energy efficiency - made in germany february 16 th, 2011 exportinitiative energy efficiency in dutch...
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Energy Efficiency - Made in Germany
February 16th, 2011Exportinitiative Energy Efficiency in Dutch Greenhouse Industry
Hans-Jürgen Tantau
on behalf of the German Federal Ministry of Economics and Technology
www.efficiency-from-germany.info
The Low Energy Greenhouse - An Approach to Sustainability
Contents
Introduction: energy situation, global warming
Objectives
Research project “ZINEG”
Conclusions
Acknowledgements
Introduction: Energy Situation (global)
Availability of oil and gas, peak production 2010
Fuel consumption is still increasing
Emission of (fossil) CO2 is
increasing the CO2-concentration
Global warming
Reduction of fossil CO2-emission
Increase of energy efficiency in protected cultivation
Systematic approach
to reduce the energy consumption by 90 %
to operate a greenhouse
without fossil energy,
without fossil CO2-emissions
ZINEG, the Low Energy Greenhouse
Objective
Energy Efficiency - Made in Germany
www.efficiency-from-germany.info
ZINEG, the Low Energy Greenhouse
ZINEG: A Joined Research Project
Economicseconomic and
ecological evaluation
Hanovermax thermal insulation, temperature integration
Munich/Neustadt a.d. Weinstraße
neutral CO2-energy supply
Berlin, Großbeeren,Potsdam-Bornim
closed greenhouse
Public relationsAssociation for Technology and Structures in Agriculture (KTBL)
The Low Energy Greenhouse in Hannover
Reduction of energy consumption using
new covering materials
triple thermal screens
solar energy by day and night storage
climate control strategies
energy optimized cultivation programs
Maximum energy saving for the production of pot plants
New Covering Materials
Requirements:
high light transmittance
good thermal insulation
Technical solution:
double glazing with anti reflective coating,filled with Argon
Problems:
- increase of air humidity
Covering Material
300 500 700 900 1100 1300 1500 1700 1900 2100 2300 25000
102030405060708090
100
wavelength, nm
tra
nsm
itta
nce
, %
Spectral transmittance of GroGlass (single and double glazing)(high PAR and lower NIR transmittance)
Source: v. Elsner, 2010
Float glass
GroGlass single
GroGlass double
Thermal Screen
Requirements:
no light reduction during day time
no leakages, when closed
Technical solution:
triple thermal screen different materials (aluminised, clear, black)
Problems:
- air humidity (control of thermal screen)
Thermal Screen
clear screen, 20 % shading
thermal screen, 50 % shading
black out system, 100 % shading
Use of Solar Energy
Requirements: expanded time for CO2-supply crop orientated climate control strategies
Technical solution: ventilation as late as possible (CO2-supply) low temperature heat exchanger storage of solar energy in water tanks
(day and night storage)
Yearly Solar Radiation and Heat Requirement
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
0 1 2 3 4 5 6 7 8 9 10 11 12
Month
En
erg
y, k
Wh
m-2
d-1
Low Energy Greenhouse, location: Hanover (example), i = 15 °C,
double glazing, triple thermal screen
solar radiation
mean heat requirement
Use of Solar Energy by Day and Night StorageM
warmwater
storage
heat pump
coldwater
storage
greenhouse 1
greenhouse 2
heat exchanger
condenser
condenser
boiler
heat exchanger
M
M
M
M
M
Climate Control Strategies
0
10
20
30
40
50
0 2 4 6 8 10 12 14 16 18 20
En
erg
y c
on
su
mp
tio
n c
ha
ng
ing
ra
te,
kW
h m
-2K
-1a
-1
Temperature set point, °C
Low energy greenhouse, Triple thermal screen, 80 % saving at night
energy partition at day
energy partition at night
Energy Saving Potential (values are examples)
energy saving method energy saving (%)
consumption (%)
consumption oil equival.
L/(m2.a)
starting point 0 100 40 double glazing 45 55 22 thermal screen (conventional) 28 40 16 thermal screen (day) 26 29 12 black out system 35 19 8 solar energy (day-night) 20 15 6 control strategies 15 13 5 adapted crop sequence 20 10 4 final consumption 90 10 4
The technical realisation of the Low Energy Greenhouse is possible!
Conclusions
The realisation of the Low Energy Greenhouse is a challenge!
an Approach to Sustainability
Limitations:
crop response (humidity)
disease infections
plant nutrition (etc. Ca)
economical evaluation
ecological evaluatione.g. cumulative energy demand carbon footprint
ACKNOWLEDGEMENTS
Project grant:
Sponsored by the Federal Ministry for Environment, Nature
Conservation and Nuclear Safety and the Rentenbank
managed by the Federal Ministry of Food, Agriculture and
Consumer Protection with assistance of the Federal Agency
for Agriculture and Food.