sdar journal 2015

November 2015 Issue 5

The Journalof Applied Research

in InnovativeEngineering

and the BuiltEnvironment

Sustainable Design & Applied Researchin Engineering and the Built Environment

JournalJournal

BuildingBuildingServicesServicesnews

School of Multidisciplinary Technologies

Engineering and the

Built Environment

SDAR Cover 2015:Layout 1 10/11/2015 11:08

School of Electrical and Electronic Engineering The School of Electrical and Electronic Engineering, Dublin Institute of Technology (SEEE), is thelargest education provider in the electrical and electronic engineering space in Ireland in terms ofprogramme diversity (apprentice to PhD), staff and student numbers.

Based in Dublin city centre (Kevin Street) and established since 1887, it prides itself in providingpractice-based and professionally-accredited programmes across a variety of full-time and part-time options.

The School also focuses on applied research with a strong emphasis on producing useful and novelideas to help Irish industry compete globally. SEEE research is recognised for its impact and quality,which in many cases is on a par with that of the very best groups internationally.

For further information on the school contact:

School of Electrical and Electronic Engineering,

Dublin Institute of Technology, Kevin Street, Dublin 8

Tel: + 353 1 402 4617/4650/4575 Email: [email protected]/colleges/collegeofengineeringbuiltenvironment

SEEE Programmes

Level 9 (Masters)

MSc – Energy Management DT711 or DT015

ME – Sustainable Electrical Energy Systems DT704 or DT705

Level 8 (Hons)

BE in Electrical and Electronic Engineering DT021

BE in Computer and Communications Engineering DT081

BSc in Electrical Services and Energy Management DT712 or DT018

Level 7

BEngTech in Electrical Services Engineering

Institiúd Teicneolaíochta Átha CliathDublin Institute of Technology

MSc in Electronic and Communications Engineering DT085 or DT086

BEngTech in Electronic and Communications Engineering DT008

BEngTech in Sustainable Design for Electrical Services Engineering DT010

BTech in Networking Technologies DT080A

BSc Networking Applications and Services DT080B

BEngTech in Electrical and Control Engineering DT009

School Elec Eng:Layout 1 10/11/2015 10:49 Page 1

Contents Introduction

Welcome to the fifth edition of the SDAR Journal which the CharteredInstitution of Building Services Engineers (CIBSE) produces in partnership with theDublin Institute of Technology (DIT).

CIBSE partners with DIT throughout the year on Continuous ProfessionalDevelopment (CPD) events. We feel it is essential to have strong relationships witheducational bodies such as DIT, and the SDAR Journal is a showcase for this ongoingrelationship.

CIBSE Ireland represents circa 800 members, the majority of whom are graduate andstudent members. In co-publishing the SDAR Journal with DIT we play a proactive rolein supporting them, and in promoting research to help sustain the future of theengineering sector as a whole.

It is encouraging to see strong educational and research papers being presented, andit instils confidence in the sector going forward as the economic indicators continueto be positive.

I would encourage all in research and academia to review the papers in this year’sSDAR Journal and to consider their own research and studies with a view topublication in the next edition.

As Director and Dean of the College of Engineering and Built Environment at DIT I am delighted to welcome the fifth edition of the SDAR Journal.

This journal is an excellent example of academia working closely with industry tosupport good-quality applied research that has a genuinely useful impact. This helpsDIT as an institution to fulfill a core objective of our mission which is to build strongand lasting relationships with industry and to disseminate new knowledge and ideasas widely as possible. It also offers practicing engineers an opportunity to publish incollaboration with experienced academics.

Applied research in DIT is recognised for its impact and quality, and in many cases ison a par with that of the very best groups internationally. DIT is in the top 3% ofuniversities worldwide and as a college we have a strong emphasis on research inareas such as energy management, renewable energy technologies, electrical energysystems and sustainable design in the built environment. These research areas are of

vital importance as Ireland faces future challenges in areas such as sustainability and energy supply.

In closing I want to congratulate the editorial team and all the authors on the high quality of their work and on theircontributions to research in this area, both in Ireland andworldwide.

David DohertyChairman, CIBSE Ireland

Professor Gerald FarrellDirector and Dean of the College of Engineering and Built Environment, DIT

2 Editor’s foreword

3 A reader’s guide to this issue

5 Validating the performance of a prototype phase change material for a thermal energy storage tank, connected to micro-CHPDr Michael McKeever

13 Evaluation of building performance in use– a case study of the Seager Distillery developmentMichael CN Lim, David Ross, Steve Harper

25 First steps in developing cement-based batteries to power cathodic protection of embedded steel in concreteDr Niall Holmes, Dr Aimee Byrne, Professor Brian Norton

33 The lighting of St Mel’s CathedralMark Reilly

43 The Pavilion of Light, Mardyke Gardens, Fitzgerald Park, CorkStephen Robinson

The SDAR Journal is a sustainable design and applied researchpublication written by engineers and researchers forprofessionals in the built environment. It is edited by staff of the Dublin Institute of Technology.

Editor: Dr Kevin Kelly, DIT and CIBSEContact: [email protected]

Deputy Editor: Dr Keith Sunderland, Head of Electrical Services Engineering, DITContact: [email protected]

Editorial Team: Yvonne Desmond, Pat Lehane, Kevin Gaughan

The Reviewing Panel is: Dr Martin Barrett, Professor MichaelConlon, Professor Tim Dwyer, Dr Avril Behan, Ciara Aherne, Kevin Gaughan, David Doherty, Dr Marek Rebow, ProfessorDavid Kennedy and Professor Gerald Farrell

Upload papers and access articles online:http://arrow.dit.ie/sdar/

Published by: CIBSE Ireland and the College of Engineering & Built Environment, DIT

Produced by: Pressline Ltd, Carraig Court, George’s Avenue,Blackrock, Co Dublin. Tel: 01 - 288 5001/2/3.email: [email protected]

Printed by: Swift Print Solutions (SPS)

ISSN 2009-549X

© SDAR Research Journal

Additional copies can be purchased for €50

1

1-3 Intro pages 2015:Layout 1 10/11/2015 13:40 Page 1

Editor’s foreword

This is the fifth edition of the SDAR Journal and all 25 papers are now available

online at: http://arrow.dit.ie/sdar/

Presently we publish five papers in one edition annually but we are considering

extending to more papers in 2016. The SDAR Journal is coming in for very

favourable comment, both in Ireland and internationally, and you will see if you

open the link above that there have been 12,000 downloads of papers from

over 100 countries worldwide. Presumably, you are currently reading a hard-

copy printed edition and you may be interested to know that we have also

distributed 10,000 paper copies to industry and academia throughout Ireland.

The intention of the SDAR Journal is to encourage the publication of insightful

evidence-based findings from innovative practice in low-energy design of the

built environment. Industry engineers who submit their work can rely on us

to assist by offering free support and peer review processes supported

by experienced authors and academics. SDAR Journal papers come from a

combination of experienced authors, practicing engineers and researchers.

However, many of our authors have not previously published in a scholarly

journal and so we consciously act as an entry point for working engineers and

inexperienced researchers.

To publish, we demand critical reflection and objective evaluation of real-world

projects, but we help authors achieve this. I would encourage every company

to implement applied research in their companies through post-occupancy

evaluations and similar evaluation. If you are doing this already, then consider

submitting short abstracts of proposed papers to us so that we might engage

with you to help bring these ideas to fruition through publication of the

findings. Such publications help leading companies add value to their work by

evidencing claims through a rigorous (and free) peer-review process.

Would-be contributors are also encouraged to submit abstracts for the annual

SDAR Awards and Irish Lighter competitions. This issue carries two papers from

this year’s SDAR Awards and two papers from the Irish Lighter competition. The

final paper is derived from a presentation at the CIBSE/ASHRAE annual

conference.

SDAR Journal 2015

2

Dr Kevin T. KellyC Eng FCIBSE FSLL FIEIHead of School of Multidisciplinary TechnologiesDublin Institute of TechnologyPast President Society of Light & [email protected]

Editorial Board

Professor Brian Norton,Dublin Institute of Technology

Professor Andy Ford, London South Bank University

Professor Tim Dwyer, University College London

Dr Hywel Davies, CIBSE

Mr David Doherty,Chairman,CIBSE Ireland

Professor Gerald Farrell, Dublin Institute of Technology

Professor John Mardaljevic,Loughborough University

Professor Michael Conlon, Dublin Institute of Technology

Professor David Kennedy,Dublin Institute of Technology

Dr Kevin Kelly,Dublin Institute of Technology,

CIBSE, SLL


A Reader’s Guide

3

A Reader’s Gude

In this issue we have five papers — one on energy storage,another on post-occupancy evaluation from the UK and a third onmaking cathodic protection of concrete more sustainable. Theother two papers are on lighting, a topic that is presently the mostdownloaded online from the SDAR Journal.

The first paper addresses the challenge of storing energy moreefficiently. This research builds and tests an innovative phasechange material, the thermal energy storage unit (PCM-TES), thatwas invented at DIT’s Dublin Energy Lab and installed in an officebuilding in Cork in 2014. The PCM-TES is connected to a micro-CHP unit and also addresses the problem of what to do with wasteheat from a combined heat and power unit at evening peak tariffperiods, when the buildingheating loads are lowest.

The research is carried out usinga 2000-litre water tank and a2000-litre PCM-TES unit andcomparing both storage systems.Test results prove that the PCM-TES stores 6.5 times moreheat for the same plantroomfootprint, allowing the CHP unitto run continuously during peakperiods. The stored energy isthen used to pre-heat the building early in the morning. This allowsCHP thermal demand to align better with the electrical tariff,reduce utility bills and eliminate the need for back-up boilers.

The second paper is a two-year post-occupancy performanceevaluation of a new high-density development in London. Threeapartments were studied in detail whereby the building

fabric, MVHR units and thecommunal heating systemwere evaluated by comparingactual performance againstdesign intent.

The study findings high-light the gaps in expectedperformance. The buildingfabric has been shown toperform well but some issueshave been identified with the performance of theMVHR systems. The study also

summarises the lessons learnt, which informs the delivery of futuredevelopments and highlights areas for improvement in terms of design, installation, commissioning and post-occupancymaintenance.

The research for the third paperinvestigates the first steps in developinginnovative cement-based batteries topower cathodic protection in reinforcedconcrete structures. Cathodic protectionis a well-used method to protectembedded steel in concrete but researchinto more sustainable alternatives tosupply the external electrical supply has

not received much attention to date. This research focuses ondeveloping cement-based batteries which increases the ionicconductivity of the solution in the cement pores, how best to sealthe batteries from moisture loss and comparing different electrodematerials and treatments.

The preliminary findings demonstrate that cement-based batteriescan sustainably produce sufficient electrical outputs for cathodicprotection by using the correct materials and arrangement of cast-in anodes and cathodes.

The fourth paper focuses on the design and methodology of aninteresting lighting installation at the re-constructed St Mel’sCathedral in Longford, Ireland. Restored after a catastrophic fire in2009, a lighting scheme using modern LEDs and intelligent lightingcontrols is used to recreate the historic atmosphere of thissignificant building. The projectposed particular problems and the way they are addressed isinsightful in that it moves awayfrom standard lighting practiceusing horizontal illuminance asthe main emphasis, to a more tailored methodology focused onreal user need, producing anappropriate atmosphere in thisbuilding that emphasises visualquality.

The final paper is from an engineer who does not rely onstandard practice but worksmuch more intuitively to providea more artistic outcome and astunning visual effect. This is aunique project posing artisticand many practical challengeswith respect to local fauna andwildlife. The former were dealtwith intuitively and the latter by using sound engineeringevaluation.


AWARDS2016Short abstracts (between100/200 words max) for entry into theSDAR Awards 2016 must be submittedby Monday, 14 December 2015,by email directly to Michael McDonald and/or Kevin Kelly of DIT [email protected] [email protected]

The SDAR Awards is a joint initiativebetween CIBSE Ireland and DIT,supported by Building Services News,and sponsored by John Sisk & Son. Theawards are unique in that they are intended to disseminateknowledge, encourage research in sustainable design of the builtenvironment and raise the quality of innovation and evaluation of such projects. Entries are required to critically evaluate real life data, andexamine both successes andchallenges within leading-edge

projects throughout Ireland or furtherafield. This competition is open toarchitects, engineers and all professionals involved inconstruction projects.

Now more than ever as positive signsripple through the built environment,this unique synergy between industryand academia allows greater potentialfor integration of modern low-carbontechnologies and low-energy design methodologies.

The SDAR Awards competition isintended to create a platform for thegrowth of applied research in theexpanding green economy. Postoccupancy evaluations and similarcritical appraisal of low-energyprojects facilitate the transition from ideologically-driven innovations,sometimes offering poor value, toevidence-based applied research

that proves value or identifiesweaknesses that the industry can learnfrom. These successes and failures helpinform the professional communityacross all the building industrydisciplines.

From the abstracts submitted bythe Monday, 14 December 2015deadline, a shortlist will be selected bypeer review, and those selected will beinvited to prepare final papers by 1February 2016.

First prize is a cheque for €1000.Candidates that present at the awardsalso have a chance of publishing theirpapers in the SDAR Journal –arrow.dit.ie/sdar/

Next year’s final will take place inMarch 2016 in DIT, Bolton Street.

For further information contact:[email protected] [email protected]

http://arrow.dit.ie/sdar/ Sponsored by :

Call for Abstracts

SDAR Awards2015:Layout 1 10/11/2015 11:11 Page 1

Validating the performanceof a prototype phasechange material for athermal energy storagetank, connected to a micro-CHP

Dr Michael Mc KeeverSCHOOL OF ELECTRICAL AND ELECTRONIC ENGINEERING

DUBLIN INSTITUTE OF TECHNOLOGY

[email protected]

SDAR AWARD WINNER 2015

Mick McKeever Paper:Layout 1 10/11/2015 13:31 Page 5

Abstract

This paper describes the performance testing of a

2000-litre phase change material used in a Thermal

Energy Storage (PCM-TES) demonstrator unit

invented in DIT’s Dublin Energy Lab and installed in

an office building in Cork in 2014. The PCM-TES is

connected to a Micro-CHP unit and stores waste heat

from the CHP at evening peak tariff periods when the

building heating loads are lowest. The CHP is also

connected to a 2000-litre water tank allowing direct

comparison of the energy storage capacities and

performances of both storage systems. Charging

results presented show that the PCM-TES holds 6.5

times more heat for the same plant room footprint,

allowing the CHP to run continuously during peak

periods and producing a better overall electrical/

thermal efficiency. Discharging results show how the

PCM-TES stored energy can be used to pre-heat the

building heating system early in the morning, shifting

CHP thermal demand to align better with the day

rate electrical tariff period. The PCM-TES eliminates

the need for back-up gas boilers to be used for the

early morning heat demand peak. A discussion of

PCM-TES benefits over a water-based TES is supported

and presented here.

Key words:Phase change materials, latent heat storage, thermalstorage and CHP

Glossary:PCM Phase change materialTES Thermal energy storeCHP Combined heat and powerNPV Net present value SPP Simple payback periodROI Return on investment

1. IntroductionIdentifying the economic advantages of installing micro-CHP in buildings requires a techno-economic analysis over the full life-cycle of the system. Financial decision makers have to beconvinced that a proposed plant room installation has a reasonablepayback and is a sustainable acceptable risk investment. Thisargument can be made using estimated up-front capital costs,running costs and disposal costs, in calculation of Net Present Value(NPV), Simple Payback Period (SPP) or Return on Investment (ROI)analysis. The most difficult costs to predict are the fuel consumptionand maintenance costs of running the equipment over its lifespan.Techno-economic results are always compared to other benchmarktechnology solutions on the market. In retrofitting, the availabilityof plant room space and the footprint of the equipment must notbe overlooked.

The argument for CHP is that the electrical power can be exportedat a profit, but this only makes economic sense if the heat can beused directly or stored for later use. The heat energy needs to beused to make CHP a viable and sustainable solution. This requiresstorage as the heat demand profiles do not necessarily coincidewith high electric tariff periods. Thermal energy storage allows theCHP to export electrical power at peak electrical demand periodsand to release heat when building thermal demands are highduring low electrical tariff periods. This has traditionally beenimplemented using Sensible Heat Thermal Energy Store (SH-TES)water tanks that store energy by raising the temperature of waterinside the tank. This solution is low risk and the benchmark used tocompare thermal energy storage solutions. However, these SH-TESunits are large, often occupying significant plant room floor spaceor, if very large, they may require planning permission wheninstalled outside the building.

A new 500-litre Phase Change Materials Thermal Energy Store(PCM-TES) was developed at the Dublin Institute of Technology.The PCM-TES was designed to store six times the energy storagecapacity of a SH-TES operating on a 5°C differential temperature.A building heated by a micro-CHP with a 2000-litre SH-TES wasselected as an ideal demonstration site. A 2000-litre PCM-TES (4 x500-litre) was retrofitted in parallel to the 2000-litre SH-TES toenable comparative testing of both energy stores. The objectivewas to produce data suitable for a techno-economic analysis of thePCM-TES system.

2. BackgroundPCM is a material that absorbs latent energy as heat when it meltsand releases this latent heat back when solidifying(1)(2). Thetemperature of melting and solidifying are separated by a fewdegrees and high quantities of heat can be stored over smalldifferential temperatures (Delta-T)(3). An example of this is a 1kg ofRT70HC wax(4) which melts and solidifies in the temperature range69°C to 71°C and stores 64Wh/kg. A corresponding 1kg of waterover the same temperature range stores only 2.3Wh/kg. In practice,the energy storage density ratio between PCM and water islower(5). If the operating temperature range was increased to 66°C

SDAR Journal 2015

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Validating the performance of a prototype phase change material for a thermal energy storage tank, connected to a micro-CHP

to 71°C, the energy density ratio would drop to around 9:1 whencomparing PCM to water on a volumetric basis.

PCM absorbs heat more slowly than water and large blocks of PCMdo not have the dynamic response times required by buildingheating systems to meet load fluctuations. The thermal conductivityof wax-based PCM is 0.2W/mK compared to 0.58W/mK for water.Charging and discharging response times are proportional to theratio of the PCM volume to surface area(6).

The low thermal conductivity problem with PCM can be overcomeby distributing the heat source and heat sink inside the PCM usingpipes, fins and plates. This increases the heat transfer rates byincreasing the heat exchange surface area but, as a consequence,it reduces the quantity of PCM for a fixed volume. A significantPCM-TES design challenge is to find the correct compromisebetween energy storage density and heat response rates to meetheat demand peaks and troughs(7).

This research set out to develop and evaluate a novel PCM-TESdesign for use in buildings. The PCM-TES demonstrator unit isinstalled in the CIT Nimbus building plant room and coupled to amicro-CHP unit(8). The focus of this paper is not on the internaldesign of the PCM-TES unit but on a comparative study of theperformance of this system compared to an identical sized watertank operating in a live building. The test results on the PCM-TESunit are presented to validate the system design concept andperformance when coupled to a micro-CHP.

3. The PCM-TES demonstrator tankThe PCM-TES prototype uses four 500-litre metallic tanks, eachwith two suitably-shaped hydraulic coils and inner space filled withPCM. A picture of one tank is shown in Figure 1 with the lidpartially removed, revealing the internal PCM and two heat transfercoils. The inlet piping of the system at the front shows the pipingterminals for each coil.

The PCM-TES unit operates as follows in the demonstrator. Theprimary coil is used to supply thermal output from the micro-CHPinto the PCM-TES. The PCM-TES unit discharges its energy throughthe secondary coil. This allows the primary and secondary circuitsto be operated separately so the unit may charge and discharge

simultaneously or independently as required by the CHP controllerand BMS system. The thermal storage capacity of a 500-litre unitis 29kWh for a delta-T of 5°C across the primary coil. The PCMused in this demonstrator is a wax-based commercial PCM that isnon-corrosive and has a life of over 10,000 solid-liquid chargingcycles. Unlike salt-hydrate PCM materials, wax PCM does not sufferfrom under-cooling, or permanent material segregation, and has apH close to 7(9). The four unit demonstrator is shown in Figure 2.

This gives a total capacity of 126 kWh of storage for a delta-T of 20°C across each unit connected in series. Two PCM materialsare used. The top unit is filled with a PCM with a melt temperaturein the range 80°C to 82°C, while the other three units are filledwith a PCM that melts in the range 68°C to 70°C. The 2000-litrePCM-TES allows direct comparison between the PCM-TEStechnology and the 2000-litre SH-TES installed as part of theoriginal plant room CHP installation.

4. The demonstrator site installationand operation

The Micro-CHP unit is a natural gas-fired Sokratherm GG50 with a90°C/70°C thermal circuit(10). The CHP installation is controlled bya PLC-based SCADA system allowing set point control of boththermal and electrical outputs.

The SCADA system has full integration with the BMS system that

Figure 1: Prototype 500-litre PCM-TES unit.

Figure 2: PCM-TES installation during commissioning (only top unit showninsulated).

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controls the energy requirements of the building. The initial plantroom design incorporated a 2000-litre Sensible Heat ThermalEnergy Storage tank (SH-TES). Figure 3 shows the SH-TES (red andwhite in the background), the CHP unit and the PCM tank duringits commissioning. A simplified process schematic of the heatingsystem is shown in Figure 4 for the PCM tank only. The sensibletank operates in parallel with the PCM tank connections (notshown in Figure 4). The CHP-PCM-TES heating circuit systemconsists of two parts, the primary charging loop operating on a90°C/70°C supply heat from the CHP and return line operating ona 70°C/50°C loop. The thermal output of the CHP is controlled byvarying flow through the VSD pump (P01) to maintain a 90°C CHPoutput temperature. The CHP trips out if the return temperatureexceeds 75°C for a period of time.

The secondary side of the PCM-TES is connected to the buildingsystem header and return pipework. This is controlled by a variablespeed pump (P02) drawing water from the return manifold whichis heated in the PCM tank before discharge into the buildingheating header manifold.

The heating system also includes two back-up gas-fired boilerswhich are activated if the header return temperature drops below62.5°C. Gas consumption of the boilers in the morning was in theregion of 70kWh during the heating season.

The heating system operates as follows under BMS control. At 7amthe BMS calls for heat and the CHP starts. Normally the large

thermal load on the return manifold causes the gas fired boilers to both activate and complement the CHP. When temperatures stabilise, the CHP operates alone and supplies heat to the building.When the thermal demand drops, the CHP charges the SH-TES and shuts down when the SH-TES exceeds 85°C. The CHP kicks inagain when tank temperatures drop below 74°C. During peak tariffperiods the CHP exports electrical power. However, the heatdemand of the building is low at this time and excess heat isdumped to air to prevent the CHP tripping out on high returntemperature.

The retrofitting of the PCM-TES to the CHP was carried out toproduce real building data to answer three key research questions:

1. How much energy could the PCM-TES store when operatingin a real building driven by a micro-CHP?

2. How long could the PCM-TES extend the operation of theCHP without dumping heat to air?

3. What percentage of the operation of the gas fired boilerscould be eliminated in the morning by discharging the PCM-TES prior to 7am?

Validating the performance of the prototype PCM-TES tankconnected to a Micro-CHP is essential to demonstrating systemperformance. This provides data to allow cost benefit analysis ofPCM-TES for other installations.

5. ResultsThe testing scenario for the PCM-TES and SH-TES was identical.The CHP thermal output was used to charge one tank at a time,with no heat being delivered to the building during charging. Thishelped to make the PCM-TES and SH-TES tests comparable byremoving the variable building loads affecting test results. As a consequence, the CHP outputs were turned down to 50%operation to replicate the normal charging process with thebuilding load taking the other 50% output. CHP thermal output inthe range 20kW to 25kW thermal and electrical output variedbetween 20kW to 30kW.

During the discharging both systems were allowed to dischargetheir energy into the building manifold under the same conditions.This occurred when the manifold return temperature was 60°C.

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Figure 3: Plant room showing the CHP, PCM tanks and sensible water tank.

Figure 4: Process and instrumentation drawing for the PCM tank demonstrator site.

Water

PCM tanks CHP


6. CPH thermal operation duringcharging

The first test conducted was the charging of the SH-TES as shownin Figure 5. The heating control system kicks in when the toptemperature of the SH-TES drops below 75°C. Stratification in thetank can clearly be seen as the bottom temperature in the tank is55°C. The charging takes 17 minutes and the total energy storedby the SH-TES is 13.5kWh over this period. The CHP stops whenthe upper temperature limit of the top temperature is exceeded at86°C. It should be noted that the lowest temperature in the SH-TESis 73°C, showing large temperature stratification within the tank.This is significant when discharging the tank into the header as thereturn temperature is below the 60°C set point start of the boilers.

During early morning heating of the building, the PCM-TES isallowed to discharge to below 60°C into the header manifoldwhich is the cut-in set-point for the back-up boilers. In this set-upit takes 200 minutes to fully charge the PCM-TES as can be seen inFigure 6.

Energy total stored by the PCM store is shown in Table 1 for a full charge cycle of the PCM-TES between 60°C and 85°C which is defined by the BMS control system. The PCM inside all the units heat above their melt temperatures and the control system shuts down the CHP when the highest temperature reaches85°C.

Comparing the energy storage densities over the operating rangeof the building heating system, the PCM-TES holds 6.56 times moreheat energy.

7. CHP electrical operation during charging

The significance of charging times and storage density has a directinfluence on the electrical operation of the CHP. When testing theCHP power output, both storage units were charged from ambienttemperature to full operating temperature. When the SH-TES wasfully charged, the unit was discharged directly into the building toallow the CHP recharge the tank a number of times as shown inFigure 7. Significantly, the SH-TES was charged three times in thesame period it took to charge the PCM-TES from ambient.However, this represents three starts for the CHP whereas the CHPruns continuously when charging the PCM-TES.

The electrical output totals are shown in Table 2. The CHP runscontinuously as the PCM-TES charges. Compare this to the SH-TESwhich charges from cold three times faster than the PCM-TES butas a consequence the electrical outputs are far lower over the first150 minutes. The SH-TES is discharged twice in order to comparethe total possible CHP operation over a single charge time of thePCM-TES.

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60 to 85 89.95 200

Temperature PCM Energy CHP Run Rise °C Stored kWh Time (mins)

Figure 5: Single charge of the SH-TES from 75°C to 85°C.

Figure 7: CHP electrical output when charging the PCM-TES and SH-TES fromfully cold.

Table 1: Energy stored by PCM during charging from 60C to 85C.

Average SH-TES charging Electrical Output kWe 61

Average PCM-TES charging Electrical Output kWe 103

Table 2: The average electrical output during charging of the thermal storageunits.

Figure 6: Single charge of the PCM-TES from 60°C to 85°C.


8. Discharging performance conparison of the PCM-TES

The results presented in this section show the SH-TES and PCM-TES discharging characteristics when feeding the building heatingmanifold early morning prior to the CHP starting at 7am. Normallywhen the CHP starts, the back-up gas boilers activate as there is alarge demand due to all the cold liquid in radiators and piping inthe building overnight. Figure 8 shows the operation of the gasboilers.

The total additional energy used by the boilers which is derivedfrom gas is calculated from Figure 8 and shown in Table 3.

The minimum requirement for any thermal storage device installedin the current building must be above 67.64kWh if the boiler gas costs are to be eliminated. The current 2000 litre SH-TES onlystores 13.4 kWh. If the energy was stored in a water tank for theoperating differential temperatures of the heating system, the10000-litre tank would be required. The discharge curve for the2000-litre SH-TES is shown in Figure 9. The discharge only takeseight minutes due to a combination of the low level of energystored and the rate at which the stored energy can be released.

The PCM-TES discharge is shown in Figure 10. The discharge in thiscase takes 50 minutes to reach 70°C from a fully charged state. The time to discharge is a combination of the 6.5 times higherenergy density and the lower rate of release of energy from thePCM material.

This longer discharge time of the PCM-TES can be compensatedfor by programming the SCADA/BMS system to discharge thePCM-TES 50 minutes before the CHP starts at 7am. The only reasonthe CHP starts at 7am is due to the economics of the feed-in tariffperiods. The boilers never kicked in when the PCM-TES dischargesearly morning. The PCM-TES and CHP working together nevercause the header return temperatures to drop below the activationset-point temperatures of Boiler 1 or Boiler 2 after 7am. Using thedata in Table 3, a saving of 67.64 kWh of gas per heating day isachieved by allowing the PCM-TES to discharge and eliminate theneed to use the backup boilers.

9. DiscussionThe charging and discharging results show that the PCM-TES holds6.5 times the heat energy of a SH-TES water tank of identicalvolume when connected to this CHP operating on a 90/70°Cheating system. The advantages of the PCM-TES are that it allowsthe CHP to run longer when there is no heat demand in thebuilding. This normally coincides with the peak tariff period in theevening which is exactly when commercial building workers leaveto go home at the end of their working day. The heat energy isstored overnight and used to pre-heat the building heating systemin preparation for when the CHP operates early the following day.This results in the building being at the correct temperature whenthe workers enter the building at the start of their working day.

Referring back to the economic advantages of installing a PCM-TES, there are three findings made using data generated for thedemonstrator PCM-TES.

The first relates to the need for two back-up gas fired boilers. Thiscould be reduced to one single boiler, used primarily when the CHPis being serviced. This represents a capital expenditure saving, a gassaving and an annual maintenance saving.

The second relates to the plant floor space being saved by havingone PCM-TES. Five to six water tanks would be required in thedemonstrator site to hold the energy of the PCM-TES. Indeed, the

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Figure 8: Gas boiler heat curves when assisting the CHP early in the morning.

Figure 10: Discharge characteristic for the PCM-TES.

Figure 9: Discharge characteristic for the SH-TES.

Table 3: Gas energy consumed by the backup gas boilers without the PCM-TES fitted.

37.93519 29.70833 67.64352

Boiler 1 kWh Boiler 2 kWh Total kWh


space saved by having only one backup boiler increases this figurefurther.

The third relates to the overall electrical performance during peak tariff periods. The PCM-TES allows the generator to runcontinuously during evening peak tariff windows, maximising therevenues generated for power export, especially as the buildingoccupancy is normally low at the end of the working day.

10. ConclusionThis paper presents real building performance data for a noveldesign PCM-TES. The PCM-TES has been installed in a commercialbuilding and its operation is compared to a SH-TES of the samesize. Results show the PCM-TES holds 6.5 times more heat, allows the CHP to run longer at peak tariffs and has the capacityto eliminate one of the backup gas boilers, saving on CapEx andgas energy consumption when compared to the SH-TES.

It is concluded that the demonstration of a 6.5:1 energy densityratio for the same plant room space represents a viable propositionfor heating system design engineers.

The current technology is now being designed to reduce theembodied energies by considering alternative materials to thestainless steel and using bio-degradable PCM materials which will influence the life-cycle costs and sustainability of this novelthermal energy storage technology.

References[1] S. McCormack, P. Griffiths. Phase Change Materials – A Primer

for Architects and Engineers (20120 –ISBN 978-1-85923-260-6.

[2] L.F. Cabeza, Heat and Cold Storage with PCM (2013). ISBN 978-3-540-68556-2.

[3] A. de Gracia, L. F. Cabeza, Phase change materials and thermalenergy storage for buildings, Energy and Buildings, Volume103, 15 September 2015, Pages 414-419.

[4] http://rubitherm.de

[5] R.K. Sharma, P. Ganesan, V.V. Tyagi, H.S.C. Metselaar, S.C.Sandaran, Developments in organic solid–liquid phase changematerials and their applications in thermal energy storage,Energy Conversion and Management, Volume 95, 1 May 2015,Pages 193-228

[6] G.R. Dheep, A. Sreekumar, Influence of accelerated thermalcharging and discharging cycles on thermo-physical propertiesof organic phase change materials for solar thermal energystorage applications, Energy Conversion and Management,Volume 105, 15 November 2015, Pages 13-19.

[7] A. de Gracia, L.F. Cabeza, Phase change materials and thermalenergy storage for buildings, Energy and Buildings, Volume103, 15 September 2015, Pages 414-419.

[8] M. Delgado, A. Lázaro, J. Mazo, C. Peñalosa, P. Dolado, B.Zalba, Experimental analysis of a low cost phase changematerial emulsion for its use as thermal storage system, EnergyConversion and Management, Volume 106, December 2015,Pages 201-212.

[9] Nimbus Centre, Cork Institute of Technology.http://Nimbus.cit.ie/tec/case-studies/etb/

[10] PSE Power http://www.pse.ie/wpcontent/uploads/2012/05/GG-50-09_1-engl-JV1.pdf


11


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Evaluation of buildingperformance in use – acase study of the SeagerDistillery development

Michael CN LimAECOM, [email protected]

David RossAECOM, [email protected]

Steve Harper GALLIARD HOMES

[email protected]

Michael Lim, A case study of the Seager Distillery development NEW:Layout 1 10/11/2015 10:32 Page 13

Abstract

A two-year post-occupancy performance evaluation

has been undertaken of the apartments within

Galliard Homes’ Seager Distillery redevelopment site

in London. The Seager Distillery site is typical of the

many new high-density developments in London,

reflecting the tightening standards on energy use

and pressure on land use. This paper presents the

energy and environmental performance of three

apartments studied in detail, including the assessment

of the performance of the building fabric, MVHR

units and the communal heating system.

The paper compares the actual performance against

the design intent of the apartments and summarises

the performance of the communal heating system in

use. It then highlights the reasons for any

performance gaps identified, which provide useful

learning to both Galliard Homes and the wider

building industry.

The study has demonstrated that measurements of

the actual performance of the building fabric align

with design expectations; however, issues were found

in the performance of the MVHR systems in the

apartments affecting thermal comfort and energy

use. This was further exacerbated by the under-

performing communal heating system, where various

shortcomings have affected its design, installation

and operation.

The study highlighted areas for improvement in the

building and its services in terms of design,

installation, commissioning and post-occupancy

maintenance. Better building handover and occupant

access to relevant information were identified to

promote building usability and further contribute

to closing the performance gaps.

Key Words:Building performance, post-occupancy, communalheating, MVHR, air tightness

1. IntroductionThere is increasing concern over the potential gap between thedesign intent of a building and its actual performance in terms ofenergy and summer comfort conditions. This gap is thought toarise from a variety of sources, ranging from the design of thebuilding and the methods used, through to the buildability,procurement and construction process, which affect build quality,systems integration and commissioning, as well as the handoverand operation of the building. This gap in performance couldimpact on the UK government achieving its aspiration for a low-carbon economy and its CO2 reduction commitments. It presents a reputational risk to the house-building industry and it coulddamage consumer confidence in new-housing if energy bills arehigher than expected and the buildings overheat.

In light of these concerns, the Technology Strategy Board (InnovateUK) committed up to £8 million to fund a four-year BuildingPerformance Evaluation (BPE) programme on both domestic andnon-domestic buildings, which commenced in 2010. The overallpurpose of the programme was to evaluate the performance ofbuildings and support the building industry in delivering moreenergy efficient, better-performing buildings. This was to bedelivered through detailed investigation of real buildings under useto derive substantive evidence of actual building performance andto help identify root causes, which need to be collectively addressedby the various sectors of the building industry, to close anyidentified gaps in delivered performance.

This paper presents the results of a two-year post-occupancyevaluation study undertaken under the TSB BPE programme. It hasbeen carried out on apartments within Galliard Homes’ SeagerDistillery redevelopment site in London. This study aimed to developan insight into a number of important features of recently-builthousing, not sufficiently understood, of which (a) to (c) are coveredin detail in this paper:

a) The energy performance of the apartments;

b) The efficiency of the communal heating scheme;

c) Understand differences between as-designed and actualenergy use by the apartments;

d) Whether overheating occurs in the apartments;

e) Occupant experience and satisfaction with the apartments.

2. The Seager Distillery site

2.1 OverviewThe Seager Distillery site is a regeneration project by Galliard Homeson the site of a former distillery, which includes the refurbishmentof a 19th century warehouse, a new crescent building, officepavilion and residential tower. It is typical of many developmentsthat came forward in the 2000s in London, reflecting thetightening standards on energy use and pressure on land use,

SDAR Journal 2015

14


Evaluation of building performance in use – a case study of the Seager Distillery development

which led to the building of high-density apartment blocks, ratherthan houses.

This site is distinctive in having a communal heating system toprovide heating and hot water throughout the development. Themain heat source is a gas Combined Heat and Power (CHP) plantsupplemented by a biomass boiler and two conventionalcentralised gas boilers. The apartments are equipped withmechanical ventilation with heat recovery (MVHR) systems for thecontinuous provision of fresh air ventilation.

Specifically, the study focused on Norfolk House, which is one ofthe annex blocks completed within the first phase of thedevelopment. Norfolk House is considered representative of thesite with similar build specification, design and procurement. Thereare a total of 58 apartments in Norfolk House, which feature full-height double glazing connecting the living rooms to the balconies.Various types of cladding have been used on the facade includingaluminium insulated panels, aluminium rain-screen cladding,aluminium infill panels, aluminium spandrel panels, and timbercladding. Figure 1 shows the Seager Distillery development andNorfolk House.

The study particularly focussed on three apartments comprising themost common build-types within Norfolk House, which are detailedin Table 1. AECOM undertook an independent investigation of thebuildings with support from Galliard Homes and Amicus Horizons(social housing provider, who part-owns the apartments). AECOMhad no role in the development of the Seager Distillery site.

2.2 Communal heating system

A dedicated communal heating system provides heating anddomestic hot water (DHW) throughout the development. Figure 2illustrates the communal heating system layout taking heat fromthe energy centre to the different blocks throughout site, includingNorfolk House. Separate building pipe network then distributesheat to the apartments via hydrostatic interface units (HIUs) forspace heating and DHW provision.

Figure 3 shows the energy centre, which comprises the following:

— An 800kWth wood pellets fired lead biomass boiler toprovide low carbon heat;

— An Ener-G 100 CHP plant with 165kWth and 100kWe;

— An 1000kW Hoval Cosmo gas boiler installed in Phase 1 and1500kW Hoval Cosmo gas boiler in Phase 2;

— An 18,000 litre thermal store to buffer CHP and biomassboiler output.

3. MethodologyThe study was carried out over a two-year period and comprisedboth quantitative and qualitative evaluation of the performance ofthe apartments and the communal heating system. Figure 4illustrates the setup for real-time measurement on site. Thefollowing measurements were recorded at 5-minute intervals withthe data remotely accessed on a weekly basis by AECOM:

— Total electricity, heat (space heating and DHW) and waterconsumption;

— Separate electricity sub-metering of the MVHR system,lighting, power sockets, heating system and cooking hob;

— Temperature, relative humidity and CO2 levels within theapartments as well as the local weather condition at the site.

Figure 1: The Seager Distillery site and Norfolk House.

Figure 2: Communal heating supplying heat from the energy centre throughoutthe site.

CHP UNIT 100kWe 165kWt

BIOMASS BOILER 800kW

THERMAL STORE 18m3

GAS BOILER 1500kW

GAS BOILER 1000kW

PRIMARY RETURN

PRIMARY FLOW

PRIMARY PUMPS

DIVERTING VALVE

ELECTRICITY OUTPUT

HEAT

HEAT PRIMARY HEADER

FLOW TO THE BLOCKS VIA BLOCK PLANT ROOM HEAT EXCHANGERS AND SECONDARY PUMPED CIRCUITS

Figure 3: Block diagram of the communal heating system.Flat Internal Floor Number of Aspect Floor of Number Area Bedrooms Apartment

Block

Flat 1 45m² 1 west facing 4th floor

Flat 2 74m² 2 west and east 4th floorfacing (dual

aspect)

Flat 3 63m² 1 east facing 4th/5th floor(duplex flat)

Table 1 – Details of the apartment units monitored in detail

15


In addition, plug-in energy meters were used to monitor energyuse of selected individual appliances to provide further granularityin the electricity consumption data.

Actual energy consumptions measured for each of the threeapartments were compared against their corresponding SAP figures.SAP or Standard Assessment Procedure is the UK Government'srecommended method system for measuring the energy rating ofresidential dwellings, which is used specifically for building regulationcompliance purposes. Comparison using SAP figures has beencarried out in the study to benchmark against actual consumption.

In order to assess the build quality of the development, the airleakage and fabric thermal conductive performance of NorfolkHouse were measured by a specialist contractor:

— Air tightness tests were carried out in each of the threeapartments, initially during the summer of 2013 and thenrepeated a year later. This testing was undertaken using a“blower-door” test in accordance with the proceduresdescribed in the ATTMA technical standard, TSL1 October2010;

— In-situ U-value tests were carried out to determine thethermal performance of external walls of the apartmentsusing heat flux sensors mounted on internal surfaces, whichmeasured heat flow directly through each wall to correlatewith corresponding internal and external air temperatures.Further inspection of the fabric thermal performance wascarried out using thermographic imaging survey on both theinterior and exterior of the apartments.

The performance of the MVHR system was also investigated:

— Measurement of flow rates were compared againstcommissioned figures and values from Approved Document Part F of the Building Regulations. In addition, continuousmeasurement of MVHR energy use was combined with flowmeasurements to determine the fan efficiency of the units;

— Visual inspections were carried out where possible todetermine both the quality of installation as well as the

condition of the filters, which provided a general indicationof the level of maintenance of the units.

A specialist contractor measured the MVHR air flow rates in each apartment in accordance with the BSRIA Guide BG46/2013,Domestic Ventilation Systems – A Guide to Measuring Air FlowRates. An air capture instrument was used to measure the airvolume from the supply and extract terminals in the apartments, byfully enclosing the terminals with the inlet hood of the instrument.This instrument has a built-in fan and pressure compensationfacility, with an accuracy of ±3% of reading ±1m3/h.

A series of walk-through audits and visual inspections of buildingservices and the construction details in the apartments were alsocarried out to identify any issues which might lead to shortcomingsin building performance. This was supplemented by feedbackobtained through informal occupant and developer interviews andthrough questionnaires employing the Building User Survey (BUS)methodology (1).

4. Key findings

4.1 Fabric performanceThe air tightness results are summarised in Table 2, together withthe as-designed SAP values as well as the on-completion airtightness testing for the same apartment types (not the actualapartments monitored here) obtained from test certificates issuedduring construction.

The initial and repeat air tightness tests undertaken as part of thisstudy were significantly lower than assumed in the design stageSAP assessment and 1 to 2 m³/(h.m²) better than those tested for similar apartments on-completion. Potential causes of thedifference between the on-completion and current study testinginclude the following:

— Variations between the actual apartments tested for thecorresponding given apartment type;

— Changes to the building fabric air tightness over time. Thismay be due to the building drying-out and settling down.Furthermore, leakage paths through small gaps in thebuilding fabric may get clogged up;

— Significant differences may have resulted from differentorganisations undertaking the two sets of air tightness tests

SDAR Journal 2015

16

Figure 4: Diagrammatic illustration of the real-time measurement setup inNorfolk House.

Seager Distillery Norfolk House

Dry riser

Remote data collection

Flat1

Air temp

CO2

RH

Flat3

Air temp

CO2

RH

Flat2

Air temp

CO2

RH

Main distribution board

Consumer Unit

Communityheating

Mains water

Electricity mains incomer

Sensor

Pulse meter

Pulse meter

Pulse meter

Weather station

Heat meter

Heat meter

Heatmeter

Water meter

Water meter

Watermeter

Data logger & modem

Modem

MVHR

Plug monitor

Repeater

Consumer Unit

MVHR

Consumer Unit

MVHR

Plug monitor

Plug monitor

Sensor

Sensor

Air pressure measure Air permeability at 50Pa (m³/h.m²)

Flat 1 Flat 2 Flat 3

Design air 8.0permeability (SAP)

On completion 4.5 4.2 5.6(original testing contractor)

Initial air pressure test 2.4 3.2 3.6results in the study

Repeat air pressure test 2.8 2.6 3.6results in the study

Table 2 – The air pressure test results


and arisen due to variations in the methodology employedand the calibration of the equipment used. However, therewas insufficient data collected to account for the magnitudeof discrepancy in the measurements.

Reviewing the literature, it is noted that another study of threerounds of air tightness measurements in 10 low-energy new homesduring the first 18 months of occupation also showed a generalimprovement of the air tightness across the period (2). A furtherstudy suggests that the type of dwelling, construction, heating and ventilation all have a bearing on the extent to which airpermeability changes over time(3).

While the air tightness results were relatively low, smoke tests haveidentified leakage paths under sinks, wall power sockets and lightfittings, which present potential areas for future improvement.

Limited in-situ U-value tests(4) were carried out by a specialistcontractor on the general external facing wall of the apartments.However, there were problems with the testing leading to data onlyfor one apartment and one section of wall. The results suggest thatthe actual performance is close to the design value (actual value of0.23 W/m²K compared to a design value of 0.25 W/m²K), althoughmore extensive measurements would be required to verify thisfinding.

Thermographic imaging (5) was undertaken by a specialist contractor both internal and external to the apartments. Thisincludes measurement of the Thermal Index as a metric for fabricperformance. The Thermal Index is the ratio of (surface temperature– external temperature) and (internal ambient temperature – externaltemperature). The contractor provided a correlation between theThermal Index and U-value as shown in Table 3.

The reported Thermal Index generally suggested actual U-valuesare in-line with design expectations. Some cold spots wereidentified, which highlighted potential areas for futureimprovement. Examples include: (i) colder areas at the top of “boxed-in” sections, perhaps covering section of pipe work, with airleakage problems, (ii) cold bridging from large dabs behind theplaster board, and (iii) some evidence of cold bridging due topenetration of stud-wall fixings. Figure 5 shows images of the lattertwo examples.

No specific anomalies were identified on the external façade fromthe surveys carried out. It should be noted that glazed sectionsprovide some ambiguity when interpreting fabric performance,which is prevalent for Norfolk House. In addition, a high proportionof its opaque fabric consists of ventilated rain-screen cladding,which further renders the external survey ineffective.

However, salient features remain evident from the survey in theform of higher recorded temperatures related to MVHR outlet ventsabove windows and thermal bridging around some openable

windows as shown in Figure 6. Also shown are the thermographyimages of the underside of some of the apartment balcony floorslabs. It can be seen that the surface temperature is higher at theinterface with the external wall, indicating potential thermalbridging caused by the penetration of steel structure.

4.2 Ventilation: MVHR systemThe MVHR system is used to provide fresh air supply into the livingroom and the bedrooms, tempered via heat recovered from returnair extracted from the kitchen and bathroom. The MVHR unit iscapable of a normal and boost operation with a manufacturer-specified heat recovery effective up to 95% (not tested in thestudy). Both the supply and extract air are filtered at the MVHR unit.

Visual inspection of the MVHR system in the apartments high-lighted several issues which might potentially affect the overallperformance in the provision of ventilation and energy use. On first

17


Thermal index 0.50 0.75 0.80 0.85 0.90 0.95 0.97

U-value 3.8 1.9 1.5 1.2 0.9 0.35 0.25

Table 3 – Equivalence of Thermal Index and U-values

Figure 5: Thermography images showing (top) cold bridging (dark-bluepatches) from dabs on plasterboard and (bottom) from penetration of stud-wallfixings.

Figure 6: Thermography image showing heat loss (a) on the external façade ofNorfolk House associated with the inlet/exhaust vents of the MVHR system, (b)thermal bridging around an openable window and (c & d) thermal bridging onthe underside of the apartment balcony floor slab of Norfolk House potentiallydue to structural steel penetration at the façade..

(a) MVHR exhaust grille (b) Thermal bridging aroundopenable window

(c) Thermal bridging along floorpenetration

(d) Thermal bridging along floorpenetration


impression, it would appear that considerable amount of flexibleducts could have been used at the MVHR unit connections as wellas near the extract and diffuser terminations. However, due tolimited access it has not been possible to fully ascertain this. Therewere also some diffuser caps which appear to have been adjustedand these affect flow rate as the locks have not been properlyfastened.

In general, the location where the MVHR units were installed madeaccess difficult, being part-constricted by soffit in the airing cup-board, which would require removing to access the MVHR units. Avisual inspection of the interior of one of the MVHR units revealedthe following, for which photos in Figure 7 illustrate the findings:

— The filters were dirty, particularly the extract air filters. This is likely due to the units being installed and commissionedduring on-going construction work and, thus, capturing dust.The occupants appeared unclear as to what maintenancewas necessary and who was responsible. Indeed, this isrepresentative of a wider concern from residents that theyhad not received instruction on the use of their ventilation and heating systems. Impeded access could have furthercontributed to lack of filter cleaning/change;

— The external supply grilles were found to be covered withdust. The location of some of the external grilles does notallow easy access for cleaning.

The measurements of the MVHR ventilation rates for theapartments recorded by the specialist contractor are presented inTable 4 to Table 6. Measurements were also taken after the extractfilter of the MVHR unit in Flat 1 was cleaned in order to assess thedifference in performance. Upon cleaning, the airflow ratesapproached those from the commissioning data as shown in Table4. This observation may also apply to the other two apartmentswhich, if the filters were cleaned, may result in the commissioningtest figures being achieved.

In general, the air flow rates measured on the supply and extractterminal in Flats 1, 2 and 3 are all below the values reported in thecommissioning certificates. Furthermore, at normal mode operation,the flow rates did not appear to achieve the recommendedventilation rates in Part F 2006 of the Building Regulations for Flats2 and 3.

Under-ventilation in dwellings can lead to problems of poor indoorair quality and health. For example, excessive moisture build-up from cooking, bathing and other processes can lead tocondensation and mould growth. Occupant exposure to resultantmoisture-related allergens can increase the risk of respiratory

symptoms and asthma(6). It should be noted that no health-relatedissues were reported in this study.

The MVHR Specific Fan Power (SFP) for each apartment is tabulatedin Table 7, determined by taking the metered fan powerconsumption (W) and dividing this by the measured flow rate (l/s)(maximum between the supply and extract rate) for the different

SDAR Journal 2015

18

Figure 7: Dirty extract filter (half cleaned for comparison) and clogged upexternal inlet grille.

Measured in study (l/s)Flat 1 “As-found” “Clean” Commissioning

data (l/s)

Location Normal Boost Normal Boost Normal Boost

Living room 7.2 10.3 7.8 10.5 7 No data

Bedroom 5.5 7.5 5.5 7.7 6 No data

TOTAL 12.7 17.8 13.3 18.2 13 No dataSUPPLY

Bathroom -7.7 -9.8 -8.9 -13 -7 -13

Kitchen -2.8 -4.8 -4.5 -6.0 -6 -8

TOTAL -10.5 -14.6 -13.4 -19 -13 -21EXTRACT

Table 4 – The MVHR air flow test carried out for Flat 1

Flat 2 Measured in study (l/s) Commissioningdata (l/s)

Location Normal Boost Normal Boost

Living room 1.9 2 7 No data

Master bedroom 2.4 3.8 6 No data

Bedroom 3.3 4.4 - No data

TOTAL SUPPLY 17.6 10.2 13 No data

Bathroom -3.6 -4.6 -7 -13

Kitchen -5.2 -6.4 -6 -8

TOTAL EXTRACT -8.8 -11 -13 -21


Flat 3 BSRIA measured (l/s) Commissioningdata (l/s)

Location Normal Boost Normal Boost

Living room 4.6 10 7 No data

Bedroom 4.9 10.9 6 No data

TOTAL SUPPLY 9.5 20.9 13 No data

Bathroom -3.7 -7.6 -6 -8

Toilet -3.2 -9.9 -4 -6

Kitchen -3.7 -6.8 -7 -13

TOTAL EXTRACT -10..6 -24.3 -17 -27


State Normal (W/l/s ) Boost (W/l/s )

Flat 1 “As-found” 1.34 2.08

“Clean” 1.27 1.95



Table 7 – MVHR measured SFPs under normal and boost operations


operating conditions. In all cases the measurements are poorer thanthe manufacturer stated performance of 0.59 W/l/s. For the casewhere the extract filter was cleaned and tested, while there was aslight improvement, it was still significantly poorer than themanufacturer’s data.

It is noted that the manufacturer-quoted MVHR performance isbased on laboratory testing using, for example, specific lengths andtypes of ducting, which may not be fully representative of whatwas actually installed in the apartments. The location of the MVHRunit in the centre of the apartment may lead to the use ofunnecessarily long ducts, which increases pressure drops.

Furthermore, as highlighted earlier, the quality of the installation isunknown as ducting is concealed within the ceiling void. This maycause additional pressure drop if, for example, excessive flexibleducting has been used. We note that there is no record that the efficiencies of the MVHR units were measured duringcommissioning. Furthermore, the manufacturer’s SFP test data wasused in SAP for compliance purposes, which would tend to resultin a lower predicted energy use than observed, albeit off-set tosome degree by the lower air flow rates delivered.

The Zero Carbon Hub and the NHBC Foundation (7) have reportedon studies which have consistently identified similar issues withMVHR systems reported here. The report went on to suggest theneed for improvement in current practice in respect of design,installation, commissioning, operation and maintenance of MVHR.

4.3 Communal heating systemThe findings in this section are based on the experience of GalliardHomes on the post-completion handover and operation of thecommunal heating system as well as additional assessment ofefficiency performance of the system carried out during this study.

The initial design of the main heating plant with gas boilers,biomass boiler and the CHP engine were estimated at 4,766kWcapacity. Although this was substantially reduced at the final plantinstallation to a capacity of 3,465kW, it was found to be oversizeddue to a large proportion catering to the provision of DHW,proposed by the Mechanical & Electrical Consultant at the designstage with reference to the BS6700:2006. A more appropriatesizing should have been made via the Danish DS439 standards,which take into account more appropriate diversity factor. Thisallowance, coupled with the reduction in water flow rates to cater to the Code for Sustainable Homes (CfSH) requirements,would have resulted in the predicted overall demand being much lower.

During the course of this study, only the gas boilers have beenoperating. In particular, the CHP has not run due to it beingoversized for the Phase 1 build out. Furthermore, the lowest outputavailable from the 800kW biomass boiler was more than thedaytime winter idling load of the completed scheme. This putsfuture use of the biomass boiler into question. In the EnergyStrategy, the biomass boiler was to be 700kW but the final plantselection led to the installation of an 800kW biomass boiler.

Issues were identified with regards to the installation andcommissioning of the energy plant, particularly with theimplementation of the system controls based on a largely under-developed controls philosophy from the consultant, which haveimpacted on its operation. This is compounded by the designspecifications for installation and commissioning not beingsufficiently detailed and the inexperience of the mechanical andelectrical installation company with evaluating such a system.

Table 8 summarises the communal heating system efficiency forfour periods of measurement. The system efficiency wasdetermined by comparing the fuel consumption of the gas boilerswith the heat meter readings for all apartments. The systemefficiencies are much lower than expected with an annual efficiencyof 26%.

It is expected that a key cause is significant distribution losses inthe heating pipe network. This is evidenced by three results:

— The system performance was considerably worse in thesummer period. This is likely to be due to reduced heat loadto delivering DHW only whilst significant heat losses were stillincurred at the pipework;

— As shown later in Section 4.4, significant overheating wasidentified in the apartment communal corridors;

— As shown in Section 4.5, actual space heating in theapartments was significantly below that predicted, whichcould reasonably be expected to result from heat losses inthe apartment building itself (communal areas) warming upthe apartment units.

The study did not evaluate the cause of any such distribution losses,which may be a result of the quality of the installation and/or theactual insulation standards for heating pipework being below whatis necessary to achieve a reasonable system distribution loss.Currently, a heat networks code of practice (8) is being prepared forthe UK with an aim to establish minimum standards for district andcommunal heating network schemes, including issues related toefficiency of performance.

At the time of design, the development was specified with pipeinsulation thicknesses given by BS5422:2001. Galliard Homes have since moved to adopt the ECA - NES Y50 standard for futureprojects, which is an enhanced standard for insulation materialperformance and thickness for heating and hot water services. Thisshould provide approximately 12% reduction in pipework heat losswith +14% cost increase on material cost over the standards,which the Seager development was based on.


19

Period Efficiency 2012 2013 2014

O N D J F M A M J J A S O N D J F

Winter 32%

Summer 19%

Annual 26%

Winter 34%

Table 8 – The performance of the communal heating systemover various monitoring periods during the study between

2012 and 2014


As a result of the low system efficiency and the use of gas boilersonly, it has been calculated that the CO2 emissions are significantlyhigher than predicted by SAP. These range from 74% to 182%greater than predicted by SAP, depending on the apartment unit.It can be expected that the CO2 emissions will improve somewhatas: (i) an increased number of buildings come on-line (i.e. increasingthe heat load and improving distribution efficiency), and (ii) theCHP is used.

Galliard Homes have also identified several fundamental design,installation and commissioning issues impacting on the systemperformance.

— Investigations have revealed additional and unnecessary gassolenoid valve and under-sized gas pipework, which resultedin low pressure to the boilers causing the second gas boilerbeing unable to run. The gas pipe sizes did not appear on theschematic drawings, which was not flagged up or picked upby the contractor or installer. Galliard Homes now audit allprojects to ensure that detailed gas schematics are produced;

— There were also issues with inappropriate heating pipeworkdesign and commissioning of control valves that consequentlyled to intermittent disruptions of DHW supply, which tookconsiderable effort for Galliard Homes to identify the cause.In relation to this, Galliard Homes also found unnecessarilylarge number of heat exchangers being specified. Improveddesign and tighter control of commissioning would helpalleviate issues leading to supply disruption in future;

— There have even been issues with the conventional gas boilers– incorrect wiring of the BMS modulation signal to the gasburner led to Boiler 2 modulations not being controlledcorrectly which can potentially damage the unit. This wasfurther exacerbated by problems with the air damper controlmechanism on one boiler burner, which has caused heatoutages resulting in, at times, residents left with no heatingfor periods of up to 24 hours. Remedial works to the boilerburners have since prevented further outage of the entiresystem.

4.4 OverheatingThe 2006 CIBSE Guide A (9) recommends that for living areas, less than 1% of occupied hours should be over an operativetemperature of 28˚C and for bedrooms, less than 1% of occupiedhours should be over 26˚C. We have assumed that ambienttemperature equals to operative temperature (i.e. air temperatureequals radiant temperature).

Furthermore, as the apatrments could potentially be occupied formuch of the time depending on the activities of the occupants, wehave assumed that the bedrooms are occupied from 10pm to 8am,and the living rooms are occupied from 8am to 10pm.

In summary, all three apartments experienced periods of over-heating during the summer of 2013 in both the living rooms andbedrooms monitored. In particular, during July 2013, all bedroomsand living rooms overheated for a period between 27% and 58%of occupied hours.

This overheating could be due to a combination of (i) the highamount of glazing rendering the apartments susceptible toexcessive solar gain, (ii) the MVHR in some of the apartmentsoperating with a ventilation rate below that recommended by PartF of the Building Regulations, which also appear not to feature thecapability for summer by-pass, and (iii) the three apartments wereall on upper levels of the building such that there was no shadingfrom balconies of the level above, which lower level apartmentsbenefit from.

In addition, another contributor is the likely distribution heat losseswithin the apartment building from the communal heating systemduring the summer period. The issue of overheating in theneighbouring 26-storey residential tower building on the site wassufficiently pronounced such that it became necessary to retrofitautomatic opening vents in the smoke shaft to purge heat in thesummer from the core and communal corridors.

The Building User Survey (BUS) carried out has highlighted thatoccupants perceived that internal temperatures in summer weretoo hot and that they have insufficient control of cooling. Inaddition, BUS feedback on relatively high external noise levels (it isnoted that construction was continuing on the site, which will havecontributed to external noise) may have resulted in anunwillingness to open windows to reduce the temperature.

NHBC Foundation(10) has highlighted concerns of overheating fromrecently constructed homes and identified design issues that shouldbe addressed. The report similarly recognises potential problemsarising from heat gains from communal heating systems, the needfor adequate ventilation and impact of excessive solar gains, all ofwhich are consistent with the observations made in this study.

4.5 Energy use and benchmarking against SAPMeasured heat (combined space heating and hot water) andelectricity consumption within the apartments collected betweenMarch 2013 and June 2014 were compared to that predicted bySAP. For space heating, the heating degree day method usingcorresponding local measured weather data was used to modifythe SAP predictions to better represent the influence of actualweather conditions and approximate the monthly variation in theproportion of space heating.

Figure 8 compares the predicted and measured actual heatconsumption in the three apartments. The measured consumptionis the lowest for Flat 1 among the three apartment units as it hasboth the smallest floor area and only one external façade, whereasthe other two apartments have a larger floor area and largerexternal wall area with dual-aspect external façade for Flat 2. Flat3 is a duplex unit over two storeys.

SAP over-predicted the heat consumption. The actual heat loadwould tend to be reduced by both better actual air tightness andobserved ventilation rates being less than assumed by the SAPassessment. Furthermore, the apartments are thought to benefitfrom (unmeasured) heat gains arising from the distribution heatlosses from the communal heating system (see Section 4.3).

Figure 9 shows the energy use for fans and pumps in the

SDAR Journal 2015

20


apartments. In this case, the actual consumption tends to be higherthan predicted by SAP. This was partly due to occupant behaviourwith Flat 1 continuously using the MVHR on boost setting until thestart of 2014 when the occupant was made aware by theinvestigating team of how to use the ventilation controls. Anotherkey reason is the efficiency of the MVHR units being less than halfof that given by the product test data used in SAP. However, thiswas tempered somewhat by the ventilation rates in Flat 2 and Flat3 being lower than recommended by Part F.

Figure 10 shows the lighting consumption for the apartments.The

results from Flat 1 were similar to SAP prediction. However, bothFlat 2 and Flat 3 used significantly less lighting than predicted. Thismay be explained by the feedback from the occupants of these twoapartments who preferred stand-alone lighting, which used powerfrom the wall sockets.

The electricity use for stand-alone lighting was not separatelymeasured to reconcile this lower-than-predicted consumption offixed lighting. This reduced the need, and thus energyconsumption, for ceiling lights which were on the lighting circuit.There is no evidence in this study to suggest that the reducedenergy use for artificial lighting was linked to provision of gooddaylight in the apartments, which was not investigated in the study.Finally, it is also noted that 100% low energy lighting was installedin the apartments, which is greater than that assumed in SAP andwould tend to further reduce the actual energy use.

Table 9 provides an overall summary of the annual SAP predictedand actual energy consumption (space heating, hot water andelectrifty for fan, pumps and lighting) for the three apartments. Italso shows the total measured energy use including that measuredfor power sockets for comparison between each apartment units.

5. Lessons learnedGalliard Homes have identified a series of lessons learned from thisstudy, several of which are highlighted below:

— Appraisal of the communal heating scheme design at theSeager development has led to recommendation for differentdesign approaches to be adopted for 100 to 300, and 1000or more apartment development sizes, which is vital for thedesign, to adequately account for phased completion. Forexample, smaller schemes below 300 units can have primaryheating water delivered from the plant room directly to theradiator circuits in the apartments without any heatexchanger break. Also, phasing would require separatepumped circuits to each block to facilitate phasedcommissioning of the heating system. This would allow heatmeters to be fitted to each circuit so that residents who havemoved in could be charged accordingly and fairly;

— Plant oversizing was found to result from the lack ofappropriate adjustments to accommodate changes in the


21

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Apartment Space heating and Electricity – fan, Total actualUnit hot water pump, lighting including power

sockets use SAP Actual SAP Actual

kWh/m2/yr kWh/m2/yr kWh/m2/yr kWh/m2/yr kWh/m2/yr

Flat 1 66.84 22.97 5.86 9.77 67.23

Flat 2 75.16 46.22 5.86 2.73 68.83

Flat 3 78.76 29.21 6.54 3.72 54.03

Table 9 – Comparison of annual regulated energyconsumption between measured and SAP

predictions for the three apartments

Figure 8: SAP and actual heating energy use for the three apartments for March2013 to the end of June 2014.

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Figure 9: SAP and actual fans and pumps energy use for the three apartmentsfor March 2013 to the end of June 2014.

Figure 10: SAP and actual lighting energy use for the three apartments forMarch 2013 to the end of June 2014.


demand, as the site design evolved. This then led to issueswith plant operability in practice. This is further exacerbatedduring the planning stage whereby plant sizing was derivedbased on a methodology to achieve CO2 reduction to meetplanning targets, which does not appropriately account fordiversity in DHW demand. Also, it is vital that compliancecalculations are not used for plant sizing and designcalculations. References to the Danish DS439 standards formore appropriate account of diversity in DHW demandwould further inform appropriate plant sizing;

— Current pipework insulation standards may be insufficient tolimit heat loss, prevent corridors and apartments fromoverheating and to prevent heat gains in the mains water.Galliard Homes are now moving towards adopting the ECA –NES Y50 Enhanced insulation standard (11) (12);

— Appropriate levels of heat metering should be installed toenable measurement of system operation and performance.This will enable better management of heat billing duringphased completion;

— Issues were identified with regard to the installation andcommissioning of the energy plant, particularly with thesystem controls, which have impacted on its operation. Keylearning points are the need for more detailed designspecifications for installation and commissioning and theprocurement of an experienced mechanical and electricalinstallation company, capable of delivering to expectedstandards;

— Detailed BMS control philosophy is essential to ensureaccurate description of system operation and facilitate preciseimplementation by installers;

— A more prescriptive and robust commissioning requirementwould help ensure the various issues encountered with thecommunal heating system, as well as the MVHR units in theapartments, could be significantly minimised;

— Feedback from the occupants was that whilst a large amount of useful information was provided in the form ofdocumentation, it did not provide all of the practicalinformation. In particular, it was recommended that face-to-face orientation/handover would have been helpful. Thisshould include the correct operation and maintenance of the MVHR system. Points raised in this study included theinappropriate use of the boost switch and clogged up extract filters and external inlet grilles.

6 SummaryOverall, the heat consumed by the three apartments is significantlyless than that predicted in SAP. Contributing factors are found tobe high fabric thermal performance, low ventilation rates anduncontrolled gains from solar and heating pipe distribution losses.While fabric thermal performance reflected well-executed designintent, low ventilation rates were a result of the under-performingMVHR system, which also led to relatively higher associated energyuse. Sources of heat gains, which may be desirable in winter,

exacerbated the risk of overheating in the apartment and thermalcomfort in the summer.

The electricity use for fixed building services within the threeapartments is more variable in comparison with SAP, reflecting the diverse nature of occupant behaviour and hence the use of the building. For example, the occupant preference for stand-alone lighting in two apartments resulted in lower measured fixedlighting energy than predicted for these apartments but withincreased demand from power sockets where stand-alone lightingwas used.

While a large amount of information was provided in the form ofdocumentation, the occupants identified that it did not provide all of the practical information. Face-to-face orientation would havebeen helpful. For example, the electricity consumption highlightedthat one occupant was unaware of continually using the MVHRsystem on boost setting and discussion with the occupantssuggested lack of clarity on responsibility for maintenance.

The communal heating system has not performed to expectationwith low overall system efficiency, largely thought due to highdistribution losses in the heating pipe network. Distribution lossesin the communal heating pipe could be the result of the quality ofpipework installation and/or the standards of insulation on heatingpipework being below that necessary to achieve reasonable losses.Faults due to the generally poor quality of design, installation andcommissioning have also contributed to heat outages, poorperformance and under-utilisation of the low carbon technologies(biomass boiler and CHP engine) intended to reduce CO2 emissions.

The study has highlighted some clear issues, which have resulted inperformance gaps between the design and actual buildingperformance. The causes identified cover the entire process, fromthe design stage, through to the quality of the constructionprocess, and finally to the commissioning of the building servicesand handover to the building occupants such that they understandhow, and are motivated to, operate the building in a correct andenergy-efficient manner. Indeed, the highly-diverse occupantbehaviour in a domestic setting results in an inherent tendency forsignificant differences between actual and predicted performance.This should also be recognised when highlighting the performancegap.

SDAR Journal 2015

22


References(1) BUS Methodology, URL: http://www.busmethodology.org

(2) NHBC Foundation and Zero Carbon Hub, NF52 Assessment of MVHR systems and air quality in zero carbon homes. NHBC Foundation, 2013

(3) NHBC Foundation, NF24 Ageing and air tightness – how dwelling air permeability changes over time. NHBC Foundation, 2011

(4) BS ISO 9869-1:2014 Thermal insulation – building elements –in-situ measurement of thermal resistance and thermal transmittance. Heat flow meter method, British Standards Institution, 2014

(5) Pearson C, BG 39/2011 – Thermal Imaging of Building Fabric, BSRIA, 2011

(6) Ucci M, Ridley I, Pretlove S, Davies M, Mumovic D, Oreszczyn T, McCarthy M, Singh J, Ventilation rates and moisture-related allergens in UK dwellings, 2nd WHO International Housing and Health Symposium, Vilnius, Lithuania, 2004

(7) Zero Carbon Hub and NHBC Foundation, Mechanical Ventilation with Heat Recovery in New Homes. London: Zero Carbon Hub, 2013

(8) Heat Networks: CP1 Code of Practice for the UK, CIBSE & CHPA, 2014 (draft)

(9) CIBSE, Guide A (2006) Environmental Design, 7th edition, London, 2006

(10) Richards Partington Architects, Understanding Overheating –Where to Start, NHBC Foundation, Zero Carbon Hub and RPA, 2012

(11) Energy Technology Criteria List, Department of Energy and Climate Change, 2013

(12) Kooltherm FM – HVAC & Building Services Pipe Insulation, Kingspan Tarec, 2014

AcknowledgementsThe authors would like to take the opportunity to express theirgratitude to the Technology Strategy Board (Innovate UK) for fundingthe study under the Building Performance Evaluation programme.

Glossary

MVHR Mechanical Ventilation with Heat RecoverySAP Standard Assessment Procedure is the UK Government's

recommended method system for measuring the energyrating of residential dwellings.

ECA Enhance Capital Allowance is a scheme whereby a businesscan invest in energy-saving plant or machinery that mightotherwise be too expensive. The first year allowances letbusinesses set 100% of the cost of the assets against taxableprofits in a single tax year.

NES Y50 Standard of enhanced pipework insulation specificationCfSH Code for Sustainable Homes is an environmental assessment

method for rating and certifying the performance of newhomes in England, Wales and Northern Ireland.

SFP Specific Fan PowerBMS Building Management SystemDHW Domestic Hot WaterBUS Building User Survey or BUS is a licensed methodology

created from thirty years of continuous development inbuilding use studies for post occupancy evaluation.

NHBC National House Building CouncilCHP Combined Heat and PowerBPE Building Performance Evaluation


23


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House Advert 2015:Layout 1 10/11/2015 10:50 Page 1

First steps in developingcement-based batteriesto power cathodicprotection of embeddedsteel in concrete

Dr Niall HolmesSCHOOL OF CIVIL & STRUCTURAL ENGINEERING, DUBLIN INSTITUTE OF TECHNOLOGY

[email protected]

Dr Aimee ByrneSCHOOL OF CIVIL & STRUCTURAL ENGINEERING, DUBLIN INSTITUTE OF TECHNOLOGY

[email protected]

Professor Brian NortonPRESIDENT DUBLIN INSTITUTE OF TECHNOLOGY

[email protected]

Niall Holmes - embedded steel in concrete:Layout 1 10/11/2015 10:20 Page 25

Abstract

This paper presents the first steps in developing

innovative cement-based batteries to power cathodic

protection in reinforced concrete structures. Initial

electrical outputs of 1.55V and 23mA have been

found to be sufficient to polarise prescribed

corrosion currents of 20mA per m2 of embedded

steel. Cathodic protection is a well-developed and

powerful technique to limit the effects of steel

reinforcement corrosion.

However, as it requires an electrical supply day and

night, it is often powered by non-environmentally

friendly diesel generators or connected to the

electrical grid. This paper focuses on increasing the

ionic conductivity of the solution in the cement pores,

increasing the porosity of the cement, examining

ways of sealing moisture into the cement and

comparing different electrode materials and

treatments. The batteries presented consist of

different combinations of Portland cement, water,

carbon black and salt solutions with embedded

copper acting as the cathode and magnesium,

aluminium or zinc cast as the anode.

The preliminary findings demonstrate that cement-

based batteries can produce sufficient sustainable

electrical outputs with the correct materials and

arrangement of cast-in anodes. Work is ongoing to

determine how these batteries can be recharged

using photovoltaics which will further enhance

their sustainability properties.

Key Words:

Cement-based batteries; electrolyte; pore

conductivity; concrete; corrosion; cathodic protection.

Glossary:

Impressed current cathodic protection (ICCP).

1. IntroductionCement could be considered as green as it is a rock-based material,ground into a fine powder and mixed with other raw components.However, as a result of the rock extraction and mixing, its greencredentials are somewhat lost. Therefore, sustainability discourserelated to cement primarily focuses on efforts to make it moreenvironmentally friendly over its whole life to diminish the CO2

released during its production.

However, cement-based products such as concrete can facilitateenergy efficiency in the finished structure. This includes theharnessing of concrete’s thermal mass to reduce heating andcooling needs for buildings by absorbing heat (daytime solar gainsor when indoor heating system is turned on), storage and laterrelease (at night through the release of these solar gains).

A lot of work is ongoing to reduce the environmental impact ofcement-based materials while still maintaining performance(Nanukuttan et al, 2010; EN206, 2000). This includes replacingcement with supplementary cementitious materials such as groundgranulated blastfurnace slag and pulverised fuel ash. Other areas ofresearch consider the replacement of natural aggregates in concrete with materials that would otherwise be landfilled,including crumb-rubber (Holmes et al, 2014) and bottom ash(Sandhya et al, 2013).

This paper presents the first steps in developing novel cement-based batteries designed to power low-energy cathodic protection.One example is Impressed Current Cathodic Protection (ICCP) ofreinforcement in concrete structures. ICCP protects reinforcing steelfrom corrosion by connecting it to an inert, less noble, metal andpassing low-level current through it using an external power source(Polder, 1998).

2. BackgroundIn a battery, ions move through the electrolyte and electrons movethrough the circuit from the anode to the cathode (see Figure 1).Conventional alkaline batteries use zinc as the anode, manganesedioxide compact as the cathode and salt solution as the electrolyte,with all components held together in a sealed container.

SDAR Journal 2015

26

Figure 1: Conventional battery arrangement.

First steps in developing cement-based batteries to power cathodic protection of embedded steel in concrete

27

The electrolyte in a battery is an ionic conductor but also anelectronic insulator which resists the movement of electrons. Theionic conductivity of the electrolyte should be high with a lowelectrical resistance, thus allowing the battery to carry high current(Meng and Chung, 2010). Liquid electrolytes traditionally performbetter in batteries due to the high mobility of ions with acontinuous interface between electrodes and electrolyte. Examplesof solid electrolytes are polymers or ceramics doped with ions toimprove ion movement.

The process of embedded steel corrosion in concrete is an exampleof ionic flow through hardened concrete. During corrosion, ironatoms are removed from the steel surface by electrochemicalreaction. These atoms then dissolve into the surrounding electrolytesolution which, in concrete, can only occur where pores exist at thesteel anodic site. Electrons must therefore transfer from this anodicsite to a cathodic area, which develops a surplus of electrons. Thetransfer of electrons occurs along the metal and creates a currentbetween areas of differing potential. The ions from the reactions,such as the ferrous ion (Fe2+), pass into the solution trapped in theconcrete pores and meet with hydroxyl ions (OH-) to form ferrichydroxide which further reacts to form rust as shown in Figure 2.

Meng and Chung (2010) provided the initial proof of concept thatcement-based batteries could be designed to supply a voltage andcurrent.

In their layered design the cathode was a mix of manganese dioxideparticles and cement, the electrolyte consisted of cement and theanode contained cement and zinc particles (see Figure 3).

The advantage of this design over electrode (non-cement-based)probes is that the active phase in both anode (zinc) and cathode(manganese dioxide) are in direct contact with the electrolyte (poresolution in the cement paste) in the anodic and cathodic layers andnot just at the interface with the electrolyte (Meng & Chung, 2010).The outputs from this type of battery design were very low. Open-circuit voltages of up to 0.72V and current up to 120 µA (currentdensity 3.8µA/cm2) were recorded and only operated whensaturated.

Rampradheep et al (2012) used similar constituents in a layeredbattery to produce a maximum voltage of 0.6V and an undisclosedcurrent. Cement-batteries cast with carbon fibers and carbonnanotubes in the electrolyte layers (Qiao et al, 2014) yieldedmaximum power outputs of 0.7V and 35.21µA/cm2.

There is little published research into the possibility of usingbatteries for generating low-level electrical power for use in ICCPand none, at the time of writing at least, on using cement-basedbatteries. As this area is so lightly researched there have not beenmany advances in making these batteries more efficient, powerful,longer-lasting and rechargeable.

A seawater battery to incorporate cement between the magnesiumand carbon probes and maintained in a seawater bath has beenreported (Ouellette & Todd, 2014) as a corrosion-based energyharvester. Adding the cement passively limited the amount ofconsumable oxygen rather than a functioning electrolyte system.As discussed previously, corrosion of reinforcement in concretecreates differing potentials in the steel and induces a current toflow. This corrosion energy can be harvested and used for corrosionsensors (Ouellette and Todd, 2014; Qiao et al, 2011).

3. MethodologyThe design considerations for the cement-based battery developedhere are outlined below. Firstly, increasing the ionic conductivity ofthe cement electrolyte will improve the performance. For this,water-soluble salts such as Epsom, Alum and sodium chloride areinvestigated in solution and as solid granules.

The electrically active additive carbon black enhances theconnectivity between electrodes. This is particularly true for thecathode which may use an electrochemically non-conductivematerial such as manganese dioxide (Meng and Chung, 2010). Thevolume of carbon black added should be high enough to aidelectronic connectivity but not so high as to reduce the proportionof the cathode and anode.

For conductive materials such as zinc (which forms electrically non-conductive zinc oxide on its surface), thin reaction products canimpede the output of the battery as they reduce the interfacebetween the electrodes and electrolyte. Such layers can be removedby washing with acetic acid and rinsing with a volatile liquid suchas ethanol prior to adding to the mix.

Both the anodes and cathodes need to be electrical conductors.The anode is the more active of the two as it undergoes chemicaloxidation during discharge and will be lost over time, thereby losingelectrons. The cathode is nobler than the anode and remains morestable during discharge as it gains electrons.

As a battery discharges its internal resistance increases as theelectrolyte becomes less conductive. Its open circuit voltagedecreases as chemicals become more dilute. The results herepresent the current and voltage under load.

Layered batteryThe first cement-based battery cast is shown in Figure 4 and wasbased on the work by Meng and Chung (2010). However, the mix

Figure 2: Corrosion process in embedded steel in concrete.

Figure 3: Layered cement-based battery (Meng and Chung, 2010).


resulted in an unworkably-dry paste for the electrode layers whichcrumbled when set. The electrolyte layer was too wet andsandwiched out of the mix when the top layer was placed. Theproportions of the mix are shown in Table 1. The zinc powder waswashed with acetic acid to remove any dirt or oxide layers andrinsed with ethanol to remove the acid prior to mixing.

The surface of the moulds was oiled and the dry components weremixed together before adding the water-reducer and water. Theaddition of carbon black in the electrode layers made the mixdifficult to manipulate and it had to be kneaded to ensure

adequate mixing before being pressed into the mould. The cathodelayer was placed first, followed by a single ply of tissue to preventdrying shrinkage cracks and to ensure the separation of the layers.

The electrolyte layer followed (also covered with a tissue) and finallythe anode was applied, which was levelled using a trowel. Thebattery was left to cure in the mould for 24 hours under damphessian and polythene sheets. After removal from the mould,readings for open-circuit voltage and resistor load current weretaken using a multimeter. This battery is shown in Figure 5a.

Four batteries were made using this design. Two were placed indistilled water to cure for a further 48 hours after removal from themould (Figure 5b). The other two were placed in a 0.5M solutionof Epsom salt (MgSO4.7H2O) for 48hrs (Figure 5b).

SDAR Journal 2015

28

Figure 4: Layered battery schematic.

Figure 5: Layered batteries cast.

Figure 6: Battery housed in a metal can.

Cement-based AnodeCement-based Electrolyte

Cement-based CathodeElectrical output

Electricalcontacts

10mm

5mm

20mm

150x150mm



Electricalcontacts

10mm

5mm

20mm

150x150mm

Cathode MnO2 218Water reducer 11Distilled water 22Carbon black 15

Electrolyte Cement 88Water reducer 4Distilled water 18

Anode Cement 282Zn 84Water reducer 5Distilled water 91Carbon black 7

Table 1 – Mix proportions used - layered battery

(a) Layered cement-based battery

(b) Batteries stored in water and Epsom salt

(c) Electrical contacts (conductive copper)


One Epsom salt battery and one distilled water battery were sealedwith Sikagard 680S protective coating to maintain the internalmoisture content. Electrical contacts were made using conductivecopper tape as shown in Figure 5c.

Cement-based batteries housed in a can

Cement batteries in this form (Figure 6) were not identified inacademic publications, but are prevalent in internet discussionforums, blogs and “how to” videos. They are designed in muchthe same way as traditional batteries with copper usually beingchosen as the cathode. The anode container is usually made fromcommercial aluminium cans with the top cut off and the sidessanded to expose the aluminium. For the work presented here, thecathodes were chosen as thin copper plates (or hollow narrowtubes) and an eraser prevented short circuiting between thebottom of the catode and the base of the container. A basiccement and water mixture was used as the initial electrolyte.

Various mix designs and additives were compared using this batteryform and used to examine the natural recharge abilities (or naturalcharge build-up and storage abilities) when a resistor load wasremoved for set periods of time.

Cement-based batteries housed in a blockThese battery types are similar to the can but both the anode and the cathode are in the form of metal plates (Figure 7). Plastic moulds were used to prevent short circuiting and to allow fora higher volume of sample to be made. These designs were used tocompare different additives, anode materials, shapes and sizes.

This type of design is the “best-fit” for cement-based batteries forusing with ICCP as they can be incorporated into a cladding paneland fixed onto a structure. For this, particular characteristics arerequired, namely robustness, long life and a low but consistentcurrent output under resistance load.

4. ResultsLayered batteries

Hourly current and voltage measurements were taken from thebattery using a 10Ω resistor. A very low current was generated(0.001mA) in the intervening hours but dropped back to 0mAwithin 10sec. As shown previously by Meng and Chung (2010),the batteries do not work once dried out. After 30 hours allbatteries had ceased to output electrical energy.

The air-dried Epsom salt solution did not display any measurablecurrent with only a minor difference upon sealing. Voltage didincrease over time as the battery dried as shown in Table 2.

Can batteries

Table 3 presents the results of each mix compared with the basiccement and water combination. As can be seen, there was nonoticeable increase in output from the addition of sand withdecreases observed when zinc, manganese dioxide were added, aswell as increasing the anode ratio. The higher outputs came fromincreasing the cathode ratio.

An example of the decay in current for the can battery is shown inFigure 8a. As can be seen there is a sudden drop when the open-circuit is lost and the resistor is applied from approximately 19.3 to4.8mA. Over the next seven days, the current drops below 1mA.Figure 8b shows the natural recharge/storage when the resistor isremoved after one month and no current is being drawn out.Regardless of the length of recharge time (one or two hours), theincrease in initial current is the same, as is the long-term value.

Block battery results

Voltage and current was measured through a 10Ω resistor andaveraged once they became quasi-steady. Figure 9 shows the resultsfrom the parametric study. In terms of water to cement ratio (w/c)(Figure 9a), the current steadily increased with water content.

Cathode to anode ratios (Cu:Al) 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1.4were created using different cut-plate sizes in the same basiccement paste with no discernible correlation. Distances betweenelectrodes of 5mm, 10mm, 30mm, 60mm and 80mm werecompared with no differences in output observed. As per the canbatteries, the addition of carbon black (Figure 9b) had a significantimpact on the measured outputs with lifespan, current and voltageincreases of 33%, 44% and 13% respectively.

29


Figure 6: Battery housed in a metal can.

Type/Age 0hrs 24hrs 27hrs 30hrs

Epsom solution V = 0.2V V = 0V V = 0.995V V = 0.489Vair dried I = 0 I = 0 I = 0 I = 0

Epsom solution V = 0.030V, V = 0.037V, V = 0.23V V = 0.51Vsealed I = 0-0.001mA I = 0-0.001mA I = 0-0.001mA I = 0-0.001mA

Water air dried V=0.310, V = 0.442 V = 0.400V V = 0.6VI = 0-0.001mA I = 0-0.001mA I = 0 I = 0-0.001mA

Water sealed V=0.380 V = 0.386, V = 0.37 V = 0.737VI = 0-0.004mA I=0.002-0.042mA I = 0-0.004mA I = 0- 0.001mA

Table 2 – Current, voltage and lifespan results from the layered batteries


The base mix contained only distilled water as the solution. In the other three battery designs, no water was added but different5-Molar salt solutions were included. These were sodium chloride (NaCl), Alum salt (AlKO8S2.12H2O) and Espom salt(MgSO4.7H2O). Compared to the base mix, the use of salt solutionsdecreased the current by 20% (Figure 9c) with Epsom salt havingthe least loss of 14%.

Voltage also decreased with the addition of the salt solutions.However, the lifespan was greatly increased, by 50% on average.By adding salt to the battery mix in granular form, the current andlifespan increased by 15% and 62.5% respectively, compared tothe base mix (Figure 9d).

All battery designs to this point have used copper cathodes andaluminium anodes. Anodes of aluminium, zinc and magnesiumwere also prepared with the same surface area. The magnesium

anode was in a ribbon shape rather than plate and this may haveimpacted the results. The zinc anode battery design showed verypoor results. However, the magnesium anode battery designprovided the highest current and lifespan during testing. Currentand lifespan increased by 1000% and 350% respectively comparedto the base battery with an aluminium anode.

Initial battery testing, with prioritised current and lifespan, indicatesthat optimal output could be achieved by designing high w/c ratios,the addition of carbon black, adding salt granules, usingmagnesium as the anode material and sealing the battery to retainhydration and reaction components and products.

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30

Figure 8: (a) typical current discharge and (b) natural re-charge/storage of acan battery.

A

B

Figure 9: Results of the parametric study to assess the effects of (a) w/c ratio,(b) carbon black additive, (c) salt solution and (d) salt solution and saltgranules.



Electricalcontacts

10mm

5mm

20mm

150x150mm

B

C

D

A

Additive Current Voltage

+Sand = =

+Carbon black ↑ ↑+Zinc Dust ↓ =

+Manganese dioxide dust ↓ =

Higher anode ratio ↓ ↓Higher cathode ratio ↑ ↑

Table 3 – Effect of additives on the power output in the can batteries


5. Five potential applications of this research for cathodic protection

ICCP limits the corrosion of a metal surface using inert anodes and impressing a current onto the cathode surface using anexternal direct current (DC) source. For steel reinforcement therecommended (Polder et al, 2009) design current density is20mA/m2, which refers to the circumferential surface of the bars.While the currents seen here are low, previous work has shownthat lower values for protective current can be successfully used inICCP to prevent embedded steel corroding (Polder et al, 2009;Glass et al, 2001; Glass and Chadrick, 1994; Glass and Buenfeld,1995; Koleva et al, 2006; McArthur et al, 1993).

There have been limited but reliable examples of where intermittentcurrent supply has provided adequate cathodic protection tostructures (Glass et al, 2001; Glass and Chadrick, 1994; Glass andBuenfeld, 1995; Koleva et al, 2006; McArthur et al, 1993;Christodoulou et al, 2010; Kessler et al, 1998). The ability ofcement-based batteries to recharge when the load is removed hasbeen shown here. Stand-alone cement batteries could power theprocess using a switching mechanism between individual unitsallowing them to discharge and recharge multiple times.

6. ConclusionsCan-shaped batteries have shown to have the longest lifespan.However, these batteries have a very low output range and needfurther development. Connecting them in parallel or series toincrease output is ongoing.

Carbon black proved to increase output, particularly current andincrease longevity due to its ability to increase the connectivitybetween conductive materials. However, due to its fineness, itmakes the batteries considerably brittle so a water reducer isessential.

Although salt solution increased longevity, adding the same salts insolid granule form was even more beneficial and increased currentoutput. When salts are dissolved in water they break up and movethrough the liquid.

Copper was consistently used as the cathode material in all tests asit is highly noble and easily available. Comparing aluminium, zincand magnesium anodes, it was found that magnesium produced asubstantial improvement in all areas, particularly current andlongevity. Open circuit potential values of -1.344V for untreatedmagnesium, -0.786V for zinc and -0.524V compared to copper(Bullis, 2014) indicates that the highest outputs should occur formagnesium followed by zinc and aluminium.

Layered cement batteries cease to work once dry and this paperpresents some first steps in sealing layered-style batteries. Furtherresearch into different sealing techniques could help maintainmoisture and therefore increase the longevity of batteries.

The possibility of connecting cement-based batteries in parallel hasnot yet been explored in the research but could be a way ofincreasing the current output and longevity from the batteries.

ReferencesCBullis K (2014) Storing the Sun, Aquion manu-factures cheap, long-lasting batteries for storing renewable energy [Available from:http://www.technologyreview.com/demo/524466/storing-the-sun/].

Christodoulou C, Glass G, Webb J, Austin S, Goodier C (2010)Assessing the long term benefits of Impressed Current CathodicProtection, Corrosion Science, Vol. 52(8), pp 2671-2679.

BS EN 206 Part 1, Concrete (2000) Specification, performance,production and conformity, British Standard Institute.

Glass GK, Hassanein AM, Buenfeld NR (2001) Cathodic protectionafforded by an intermittent current applied to reinforced concrete,Corrosion Science, Vol. 43(6), pp. 1111-1131.

Glass GK, Chadwick JR (1994) An investigation into the mechanismsof protection afforded by a cathodic current and the implications forad-vances in the field of cathodic protection, Corrosion Science, Vol.36(12), pp. 2193-2209.

Glass GK, Buenfeld NR (1995) On the current density required toprotect steel in atmospherically exposed concrete structures,Corrosion Science, Vol. 37(10), pp. 1643-1646.

Kessler RJ, Powers RG, Lasa IR (1998). Intermittant cathodicprotection using solar power, Corrosion. San Diego.

Koleva DA, Hu J, Fraaij ALA, Stroeven P, Boshkov N, van Breugel K(2006) Cathodic protection revisited: Impact on structural morphol-ogy sheds new light on its efficiency, Cement and ConcreteComposites, Vol. 28(8), pp.696-706.

Nanukuttan, S.V., Holmes, N., Srinivasan, S., Basheer, L., Basheer,P.A.M., Tang, L. & McCarter, W.J. (2010), Methodology for designingstructures to withstand extreme environments: Performance-basedSpecifications, pp. 663-670, Bridge and Concrete Research in IrelandConference, DIT & TCD, September.

McArthur H, D’Arcy S, Barker J (1993) Cathodic protection byimpressed DC currents for construction, maintenance andrefurbishment in reinforced concrete, Construction and BuildingMaterials, Vol. 7(2), pp. 85-93.

Meng Q, Chung DDL (2010) Battery in the form of a cement-matrixcomposite, Cement and Con-crete Composites, Vol. 32(10), pp. 829-39.

Ouellette SA, Todd MD (2014) Cement Seawater Battery EnergyHarvester for Marine Infrastructure Monitoring, Sensors Journal, Vol. 14(3), pp. 865-872.

Polder RB (1998) Cathodic protection of rein-forced concrete structuresin the Netherlands – Experience and developments: Cathodic protec-tion of concrete - 10 years experience. Heron, Vol. 43(1), pp. 3-14.

Polder R, Kranje A, Leggedoor J, Sajna A, Schuten G, Stipanovic I(2009) Guideline for smart cathodic protection of steel in concrete:Assessment and Rehabilitation of Central Euro-pean HighwayStructures.

Qiao G, Sun G, Li H, Ou J (2014) Heterogeneous tiny energy: Anappealing opportunity to power wireless sensor motes in a corrosiveenvironment, Applied Energy, Vol. 131(0), pp. 87-96.

Qiao G, Sun G, Hong Y, Qiu Y, Ou J (2011) Remote corrosionmonitoring of the RC structures using the electrochemical wirelessenergy-harvesting sensors and networks, NDT & E Inter-national, Vol.44(7), pp. 583-588.

Rampradheep GS, Sivaraja M, Nivedha K (2012) Electricity generationfrom cement matrix incor-porated with self-curing agent, Advancesin Engineering, Science and Management (ICAESM), 2012International Conference, 30-31 March, pp. 377-82.

Sandhya B and Reshma E.K (2013) A study on mechanical propertiesof cement concrete by partial replacement of fine aggregate withbottom ash, International Journal of Students Research in Technology& Management, Vol 1(4), August, pp 416-430.


31


The Irish Lighter and YoungLighter Awards are annualapplied research eventspromoted jointly by CIBSE andDIT. They are open to allbuilding services professionals,with SLL members particularlyencouraged to participate.

THE IRISHLIGHTER& YOUNGLIGHTERAWARDS

Projects must be located in Ireland, andsubmissions can also be made which arebased on lighting research. Best abstractsare selected by a distinguishedinternational panel of assessors and ashortlist of entrants is then invited tosubmit full papers.

For the Irish Lighter Award, entries areencouraged from experienced lightingdesigners, or engineers who can present apaper about a finished project.

• There may be post-occupancyevaluation evidence that is analysedcritically and provides insight for theprofessional lighting community;

• There may be an innovative and/or sustainable design that is at the industrycutting edge;

• Or it may be something worthpublishing that will be of interest, andbenefit, to the professional community.

The Irish Young Lighter competition beganin DIT in 2003 when the first students onthe programme in Electrical ServicesEngineering graduated. Ken Winters wasthe inaugural overall winner and he thenwent on to represent Ireland at theinternational Young Lighter in London in2004, where he won the BestPresentation.

Published research papers by winners ofboth the Irish Lighter and Young Lightercompetitions may also feature in the SDAR Journal.

Who to contact

[email protected] or

[email protected]

Irish Lighter Advert:Layout 1 10/11/2015 10:52 Page 1

The Lighting ofSt Mel’s Cathedral

Mark [email protected]

IRISH LIGHTER AWARDS WINNER 2015

Mark Reilly - St Mels:Layout 1 10/11/2015 10:41 Page 33

Abstract

The destruction of St Mel’s Cathedral by fire brought

the local community together to fund its restoration.

Part of this initiative was the development of a

lighting scheme using modern LEDs and intelligent

lighting controls to recreate the atmosphere and

reverence deserving of this historic house of worship.

Problems encountered associated with the age and

style of the building to be illuminated are discussed

in the paper. A description of the design process

and methodology is also included, along with the

appropriate lighting conditions necessary to

emphasize certain architectural points. The paper

covers the illumination of the cathedral for the

21st century by discussion of the methods used

and the development of the design.

Key Words:

Lighting, cathedrals, places of worship, LED,

intelligent controls

1. IntroductionThere has been considerable interest in the lighting of cathedralsand churches recently, largely due to the necessity of renewinginstallations which were made in the early years of the century andare by now unsafe electrically, as well as being inadequate bypresent-day lighting standards.

More recently, the advent of new and more efficient light sourceshas led to some radical rethinking of the design standards possible,and, in addition, the liturgical reforms of recent years have led tothe rearrangement of many interiors, necessitating alterations toexisting lighting schemes.

Furthermore, the publication by the Society of Light and Lightings(SLL) Lighting Guide 13 (LG13) provided guidance on methods and arrangements of applying lighting. The lighting design of St Mel’s cathedral was already completed before the release of this guidance, therefore the design was scrutinised and evaluatedagainst LG13(1). Some key differences emerged, including therecommended uniform lighting levels for the different areas withinthe building and the methods of achieving and controlling thelighting scheme suitable for such a building.

A number of factors enter into the design which are commonlyfound in other fields of lighting. However, considerations of theage and architectural style of the building, the proper balancebetween lighting to display architectural or archaeological featuresand for use during church services, and the daylight appearancewere all taken into account.

The lighting scheme for the St Mel’s cathedral was sympathetic tothe form, function and history of the building. The interior lightscheme was designed for multiple light scenes according to theusage. Special attention was drawn to the method of installationof all new equipment and services routing.

The cathedral presented a number of challenging issues whendeveloping the lighting design, some of them architectural innature, others to do with how the building was to be used, and yetmore focused on conservation, technology and cost.

High ceilings and obstructions, such as pillars and arches, allneeded to be considered in terms of light distribution and liturgicalitems such as Stations of the Cross, statues and the baptismal font.Soft, lighting accents emphasised the three-dimensionality of theseitems. Thanks to high positioning of the luminaires and glarereduction, visitors' enjoyment of art pieces is aided by high levels ofvisual comfort.

It was also important to apply the correct source of lighting so thata specified illuminance was accurately achieved as well as meetingthe budget for the project. The success of the installation was notto be judged by light meters but through the eyes of those whohave to perform the ceremonies as well as those who watch them.Similarly, efficiency was not rated simply by the effectiveness ofgathering all the lamp lumens and exclusively directing them onto

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34


The Lighting of St Mel’s Cathedral

35

the task plane, but rather by the ease with which the task can beseen and by the contribution of the lighting installation to makingthe environment more agreeable. This was achieved by carefulcommissioning of the lighting and creation of the different lightingcontrol “scenes” with the St Mel’s Committee whose membersincluded the local priests, key stakeholders and local engineers.This insured that the lighting was adequate and operated for thetasks planned. However, the design intent was for a robust schemethat would mitigate any contract variations. Ensuring that therequirements of the client had been met required the addition of asmall number of luminaires where an increase in lighting wasdeemed beneficial.

The lighting scheme was installed and the building reopened tothe public in December 2014.

2. BackgroundThe cathedral is a neo-classical stone building, at the north eastside of the town. Construction began in 1840 to the design ofJoseph B. Keane and was finally consecrated on 19 May 1893. Thecathedral is constructed like many churches in the shape of a cross.

Due to the cold, the heating ran at a high setting continuously for17 hours on Christmas Eve 2009 to cater for the many visitorscoming to say a prayer, light a candle or attend confession duringthe day and the for the large attendance at Mass that night. AfterMass the temperature outside plummeted to -8°C. Sometime after5am a local called the fire brigade and raised the alarm of a fire.

Despite efforts by the fire service, as Christmas morning dawned itwas clear the interior of St Mel’s Cathedral was lost.

The heating system consisted of an oil fired burner located in thecrypt, with a flue connected to an original brick lined chimney. It islikely that combustible material may have accumulated in thechimney. Due to the prolonged running of the heating system, it islikely that this material became superheated.

Figure 1: The official reopening of St Mel’s Cathedral, Midnight Mass 2014. Figure 2: Pre-fire condition of the cathedral.

Figure 3: Post-fire condition of the cathedral.


When the burner was switched off, the natural draught allowedthe ingress of oxygen causing the combustible material to ignite inwhat was, in effect, a chimney fire. Unfortunately, this chimneywas fitted with inspection hatches. It is believed that burningembers from the chimney fire escaped via an inspection hatch doorin the sacristy. There it ignited some further combustible materialwhich then spread to destroy the entire interior of the Cathedral.

3. MethodologyThe artificial lighting offered unique opportunities to integrate intoits building fabric seldom possible in an existing place of worshipstructure. It cannot be emphasised too strongly how beneficial itwas to discuss the lighting concepts with the architect at theearliest possible stage of the design of the building, and not leaveit until detailed and finished drawings, which cannot be easilyamended, were produced.

The advantages of designing the lighting at an early stage includedsimplicity in wiring and ease of maintenance, a point that is notalways considered, but it is especially important in this situationwhere a regular maintenance staff are not employed(3).

The project was about marrying what was lost with what remainedand putting in place something for the future. Historically, brassluminaires were mounted on walls and robust brass poles had beenused to help illuminate the space. These were later refurbished withan LED source and reused as suspended chandeliers within themeeting rooms and the sacristy. Lighting of the cathedral spacewas a key area with modern technology used to visually enhancethe cathedral.

Since St Mel’s cathedral differs greatly from most secular buildingsboth in its use and architectural design, the lighting installationcould not be designed on the conventional lines of a traditionalworkspace as it also had to be flexible to fulfil a number ofpurposes.

One aspect which was carefully considered was the balance ofdramatic and utilitarian lighting. For cathedrals a “numinous”atmosphere which is conducive to worship is required(2). This canoften be achieved by dramatic lighting of the sanctuary, althoughit must always be remembered that the ambo and altar positionslocated within the sanctuary must have sufficient and suitable lightfor reading.

Regarding the visual task that would be undertaken by thecongregation in the pews, they tend to sit in one particular areaand this was to be a focus of the design brief. In addition to tasklighting, this particular light is required to reveal texture andimprove the appearance of the people within the space; thus goodvisual communication and recognition of objects within the spacewas essential. The average (mean) cylindrical illuminance wasdesigned to be 50 lux, and uniformity (min/average) over 0.1,calculated 1.2m above the floor level. Each of the directionalluminaires providing the functional lighting in the space wascarefully angled towards the rear of the nave; this allowed thecylindrical illuminance required to be achieved.

Subtle emphasis of architectural features was also considered tohelp achieve the required atmosphere, but care was taken not tolight a cathedral merely to show off its architecture. Indeed, thelighting design concentrated on creating contrasting effects sinceit is difficult to light a building by artificial means to give the sameeffect as is seen by daylight but to maintain the buildingsfunctionality(4).

The lighting brief was to bring the 19th century building into the21st Century. This included a lighting system that was to be energyefficient but would also capture the atmosphere essential to thecathedral. The level of control and scene-setting would also allowthe priests to pre-set specific lighting scenes for specific liturgicaloccasions.

The lighting had four objectives:

– to enable participants in the religious activity or ceremony tosee what they are doing;

– for the congregation to see what is happening around them byproviding horizontal illuminance (maintained 100-150 lux) andcylindrical illuminance (50 lux) on the pews measured duringcommissioning using lux meters;

– to contribute to the safety of everyone within building;

– to create a good visual environment.

4. Spotlights or pendantsThe use of pendant luminaires, either in the form of branchedcandelabra or of individual lamp housings mounted on a hoop orhoops, is often recommended, especially in the nave. The theory isthat they more closely resemble the sort of lighting that may havebeen originally installed and that they have some decorative valuein their own right. Such a system has the advantage of providingadequate illumination at “prayer-book level” economically, but itcan give rise to considerable glare and also cause a ‘tunnel effect’unless the fittings allow some upward light on the vaults. There is,however, considerable force in the objection that they are out of place in an environment that was never designed to take them, and that in daylight they ‘pollute the space and spoil theappearance of the building(5).

The alternative of spotlighting using an LED source was used for St.Mel’s cathedral but it was not without its disadvantages as itrequired careful consideration of their placement so they could bediscreet. The lighting equipment is usually unobtrusive by day, butat night banks of spotlights can be remarkably glaring and seriouslyinterrupt the soaring vertical lines of the architecture. The optimalposition found was on the tops of the limestone columns forprojection of light onto the side aisle and on the above-the-stringcornice for the central aisle. From a lighting perspective this methodis normally not to be encouraged in most other situations due to the glare caused by luminaires at lower mounting heights.However, as it was possible to keep the fixtures above 10m, thesolution was both discreet and effective.

A recent departure used for the Cathedral, made possible by thehigh-efficiency LED lamps now available, is indirect lighting of the

SDAR Journal 2015

36


main barrel ceiling from uplighting projectors mounted on thestring cornice, but this necessitates supplementary direct lightingfor the congregation to be able to see and read. As the aisles are also lit in this way, a fairly close approximation to the daylightdistribution of light in the building was achieved.

5. Lamp sourceWith the reducing price and increasing availability of good qualityLED spot and floodlights, they were considered as a first option.They provide a good low-energy solution with a very long life, thusreducing the need for maintenance access to what is a highlocation(6). The wide availability of LEDs with different beam anglesmeans that one family of fittings provided light for many differentpurposes. Wide beams were used for washes over vaulted ceilings,medium beams for lighting down over seating areas and narrowbeams for picking out altars or features in the space. The LEDspotlights came with integral dimming with DALI (digitaladdressable lighting interface).

6. Highlights and ShadowsIt was important that glare was avoided wherever possible. Acommon fault is glare caused by an array of spotlights at low levelor aimed without care from the cornice.

Glare was not simply a matter of the intensity of the light source;it is related to the contrast between a lighted object and itsbackground. The illumination of the ceiling helped to counteractthis issue.

This does not mean, of course, that a bland shadowless effect was the aspiration. The modelling of shafts and pillars, arches andsculpture was essential as their form was to be perceived. The

contrast between the illuminated and unlit parts of the cathedralproduced dramatic effects without apparent effort.

Picking out salient features in daylight by means of carefully placedspotlights is equally permissible, and can give the effect of shafts ofsunlight if carefully done. The concealment of the equipment hasbeen made easier by the introduction of very compact narrowbeam spotlights.

7. Design conceptsIt was immediately apparent that the “lumen method” of lightingdesign, intended to produce an average maintained illuminanceover an area, could not be applied to this building. Certainly,enough light to allow priests, choir and congregation to read easilyis necessary, and the recommended illuminances in the LG13 codeshould be adhered to, but a flat, even distribution of light is neithernecessary nor desirable.

It was equally obvious that with the exception of decorativechandeliers the lighting equipment should be as unobtrusive as

37


Figure 4: Discreet positioning of the luminaires was key.

Figure 5: Vertical illuminance on the Stations of the Cross.

Figure 6: Functional lighting concept.

Figure 8: Uplighting concept.

Figure 7: Accent lighting concept.


possible. These buildings traditionally were not used after dark bythe laity and, apart from the dim gleam of sanctuary lamps beforethe altars, the rest of the church would be in darkness. Even inparish churches the custom of a late evensong is comparativelyrecent, dating only from the 19th century, so that any form of artificial lighting is bound to be out of character with itssurroundings. However, lighting essential to the present use of thebuilding and the advent of first gas and then electric lighting in thel9th century has accustomed people to its use.

The lighting of some areas had been varied to suit their use; forexample, as the nave was to be used for worship, lighting wasconcentrated on this area used by congregation and on the altarwith the rest of the building left in comparative, although notabsolute, darkness. In contrast, when used during the day forvisitors or quiet reflection, less light is needed on the seating, andarchitectural features were emphasised, with indirect lighting ofthe ceiling vault, and some lighting in the organ and architecturalelements.

Based on the objects, the lighting concepts focused on how and what elements required illumination. These main conceptsincluded:

– the function lighting on the horizontal plane by wide beamprojection LED luminaires at the tops of columns;

– accent lighting of the key architectural elements and art piecesby discreetly located LED projection lighting;

– uplighting of the barrel ceiling which would highlight the greatcraftsmanship put into the plastering detail.

8. Areas requiring special lightingOrgan and choir: Light for reading music was a vital element forthe cathedral. A technical problem was that organ furniture wasdark and absorbs light while choristers using sheet music look atmusic on a white background. To light the choir area, individualluminaires were recessed within the choir stall which providedfunctionality without taking away from the overall feel of thespace.

Altar and ambo: The altar is the focal point of the cathedral; it isalso a centre of worship, the table on which Holy Communion iscelebrated. It must therefore be illuminated dramatically, but not insuch a way as to make it difficult for the priest to see both his Bibleand the congregation.

The readers at the ambo not only need to be able to see what theyare reading, but must themselves be visible, for a great manyelderly and deaf people rely on lip reading or on the facialexpression as well as the sound of the readings.

The use of a strip light mounted at the top of the reading area alsohas serious disadvantages. Reversed shadows on the reader’s facecan have a negative effect on their appearance and a furtherdisadvantage is that, if the strip light is mounted too close to thesurface of the desk, it may cast shadows across the page makingit difficult to read(7).

The solution implemented was to provide dedicated spotlights withcarefully shielded lamps to light the book or typescript. Thespotlights were mounted 12m high and to the sides, so as to avoidglare and shadows to the reader, and to give natural modelling tothe persons face.

9. Emergency lightingThe actual placing of luminaires presents the greatest difficultyrather than achieving the lighting requirements indicated in IS 3217Code of Practice for Emergency Lighting with a recommendedaverage maintained illuminance at floor level of at least 0.5 luxalong the centre-line of the gangways. The main emergencylighting arrangement internally included recessed emergencylighting “nodes” in the side aisles and projector versions of theseminiature nodes adjacent to the array of spotlights on the stringcornice in the central nave(8).

The choice of system was mainly between a centrally controlledsystem, in which all the luminaires would be fed from a centralpoint, using a large storage battery, and one of self-containedluminaires powered by nickel-cadmium cells actuated by mainsfailure. The former solution was implemented as it reduced the riskof battery failure at the lamp hence decreasing the amount ofmaintenance required at heights(9).

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38

Figure 9: The Ambo during commissioning of the lighting.


10. Methods of calculating lighting values

The modelling and calculation used throughout was by the ReluxPro lighting software. Working with a 3D model enabled thediscussions with the architect to be more productive and efficient,clearly indicating the intent and assisting with the designdevelopment.

The need for modelling and the provision of a “numinous”atmosphere governed the placing of the lighting equipment andthe direction of the light. There is always a certain amount of “spilllight” in the beam of a spotlight so that a certain amount ofambient light will be present on vertical surfaces, but it is importantto provide variations of brightness. Therefore, carefully calculatedpositioning of the lighting equipment is recommended.

As a system of indirect lighting is used in the form of lighting theceiling vaults, the reflectance of the vault or ceiling is of greatimportance. As it was a white plaster ceiling it reflects about 70%

of the light falling on it, but a stone vault as per the crypt wouldreflect no more than 50% at most(10). As the ceiling is intersectedby ribs, this figure would be still lower. Consequently, the indirectlighting of the vaults was not expected to provide a significantproportion of the light at ‘prayer-book level’, and the need tosupplement it with direct spotlighting was imperative. The indirectlighting component was effectively no more than a decorativeelement especially when the number and power of direct lightingunits was calculated but, nevertheless, uplighting of the vaults doesproduce ambient lighting needed for casual perambulation of thebuilding.

If it was simply a matter of providing the recommended illuminanceon the bible, choir or congregation, the reflectance of surfaces is ofcourse irrelevant. However, it was important in calculating the sizeof the lamp and type of reflector to light vertical surfaces and theunderside of the ceiling.

LG13 was not released during the design, therefore similarexamples had been used as benchmarks as well as the illuminancerecommendations for similar applications indicated in the SLL codefor lighting 2012. The illumination on the horizontal plane invarious parts of a church was designed to 100 lux in the “body” ofthe church, and 200 lux within the sanctuary with further accentlighting where required.

It transpired that the recommendations given with LG13 wereconsistent with the design approach(12). However, the design didnot include for the recommended maintained horizontalilluminance of 500lux for the altar area. The design approach wasrather less uniform and focused more on making the altar the focus


39

Figure 13: Design lighting levels taken from the lighting software.

Figure 10: Modelling of thelLighting taken from the lighting software.

Figure 12: Lighting installed and operating.

Figure 11: Rendered view taken from the lighting software.


of the building with lighting but by using accent and verticallighting as well as a base line 200lux of horizontal illuminance. Thiswas achieved by using different ‘layers’’ of light which includeuplighting of the alter back wall and dedicated accent lighting oftask areas such as the ambo and the bishops chair so that readingcan be achieved during services without issue.

11. Lighting controlsThe key client aspirations for the lighting control system wereflexibility, ease of use and energy efficiency.

In order to deliver on this ambition, an intelligent control systemusing DALI (Digital Addressable Lighting Interface) was installed toenable a variety of fittings and controllers to be integrated withina single control system. The dimming system allows simple changesin the feel of the space, from simple lighting for general use tohigher levels for services, with special scenes reserved for weddings,High Mass or quiet reflection.

The scene settings activate and/or dim specific light fittings and harnesses natural light when available to reduce energyconsumption. The system also provides status reports for the userand allows remote access to the lighting system.

The centralised lighting control system with pre-set scene controlmakes it easy to set and change the mood for any activity at thetouch of a button. The touch screen panel allows for the priest toselect up to 12 different lighting scenes within the main sacristy.

11. DiscussionFor specialist designs such as this, it is imperative that earlycoordination and agreement of the lighting concepts are carriedout with the architect and client. The levels of illuminance, lampsource and controls are important but the visual effect on the spacewas the most critical factor on this project.

Many of the design fundamentals have been highlighted with theSLL’s Lighting Guide 13: Lighting of Places of Worship whichprovides up-to-date guidance where relevant and incorporates bestpractice principles throughout, including the introduction of adistinction between task area and surrounding areas, and thesubsequent recommendation of uniformity for those areas.However, uniformity is an issue that requires careful considerationas a less utilitarian approach was achieved with St Mels Cathedral.The approach here provided a more dramatic result while keepingthe building functional.

Further evaluation of how the lighting has been adapted andcontrolled by the sacristan and priests, particularly with regard to the scene setting and the relationship between energyconsumption and providing a decorative scene suitable for thedifferent situations would be desirable. However, that was not partof this paper and would be recommended for future research.

References

(1) SLL (2013) Lighting Guide 13: Guide to places of worship

(2) Inter Faith Network for the UK (2010) Building good relationswith people of different faiths and beliefs (London: Inter FaithNetwork for the UK)

(3) CIE (2005) CIE 097:2005: Guide on the maintenance of indoorelectric lighting systems (Vienna: CIE)

(4) IS EN 12464-1 (2011) Light and lighting. Lighting of workplaces. Indoor work places

(5) SLL (2013) Lighting Guide 10: Daylighting and window design

(6) IS EN 15193: 2007: Energy performance of buildings. Energyrequirements for lighting

(7) Boyce P R (1981) Human factors in lighting (London: AppliedScience Publishers)

(8) IS 3217: 2013:Code of practice for the emergency escapelighting of premises

(9) SLL (2004) Lighting Guide 12: Emergency lighting design guide

(10) SLL (2012) The SLL Code for lighting

SDAR Journal 2015

40

Figure 14: Commissioning of the lighting controls.


The history of building services engineering in Ireland dates back to when

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The Pavilion of Light,Mardyke Gardens,Fitzgerald Park, Cork

Stephen [email protected]

Stephen Robinson Pavilion of Light:Layout 1 10/11/2015 13:39 Page 43

Abstract

This paper describes the lighting design and rationale

for the Mardyke Garden project. It is realised through

accentuating the historic buildings and integrating

the local biodiversity issues such as the park’s bat

population. Many new modern structures have been

added to this historic park such as a pavilion

bandstand, called the “Pavilion of Light”, with colour-

changing luminaries and in-ground, star-scape, fibre-

optic lighting in the children’s play area.

This paper discusses the background behind the final

lighting design and how integral elements such as the

walkway bollards were designed so that bats would

avoid the area involved, thereby sustaining their

participation in the local ecology. Furthermore, the

bandstand is now used as a reflector that not only

changes the colour of the stage but as a projector

into the sunken garden, synergising performance

with the experience of patrons.

Also discussed will be how the lighting designer drew

from localised landscaping in maximisinging optimal

experience. Lighting controls are also discussed. Cork

City Council can now manage this complex lighting

design so that patron’s experiences can evolve based

on multi-faceted elements such as season, event and

even occasion.

Key Words:

Innovative lighting, colour-changing lighting, LEDs,

ecological friendly lighting.

1. IntroductionThe redevelopment of Fitzgerald’s Park has created a state-of-the-art public facility in the heart of the city. The thoughtful re-imagining of the space, driven by the relocation of the bandstandto the front lawn, was integral to the success of the scheme and ofreinventing the park. The Pavilion is now a modern landmark,conjuring memories of the grand bandstand of the internationalexhibition held at the site in 1902. Its success has acted as a catalystfor community engagement and has facilitated a range of eventsenjoyed by locals and tourists alike. As an icon of collectivememory, it forms the heart of a wider community, designed toserve diverse ages and interests. It is a wonderful facility, whoseflexibility of use will attract visitors from near and far for years tocome as the park evolves and grows.

This paper discusses the lighting design of the Mardyke Gardensand covers many aspects of outdoor lighting. The bandstand is up-lit with RGB LEDs to allow automated colour change of the Pavilion,which can subsequently be reflected onto the garden performanceviewing area because of the reflective nature of the Pavilion. Thewalkway lighting is designed to be low energy and architecturallycoherent with the surrounding design. The children’s play areafeatures fibre-optic lighting in the ground to form a “Starscape” atnight and the POD, which was originally Dermot Gavin’s award-winning Hanging Garden at the Chelsea Flower Show in 2011, isnow fixed firmly to the ground. Mounted on a podium, wide anglelow-level luminaires illuminate this structure from below toaccenuate the elevated “floating” POD effect.

The controls bring all of these separate lighting aspects togetherinto one coherent design. The lighting controls use manual andDali devices, along with an astronomical timer and web appfacilities to ensure maximum flexibility of when and where theseluminaires can be controlled or configured. This gives the CityCouncil great scope to adapt and adjust the lighting design to suitthe current need within the spaces.

The need to create an effective design in harmony with the existingenvironment was a key part of this project and introduced somechallenges with regard to a local bat roost.

The complexity of working with bespoke structures provideschallenges when attempting to calculate or model such areas. Partsof this lighting design did not rely on calculations but rather theexperience of the designer. These challenges are also discussedwithin.

2. BackgroundThe Mardyke Gardens was founded in 1845 by the building ofShrubbery House on its land by local brewer Charles Beamishbefore being bought by the Bon Secours Sisters in 1861. In 1902it played host to the International Cork Exhibition for more than a year. Once the International Exhibition was finished, the park was handed over to the corporation for the people of Cork withShrubbery House later becoming a Museum in 1942. Since thenthe citizens of Cork have enjoyed walking through the park andenjoying the gardens. In 2011 Cork City Council and Failte Ireland

SDAR Journal 2015

44


The Pavilion of Light, Mardyke Gardens, Fitzgerald Park, Cork

agreed to fund a renovation of the park and to focus attention ontwo separate areas;

(1) Relocating the bandstand and creating a new pavilion in frontof a viewing lawn to facilitate public access to numerous stageperformances throughout the year;

(2) The addition of the POD in the Gallery Garden overlooking theriver Lee to the rear of the park with a new walkway linking it to themain entrance. The Gallery Garden area also includes a new children’splay area in and around new and exciting landscape spheres (Figure2a and Figure 2b).

3. MethodologyThe objective of the lighting design was primarily to improve theexperience associated with the architecture and to carry thisheightened experience into the evening and night for theoccupants of the park. This was broken down into four main areasof light.

Firstly, the Pavilion of light is a bespoke structure with smoothcurves and high reflectance to enhance acoustic performance ofbands playing by directing sound outwards towards the frontgarden. The objective was to use this structure to enhance thevisual experience also by using the white surface as both a canvasand a reflector. The challenges this posed was the fact that it wassuch a complex structure that modelling it or calculating it wouldnot prove to be an accurate estimate. The design was largely basedon manual estimations and mock-ups on site.

The second lighting task was to highlight some of the new treesplanted in the garden. For this, narrow beam LEDs are used with a40° cut-offf to ensure only the targeted tree is illuminated.

The third area of interest from a lighting design perspective wasthe children’s play area. This area is open-plan between the PODand the museum with a clear canopy structure located within it.Fibre-optics are used to create a starscape in the ground which cantwinkle in the dark, replicating the night sky on the ground.

The fourth area of interest was the POD, located at the rear of thepark beside the children’s play area. The POD was originallysuspended from a crane at the Chelsea Flower Show but, as thiscould not be replicated in a public park, the POD was mounted ona podium. The lighting design in this area was designed toilluminate the POD from below to highlight the structure without

attracting emphasis on the mounting. This approach provided theillusion (at night time) of a floating structure as the light shiningbeneath it was evenly distributed along the front of the object andits linear length. The podium it was mounted on was not the focusof illumination.

Figure 1: Pavilion of Light and front lawn with the Museum in the backgroundleading to the Gallery Garden.

Figure 2b: Children’s play area with clear canopy (above).

Figure 2a: Walkway, Gallery Garden, POD and Landscape Spheres.

45

Figure 3: Design approach incorporating control elements for each facet of theproject.

Walkway

Uplighting

Starscape

Manual controldimming

Astronomical timer

Scene settingColour control

Web App control

Pavilionof Light


Finally, the walkway from the main entrance to the POD andsurrounding areas was designed to ensure adequate light topedestrians walking through the park, but also to not interfere withthe local bat population in the park. Cork City Council requiredassurances that local bat life would not be effected by the lightingin all of the circulation spaces that the public would frequent. Thedesign approach is illustrated in Figure 3 (page 45).

The four separate aspects of the design were all integrated onto acommon control platform (Philips Dynalite) that brought togethercontrol protocols; such Dali protocols outlined in IEC Standard60929 are used for dimming and switching, and DMX controls forcolour-changing to DMX 512. The control strategy developedensured all the above criteria were met. It also complemented thevision of the new landscape architecture.

3.1 The Pavilion of Light

The Pavilion of Light is illuminated via nine 900mm-long in-groundasymmetric RGB (18W x 3) LEDs spaced evenly across the undersideof the structure. The structure is white, giving an accurate reflectionof the light being directed towards it. The Pavilion reflects the lightoutward onto the front lawn giving a spectacular light show eachnight. The luminaires are Dali controlled from within the museumand are set on the colour-changing loop each night. The coloursand sequence can also be controlled via Cork City Council’s office,or from an iPhone/Android app. This allows the bandstand tochange to any colour of the spectrum at anytime from anywhere.

3.2 Up lighting of the new horticulture

As part of this project many new trees and foliage were plantedand the landscape architect wished to highlight some of these atnight time. To do this, in-ground IP67 LEDs with a colour temp of3000K were used. In order to limit upward light pollution a narrowbeam angle of 40° was chosen (Figure 45). The lamp was alsorecessed down inside the fitting to limit glare to pedestrians.

3.3 Starscape

The Starscape is located in the children’s play area of the park. Theidea behind this is to create some in-ground lighting that would

SDAR Journal 2015

46

Figure 5: Narrow beam angle of uplighter.

Figure 4: Pavilion of Light (top) and some spot lighting highlighting new trees(below).

Figure 6: Narrow beam uplighters focus light on trees and limit upward glare.

Figure 7: Starscape employing bespoke sculpture as well as shrubbery in thecobble lock area.


add a sense of fun to the space. The light engine was located in adry enclosure hidden within the new shrubbery and the light wascarried by sheathed end–emitting polymer optical fibre. Thesefibres were located within the cobble lock of the play area.

3.4 Walkway Lighting

The walkway from the main entrance of the park to the rear(towards the POD) posed some concern to Cork City Council as a known bat roost was in the area. The walkway lighting wasdesigned to ensure the bat flight pathways between the roost andthe river Lee where unaffected.

To achieve this it is important to understand what effects bats andtheir feeding habits with regard to the surrounding light.

Bats are nocturnal and only come out at night after the sun has setand light levels are low. Most bat species are photophobic andbright lights near or around a bat roost have been known to impactthe population in the area. “The direct and artificial illumination ofa bat roost area may reduce activity resulting in later emergence,giving bats less time to forage which may result in bats beingunderweight, thereby increasing the risk of mortality during winterhibernation (Bat Conservation Trust, 2009)”.

Light emitted at one wavelength with no ultraviolet light helps to maintain the bats’ environment as normal. Low temperatureluminaires are recommended for use in areas of known bat activitydue to the low levels of UV emitted. Light at this colour temperaturedoes not attract insects and thus does not interfere with the batsusual feeding habits.

It is also recommended that lighting in these areas be kept low andfocused on the task area to minimise light spill. The UK batorganisation recommends that luminaires should not exceed eightmetres tall and that a 10-metre corridor adjacent to the illuminatedarea should be maintained to allow bats to travel in parallel.

For this project, 1-metre tall LED bollards were used with a colourtemperature of 3000K. The light level on the pathway was kept tothe required minimum of 5 lux. This was achieved by specifyingdimmable luminaires and physically calibrating (dimming down)each one in position to gain the correct minimum light level, andto eliminate any unnecessarily high levels along this pathway.

After occupied hours the luminaires, which are controlled via anastronomical clock, ramp down even further to give a 3 luxaverage. This is to further improve the bats’ night time environmentand also not to attract unwanted anti-social behavior. The bollardsare IP67 and IK10 which are particularly suited to this project.

Under CIBSE Guidelines (CIBSE, 1991) 10 lux for primary pathwaysand 5 lux for secondary pathways in public parks is required. Thelighting calculation was designed to meet the 10 Lux but, as the luminaires were dimmable, a derogation was allowed by Cork City Council to designate this pathway a secondary route and the luminaires’ outputs were dimmed down to meet thisrequirement.

3.5 The POD

The emphasis on lighting the POD was to evenly distribute the lightacross the front of the POD but, at the same time, to ensure themounting platform stays in some darkness. To do this wide-angleluminaires were positioned at each end of the structure, mountedslightly in front and hidden from view behind some shrubbery. Theluminaires adequately light the structures’ façade facing theoccupants of the park and do not highlight the mounting bracketsunderneath.

47

The Pavilion of Light, Mardyke Gardens, Fitzgerald Park, Cork

Figure 8: Bollard lighting model – 10m bat corridor to the right, low level directlight on the pathway at 300K minimises the impact on the bats’ habitat.

Figure 9: Dialux calculation to achieve 10 lux average if required, luminairesare running at 50% of this value on site.

Figure 10: The POD illuminated by wide angle floodlights at each end frombelow.


5. DiscussionThis lighting design had many challenging aspects, most notablythe local fauna. This was successfully overcome with the use of 3000K low UV output lighting mounted at one metre fromground level. The selection of the LED bollards not only fitted wellwith the architectural landscape furniture, but also allowed thelight to be distributed at low level under the recommendedguidelines, and within the 5 lux maximum level. The use of anastronomical timer ensured the luminaires were only on for theminimum required duration.

At the beginning of the design stage the Pavilion represented alarge unknown as this was a bespoke structure. The lighting designfor this object developed with the pavilion design and turned outto be very effective and achieved its objectives. The use of cloud-based Dali controllers ensured full adaptability for the Pavilion tochange colour and output levels easily to suit any band/stage act.

ReferencesBat Conservation Trust. (2009, May 01). Bats and the BuiltEnvironment Series. Retrieved September 01, 2015, from Bats & lightin the UK: http://www.bats.org.uk/data/files/bats_and_lighting_in_the_uk__final_version_version_3_may_09.pdf

BSI. (2013). BS 5489-1:2013 Code of practice for the design of roadlighting. Lighting of roads and public amenity areas. London: BSI.

CIBSE. (1991). Lighting; The outdoor environment. London: CIBSE.

Commission, I. E. (2014). IEC 62386. IEC.

International Electrotechnical Commission. (2014). IEC/PAS 62717LED modules for general lighting – Performance requirements. IEC.

SDAR Journal 2015

48


The School of Multidisciplinary Technologies provides modules and programmes at undergraduateand postgraduate level which link engineering and built environment disciplines to design andoperate healthy low energy buildings and infrastructure for a modern sustainable world.

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