiskussion,Ehrenstetten, 17.5.2000

Hube, W.; Wittwer, Ch.“Entwicklung von neuartigenRegelungskonzepten mit Hilfe derSimulationsumgebung ColSim undderen Validierung im Feldtest”,10. Symposium ThermischeSolarenergie, OTTI-Technologie-Kolleg, Staffelstein, 10.-12.5.2000

Hube, W.; Wittwer, Chr.“Experimentelle Untersuchung vonneuartigen Regelungskonzeptenfür aktive thermische Systeme aneinem Mehrfamilienhaus”, 12. Internationales Sonnenforum,6.-7.7.2000

Kiefer, K.“Photovoltaik-Strom von derSonne, Karlsruher Solaranlagen imVergleich - Technik, Ergebnisseund Bewertung”, KundenberatungStadtwerke Karlsruhe, Karlsruhe,9.5.2000

Kiefer, K.“Strom von der Sonne”,Informationsveranstaltung derGemeinde Bad Krozingen,29.9.2000

Köhl, M.“Einsatzmöglichkeiten von poly-meren Materialien in der Solar-thermie”, Fa. Bayer, Leverkusen,9.3.2000

Köhl, M.“New IEA-SHC Task: Performanceof Solar Façade Components”,EuroSun 2000, 3rd ISES-EuropeSolar Congress, Copenhagen,Denmark, 19.-22.6.2000

Köhl, M.“Solar Building Façades”, EuroSun2000, 3rd ISES-Europe SolarCongress, Copenhagen, Denmark,19.-22.6.2000

Köhl, M.“Durability of Solar EnergyMaterials”, WREC, Brighton,United Kingdom, 1.-5.7.2000

Köhl, M.“Singulett-Sauerstoff undWasser”, Kolloquium desFraunhofer-Instituts fürGrenzflächen und Biover-fahrenstechnik IGB, Stuttgart,17.7.2000

Bopp, G.“Ländliche Energieversorgung unddie Perspektiven der Photo-voltaik”, 12. InternationalesSonnenforum, Freiburg, 7.7.2000

Borchert, D.“ITO als Top-Coating für Silizium”,2. Workshop TCO für Dünn-schichtsolarzellen, Forschungs-verbund Sonnenenergie FVS,Jülich, 10.-11.2.2000

Borchert, D.“Kristalline Silizium-Solarzellen:Materialien, Herstellung undCharakterisierung”, MessemegaWatt, Gelsenkirchen,24.-25.2000

Erge, T.“Solar Electricity from a ThousandRoofs”, PV Field Trial ConsultationMeeting, Watford, UnitedKingdom, 3.4.2000

Ferber, J.1; Kern, R.1; Luther, J.“Investigation of the Long-TermStability of Dye-Sensitized SolarCells”, Workshop Quantsol2000,Wolkenstein, Italy, 11.-18.3.2000(1: MaterialforschungszentrumFMF, Freiburg)

Glunz, S.“Silicon Solar Cell Research atFraunhofer ISE”, Seminar bei Fa.Samsung, Suwon, Korea,7.11.2000

Gombert, A.“Neue Anwendungen nanostruk-turierter Oberflächen”, NATI-Seminar Kunststofftechnik, FHOsnabrück, 20.6.2000

Hahne, P.“Drucktechnologien für dieSolarzellenfertigung”, SolPro IIIExpertentreffen Druck, FirmaMerck, Darmstadt, 30.5.2000

Heinzel, A.“Brennstoffzellen – ein neuerEnergiewandler für mobile, sta-tionäre und portable Anwen-dungen”, Messe Zürich, 8.2.2000

Heinzel, A.“Brennstoffzellen mit variablerAusgangsspannung zur Energie-versorgung elektronischerGeräte”, Hanover Trade Fair 2000,Hanover 20.-25.3.2000

Heinzel, A.“Kleine Brennstoffzellen für denmobilen Einsatz” VDI-VDE-TagungSensorik, Bad Kissingen, 3.-4.5.2000

Heinzel, A.“Brennstoffzellen-Technologienund Stand der Entwicklung”,WinGas-Forum, Kassel, 6.-7.9.2000

Heinzel, A.“Brennstoffzellentechnologie”,Hyforum 2000, Munich, 11.-15.9.2000

Heinzel, A.; Rampe, T.; Vogel, B.1;Haist, A.; Hübner, P.“Reforming of Fossil Fuels – R&Dat Fraunhofer Institute for SolarEnergy Systems”, Seminar on Fuel Cells 2000, Portland, USA,30.10.-2.11.2000, Poster (1: DaimlerChrysler AG, Ulm)

Heinzel, A.“Neue Gesamtenergieversor-gungskonzepte für Gebäude”, 5. Kasseler Symposium Energie-Systemtechnik, Kassel, 9.-10.11.2000

Heinzel, A.“Brennstoffzellen – attraktiveEnergiewandler für den sta-tionären, mobilen und portablenEinsatz” Zukunftstag WVIBFreiburg, 16.11.2000, Freiburg

Heinzel, A.“Brennstoffzellen im kleinenLeistungsbereich – PortableAnwendungen”, BASF Ludwigs-hafen, 13.12.2000

Hindenburg, C.“Solargestützte Klimatisierung”,Thermodynamikseminar, Tech-nische Universität München,Munich, 28.7.2000

Hoffman, V.U.“Entwicklungsstand der Photo-voltaik in Deutschland”, Klausur-veranstaltung VisionäreDachsysteme, Feusisberg,Switzerland, 19.1.2000

Hoffman, V.U.“Photovoltaik-Vorhaben anSchulen – Erfahrungen undErgebnisse aus SONNEonline undSonne in der Schule”, Vortrag aufder Informationsveranstaltung fürLehrer, Neubrandenburg,20.3.2000

Hoffmann, V.U.“Grundlagen der Photovoltaik”,Fortbildungsseminar: Bauen mitSolartechnik für Architekten,Leipzig, 7.4.2000 und 17.11.2000

Hoffmann, V.U.“Photovoltaik in Gebäuden –Techniken, Auslegung, Beispiele”,Fortbildungsseminar: Bauen mitSolartechnik für Architekten,Leipzig, 8.4.2000 und 18.11.2000

Hoffmann, V.U.“Grundlagen der Photovoltaik –Einsatzgebiete und Marktsituationsowie Betriebserfahrungen”,Fortbildungskurs „Energie- undGebäudemanagement”, Büro fürUmweltpädagogik, Freiburg,15.5.2000

Facts and Figures


Köhl, M.“Neue Materialien für die Solar-technik: Selektive Solarabsorber –Schichten für unverglasteFassaden”, Solar 2000, Gleisdorf,Austria, 4.-9.9.2000

Köhl, M.“Selective Solar Absorbers – AnIntroduction”, ÅngströmLaboratory, University of Uppsala,Uppsala, Sweden, 29.9.2000

Köhl, M.“New IEA-SHC Task: Performanceof Solar Façade Components”,CEN-STAR Workshop, Paris, France6.10.2000

Köhl, M.“Solare Energietechnik, Zukunfts-markt für Kupferprodukte?”,Outokumpo-Tag, Expo, Hanover,16.10.2000

Köhl, M.“Singulett-Sauerstoff undWasser”, Kolloquium des Institutsfür Bodenkunde am Umwelt-forschungszentrum Halle-Leipzig,Leipzig, 20.10.2000

Kuckelhorn, T.; Goetzberger, A.;Herzog, Th.“CPC-Strukturen zur Tageslicht-nutzung”, 6. Symposium Inno-vative Lichttechnik in Gebäuden,OTTI-Technologie-Kolleg,Staffelstein, 27.-28.1.2000

Kuhmann, J.“Elektrische Energiespeicher fürGeräte und Kleinsysteme”,Seminar PVG, Freiburg, 2.2.2000

Kuhmann, J.“Lithium-Ionen-Akkus für Photo-voltaik-Geräte der Zukunft?”, D&EEntwicklungsforum: Batterien,Ladekonzepte und Stromver-sorgungsdesign, Munich,28.3.2000

Kuhn, T.; Platzer, W.; Eder, K.1;Sack, N.1; Beck, A.2; Hauck, M.2;Haug, I.2; Wirth, H.3; Simon, R.4;Kasper, F.J.5

“Reges-Projektpräsentation”, 6. Symposium InnovativeLichttechnik in Gebäuden, OTTI-Technologie-Kolleg, Staffelstein,27.-28.1.2000, Poster (1: Institut für Fenstertechnik e.V.,Rosental) (2: Bayerisches Zentrum fürAngewandte EnergieforschungZAE e.V., Würzburg) (3: OKALUX Kapillarglas GmbH,Marktheidenfeld-Altfeld) (4: WAREMA Renkhoff GmbH,Marktheidenfeld-Altfeld) (5: Grünzweig + Hartmann AG,Ladenburg)

Laukamp, H.“Elektrische Sicherheit, Errich-tungsbestimmungen, Blitzschutz”,Fachseminar Photovoltaik-Anlagen, OTTI-Technologie-Kolleg,Freiburg, 23.-24.5.2000

Lerchenmüller, H.; Gombert, A.“Mikrostrukturierte Oberflächen”,Hanover Trade Fair, Hanover,23.3.2000

Lustig, K.; Rommel, M.;Stankowski, D.; Wittwer, Chr.;Fink, C.1; Hausner, R.1

“Experimentelle Untersuchungenzum Stillstandverhalten solarther-mischer Anlagen”, 10. SymposiumThermische Solarenergie, OTTI-Technologie-Kolleg, Staffelstein,10.-12.5.2000, (1: Arbeitsgemeinschaft Erneu-erbare Energie AEE, Gleisdorf,Austria)

Luther, J.“Energiegewinnung ausSonnenlicht”, Workshop OptischeTechnologien für das 21. Jahr-hundert, VDI, Dresden-Radebeul,23.-24.11.1999

Luther, J.“Photovoltaische Energiekon-version – Status, Zukunft,Visionen”, Hahn-Meitner-Institut,Berlin, 8.12.1999

Luther, J.“Zukünftige Nutzung erneuerbarerEnergiequellen”, Workshop VisionKeramik 2000+ Dresden,13.1.2000

Luther, J.“Technische Entwicklungen imBereich Photovoltaik und Solar-thermie”, 25 Jahre BundesverbandSolarenergie, Berlin, 19.5.2000

Luther, J.“Photovoltaische Energiever-sorgung – Stand der Technik undAussichten”, Deutsche Physika-lische Gesellschaft, Magnus Haus,Berlin, 23.5.2000

Luther, J.“Solar Electricity”, EuroSun 2000,3rd ISES-Europe Solar Congress,Copenhagen, Denmark, 19.-22.6.2000

Luther, J.; Voss, K.“Solares Bauen – Konzepte undMärkte”, Solarimpulse Freiburg2000, Freiburg, 5.-9.7.2000

Müller, M.; Hebling, C.; Heinzel, A.“Mini-Brennstoffzellen für porta-ble elektronische Geräte”,Hanover Trade Fair, Hanover, 20.-25.3.2000

Platzer, W.“Innovationen in der Fassade.Elektrochemische, gasochromeund thermotrope Verglasungen”,Seminar, Fachhochschule Basel,Basel, Switzerland, 23.5.2000

Parodi, O.“Clean Water with Clean Energy.Drinking Water Provision inRemote Regions withDecentralised Solar PowerSupply”, Seminar for RenewableEnergies and Infrastructure, Arica,Chile, 24.11.1999

Rau, A.; Heinzel, A.“Reversibles Electrolyse-/Brenn-stoffzellen-System zur Energie-speicherung”, Tagung derGesellschaft Deutscher Chemikere.V., Fachgruppe AngewandteElektrochemie, Ulm, 27.-29.9.2000, Poster

Rommel, M.; Hermann, M.;Koschikowski, J.; Schäfer, A.“SODESA: Entwicklung von korro-sionsfreien Kollektoren zurMeerwasserentsalzung”, 10. Symposium ThermischeSolarenergie, OTTI-Technologie-Kolleg, Staffelstein, 10.-12.5.2000

Roth, W.“Prinzipieller Systemaufbau,Anwendungsbeispiele undMarktpotenzial photovoltaisch ver-sorgter Geräte und Kleinsysteme”,Fachseminar Photovoltaisch ver-sorgte Geräte und Kleinsysteme,OTTI-Technologie-Kolleg, Freiburg,2.-3.2.2000

Roth, W.“Grundlagen zur Solarzelle, zumModul und zum Solargenerator”,Fachseminar Photovoltaisch ver-sorgte Geräte und Kleinsysteme,OTTI-Technologie-Kolleg, Freiburg,2.-3.2.2000

Roth, W.“Mit der Sonne telefonieren:Solargeräte für den privaten undkommerziellen Gebrauch”, ÖKO2000 und ÖKO BAU, Freiburg,14.5.2000

Roth, W.“Photovoltaische Energiever-sorgungssysteme – KlimatischeRandbedingungen, prinzipiellerSystemaufbau und Einsatzmög-lichkeiten”, FachseminarPhotovoltaik-Anlagen, OTTI-Technologie-Kolleg, Freiburg, 23.-24.5.2000

Roth, W.“Elektrische Eigenschaften undVerschaltung von Solargenera-toren”, Fachseminar Photovoltaik-Anlagen, OTTI-Technologie-Kolleg,Freiburg, 23.-24.5.2000

Roth, W.“Von der Küchenwaage bis zumRasenmäher – Solarprodukte fürden privaten und kommerziellenGebrauch”, Badische Zeitung,Vortragsreihe BZ-Ratgeber,Freiburg, 5.10.2000

Sauer, D.U.“PV in netzfernen Anwendungenund Batterien”, VDE Mannheim,Mannheim, 12.4.2000

Sauer, D.U.“Speichertechnologien – eineÜbersicht”, DGS Südhessen,Frankfurt a/M., 15.6.2000

Sauer, D.U.; Bopp, G.“Batteries in Hybrid Systems”,Village Power – EmpoweringPeople and Transforming Markets,Washington, Poster, 4.-8.12.2000

Schäfer, A.; Rommel, M.“Neue Messeinrichtung desPrüfzentrums für thermischeSolaranlagen im Hinblick auf dieneue Europäische KollektornormDIN EN 12975-1 und 2”, 10. Symposium ThermischeSolarenergie, OTTI-Technologie-Kolleg, Staffelstein, 10.-12.5.2000, Poster

Schindler, R.“Erneuerbare Energien”, TechnicalUniversity of Monterrey,Guadalajara, Mexico, 10.11.2000

Schindler, R.“Solarenergie”, University ofColima, Mexico, 11.11.2000

Schmidt, H.“Kleine Spannungen, hohe Ströme– Neues Konzept für Spannungs-wandler”, VDE-Bezirk Kurpfalze.V., Mannheim, 8.11.2000

Schossig, P.; Henning, H.M.“Mikroverkapselte Phasenwechsel-materialien in Wandverbund-systemen”, 10. SymposiumThermische Solarenergie, OTTI-Technologie-Kolleg, Staffelstein,10.-12.5.2000, Poster

Sölter, J.; Dicker, J.; Schumacher,J.; Glunz, S.W.; Warta, W.“Charakterisierung von industrie-relevanten rückseitenkontaktiertenSilizium-Solarzellen”, Tagungs-band, DPG-Frühjahrstagung,Regensburg, 27.-31.3.2000

Publications

Adib, R.“Crédits à l’Electricité Rurale”,Echos du Cota, N°85 (1999),Brussels, Belgium, 14-16

Adib, R.“Microfinance - a Way to surpassthe Obstacles of Financing RuralElectrification with Photovoltaics”,Proceedings of Seminar on RuralElectrification in Africa, Johannes-burg, South Africa, 17.-18.4.2000,CD-ROM

Agert, C.; Dimroth, F.; Schubert, U.; Bett, A.W.; Leu, S.;Stolz, W. “High-Efficiency (AlGa) As/ GaAsSolar Cells Grown by MOVPEUsing TBAs and Low Temperaturesand Low V/III-Ratios”, in: SolarEnergy Materials & Solar Cells,Vol. 66 (2001), 637-644

Agert, C.; Dimroth, F.; Schubert,U.; Bett, A.W.; Smith, L.1;Rushworth, S.1; Kanjolia, R.1

“Low Oxygen Levels ~ 1017 cm-3

in MOVPE Grown AL0.8Ga0.2As”,Tagungsheft 14. Workshop desDGKK-Arbeitskreises Epitaxie vonIII-V Halbleitern, Stuttgart, 8.-9.12.1999 (1: Epichem Ltd., Merseyside,United Kingdom)

Agert, C.; Lanyi, A.; Bett, A.W.“Wachstumsbedingungen GaSb-basierender Materialien im Multi-wafer-Planetenreaktor”, Tagungs-heft 14. Workshop des DGKK-Arbeitskreises Epitaxie von III-VHalbleitern, Stuttgart, 8.-9.12.1999

Agert, C.; Lanyi, P.; Sulima, O.V.;Stolz. W.; Bett, A.W.“Growth of Antimony-BasedMaterials in a Multiwafer PlanetaryMOVPE-Reactor for PhotovoltaicApplications”, IEE Proceedings –Optoelectronics: Materials andDevices, Vol. 147, (3/2000), 188-192

Andreev, V.M.1; Bett, A.W.;Dimroth, F.; Hein, M.; Letay, G.;Rumyantsev, V.D.1; Shvarts, M.Z.1;Sulima, O.V.“Concentrator Array Based onGaAs Cells and Fresnel LensConcentrator”, Proceedings 16thEuropean Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1-5.5.2000, im Druck (1: Ioffe Physico-Technical Institute,St. Petersburg, Russia)

Facts and Figures


Wittwer, Chr.“Regelungssystementwicklung miteiner virtuellen Testumgebung aufBasis der SimulationsumgebungColSim”, 10. Symposium Ther-mische Solarenergie, OTTI-Tech-nologie-Kolleg, Staffelstein, 10.-12.5.2000

Wittwer, V.“Nano- and Micro-structuredFunctional Surfaces”, the 4thSino-German Symposium of SolidState Physics, Tonyji-University,Shanghai, China, 22.-25.10.2000

Steinhüser, A.“Grundlagen zur Nutzung derSonnenenergie”, FachseminarPhotovoltaisch versorgte Geräteund Kleinsysteme, OTTI-Tech-nologie-Kolleg, Freiburg, 2.-3.2.2000

Steinhüser, A.“Aspekte zur Entwicklung von PV-Geräten”, Fachseminar Photo-voltaisch versorgte Geräte undKleinsysteme, OTTI-Technologie-Kolleg, Freiburg, 2.-3.2.2000

Steinhüser, A.“Kompakte PV-Hybridsysteme”,Fachseminar Photovoltaisch ver-sorgte Geräte und Kleinsysteme,OTTI-Technologie-Kolleg, Freiburg,2.-3.2.2000

Steinhüser, A“Computerunterstützte Auslegungund Simulation von PV-Kleinsystemen”, FachseminarPhotovoltaisch versorgte Geräteund Kleinsysteme, OTTI-Techn-ologie-Kolleg, Freiburg, 2.-3.2.2000

Steinhüser, A.“Auslegung von Photovoltaik-Anlagen”, Fachseminar Photo-voltaik-Anlagen, OTTI-Technologie-Kolleg, Freiburg, 23.-24.5.2000

Steinhüser, A.“Kompakte PV-Hybridsysteme”,Vortrag im Rahmen der Vorlesung“Photovoltaik-Systemtechnik”ander Universität Karlsruhe,Karlsruhe, 25.7.2000

Steinhüser, A.“Computerunterstützte Auslegungvon PV-Kleinsystemen”, Vortrag imRahmen der Vorlesung“Photovoltaik-Systemtechnik”ander Universität Karlsruhe,Karlsruhe, 25.7.2000

Willeke, G.“Solarzellen – Stand der Technikund Trends”, Universität Karlsruhe,Karlsruhe, 21.2.2000

Willeke, G.“Photovoltaik – Potenziale,Nachhaltigkeitschancen undKonflikte”, HGF-ExpertenWorkshop, Munich, 22.11.2000

Andreev, V.M.1; Rumyantsev, V.D.1;Shvarts, M.Z.1; Bett, A.W.;Dimroth, F.; Hein, M.; Letay, G.;Sulima, O.V.“All-Glass Terrestrial ConcentratorModules Based on CompositeFresnel Lenses and III-V SolarCells”, Proceedings 28th IEEEPhotovoltaic Specialist Conference,Anchorage, USA, 17.-22.9.2000,im Druck (1: Ioffe Physico-Technical Institute,St. Petersburg, Russia)

Bau, S.; Zimmermann, W.; Dicker,J.; Schumacher, J.“Großflächig rekristallisierte Si-Schichten für Kristalline-Dünn-schichtsolarzellen”, Tagungsband,Frühjahrstagung der DeutschenPhysikalischen Gesellschaft DPG,Dresden, 20.-24.3.2000, 321

Bendel, Ch.1; Landau, M.1; Roth,W.; Steinhüser, A.“Photovoltaische Produktionsent-wicklungen mit kleinen und mitt-leren Unternehmen (KMU)”,Tagungsband 15. SymposiumPhotovoltaische Solarenergie,OTTI-Energie-Kolleg, Staffelstein,15.-17.3.2000, 216-222 (1: Institut für SolareEnergieversorgungstechnik ISET,Kassel)

Bett, A.W.; Dimroth, F.; Meusel, M.; Schubert, U.;Adelhelm, R.“Development of Ga5.51In0.49P/GaAs Tandem Solar Cells on anIndustrial Size MOVPE Reactor”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Bett, A.W.; Dimroth, F.; Lange, G.;Meusel, M.; Beckert, R.; Hein, M.;Riesen, S.v.; Schubert, U.“30 % Monolithic TandemConcentrator Solar Cells forConcentrations Exceeding 1000Suns”, Proceedings 28th IEEEPhotovoltaic Specialist Conference,Anchorage, USA, 17.-22.9.2000,in press

Bett, A.W.“Tandem and Concentrator Cells”,Proceedings PVTEC Super-HighSolar Cell Efficiency ResearchCommittee Meeting, Tokyo, Japan,16.11.2000, in press

Bläsi, B.; Boerner, V.; Gombert, A.;Heinzel, A.; Kübler, V.; Wittwer, V. “Combined Functional Surface-Relief Structures for VariousApplications” Proceedings 10thInternational Colloquium onSurfaces, Chemnitz, 31.1.-2.2.2000, 222-229

Facts and Figures


Bläsi, B.; Lalanne, Ph.1; Rodier, J.-C.1; Gombert, A. “Surface Structures Produced by aNear-Field Process”, Proceedings6th International Conference onNear Field Optics, University ofTwente, the Netherlands, 27.-31.8.2000, 190 (1: CNRS, Orsay, France)

Boerner, V.; Bläsi, B.; Gombert, A.;Heinzel, A.; Kübler, V.; Popp, P.;Wittwer, V.“Large Area Surface-Relief Microstructures for Optical Applications”, Proceedings Micro Materials Conference“MicroMat2000”, Berlin, 17.-19.4.2000, in press

Boerner, V.; Bläsi, B.; Gombert, A.;Heinzel, A.; Kübler, V.; Popp, P.;Wittwer, V.;“Holographic Surface-ReliefMicrostructures for Large AreaApplications”, Proceedings, 1steuspen Topical Conference onFabrication and Metrology inNanotechnology, Copenhagen,Denmark, 28.-30.5.2000, 18-25

Bopp, G.; Bonneviot, H.1; Hankins, M.2; Paradzik, T.5; Preiser, K.; Nuh, D.3; Rouvière, B.4

“Datenbank von europäischenHerstellern und Distributorensowie Komponententests für SolarHome Systeme (SHS)”, Tagungs-band 15. Symposium Photo-voltaische Solarenergie, OTTI-Energie-Kolleg, Staffelstein, 15.-17.3.2000. 377-381 (1: IED, Paris, France) (2: ESD, Wiltshire, UnitedKingdom) (3: EETS, Cardiff, United Kingdom)(4: APEX, Laverune, France) (5: PSE Projektgesellschaft SolareEnergiesysteme mbH, Freiburg)

Bopp, G.; Bonneviot, H.1; Hankins, M.2; Paradzik, T.3; Preiser, K.; Nuh, D.4; Rouvière, B.5

“Database of European Manu-facturers and Distributors andTests of Components for SolarHome Systems”, Proceedings 16thEuropean Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press (1: IED, Paris, France) (2: ESD, Wiltshire, UnitedKingdom) (3: PSE Projektgesellschaft SolareEnergiesysteme mbH, Freiburg) (4: EETS, Cardiff, United Kingdom)(5: APEX, Laverune, France)

Bopp, G.; Gabler, H.; Hille, G.;Puls, H.-G.; Rehm, M.; Sauer, D.U.;Schulz. M.; Schweizer-Ries, P.“Qualitätssicherung von photovol-taischen Energieversorgungs-systemen”, Abschlussbericht fürdas BMBF Forschungsvorhaben0329596 (6/2000), Freiburg

Bopp, G.; Neufeld, R.; Senft, S.;Schulz, M.“Long-Term Operating Experiencewith Thirty Stand-Alone PVSystems”, Proceedings PV HybridPower Systems 2000 Conference,Aix-en-Provence, France, 7.-8.9.2000, in press

Bopp, G.; Puls, H.-G.; Sauer, D.U.“TALCO – a New Technical andLeast Cost Optimisation Tool”,Proceedings PV Hybrid PowerSystems 2000 Conference, Aix-en-Provence, France, 7.-8.9.2000, inpress

Borchert, D.“Solarzellen – Technologien undWirkungsgrade”, Elektor(März/2000), 19

Bourdais, S.1; Reber, S.;Lautenschlager, H.; Hurrle, A.;Sloui, A.1

“Recrystallized Silicon Thin FilmSolar Cells on Mullite CeramicSubstrates”, Proceedings 16thEuropean Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press (1: Laboratoire PHASE CNRS,Strasbourg, France)

Bourdais, S.1; Slaoui, A.1;Beaucarne, G.2; Poortmans, J.2;Reber, S.“Deposited Polycrystalline SiliconLayers on Mullite Substrates forSolar Cells”, Proceedings 10thWorkshop on Crystalline SiliconSolar Cell Materials and Processes,Copper Mountain Resort, Co,USA, 13.-16.8.2000, 133-134 (1: Laboratoire PHASE CNRS,Strasbourg, France) (2: IMEC, Leuven, Belgium)

Brunold, S.1; Frei, B.1; Carlsson, K.2; Köhl, M.“Round Robin on Accelerated LifeTesting of Solar Absorber SurfaceDurability”, in: Solar EnergyMaterials and Solar Cells, Vol. 61,No. 3, 239-253 (1: Solar Energy Testing andResearch Group, ITR, Rapperswil, Switzerland) (2: Swedish National Testing andResearch Institute, Borås, Sweden)

Bühring, A.; Russ, Chr.“Lüftungskompaktgeräte: Ange-bot, Erfahrungen und Weiterent-wicklung”, Tagungsband 4. Passiv-haus-Tagung, Kassel, 10.-11.3.2000, 49-58

Bühring, A.; Russ, Chr.“Wärmeversorgung mit Lüftungs-Kompaktgeräten für Solar-Passivhäuser, Erfahrungen undWeiterentwicklung”, Tagungsband10. Symposium ThermischeSolarenergie, OTTI-Technologie-Kolleg, Staffelstein, 10.-12.5.2000, 35-41

Bühring, A.“Lüftungs-Kompaktgeräte: Standder Weiterentwicklung undMessungen im Einsatz”, Band der20. Sitzung des Arbeitskreises“Kostengünstige Passivhäuser”,11.5.2000 Darmstadt, 53-66

Bühring, A.“Lüftungs-Kompaktgeräte:Angebot, Erfahrungen,Weiterentwicklung”, Tagungsbanddes Arbeitskreises “Kostengün-stige Passivhäuser”, Wuppertal,16.6.2000, 34-44

Bühring, A.;“Solar-Passivhäuser:Wärmeversorgung mit Lüftungs-Kompaktgeräten”, Tagungsband“Das ökologische Passivhaus”, St.Pälten, Austria, 16.-17.10.2000, inpress

Bühring, A.“Feldtest von Lüftungs-Kompaktgeräten”, in: Heizung,Lüftung, Klimatechnik – HLK (10/2000), 10-15

Bühring, A.“Lüftungs-Kompaktgeräte:Erfahrungen und Weiterent-wicklung”, in: Seminar-Ordner v.Seminaren der Passivhaus-Dienstleistungs GmbH,23.11.2000 Ulm, und 7.12.2000Hamburg

Bühring, A.“Niedrige Heizkosten garantiert”in: Handelsblatt, 27.12.2000, 46

Carlsson, B.1; Möller, K.1; Frei, U.2;Brunold, S.2; Köhl, M.“Comparison between Predictedand Actually Observed In-ServiceDegradation of a NickelPigmented Anodized AluminiumAbsorber Coating for Solar DHWSystems”, in: Solar EnergyMaterials and Solar Cells, Vol. 61,No. 3, 223-238 (1: Swedisch National Testing andResearch Institute, Borås, Sweden)(2: Solar Energy Testing andResearch Group, ITR, Rapperswil,Switzerland)

Carlsson, B.1; Möller, K.1; Köhl, M.; Frei, U.2; Brunold, S.2

“Qualification Test Procedure forSolar Absorber SurfaceDurability”, in: Solar EnergyMaterials and Solar Cells, Vol. 61,No. 3, 225-275 (1: Swedish National Testing andResearch Institute, Borås, Sweden)(2: Solar Energy Testing andResearch Group, ITR, Rapperswil,Switzerland)

Carlsson, B.1; Möller, K.1; Frei, U.2;Köhl, M.“Accelerated Testing for LifeAssessment of Solar AbsorberSurfaces”, in: CEEES-Publication:Climatic and AtmosphericPollution Effects on Materials andEquipment (2/1999), 93-107 (1: Swedish National Testing andResearch Institute, Borås, Sweden)(2: Solar Energy Testing andResearch Group, ITR, Rapperswil,Switzerland)

Dicker, J.; Schumacher, J.O.; Sölter, J.; Zimmermann, W.; Bau, S.; Warta, W.“Numerical Analysis of CrystallineSilicon Thin Film Solar Cells onPerforated SiO2 Barrier Layers”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Dicker, J.; Sölter, J.; Schumacher,J.O.; Glunz, S.W.; Warta, W.“Analysis of Rear Contacted SolarCell Structures for Cost-EffectiveProcesses and Materials”,Proceedings 28th IEEE PhotovoltaicSpecialist Conference, Anchorage,USA, 17.-22.9.2000, in press

Dimroth, F.; Lanyi, P.; Schubert, U.;Bett, A.W.“Wachstum von dicken, verspann-ten Ga1-xInxAs Schichten auf GaAsSubstrat für die Solarzellenan-wendung”, Tagungsheft 14.Workshop des DGKK-Arbeits-kreises Epitaxie von III-V Halb-leitern, Stuttgart, 8.-9.12.1999

Georg, A.; Graf, W.; Wittwer, V.“The Gasochromic Coloration ofSputtered WO3 Films with LowWater Content”, Proceedings 4thInternational Meeting on Electro-chromics IME4, Uppsala, Sweden,21.-23.8.2000, in press

Glaubitt, W. 1; Sporn, D.1;Hußmann, E.1; Gombert, A.;Wittwer, V.“High Transmission Float for SolarApplications”, in: Glastech. Ber.Glass Science Technology 73, No. 6 (2000), 193-195 (1: Fraunhofer-Institut fürSilicatforschung ISC, Würzburg)

Glunz, S.W.; Rein, S.; Knobloch, J.“Stable Czochralski Silicon SolarCells Using Gallium-Doped BaseMaterial”, Proceedings 16thEuropean Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Glunz, S.W.; Rein, S.; Warta, W.;Knobloch, J.; Wettling, W. “Degradation of Carrier Lifetimein CZ Silicon Solar Cells”, in: SolarEnergy Materials & Solar Cells,Vol. 65 (2000), 219-229

Glunz, S.W.“Neue Konzepte für Silicium-solarzellen”, Tagungsband 12. Internationales Sonnenforum,DGS und 11. JahrestagungForschungsverbund Sonnen-energie, FVS, Freiburg, 5.-7.7.2000, in press

Glunz, S.W.; Lee, J.Y.; Rein, S.“Strategies for Improving theEfficiency of CZ-Silicon SolarCells”, Proceedings 28th IEEEPhotovoltaic Specialist Conference,Anchorage, USA, 17.-22.9.2000,in press

Glunz, S.W.; Schaefer, S.; Preu, R.;Schneiderlöchner, E.; Pfleging, W.1; Lüdemann, R.;Willeke, G.“New Simplified Methods forProcessing the Rear ContactPattern of PERC High-EfficiencySolar Cells”, Proceedings 28thIEEE Photovoltaic SpecialistConference, Anchorage, USA, 17.-22.9.2000, in press (1: Forschungszentrum KarlsruheGmbH, Karlsruhe)

Goerdt, W.1; Platzer, W.J.“Solar Walls with VentilatedTransparent Insulation:Performance, Properties, Problemsand Prospects”, ProceedingsEuroSun 2000, 3rd ISES-EuropeSolar Congress, Copenhagen,Denmark, 19.-22.6.2000, CD-ROM (1: PSE Projektgesellschaft SolareEnergiesysteme mbH, Freiburg)

Goetzberger, A.; Bühler, Ch.;Goller, M.1

“Ein statischer, diffuslicht-trans-mittierender Blend- und Sonnen-schutz”, Tagungsband 6. Sympo-sium Innovative Lichttechnik inGebäuden, OTTI-Technologie-Kolleg, Staffelstein, 27.-28.1.2000, 253-258 (1: Materialforschungzentrum FMF,Freiburg)

Goetzberger, A.“Solarthermie: Woher kommenwir, wohin gehen wir?”,Tagungsband, 10. SymposiumThermische Solarenergie, OTTI-Technologie-Kolleg, Staffelstein,10.-12.5.2000, 424-434

Goetzberger, A.; Müller, M.;Goller, M.1

“A Self-Regulating Sun ProtectionSystem Using Concentrated SolarRadiation and ThermotropicCoating”, Proceedings EuroSun2000, 3rd ISES-Europe SolarCongress, Copenhagen, Denmark,19.-22.6.2000, CD-ROM (1: Materialforschungzentrum FMF,Freiburg)

Goetzberger, A.; Hebling, Chr.“Photovoltaic Materials, Past,Present and Future”, in: SolarEnergy Materials and Solar Cells,Vol. 62 (2000), 1-19

Goller, M.1; Reise, Chr.“Über die Veränderlichkeit desTageslichtes”, Tagungsband 6.Symposium Innovative Lichttechnikin Gebäuden, OTTI-Technologie-Kolleg, Staffelstein, 27.-28.1.2000, 85-90 (1: MaterialforschungszentrumFMF, Freiburg)

Gombert, A.“Future Steps Towards Large-AreaMicrostructured Surfaces”,Proceedings euspen InternationalSeminar on Precision Engineeringand Micro Technology, Aachen,19.-20.7.2000, 195-203

Gombert, A.“Surface Patterns to Serve aPurpose”, in: Materials World, Vol.8 (9/2000), 25-27

Gombert, A.; Bläsi, B.; Boerner, V.;Kübler, V.; Niggemann, M.“Holographic Microstructures forLarge-Area Applications”,Proceedings of MICRO.tec 2000,VDE World MicrotechnologiesCongress, 25.-27.10.2000, Expo2000, Hannover, 103-106

Graf, W.; Georg, A.; Wittwer, V.“Gasochrome Verglasungen alsÜberhitzungs- und Blendschutz”,in: Stahlbau (Mai/2000), 483-484


Facts and Figures Eversheim, W.1; Güthenke, G.1;Lüdemann, R.; Preu, R.;Schweitzer, G.1; Wettling, W.“Innovative ProductionTechnologies for Solar Cells – SOLPRO”, Proceedings 16thEuropean Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press (1: Fraunhofer-Institut fürProduktionstechnologie IPT,Aachen)

Eyer, A.; Haas, F.; Kieliba, T.;Oßwald, D.; Reber, S.;Zimmermann, W.; Warta, W.“Chrystalline Silicon Thin Film(CSITF) Solar Cells on SSP and onCeramic Substrates”, in: Journal ofCrystal Growth, 12th AmericanConference on Crystal Growthand Epitaxy, ACCGE-12, Vail, CO,USA, 13.-18.08.2000, 83

Feddeck, P.1; Roth, W.; Bendel, Ch.2

“Geräte mit integrierter Solar-stromversorgung”, BINE-Informa-tionsdienst, Projektinfo (4/00),Broschüre (1: BINE FachinformationszentrumKarlsruhe, Bonn) (2: Institut für Solare Energiever-sorgungstechnik ISET, Kassel)

Ferber, J.2; Kern, R.2; Sastrawan, R.2; Schill, C.2;Schubert, M.2; Hinsch, A.1; Kroon, J.1; Späth, M.1; Roosmalen, J.A.M. van1; Meyer, A.3; Meyer, T.3; Niepmann, R.4;Holzbock, J.4;Uhlendorf, I.4

“Long-Term Stability of Dye-Sensitized Solar Cells for LargeArea Power Applications”,Proceedings IPS-2000, Snowmass/Aspen, CO, USA, 30.7.-4.8.2000(1: Netherlands Energy ResearchFoundation ECN, Petten, theNetherlands) (2: MaterialforschungszentrumFMF, Freiburg) (3: Solaronix SA, Aubonne,Switzerland) (4: Institut für Angewandte Photo-voltaik INAP, Gelsenkirchen)

Ferber, J.1; Aschaber, J.; Hebling, Chr.; Heinzel A.; Wiehle, R.; Zenker, M.; Luther, J.“Microstructured TungstenSurfaces as Selective Emitters inThermophotovoltaic Systems”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press (1: MaterialforschungszentrumFMF, Freiburg)

Dimroth, F.; Lanyi, P.; Schubert, U.;Bett, A.W.“Optimierung der Abscheidungs-homogenität von Ga0.51In0.49P undGaAs auf einer AIX 2600-G3MOVPE Anlage”, Tagungsheft 14.Workshop des DGKK-Arbeits-kreises Epitaxie von III-V Halb-leitern, Stuttgart, 8.-9.12.1999

Dimroth, F.; Lanyi, P.; Meusel, M.;Schubert, U.; Bett, A.W.“New Lattice MismatchedGaInP/GaInAs Tandem Solar CellConcepts for High EfficiencySpace- and TerrestrialConcentrator Solar Cells”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Dimroth, F.; Bett, A.W.; Walters, R.J.1; Summers, G.P.1;Messenger, S.R.2; Takamoto, T.3;Ikeda, E.3; Imaizumi, M.4; Anzawa, O.4; Matsuda, S.4

“Radiation Response of Dual-Junction GayIn1-yP/Ga1-xInxAs SolarCells”, Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press (1: U.S. Naval Research Lab.,Washington, DC, USA) (2: SFA, Largo, MD, USA) (3: Japan Energy Corp., Saitama,Japan) (4: National Space DevelopmentAgency of Japan, Ibaraki, Japan)

Dimroth, F.; Sulima, O.V.; Bett, A.W.“Recent Progress in theDevelopment of III-V Solar andThermophotovoltaic Cells”, in:Compound Semiconductors 6 (6),(August/2000), 1-4

Emery, K.1; Moriarty, T.1; Kurtz,S.1; Meusel, M.; Beckert, R.;Dimroth, F.; Bett, A.W.; Warta, W.“Procedures for EvaluatingMultijunction Concentrators”,28th IEEE Photovoltaic SpecialistConference, Anchorage, USA, 17.-22.9.2000, in press (1: National Renewable EnergyLaboratory, Golden, CO, USA)


Facts and FiguresHaller, A.1; Humm, O.2; Voss, K.“Renovieren mit der Sonne”, 1. Aufl. 2000, ISBN: 3-922964-81-8 (1: Ernst Schweizer AG, Hedingen,Switzerland) (2: free-lance Journalist, Zurich,Switzerland)

Hauch, A.1; Georg, A.; Orel, B.2;Opara Krasovec, U.2

“New PhotoelectrochromicDevice”, Proceedings 4thInternational Meeting onElectrochromics IME4, Uppsala,Sweden, 21.-23.08.2000, in press (1: MaterialforschungszentrumFMF, Freiburg) (2: National Institute of Chemistry,Ljubljana, Slovenia)

Hebling, Chr.“Principles of Fuel Cells andPortable PEFC-Systems”,Tagungsmappe (SZ) CeBit, TradeFait and Exhibition, Hanover,24.2.–1.3.2000

Hebling, Chr.; Müller, M1.; Müller, C.1

“Fuel Cell Using Micro-StructuredFlow Fields”, 4th Int. Conferenceon Microreaction Technology,Atlanta, USA, 5.-9.3.2000 (1: Institut für MikrosystemtechnikIMTEK, Freiburg)

Hebling, Chr.; Ferber, J.1

“Solar Cells and Fuel Cells asDevice Integrated Power Sources”,Batteries 2000, Paris, France, 28.-30.3.2000 (1: MaterialforschungszentrumFMF, Freiburg)

Hebling, Chr.“Fuell Cells with Micro-StructuredFlow Field for Portable ElectronicDevices”, Proceedings ConferenceSmall Fuel Cells and BatteryTechnology for Use in PortableApplications, The KnowledgeFoundation, New Orleans, USA,26.-28.4.2000

Hebling, Chr.; Müller, M.1; Heinzel, A.“PEM-Fuel Cell with a Micro-Structured Flow Field”, Tagungs-band HYFORUM 2000, Munich,11.-15.9.2000, 245-253 (1: Institut für MikrosystemtechnikIMTEK, Freiburg)

Hebling, Chr.; Heinzel, A.; Müller, M.1; Müller, C.1; Tüber, K.;Schmitz, A.“Fuel Cells for Low PowerApplications: Construction,Simulation and Measurement”,Tagungsband HYFORUM 2000,Bd. 2, Munich, 11.-15.9.2000,245 (1: Institut für MikrosystemtechnikIMTEK, Freiburg)

Hebling, Chr.; Heinzel, A.; Müller, M.1; Tüber, K.; Schmitz, A.“Fuel Cells for the Low PowerRange – the Banded StructureMembrane and the Micro-Structured Flowfield”, ProceedingsSeminar on Fuel Cells 2000,Portland, USA, 30.10.-2.11.2000,134-137 (1: Institut für MikrosystemtechnikIMTEK, Freiburg)

Hebling, Chr.; Heinzel, A.; Zedda, M.“Die portable Brennstoffzelle”,Kongressband Kongress “EnergieInnovativ 2000” Nürnberg 29.-30.11.2000, in press

Heinzel, A.; Boerner, V.; Gombert, A.; Bläsi, A.; Wittwer, V.;Luther, J., “Radiation Filters and Emitters forthe NIR Based on PeriodicallyStructured Metal Surfaces”, in:Journal of Modern Optics, Vol. 47,(13/2000), 2399-2419

Heinzel, A.; Rau, A.“Prospects for Fuel Cells in aEuropean Research Area”,Brochure: Energy Storage byReversible Electrolyser/ Fuel CellSystems, Brussels, Belgium, 29.-30.5.2000

Heinzel, A.; Hebling, Chr.; Müller, M.1; Zedda, M.; Müller, C.1

“Fuell Cells for Low PowerApplications”, 7. Ulmer Elektro-chemischer Tag, Ulm, 26.-27.6.2000, in: Journal ofPower Sources, in press(1: Institut für MikroenergietechnikIMTEK, Freiburg)

Heinzel, A.; Vogel, B.1; Hübner, P.“Reforming of Natural Gas –Hydrogen Generation for SmallScale Stationary Fuel CellSystems”, 7. Ulmer Elektroche-mische Tage, Ulm, 26.-27.6.2000,in: Journal of Power Sources, inpress(1: DaimlerChrysler AG, Ulm)

Heinzel, A.; Hebling, C.; Zedda, M.“Kleinst-Brennstoffzellen für por-table Anwendungen”,Symposiumsband Brennstoffzelle –effiziente Energietechnik derZukunft, Friedrichshafen, 20.-21.7.2000, 147-155

Heinzel, A.; Vogel, B.1; Kikulies,M.2; Haist, A.; Hübner, P.“Hydrogen Generation by SmallScale Reformers – the Activities ofFraunhofer ISE”, TagungsbandHYFORUM 2000, Bd. 2, Munich,11.-15.9.2000, 255 (1: DaimlerChrysler AG, Ulm) (2: Howaldswerke-Deutsche WerftAG, Kiel)

Henning, H.M.; Hindenburg, C.“Dessicant Cooling inCombination with Solar Energy –Technology and Pilot Plant withSolar Energy as Heat Source”,Proceedings EuroSun 2000, 3rdISES-Europe Solar Congress,Copenhagen, Denmark, 19.-22.6.2000, CD-ROM

Hensen, J.1; Herkel, S.; Janak, M.2;Kelly, N.2; Wilson, H.R.3

“Simulation for Design: Com-paring Two Low-Energy CoolingStrategies for an Atrium”,International Building PhysicsConference, Eindhoven, theNetherlands, 18.-21.9.2000 (1: Eindhoven University of Tech-nology, Eindhoven, theNetherlands) (2: University of Strathclyde,Glasgow, Scotland) (3: Interpane E&BmbH,Lauenförde)

Hermann, M.; Koschikowski, J.; Rommel, M.“Corrosion-Free Solar Collectorsfor Thermally Driven SeawaterDesalination”, ProceedingsEuroSun 2000, 3rd ISES-EuropeSolar Congress, Copenhagen,Denmark, 19.-22.6.2000, CD-ROM

Hindenburg, C.“Solare Kühlungssysteme”,Fachhochschulstudiengänge FH-Pinkafeld, Austria, Bd. 5, 139-156

Hoffmann, V.U.“Vorhaben Sonne in der Schule –Bericht für das Jahr 1999”, brochure

Hoffmann, V.U.; Kiefer, K.;Armbruster, A.“SONNEonline – WissenschaftlicheAuswertung für das Jahr 1999”,brochure and Internet: www.son-neonline.de

Hoffmann, V.U.“Sonne in der Schule – das PV-Schulprojekt desBundesministerium für Wirtschaftund Technologie”, 15. SymposiumPhotovoltaische Solarenergie,OTTI-Energie-Kolleg, Staffelstein,15.-17.3.2000, 519-524

Heinzel, A.“Neue Verfahren zur Energie-wandlung und -speicherung”,Tagungsmonographie, Tagung derGesellschaft Deutscher Chemikere.V., Fachgruppe AngewandteElektrochemie, Ulm, 27.-29.9.2000, in press

Heinzel, A.; Hebling, Chr.; Zedda, M.“Portable Brennstoffzellen – einÜberblick über die aktuellenEntwicklungen”, TagungsbandBrennstoffzellen, OTTI-Tech-nologie-Kolleg, Würzburg, 17.-18.10.2000, 255-268

Heinzel, A.“Brennstoffbereitstellung – Standder Technik, Praxiserfahrungen,Entwicklungen”, Tagungsmappe,Technische Akademie Wuppertal,7.11.2000

Heinzel, A.; Friedrich, K.1; Hacker,V.1; Fuchs, H.1; Fankhauser, R.1;Beckmann, G.2; Simon, O.2; Roes, R.3; Wolters, R.3; Mayer, M.4

“Biomasse-Vergasung für Brenn-stoffzellen” Schriftenreihe derForschung im Verbund, Bd. 59, (1: Technische Universität Graz,Graz, Austria) (2: Verbund, Vienna, Austria) (3: Universität Duisburg, Duisburg)(4: Preussag AG, Hannover)

Henning, H.M.“Sorptionsgestützte Klimatisierung(DEC) im Verbund mit Solarenergie– Systemtechnik und ausgeführtesBeispiel”, Tagungsband BUILDING-PERFORMANCE, InternationalerKongress für Licht und Technik,Klimatechnik und Gebäudeauto-mation, Frankfurt a/M., 20.-22.3.2000

Henning, H.M.; Franzke, U.; Lamp, P.“Solare Gebäudeklimatisierung –Ziele, Inhalte und erste Ergebnisseder neuen Task 25 der Interna-tionalen Energie Agentur (IEA)”,Tagungsband 10. SymposiumThermische Solarenergie, OTTI-Technologie-Kolleg, Staffelstein,10.-12.5.2000, 168-172 (1: Institut für Luft- und Kälte-technik ILK, Dresden) (2: Bayrisches Zentrum für Ange-wandte Energieforschung ZAE,Würzburg)

Henning, H.M.; Schossig, P.“The Effect of Phase ChangeMaterials Integrated in Con-struction Materials”, EuroSun2000, 3rd ISES-Europe SolarCongress, Copenhagen, Denmark,19.-22.6.2000, CD-ROM

Kieliba, T.; Reber, S.“Orientierte Kristallisation aufamorphen Substraten für kristalli-ne Silizium-Dünnschichtsolar-zellen”, Tagungsband, Frühjahrs-tagung der Deutschen Physika-lischen Gesellschaft DPG, Dresden,20.-24.3.2000, 321

Kieliba, T.; Reber, S.“Enhanced Zone-MeltingRecrystallization for CrystallineSilicon Thin-Film Solar Cells”, 16thEuropean Photovoltaic SolarEnergy Conference, Glasgow,United Kingdom, 1.-5.5.2000, inpress

Köhl, M.; Carlsson, B.1; Möller, K.1; Frei, U.2; Brunold, S.2

“Accelerated Life Testing of SolarAbsorber Coatings: TestingProcedure and Results”, in: SolarEnergy, Vol. 68 (4/2000), 313-323(1: Swedisch National Testing andResearch Institute, Borås, Sweden)(2: Solar Energy Testing andResearch Group, ITR, Rapperswil,Switzerland)

Köhl, M.; Heck, M.; Frei1, U.; Arntzen, M.2; Morales, A.3;Orel, B.4; Kaluza, L.4; Versluis, R.5

“Solar Absorber Coatings forUnglazed Façades”, ProceedingsEuroSun 2000, 3rd ISES-EuropeSolar Congress, Copenhagen,Denmark, 19.-22.6.2000, CD-ROM (1: ITR, Rapperswil, Switzerland) (2: Interpane E&BmbH, Lauen-förde) (3: CIEMAT-FER, Madrid, Spain) (4: National Institute of Chemistry,Ljubljana, Slovenia) (5: TNO, Delft, the Netherlands)

Köhl, M.; Heck, M.; Möller, K.1; Carlsson, B.1; Brunold, S.2;Frei, U.2; Holck, O.3; Svendsen, S.3; Oversloot, H.4;Jorgensen, G.5

“Materials in Solar ThermalCollectors”, Proceedings EuroSun2000, 3rd ISES-Europe SolarCongress, Copenhagen, Denmark,19.-22.6.2000, CD-ROM (1: Swedish National Testing andResearch Institute, Borås, Sweden)(2: Solar Energy Testing andResearch Group, ITR, Rapperswil,Switzerland) (3: Technical University ofDenmark, Lyngby, Denmark) (4: TNO, Delft, the Netherlands) (5: National Renewable EnergyLab., NREL, Golden, CO, USA)

Köhl, M.“Was leisten die Schichten?Physikalische Grundlagen, Aufbau,Qualitätskontrolle, Entwicklungs-tendenzen”, in: Sanitär- undHeizungstechnik (10/2000), 94-403

Krempel-Hesse, J.1; Preu, R.;Lautenschlager, H.; Lüdemann, R.“Sputtering – a Key Technologyfor Thin Film Coatings inCrystalline Silicon Solar CellProduction”, Proceedings 43rdAnnual Conference, Society ofVacuum Coating; Denver, Co.,USA, 15.-20.4.2000, 97 (1 – Leybold Systems GmbH,Hanau)

Krempel-Hesse, J.1; Preu, R.;Lautenschlager, H.; Lüdemann, R.“Sputtering – a Key Technologyfor Thin Film Coatings inCrystalline Silicon Solar CellProduction”, Proceedings 16thEuropean Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press (1 – Leybold Systems GmbH,Hanau)

Kuckelhorn, T.; Goetzberger, A.;Herzog, T.“CPC-Strukturen zur Tageslicht-nutzung”, Tagungsband 6. Sym-posium Innovative Lichttechnik inGebäuden, OTTI-Technologie-Kolleg, Staffelstein, 27.-28.1.2000, 28-30

Kuhmann, J.; Roth, W.; Sauer,D.U.; Steinhüser, A.; Volck, G.“Lithium-Ionen-Akkus für PV-Geräte der Zukunft?”,Tagungsband 15. SymposiumPhotovoltaische Solarenergie,OTTI-Energie-Kolleg, Staffelstein,15.-17.3.2000, 372-376

Kuhmann, J.; Roth, W.; Sauer,D.U.; Steinhüser, A.; Volck, G.“Lithium-Ionen-Akkus für Photo-voltaik-Geräte der Zukunft?”,Tagungsband D&E Entwickler-forum Batterien, Ladekonzepte &Stromversorgungsdesign, Munich,23.3.2000, 403-412

Kuhmann, J.; Roth, W.; Sauer,D.U.; Steinhüser, A.; Volck, G.“Lithium-Ionen-Akkus fürPhotovoltaik-Geräte derZukunft?”, in: Erneubare Energien,(8/2000), 34-37

Kuhn, T.; Dill, F.U.; Helde, A.;Bühler, Ch.; Wienold, J.; Herkel,S.; Platzer, W.“Sonnenlichtschutzbewertung”,in: Sonnenschutz III: Tageslicht-technik und Sonnenschutz –Sonnenschutztechnik undSonnenenergie, 2000, 256-257


Facts and Figures

Hoffmann, V.U.; Kiefer, K.; Erge, Th.“Netzgekoppelte Photovoltaik-Anlagen – welche Erträge sindmöglich?”, Tagungsband GleisdorfSolar 2000, Gleisdorf, Austria, 6.-7.9.2000, 335-343

Hoffmann, V.U.“Marktentwicklung der netzge-koppelten PV in Deutschland:Erfahrungen und Auswirkungenaus dem 100.000-Dächer-Programm und dem ErneuerbareEnergien Gesetz”, TagungsbandNationale Photovoltaiktagung,Neuchatel, Switzerland 7.-8.11.2000, 77-85

Hube, W.; Wittwer, Chr.“Entwicklung von neuartigenRegelungskonzepten mit Hilfe derSimulationsumgebung ColSim undderen Validierung im Feldtest”,10. Symposium Thermische Solar-energie, OTTI-Technologie-Kolleg,Staffelstein, 10.-12.5.2000, 288-292

Hube, W.; Wittwer, Chr.“Experimentelle Untersuchung vonneuartigen Regelungskonzeptenfür aktive thermische Systeme aneinem Mehrfamilienhaus”,Tagungsband 12. InternationalesSonnenforum, DGS, Freiburg, und11. Jahrestagung Forschungs-verbund Sonnenenergie, FVS,Freiburg, 5.-7.7.2000, 34-35

Huljic, D.M.“Schnelle Sinterprozesse für Sieb-druckkontakte auf kristallinenSiliciumsolarzellen”, Frühjahrs-tagung der Deutschen Physikali-schen Gesellschaft DPG, Dresden,20.-24.3.2000, 231

Huljic, S.; Schäfer, S.; Biro, D.;Emanuel, G.; Lüdemann, R.“Screen Printed InterdigitatedFront Side Metallisation for c-SiThin Film Solar Cells – ThreeIndustrially Applicable Concepts”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Huljic, D.; Biro, D.; Preu, R.; Craff-Castillo, C.; Lüdemann, R.“Rapid Thermal Firing of ScreenPrinted Contacts for Large AreaCrystalline Silicon Solar Cells”,Proceedings 28th IEEE PhotovoltaicSpecialist Conference, Anchorage,USA, 17.-22.9.2000, in press

Hutley, M.1; Gombert, A.“Moth-Eyes: the Tortuous Pathfrom a Glint in the Eye to aCommercial Reality”, in: PhotonicScience News, Vol. 6, Iss. 1/2(2000), 35-39 (1: Floating Images Inc., Hampton,United Kingdom)

Isenberg, J.1; Reber, S.; Aschaber, J.; Warta, W.“Silicon Dioxide and Silicon Nitrideas Diffusion Barrier for TransitionMetals in Solar Cell Applications”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press (1: MaterialforschungszentrumFMF, Freiburg)

Kallwellis, V.; Rommel, M.; Bundy, S.; Wittwer, Chr.“Wärmedämmverbundsystem inte-grierter Fassadenkollektor zurBrauchwasservorwärmung ineinem Mehrfamilienhaus”,Tagungsband 10. SymposiumThermische Solarenergie, OTTI-Technologie-Kolleg, Staffelstein,10.-12.5.2000, 87-91

Kiefer, K.“Ertragsprognose: ein Verfahrenmit vielen Unbekannten”, in:Sonne, Wind & Wärme, (2/2000),40-41

Kiefer, K.; Hoffmann, V.; Erge, T.“Gesicherte Stromerträge vonnetzgekoppelten Photovoltaik-Anlagen”, Tagungsband 15.Symposium PhotovoltaischeSolarenergie, OTTI-Energie-Kolleg,Staffelstein, 15.-17.3.2000, 46-54

Kiefer, K.; Hoffmann, V.U.; Reise, Chr.“Leistungen und Erträge von netz-gekoppelten Photovoltaikan-lagen”, Tagungsband VDI Work-shop, Technische Regeln zurPhotovoltaik, Düsseldorf,4.4.2000, 25-36

Kiefer, K.“Umwelttarif der RWE Energie”,Monitoring Bericht 1999, Freiburg,(5/2000), brochure

Kiefer, K.“Messergebnisse von Anlagen ausdem Umwelttarif der RWEEnergie”, (5/2000) brochure

Facts and Figures


Lüdemann, R.; Damiani, B.M.;Rohatgi, A.“Novel Processing of Solar Cellswith Porous Silicon Emitter”Proceedings 28th IEEE PhotovoltaicSpecialist Conference, Anchorage,USA, 17.-22.9.2000, in press

Lustig, K.; Rommel, M.;Stankowski, D.; Hausner, R.1; Fink, Chr. 1

“Experimentelle Untersuchungenzum Stillstandverhalten solarther-mischer Anlagen”, Tagungsband10. Symposium ThermischeSolarenergie, OTTI-Technologie-Kolleg, Staffelstein, 10.-12.5.2000, 445-454 (1: Arbeitsgemeinschaft Erneuer-bare Energien, Gleisdorf, Austria)

Lustig, K.; Rommel, M.;Stankowski, D.“Experimental Research ofStagnation in Solar ThermalSystems”, Proceedings EuroSun2000, 3rd ISES-Europe SolarCongress, Copenhagen, Denmark,19.-22.6.2000, CD-ROM

Lustig, K.; Rommel, M.;Stankowski, D.“Experimentelle Untersuchungenzum Stillstandverhalten vonVakuum-Röhrenkollektoren”,Tagungsband Materialien undKomponenten in Solaranlagen,Salzburg 24.11.2000, in press

Luther, J.; Jochem, E.“Erneubare Energien – ein realisti-scher Beitrag zur nachhaltigenEntwicklung”, Fraunhofer Gesell-schaft FhG Jahresbericht 1999,München, 32-40

Luther, J.“Das Haus der Zukunft”, Bandzum Symposium Techniken für dasLeben im 21. Jh., 20.9.1999(7/2000), 44-66

Luther, J.“Zum zukünftigen Beitrag derSolarenergie zur Stromversor-gung”, in: Zur Ökonomie undÖkologie künftiger Stromver-sorgung, Bayerische Akademie derWissenschaften (Hrsg.), 2000,ISBN 3-9131516-72-5

Mauk, M.G.1; Shellenbarger, Z.A.1;Cox, J.A.1; Sulima, O.V.; Bett, A.W.; Mueller, R.L.2; Sims, P.E.1; McNeely, J.B.1;DiNetta, L.C.1

“Liquid-phase Epitaxy of Low-Bandgap III-V Antimonides forThermophotovoltaic Devices”, in:Journal of Crystal Growth 211(2000), 189-193 (1: AstroPower, Newark, DE, USA)(2: Jet Propulsion Lab., Pasadena,CA, USA)

Kuhn, T.; Platzer, W.; Eder, K.1;Sack, N.1; Beck, A.2; Hauck, M.2;Haug, I.2; Wirth, H.3; Simon, R.4;Kasper, F.J.5

“Entwicklung einer Referenzme-thode zur kalorimetrischen Be-stimmung des Gesamtenergie-durchlassgrades von transparentenund transluzenten Systemen –Vorstellung des „REGES“ Pro-jekts”, 6. Symposium InnovativeLichttechnik in Gebäuden, OTTI-Technologie-Kolleg, Staffelstein,27.-28.1.2000, 103-108 (1: Institut für Fenstertechnik e.V.,Rosental) (2: Bayerisches Zentrum für An-gewandte Energieforschung ZAEe.V., Würzburg) (3: OKALUX Kapillarglas GmbH,Marktheidenfeld-Altfeld) (4: WAREMA Renkhoff GmbH,Marktheidenfeld-Altfeld) (5: Grünzweig + Hartmann AG,Ladenburg)

Kuhn, T.; Bühler, Ch.; Platzer, W.;Wienold, J.“Evaluation and Characterisationof Sun-Shading Systems”,Proceedings EuroSun 2000, 3rdISES-Europe Solar Congress,Copenhagen, Denmark, 19.-22.6.2000 CD-ROM

Kuhn, T.; Platzer, W.“Evaluation of OverheatingProtection with Sun-ShadingSystems”, Proceedings EuroSun2000, 3rd ISES-Europe SolarCongress, Copenhagen, Denmark,19.-22.6.2000, CD-ROM

Kuhn, T.; Goerdt, W.1; Wienold, J.; Platzer, W.“Complete Characterisation ofComplex Glazings and ShadingDevices. Bridging the Gap be-tween Laboratory and User-Relevant Performance Criteria”,Proceedings EuroSun 2000, 3rdISES-Europe Solar Congress,Copenhagen, Denmark, 19.-22.6.2000, CD-ROM (1: PSE Projektgesellschaft SolareEnergiesysteme mbH, Freiburg)

Laukamp, H.; Bopp, G.; Erge, T.;Schätzle, R.; Schattner, S.“Electromagnetic Pollution fromPV Systems?” ProceedingsEuroSun 2000, 3rd ISES-EuropeSolar Congress, Copenhagen,Denmark, 19.-22.6.2000, CD-ROM

Laukamp, H.“Sonne satt! Strom satt?”, in:Fassadentechnik, 7/2000, 10-14

Meusel, M.; Adelhelm, R.;Dimroth, F.; Bett, A.W.; Wettling, W.“Charakterisierung von monolithi-schen Kaskadensolarzellen”,Tagungsband, DeutschePhysikalische Gesellschaft DPG,Regensburg, 27.-31.3.2000, 555

Mittelbach, W.; Núñez, T.;Luginsland, F.; Henning, H.-M.“Solid Sorption Thermal EnergyStorage for Solar HeatingSystems”, Proceedings 8thInternational Conference onThermal Energy Storage, Terra-stock 2000, Stuttgart, 28.8.-1.9.2000, Vol. 1, 415-420

Müller, M.; Sauer, D.U.; Puls, H.-G.; Bopp, G,“Cost Optimisation of Wind-PV-Diesel Hybrid Systems”,Proceedings European Conferenceon Wind Power for the 21stCentury, Kassel, 25.-27.9.2000, 4

Nitz, P.1; Wilson, H.R.2; Raicu, A.3;Platzer, W.J.; Jahns, E.4; Wittwer, V.“Thermotrope Prototyp-Systemeim Test”, Tagungsband 12.Internationales Sonnenforum, 5.-7.7.2000, Freiburg, 106-107 (1: PSE Projektgesellschaft SolareEnergiesysteme mbH, Freiburg) (2: Interpane E&BmbH, Lauen-förde) (3: Sto AG, Stühlingen) (4: BASF AG, Ludwigshafen)

Noël, S.1; Lautenschlager, H.;Muller, J.C.1

“Rapid Thermal Processing forHigh Efficiency Silicon Solar Cells”,in: Semiconductor Science &Technology, 12 (2000), 322-324,(1: Laboratoire PHASE, CNRS,Strasbourg, France)

Parodi, O.“Balde de Leyes: the Electrificationof a Remote Village in Argentina”,Proceedings ISES Utility Initiativefor Africa – Rural Electrification inAfrica, Midrand, South Africa, 17.-18.4.2000

Parodi, O.; Preiser, K.; Schweizer-Ries, P.“Clean Water with Clean Energy –A Huge Market, but not yetExplored” Proceedings Seminar onRural Energy Provision, Nairobi,Kenya, 9.-10.11.2000, in press

Parodi, O.; Preiser, K.; Schweizer-Ries, P.“Clean Water with Clean Energy -A Huge Market for PV – but notyet Explored”, Proceedings 16thEuropean Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Peters, S.“Herstellung kristalliner Silicium-Solarzellen mittels Rapid ThermalProcessing”, Tagungsband Früh-jahrstagung der DeutschenPhysikalischen Gesellschaft DPG,Dresden, 20.-24.3.2000, 321

Peters, S.; Lautenschlager, H.;Warta, W.; Schindler, R.“RTP-Processed 17.5 % EfficientSilicon Solar Cells Featuring aRecord Small Thermal Budget”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Peters. S.; Schindler, R.; Höfs,H.U.1

“RTP Solar Cells from RapidSolidified RGS Material”,Proceedings 28th IEEE PhotovoltaicSpecialist Conference, Anchorage,USA, 17.-22.9.2000, in press (1: Bayer AG, Krefeld)

Platzer, W.“The ALTSET Project: AngularProperties of Complex GlazingsThrough Solar Calorimetry”,Proceedings EuroSun 2000, 3rdISES-Europe Solar Congress,Copenhagen, Denmark, 19.-22.6.2000, CD-ROM

Preiser, K.; Kuhmann, J.; Paradzik, T.1

“Establishment of TestLaboratories in DevelopingCountries – A Way to Ensure ofPV-Systems and to Support MarketDevelopment”, Proceedings 16thEuropean Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press (1: PSE Projektgesellschaft SolareEnergiesysteme mbH, Freiburg)

Preiser, K.; Schweizer-Ries, P.;Parodi, O.“Ländliche Elektrifizierung mitdem sozio-technischen Ansatz”,in: EnergiewirtschaftlicheTagesfragen et (7/2000), 524-529

Preiser, K.; Reiche, K.1

“Marktentwicklung für Photo-voltaik-Systeme zur ländlichenElektrifizierung”, Tagungsband 15.Symposium PhotovoltaischeSolarenergie, OTTI-Energie-Kolleg,Staffelstein, 15.-17.3.2000, 263-271 (1: The World Bank, WashingtonD.C., USA)

Reber, S.; Kieliba, T.“Enhanced Zone MeltingRecrystallization for CrystallineSilicon Thin-Film Solar Cells”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Reber, S.; Stollwerk, G.1; Osswald, D.2; Kieliba, T.; Haessler, C.2

“Crystalline Silicon Thin-Film SolarCells on Silicon Nitride Ceramics”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press, (1: Bayer AG, Krefeld) (2: Freiburger Materialforschungs-zentrum FMF, Freiburg)

Reber, S.; Zimmermann, W.;Kieliba, T.“Zone Melting Recrystallization ofSilicon Films for Crystalline-SiliconThin-Film Solar Cells”, Proceedings11th PVSEC, Sapporo, Japan, 20.-24.9.1999, in: Solar EnergyMaterials and Solar Cells 65(2001) 409-416

Reber, S.; Eyer, A.“Hochtemperatur-Prozessierungfür kristalline Silicium-Dünn-schichtsolarzellen”, Tagungsband12. Internationales Sonnenforum,DGS und 11. Jahrestagung For-schungsverbund Sonnenenergie,FVS, Freiburg, 5.-7.7.2000, inpress

Reber, S.; Eyer, A.; Osswald, D.;Lutz, C.1; Roosen, A.1; Pohlmann, H.-J.2

“Simultaneous Infiltration andRecrystallization of SiSiC Ceramicsfor Crystalline Silicon Thin-FilmSolar Cells”, Proceedings 28thIEEE Photovoltaic SpecialistConference, Anchorage, USA, 17.-22.9.2000, in press (1: Universität Erlangen-Nürnberg,Erlangen) (2: TeCe Technical CeramicsGmbH, Selb)

Reber, S.; Lutz, C.1; Faller, F.R.2;Pohlmann, H.-J.3; Eyer, A.;Osswald, D.; Roosen, A.1

“The SIR Process for CrystallineSilicon Thin-Film Solar Cells”,Proceedings 28th IEEE PhotovoltaicSpecialist Conference, Anchorage,USA, 17.-22.9.2000, in press (1: Universität Erlangen-Nürnberg,Erlangen) (2: Shell Solar, Hamburg) (3: TeCe GmbH, Selb)

Preiser, K.; Steinhüser, A.; Hille,G.1; Roth, W.“Photovoltaic Hybrid Power Supplyfor Telecommunication Systems”,Proceedings PV-Hybrid PowerSystems 2000 Conference, Aix-en-Provence, France, 7.-8.9.2000, inpress (1: Free-lance consultant, Freiburg)

Preu, R.; Glunz, S.W.; Steinbühl, S.1; Pfleging, W.1; Wettling, W.“Laser Ablation – A New Low-Cost Approach for Passivated RearContact Formation in CrystallineSilicon Solar Cell Technology”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1-5.5.2000, in press (1: Forschungszentrum KarlsruheGmbH, Karlsruhe)

Raicu, A.1; Wilson, H.R.2; Nitz. P.4;Jahns3, E.; Platzer, W.; Wittwer, V.“Thermotropic Systems – RecentResults on ComponentCharacterisation and BuildingIntegration”, EuroSun 2000, 3rdISES-Europe Solar Congress,Copenhagen, Denmark, 19.-22.6.2000, CD-ROM (1: Sto AG, Stühlingen) (2: Interpane E&BmbH, Lauen-förde) (3: BASF AG, Ludwigshafen) (4: PSE Projektgesellschaft SolareEnergiesysteme mbH, Freiburg)

Raicu, A.1; Wilson, H.R.2, Nitz, P.3;Tahus, E.4

“Überhitzungsschutz durch ther-motrop schaltbare Elemente ander Fassade – Stand der For-schung”, in: Stahlbau (6/2000),485-489 (1: Sto AG, Stühlingen) (2: Interpane E&B mbH,Lauenförde) (3: PSE Projektgesellschaft SolareEnergiesysteme mbH, Freiburg)

Rampe, T.; Hübner, P.; Vogel, B.;Heinzel, A.“Hydrogen Generation fromEthanol by AllothermalReforming”, Proceedings 1stWorld Conference andExhibitionon Biomass for Energy &Industry, Sevilla, Spain, 5.-9.6.2000, in press

Rein, S.; Rehrl, T.; Glunz, S.W.“Degradation derLadungsträgerlebensdauer inSolarzellen aus Czochralski-Silizium”, Tagungsband, DPG-Frühjahrstagung, Regensburg, 27.-31.3.2000, 524

Rein, S.; Isenberg, J.; Warta, W.;Glunz, S.W.“Lifetime Spectroscopy on Siliconfor Solar Cells”, Proceedings 16thEuropean Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Rein, S.; Knobloch, J.; Glunz, S.W.;“Analysis of the High TemperatureImprovement of Cz-Silicon”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Rein, S.; Glunz, S.W.; Warta. W.“Investigation of the CarrierLifetime in p-Type SC-Si: SpecificLimitations and Potential forImprovement” Proceedings 28thIEEE Photovoltaic SpecialistConference, Anchorage, USA, 17.-22.9.2000, in press

Reinhart, Chr.1; Herkel, S.“RADIANCE – Jahressimulationdes Tageslichtangebotes inGebäuden: Ein Raytracer - vieleErgebnisse”, Tagungsband 6.Symposium Innovative Lichttechnikin Gebäuden, OTTI-Technologie-Kolleg, Staffelstein, 27.-28.1.2000, 189-194 (1: MaterialforschungszentrumFMF, Freiburg)

Reinhart, Chr.1; Voss, K.; Wagner,A.; Löhnert, G.“Lean Buildings: Energy EfficientCommercial Buildings inGermany”, ProceedingsConference of the ACEEE SummerStudy on Energy Efficiency inBuildings, Pacific Grove, CA, USA,20.-25.8.2000, 287-298 (1: MaterialforschungszentrumFMF, Freiburg)

Reinhart, Chr.1

“Exemplary Energy EfficientCommercial Buildings inGermany”, Proceedings of ExpertGroup Meeting on DisseminatingRenewable Energy Technologies inESCWA Member States, Beirut, 2.-3.10.2000, 1-12 (1: PSE Projektgesellschaft SolareEnergiesysteme mbH, Freiburg)

Reise, Chr.; Wiemken, E.;Toggweiler, P.1; Dijk, van V.2;Heinemann, D.3

“PVSAT: SatellitengestützteErtragskontrolle für netzgekoppel-te PV-Anlagen”, 15. SymposiumPhotovoltaische Solarenergie,OTTI-Energie-Kolleg, Staffelstein,15.-17.3.2000, 335-340 (1: Enecolo AG, Lindhof,Switzerland) (2: Utrecht University, Utrecht, theNetherlands) (3: Universität Oldenburg,Oldenburg)

Reise, Chr.; Wiemken, E.;Toggweiler, P.1; van Dijk, V.2;Heinemann, D.3; Beyer, H.J.4

“Remote Performance Check forGrid-Connected PV Systems UsingSatellite Data”, Proceedings 16thEuropean Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1-5.5.2000, in press (1: Enecolo AG, Lindhof,Switzerland) (2: Utrecht University, Utrecht, theNetherlands) (3: Universität Oldenburg,Oldenburg) (4: Universität Magdeburg,Magdeburg)

Riechel, S.1; Kallinger, C.1;Lemmer, U.1; Feldmann, J.1;Gombert, A.; Wittwer, V.; Scherf, U.2

“A Nearly Diffraction LimitedSurface Emitting ConjugatedPolymer Laser Utilizing a Two-Dimensional Photonic BandStructure” in: Applied PhysicsLetters, Vol. 77, No. 15 (10/2000),2310-2312 (1: Ludwig-Maximilians UniversitätMunich, Munich) (2: Max-Planck-Institut fürPolymerforschung, Mainz)

Riechel, S.1; Lemmer, U.1;Feldmann, J.1; Benstem, T.2;Kowalsky, W.2; Scherf, U.3;Gombert, A.; Wittwer, V.“Laser Modes in Organic SolidState Distributed Feedback Lasers”in: Applied Physics B., 11/2000,online-Publication (1: Ludwig-Maximilians-UniversitätMunich, Munich) (2: TU Braunschweig,Braunschweig) (3: Max-Planck-Institut fürPolymerforschung, Mainz)

Rommel, M.; Hermann, M.;Koschikowski, J.“The SODESA Project: Develop-ment of Solar Collectors withCorrosion-Free Absorbers and FirstResults of the Desalination PilotPlant”, Proceedings MediterraneanConference on Policies andStrategies for Desalination andRenewable Energies, SantoriniIsland, Greece, 21.-23.06.2000, inpress


Facts and Figures


Facts and FiguresRommel, M.; Hermann, M.;Koschikowski, J.; Schäfer, A.“SODESA: Entwicklung von korro-sionsfreien Kollektoren zurMeerwasserentsalzung”,Tagungsband 10. SymposiumThermische Solarenergie, OTTI-Technologie-Kolleg, Staffelstein,10.-12.5.2000, 55-59

Rommel, M.; Hermann, M.;Koschikowski, J.; Kallwelis, V.;Schäfer, A.“Solarthermische Meerwasserent-salzungsanlage mit korrosionsfrei-en Kollektoren”, Tagungsband 12.Internationales Sonnenforum, DGS und 11. Jahrestagung For-schungsverbund Sonnenenergie,FVS, Freiburg, 5.-7.7.2000, inpress

Rosenfeld, J.L.J1; Platzer, W.J.“Modelling the Optical andThermal Properties of AdvancedGlazing. Overview of RecentDevelopments”, ProceedingsEuroSun 2000, 3rd ISES-EuropeSolar Congress, Copenhagen,Denmark, 19.-22.6.2000, CD-ROM (1: Cardiff University, Cardiff,United Kingdom)

Roth, W.“Mit der Sonne telefonieren:Solarprodukte für den privatenund kommerziellen Gebrauch”,Brochure for Öko 2000 + ÖkoBau, Freiburg, 14.5.2000

Roth, W.“Photovoltaische Energiever-sorgung”, Deutsche TelekomUnterrichtsblätter, die Fach-zeitschrift der Deutschen Telekomfür Aus- und Weiterbildung(1/2000), 14-25

Rumyantsev, V.D.1; Andreev, V.M.1;Bett, A.W.; Dimroth, F.; Hein, M.;Lamge, G.; Shvarts, M.Z.; Sulima, O.V.“Progress in Development of All-Glass Terrestrial ConcentratorModules Based on CompositeFresnel Lenses and III-V SolarCells”, Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press (1: Ioffe Physico-Technical Institute,St. Petersburg, Russia)

Russ, Chr.; Kappert, M.1; Klinkert, V.2

“Energieeinsparung in Schulen –Sanierung unter Nutzung solarerTechniken”, Tagungsband 12.Internationales Sonnenforum, DGS und 11. Jahrestagung For-schungsverbund Sonnenenergie,FVS, Freiburg, 5.-7.7.2000, inpress (1: Fachhochschule Erfurt, Erfurt)(2: Fachhochschule Leipzig,Leipzig)

Russ, Chr.; Bühring, A.“Wärmeversorgung von Passiv-häusern”, Tagungsband 12. Inter-nationales Sonnenforum, DGS und 11. Jahrestagung For-schungsverbund Sonnenenergie,FVS, Freiburg, 5.-7.7.2000, inpress

Russ, Chr.“Nutzung neuer Energietech-nologien für Gebäude”, HeftWorkshop „Energieeinsparung inWärmeversorgungssystemen“,Barnaul, 16.-17.10.2000

Russ, Chr.; Voss, K.“Der Balkon wird zum Winter-garten – beispielhafte Hochhaus-sanierung”, Tagungsband Balkon-Kongress, Kassel, 14.-15.11.2000,in press

Russ, Chr.; Kappert, M.“Sanierung der Regelschule Erfurt– Energieeinsparung und Verbes-serung des Nutzerkomforts”, in:EB Energie, Effizientes Bauen(4/2000), in press

Saitoh, T.1; Hashigami, H.1; Rein, S.; Glunz, S.W.“Overview of Light DegradationResearch on Crystalline SiliconSolar Cells”, in: Progress in Photovoltaics: Research andApplications, 8 (5/2000), 537-547(1: Tokyo University of Agricultureand Technology, Tokyo, Japan)

Sauer, D.U.; Bopp, G.; Höhe, W.1;Jossen, A.1; Bächler, M.2; Sprau, P.2; Willer, B.3; Wollny, M.3

“What Happens to Batteries in PVSystems or Do We Need OneSpecial Battery for Solar Appli-cations”, Proceedings PV-HybridPower Systems 2000 Conference,Aix-en-Provence, France, 7.-8.9.2000, in press (1: Zentrum für Sonnenenergie-und Wasserstoff-Forschung ZSW,Ulm) (2: Wirtschaft InfrastrukturPlanung WIP, Munich) (3: Institut für Solare Energiever-sorgungstechnik ISET, Kassel)

Santamouris, M.1; Mihalakakou, G.1; Lund, P.2;Burton, S.3; Wangusi, M.3; Lewis, J.O.4; Thynholt, M.5;Vandaele, L6; Wienold, J.; Voss, K.;“SOLGAIN – The Contribution ofPassive Solar Energy Utilisation toCover the Space Heating Demandof the European Building Stock”,Proceedings, EuroSun 2000, 3rdISES-Europe Solar Congress,Copenhagen, Denmark, 19.-22.6.2000, CD-ROM (1: University of Athens, Athens,Greece) (2: Helsinki University, Helsinki,Finland) (3: ECD Energy and Environmentalltd., London, United Kingdom) (4: University Collge Dublin,Dublin, Ireland) (5: Sintef Civil and EnvironmentalEngineering, Trondheim, Norway)(6: Centre Scientifique etTechnique de la Construction,Brussels, Belgium)

Schäfer, A.; Rommel, M.;“Messeinrichtungen desPrüfzentrums für ThermischeSolaranlagen im Hinblick auf dieneue europäische KollektornormEN 12975-1 und 2”, Tagungsband10. Symposium ThermischeSolarenergie, OTTI-Technologie-Kolleg, Staffelstein, 10.-12.5.2000, 143-147

Schaefer, S.; Glunz, S.W.;Lüdemann, R.“Reactive Ion Etched PERC andBuried Base Contact Solar Cells”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Schaefer, S.; Lautenschlager, H.;Emanuel, G.; Lüdemann, R.“Plasma Etching and its Effect onMinority Charge Carrier Lifetimesand Crystalline Silicon Solar Cells”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Schaefer, S.; Preu, R.; Lüdemann,R.; Glunz, S.W.“Plasma Etched PERC and BuriedBase Contact Solar Cells”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Schaefer, S.; Lautenschlager, H.;Juch, M.1; Siniaguine, O.2;Lüdemann, R.“An Overview of Plasma SourcesSuitable for Dry Etching of SolarCells”, Proceedings 28th IEEEPhotovoltaic Specialist Conference,Anchorage, USA, 17.-22.9.2000,in press(1: Secon GmbH, Guntramsdorf,Austria) (2: Tru-Si Technologies, Sunnyvale,CA, USA)

Schattner, S.; Bopp, G.; Erge, T.;Fischer, R.1; Häberlin, H.1;Minkner, R.1; Venhuizen, R.2;Verhoeven, B.2

“PV-EMI – Developing StandardTest Procedures for the Electro-magnetic Compatibility (EMC) ofPV Components and Systems”,Proceedings 16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press (1: HTA Burgdorf, Burgdorf,Switzerland) (2: KEMA T&D Power, Arnhem,The Netherlands)

Schattner, S.; Bopp, G.; Hofmayer, U.“The Electromagnetic Com-patibility (EMC) of Solar HomeSystems”, Proceedings 16thEuropean Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Schindler, R.; Warta, W.“Improvements and Limits of theOpen Circuit Voltage of mc-SiliconSolar Cells”, in: Physica StatusSolidi 222 (2000), 389

Schmidhuber, H.; Koltay, P.;Hebling, C.“Module Designs with ImprovedEnergy Collections Properties: aComprehensive ExperimentalStudy”, Proceedings 16thEuropean Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1-5.5.2000, in press

Schnell, M.; Huljic, D.M.“Einfluss des nasschemischen Ätz-prozesses für poröses Silicium aufsiebgedruckte Metallkontakte fürSiliciumsolarzellen”, TagungsbandDPG-Frühjahrstagung,Regensburg, 27.-31.3.2000, 525

102 Fraunhofer ISE 2000

Voss, K.“Fassaden für dieSolarenergienutzung bei Büro-und Industriebauten”, in:Industriebau, (3/2000)

Voss, K.“Solares Bauen – Demonstrations-projekte und Technologieent-wicklung für den Wohnungsbau”,Tagungsband 1. Freiburger Praxis-Symposium Passivhäuser,7.4.2000, Freiburg

Voss, K.; Loehnert, G.2; Wagner, A.3; Rolfs, K.3; Reinhart, Chr.1

“On the Way to Lean Buildings –Examples and Experiences from aGerman Demonstration Pro-gramme for Energy Efficiency andSolar Energy Use in CommercialBuildings”, Proceedings EuroSun2000, 3rd ISES-Europe SolarCongress, Copenhagen, Denmark,19.-22.6.2000, CD-ROM (1: MaterialforschungszentrumFMF, Freiburg) (2: sol°id°ar, Architekten &Ingenieure, Berlin) (3: Universität Karlsruhe, Karlsruhe)

Voss, K.; Buehring, A.; Russ, Chr.;Neumann, Chr.1; Ufheil, M.1

“Solar Low Energy Houses –Examples from Germany”,Proceedings, EuroSun 2000, 3rdISES-Europe Solar Congress,Copenhagen, Denmark, 19.-22.6.2000, CD-ROM (1: solares bauen GmbH, Freiburg)

Voss, K.1; Reinhart, Ch.1

Löhnert, G.2; Wagner, A.3

“Toward Lean Buildings –Examples and Experience from aGerman Demonstration Pro-gramme for Energy Efficiency andSolar Energy Use in CommercialBuildings”, Proceedings, EuroSun2000, 3rd ISES-Europe SolarCongress, Copenhagen, Denmark,19.-22.6.2000, CD-ROM (1: solares bauen, GmbH, Freiburg)(2: sol°id°ar, Architekten &Ingenieure, Berlin) (3: Universität Karlsruhe, Karlsruhe)

Voss, K.; Bühring, A.; Russ, Chr.;Neumann, Chr.1; Ufheil, M.1

“Solares Bauen – Demonstra-tionsprojekte und Technologie-entwicklung für den Wohnungs-bau”, Tagungsband 12. Inter-nationales Sonnenforum, DGS und11. Jahrestagung Forschungs-verbund Sonnenenergie, FVS,Freiburg, 5.-7.7.2000, in press (1: solares bauen GmbH, Freiburg)

Smith, L.M.1; Rushworth, S.A.1;Ravetz, M.S.1; Odedra, R.1;Konjolia, R.1; Agert, C.; Dimroth, F.; Schubert, U.; Bett, A.W.“Low Oxygen Content Trimethyl-aluminium and Trimthylindium forMOVPE of Light EmittingDevices”, in: Journal of CrystalGrowth 221 (2000), 86-90 (1: Epichem Ltd., Merseyside,United Kingdom)

Stangar, L.U.1; Groselj, N.1; Orel, B.1; Schmitz, A.; Colomban, Ph.2

“Proton Conducting Sol-GelHybrids Containing HeteropolyAcids”, Proceedings 10th Inter-national Conference on Solid StateProtonic Conductor, Montpellier,France, 24.-28.9.2000, in press (1:National Institute for Solar EnergySystems, Ljubljana, Slovenia) (2: CNRS, Thiais, France)

Steinhüser, A.; Schulz, W.;Schmidt, H.; Roth, W.“Photovoltaic Power Supply forTelecommunication NetworkComponents in Remote Areas”,Tagungsband TELESCON 2000,Dresden, 7.-10.5.2000, 221-225

Steinhüser, A.; Roth, W.; Laukamp, H.“PV Power Supply for IntelligentStreet Furniture – a Multi-functional Emergency Call andInformation Post”, Proceedings:IEA PVPS Task VII, PV in the BuiltEnvironment, Workshop: Non-Building Structures, Stockholm,Sweden, 6.9.2000

Sulima, O.V.; Bett, A.W.; Dutta, P.S.1; Ehsani, H.1; Gutmann, R.J.1

“Thermophotovoltaic Cells on ZincDiffused Poly-Crystalline GaSb”,Proceedings16th EuropeanPhotovoltaic Solar EnergyConference and Exhibition,Glasgow, United Kingdom, 1-5.5.2000, in press (1: Rensselaer Polytechnic Institute,Troy, NY, USA)

Sulima, O.V.; Beckert, R.; Bett, A.W.; Cox, J.A.1; Mauk, M.G.1

“InGaAsSb Photovoltaic Cells withEnhanced Open-Circuit Voltage”,Proceedings, 28th IEEE Photo-voltaic Specialist Conference,Anchorage, USA, 17.-22.9.2000,in press (1: AstroPower, Newark, De, USA)Thoben, B.; Sauer, D.U.

“Untersuchung des Einflusses vonpulsförmigen Strömen auf daselektrische Verhalten von Blei-batterien”, in: Tagungsband 12.Internationales Sonnenforum, DGSund 11. Jahrestagung Forschungs-verbund Sonnenenergie, FVS,Freiburg, 5.-7.7.2000, in press

Vallvé, X.1; Merten, J.1; Preiser, K.;Schulz, M.“Energy Limitation for BetterEnergy Service to the User: FirstResults of Applying EnergyDispenser in Multi-User PV Stand-Alone Systems”, Proceedings 16thEuropean Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1-5.5.2000, in press (1: Trama Tecno Ambiental,Barcelona, Spain)

Vazques, M.1; Vegas, A.2; Daza, L.3; Guerrero, A.4; Sauer, D.U.; Omelas, R.5; Liebig, R.6

“Fuel Cells for Powering RemoteTelecom Equipment”, Proceedings2000 Fuel Cell Seminar, Portland,Oregon, 30.10.-2.11.2000, inpress (1: Alcatel, Madrid, Spain) (2: INTA, Madrid, Spain) (3: CIEMAT, Madrid, Spain) (4: ICP-CSIC, Madrid, Spain) (5: Nuvera Fuel Cells Europe,Milano, Italy) (6: Würth Elektronik, Marbacha/N.)

Vogel, B.; Haist, A.; Heinzel, A.;Baumann, F.1; Wieland, S.1

“Selektive CO-Oxidation in was-serstoffreichen Gasgemischen -Brenngasaufbereitung für Mem-bran-Brennstoffzellen”, Tagungs-band XXXIII. JahrestreffenDeutscher Katalytiker, Weimar,22.-24.3.2000 (1: dmc2 Degussa Metals CatalystsCerdec, Hanau)

Voss, K.“Ein Institutsgebäude für ein son-niges Jahrtausend”, Bundes BauBlatt (11/1999), 22-26

Voss, K.; Reinhart, Chr.1

“Die Tageslicht- und Beleuch-tungskonzepte der Demonstra-tionsprojekte des Förderpro-gramms SolarBau des BMWI: EineQuerschnittsbetrachtung”,Tagungsband 6. SymposiumInnovative Lichttechnik in Ge-bäuden, OTTI-Technologie-Kolleg,Staffelstein, 27.-28.1.2000, 279-283 (1: MaterialforschungszentrumFMF, Freiburg)

Schnell, M.; Schäfer, S.; Reiß, J.;Lüdemann, R.“Stain Etched Porous Silicon – ASimple Method for the Simul-taneous Formation of SelectiveEmitter and ARC”, Proceedings16th European Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom,in press

Schnell, M.; Schaefer, S.;Lüdemann, R.“Plasma Surface Texturization forMulticrystalline Silicon SolarCells”, Proceedings 28th IEEEPhotovoltaic Specialist Conference,Anchorage, USA, 17.-22.9.2000,in press

Schulz, W.; Roth, W.“Photovoltaisch versorgte Tele-matiksysteme”, 15. SymposiumPhotovoltaische Solarenergie,OTTI-Energie-Kolleg, Staffelstein,15.-17.3.2000, 313-317

Schweizer-Ries, P.; Schulz, M.;Ramirez, E.1; Vallvé, X.1; Vosseler, I.1

“Success Factors in PV-Hybrid-systems for Off-Grid PowerSupply: Results of a Socio-Tech-nical Investigation in Germany andSpain, Proceedings 16th EuropeanPhotovoltaic Solar Energy Con-ference and Exhibition, Glasgow,United Kingdom, 1.-5.5.2000, inpress (1: Trama Tecno Ambiental,Barcelona, Spain)

Schweizer-Ries, P.; Djuwita, R.1;Will, S.; Uenze, B.; Djajasoekarsa,A.1; Ginting, K.1

“Psychologische Untersuchungvon drei Dorfstromanlagen inIndonesien – Anwendung derGemeingutforschung auf Solar-nutzung”, Tagungsband DGPS –Kongreß, Jena, 24.-28.9.2000, inpress (1: Universitas Indonesia, Jakarta,Indonesia)

Schweizer-Ries, P.; Schulz, M.;Vallvé, X.1; Vosseler, I.1; Serrano, J.2

“Successful User Schemes forPhotovoltaic Stand-AloneSystems”, brochure (1: Trama TecnoAmbiental,Barcelona, Spain) (2: Associación SEBA, Barcelona,Spain)

Facts and Figures


Facts and FiguresVoss, K.; Reinhart, Chr.1, Loehnert, G.2; Wagner, A.3; Rolfs, K.3

“Energieeffizienz und Solar-energienutzung im Nicht-wohnungsbau – Erfahrungen undErgebnisse aus Demonstrations-projekten”, Tagungsband 12.Internationales Sonnenforum, DGSund 11. Jahrestagung Forschungs-verbund Sonnenenergie, FVS,Freiburg, 5.-7.7.2000, in press (1: MaterialforschungszentrumFMF, Freiburg) (2: sol°id°ar, Berlin) (3: Universität Karlsruhe, Karlsruhe)

Voss, K.; Reinhart, Chr.1; Wagner, A.2; Loehnert, G.3

“Lean Buildings: Energy EfficientCommercial Buildings inGermany” Proceedings ACEEESummer Study on EnergyEfficiency in Buildings, PacificGrove, USA, 20.-25.8.2000 (1: MaterialforschungszentrumFMF, Freiburg) (2: Universität Karlsruhe, Karlsruhe)(3: sol°id°ar, Berlin)

Voss, K.“IEA Solar Heating and Cooling(SHC) Programme, Task 20: SolarEnergy in Building Renovation”,brochure

Wagner, R.1; Bopp, G.; Sauer,D.U.; Theimann, U.1

“Langzeittests von Gel- und Vlies-Batterien in realen PV-Anlagen –Konzepte und erste Ergebnisse”,Tagungsband 15. SymposiumPhotovoltaische Solarenergie,OTTI-Energie-Kolleg, Staffelstein,15.-17.3.2000, 236-242 (1: ExideGerman Group, Büdingen)

Wagner, R.1; Sauer, D.U.“Was leisten neue Bleibatterien inPV-Anlagen? Betriebsstrategien fürGel- und Vlies-Batterien in realenPV-Anlagen”, ErneuerbareEnergien (10/2000), 55-57 (1: Exide German Group,Büdingen)

Walters, R.J.1; Messenger, S.R.2;Summers, G.P.1; Bett, A.W.;Dimroth, F.; Hoffmann, R.W.3;Stan, M.A.3; Takamoto, T.4; Ikeda, E.4; Imaizumi, M.5; Anzawa, O.5; Matsuda, S.5

“Radiation Response of GaxIn1-xAsSolar Cells”, 16th EuropeanPhotovoltaic Solar Energy Con-ference and Exhibition, Glasgow,United Kingdom, 1.-5.5.2000, inpress (1: U.S. Naval Research Laboratory,Washington, DC, USA) (2: SFA, Inc., Largo, MD, USA) (3: Essential Research Inc.,Cleveland, Ohio, USA) (4: Japan Energy Corporation,Toda-shim, Saitama, Japan) (5: National Space DevelopmentAgency of Japan NASDA, Ibaraki,Japan)

Walters, R.J.1; Summers, G.P.1;Bett, A.W.; Dimroth, F.; Hoffman,R.W.2; Stan, M.A.2; Takamoto, T.3;Ikeda, E.3

“Radiation Response of Dual-Junction GaXIn1-XP/GaYIn1-YAsSolar Cells”, Proceedings 28thIEEE Photovoltaic Specialist Con-ference, Anchorage, USA, 17.-22.9.2000, in press (1: National Renewable EnergyLaboratory, Washington, USA) (2: ERI, Cleveland, OH, USA) (3: Japan Energy Corporation,Toda-Shim, Japan)

Warta, W.; Glunz, S.W.; Dicker, J.;Knobloch, J.“Highly Efficient 115 µm ThickSolar Cells on IndustrialCzochralski Silicon, in Progress inPhotovoltaics: Research andApplications 8 (5/2000), 465-471

Weber, P.1; Ehm, E.2; Vallvé, X.3;Kiefer, K.; Rössler, E.“Highly Reliable PV Applications inRegions of the European Alps(EURALP)”, Proceedings PV-Contractors Meeting, 23.-24.3.2000, Barcelona, Spain,131-136 (1: Deutscher Alpenverein DAV,München) (2: OEAV ÖsterreichischerAlpenverein, Innsbruck, Austria) (3: SEBA/ Trama Tecno Ambiental,Barcelona, Spain)

Weber, P.1; Herrlich, A.1; Kiefer, K.;Rössler, E.“PV Hybrid Systems in theEuropean Alps – the EURALPProgramme”, Proceedings 16thEuropean Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press (1: Deutscher Alpenverein DAV,München)

Weismüller, G.1; Kiefer, K.; Rössler,E.; Schmid, J.2

“ZKM Karlsruhe – TramwaySystem with Directly CoupledPhotovoltaic Power Supply”,Proceedings PV-ContractorsMeeting, Barcelona, Spain, 23.-24.3.2000, 63-68 (1: Stadtwerke Karlsruhe,Karlsruhe) (2: Universität Kassel, Kassel)

Wettling, W.“Solarzellen”, in: EnzyklopädieNaturwissenschaft und Technik:Astronomie, Bautechnik, Biologie,Chemie, Elektrotechnik, Energie-technik, Geowissenschaften,Informatik, Mathematik, Medizin,Physik, Verfahrens- und Ferti-gungstechnik, Verkehrstechnik,Werkstofftechnik, 2. Aufl., 4.Ergänzungslieferung 12/1999, 1-8

Wiemken, E.“Monitoring of Grid-ConnectedPV Systems from the German1000-Roofs Programme: Com-parison of Systems with Amor-phous and Crystalline SiliconCells”, Proceedings of Workshop„Energias Alternativas para aProdução de Calor, Frio e Geraçãoe Conservação de EnergiaEléctrica“, Florianopolis, Brazil, 6.-8.12.1999, (in Portuguese)

Wienold, J.1; Voss, K.; Vandaele, L.2; Lund, P.3; Thynolt, M.4; Santamouris, M.5;Mihalakakou, G.5; Lewis, J.O.6;Wangusi, M.7; Burton, S.7

“SOLGAIN – The Contribution ofPassive Solar Energy Utilization toCover the Space Heating Demandof the European ResidentialBuilding Stock”, ProceedingsEuroSun 2000, 3rd ISES-EuropeSolar Congress, Copenhagen,Denmark, 19.-22.6.2000, CD-ROM (1: solares bauen GmbH, Freiburg)(2: Centre Scientifique etTechnique de la Construction,Brussels, Belgium) (3: Helsinki University of Tech-nology, Hut, Finland) (4: University of Athens, Athens,Greece) (5: University College Dublin,Dublin, Ireland) (6: ECD Energy and Environmentalltd., London, UK)

Wilson, H.R.1; Georg, A.; Nitz, P.2

“Switchable Glazing with a LargeRange in Total Solar EnergyTransmittance (g value)”,Proceedings, 6th World RenewableEnergy Congress, WREC, Brighton,United Kingdom, 1.-7.7.2000,195-200 (1: Interpane E&B mbH,Lauenförde) (2 PSE Projektgesellschaft SolareEnergiesysteme mbH, Freiburg)

Wilson, H.R.1

“Solar Control Coatings forWindows”, in: FunctionalMaterials, Vol. 13 (2000), 221-233(1: Interpane E&B mbH,Lauenförde)

Wittwer, Chr.“Regelungssystementwicklung miteiner virtuellen Testumgebung aufBasis der SimulationsumgebungColSim”, Tagungsband 10. Sym-posium Thermische Solarenergie,OTTI-Technologie-Kolleg, Staffel-stein, 10.-12.5.2000, 293-297

Wittwer, Chr.; Rolfs, K.1; Mertins, M.1

“Evaluation of a Fuzzy BasedControl Concept by Means of aComplex Thermo HydraulicSimulation Model of a HeatingSystem in a Low Energy Building”,EuroSun 2000, 3rd ISES-EuropeSolar Congress, Copenhagen,Denmark, 19.-22.6.2000, CD-ROM (1: Universität Karlsruhe, Karlsruhe)

Wittwer, V.; Gombert, A.“Nano- and Micro-structuredFunctional Surfaces”, ProceedingsCOMBI EUROPE, Frankfurt a/M,28.-30.6.2000

Wittwer, V.; Gombert, A.; Rose,K.1; Löbmann, P.1; Sporn, D.1;Manns, P.2; Döll, W.2; Konz, W.3;Seibert, K.3

“Applications of PeriodicallyStructured Surfaces on Glass”, in:Glastec. Ber. Glass Science Tech-nology 73, No. 4 (2000), 116-118(1: Fraunhofer-Institut fürSilicatforschung ISC, Würzburg) (2: Fraunhofer-Institut für Werk-stoffmechanik IWM, Freiburg) (3: Fraunhofer-Institut fürPhysikalische Messtechnik IPM,Freiburg)

Zickermann, D.; Preu, R.“Herstellung von selektivenEmittern im Siebdruckverfahrenfür kristalline Siliciumsolarzellen”,Tagungsband, Frühjahrstagung derDeutschen Physikalischen Gesell-schaft, Dresden, 20.-24.3.2000,321

Zimmermann, W.; Bau, S.; Eyer,A.; Haas, F.; Oßwald, D.“Crystalline Silicon Thin Film SolarCells on Low Quality SiliconSubstrates with and without SiO2Intermediate Layer”, Proceedings16th European Photovoltaic SolarEnergy Conference and Exhibition,Glasgow, United Kingdom, 1.-5.5.2000, in press

Zimmermann, W.; Eyer, A.“Coarse-Grained Crystalline SiliconThin-Film Solar Cells on LaserPerfored SiO2 Barrier Layer”,Proceedings 28th IEEE PhotovoltaicSpecialist Conference, Anchorage,USA, 17.-22.9.2000, in press


Facts and Figures

FF fill factorFhG Fraunhofer-Gesellschaft

(Fraunhofer Society)FCHC fluorinated/chlorinated

hydrocarbonsFZ float zoneGaAs gallium arsenideGaInP gallium indium phosphideGaSb gallium antimonideGe germaniumGSM Global System for Mobile

CommunicationIEA International Energy

AgencyIR infraredK KelvinkWp kilowatt peakLBIC light beam induced currentLBSF local back surface fieldLPE liquid phase epitaxymc multicrystallinemc-Si multicrystalline siliconMFCA modulated free carrier

absorptionMgF2 magnesium fluorideMOCVD metal organic chemical

vapour depositionMOVPE metal organic vapour

phase epitaxyMPP maximum power pointMSCM miniature solar cell

mappingMW-PCD microwave-detected

photoconductance decayNOCT nominal operating cell

temperaturePCVD photocurrent and voltage

decayPd palladiumPECVD plasma enhanced chemical

vapour depositionPEM polymer membranePERC passivated emitter and rear

cell

Abbreviations

Ag silverAl aluminiumAlGaAs aluminium gallium arsenideAM air massAPCVD atmospheric pressure

chemical vapour depositionBi bismuthBFC bifacial cellBMBF Bundesministerium für

Bildung und Forschung (German Federal Ministry of Education and Research)

BMWi Bundesministerium für Wirtschaft und Technologie(German Federal Ministry of Economics and Technology)

BMZ Bundesministerium für wirtschaftliche Zusammenarbeit und Entwicklung (German Federal Ministry of Economic Co-operation and Development)

BSF back surface fieldCIS copper indium diselenideCNRS Centre Nationale de la

Recherche Scientifiquec-Si crystalline siliconCV capacitance/voltageCVD chemical vapour depositionCz CzochralskiDLTS deep level transient

spectroscopyEBIC electron beam induced

currentEBR etchback regrowthECR electron cyclotron

resonanceEFG edge-defined film-fed

growthEMC electromagnetic

compatibilityEU European Union

PV photovoltaicRCC rear contacted cellRIE reactive ion etchingRPHP remote plasma hydrogen

passivationRP-PERC random pyramid,

passivated emitter and rearcell

RRC realistic reporting conditions

RTCVD rapid thermal chemical vapour deposition

RTP rapid thermal processingS/C steam/carbon ratioSDCS solar desiccant cooling

systemSEM scanning electron

microscopeSME small and medium-sized

enterprisesSi siliconSIMOX separation by implanted

oxygenSiNX silicon nitrideSiO2 silicon dioxideSIR simultaneous infiltration

and recrystallisationSn tinSPV surface photovoltageSSP silicon sheets from powderSR spectral responseSR-LBIC spatially resolved light

beam induced currentTI transparent insulationTi titaniumTiO2 titanium dioxideTPV thermophotovoltaicsVOC open circuit voltageWPVS world photovoltaic scaleZn zincη efficiency value

EditorsPress and Public RelationsKarin Schneider M.A.(Head)Rosemarie Becker(Overall Co-ordination)

Solar Consulting, FreiburgDr Klaus Heidler

Translation from the GermanDr Helen Rose Wilson, Freiburg

Layout and Typesettingnetsyn GbRHoffmann & Würger M.A., BDW,Freiburg

PrintingKaiser Druck, Freiburg

Editorial AddressFraunhofer Institute for Solar Energy Systems ISEPress and Public RelationsOltmannsstr. 579100 FreiburgGermanyTel. +49 (0) 7 61/45 88-1 50Fax. +49 (0) 7 61/45 88-3 42http://www.ise.fhg.de

New Address 1st July 2001Fraunhofer Institute for Solar Energy Systems ISEPress and Public RelationsHeidenhofstr. 279110 FreiburgGermany

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