Transcript Folie 1

Energy Efficiency - Made in Germany
The Low Energy Greenhouse
- An Approach to Sustainability
February 16th, 2011
Exportinitiative 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
Contents
 Introduction: energy situation, global warming
 Objectives
 Research project “ZINEG”
 Conclusions
 Acknowledgements
Energy Efficiency - Made in Germany
Introduction
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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
Energy Efficiency - Made in Germany
Objectives
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Objective
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
Energy Efficiency - Made in Germany
ZINEG, the Low Energy Greenhouse
www.efficiency-from-germany.info
ZINEG: A Joined Research Project
Berlin, Großbeeren,
Potsdam-Bornim
closed greenhouse
Munich/
Neustadt a.d. Weinstraße
neutral CO2-energy supply
Public relations
Hanover
max thermal insulation,
temperature integration
Economics
economic and
ecological evaluation
Association for Technology and Structures in Agriculture (KTBL)
The Low Energy Greenhouse in Hannover
Maximum energy saving for the production of pot plants
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
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
Spectral transmittance of GroGlass (single and double glazing)
transmittance, %
(high PAR and lower NIR transmittance)
100
90
80
70
60
50
40
30
20
10
0
300
Float glass
GroGlass single
GroGlass double
500
700
900 1100 1300 1500 1700 1900 2100 2300 2500
wavelength, nm
Source: v. Elsner, 2010
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
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
Low Energy Greenhouse,
location: Hanover (example), i = 15 °C,
double glazing, triple thermal screen
4,5
Energy, kWh m-2 d-1
4
3,5
3
2,5
solar radiation
2
1,5
1
mean heat requirement
0,5
0
0
1
2
3
4
5
6
Month
7
8
9
10
11
12
Use of Solar Energy by Day and Night Storage
M
M
heat exchanger
boiler
warm
water
storage
greenhouse 1
M
condenser
heat
pump
M
condenser
cold
water
storage
M
greenhouse 2
M
heat exchanger
Low Temperature Heat Exchanger
inlet
heat exchanger
0.2 m
1.0 m
fan
return
Source: v. Elsner, 2009)
Heat Pump and Water Storage
Warm and cold water
storage (50 m3)
Heat pump (28 kW)
 30 W/m2
Climate Control Strategies
Energy consumption changing rate,
kWh m-2 K-1 a-1
Low energy greenhouse, Triple thermal screen, 80 % saving at night
50
40
30
energy partition at day
20
energy partition at night
10
0
0
2
4
6
8
10
12
Temperature set point, °C
14
16
18
20
Energy Efficiency - Made in Germany
Energy Saving Potential
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Energy Saving Potential (values are examples)
energy saving method
starting point
double glazing
thermal screen (conventional)
thermal screen (day)
black out system
solar energy (day-night)
control strategies
adapted crop sequence
final consumption
energy saving
(%)
0
45
28
26
35
20
15
20
90
consumption
(%)
consumption
oil equival.
L/(m2.a)
100
55
40
29
19
15
13
10
10
The technical realisation of the Low Energy Greenhouse is possible!
40
22
16
12
8
6
5
4
4
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 evaluation
e.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.
Thank you very much for your attention!
Further information: www.zineg.de