Energy Efficiency - Made in Germany February 16 th, 2011 Exportinitiative Energy Efficiency in Dutch...

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

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



Objectives

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



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

Low Temperature Heat Exchanger

inlet

heat exchanger

fan

return

1.0 m

0.2 m

Source: v. Elsner, 2009)

Heat Pump and Water Storage

Heat pump (28 kW) 30 W/m2

Warm and cold water storage (50 m3)

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

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.

Thank you very much for your attention!

Further information: www.zineg.de

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