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The Low Energy Greenhouse - An Approach to Sustainability. February 16 th , 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.
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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
Introduction www.efficiency-from-germany.info
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 www.efficiency-from-germany.info
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
ZINEG, the Low Energy Greenhouse www.efficiency-from-germany.info
ZINEG: A Joined Research Project Berlin, Großbeeren, Potsdam-Bornim closed greenhouse Hanover max thermal insulation, temperature integration Munich/ Neustadt a.d. Weinstraße neutral CO2-energy supply Economics economic and ecological evaluation Public relationsAssociation 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)(high PAR and lower NIR transmittance) Float glass GroGlass single GroGlass double 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 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 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 Storage M M M M M M heat exchanger warmwater storage boiler greenhouse 1 condenser heat pump condenser greenhouse 2 coldwater storage 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 Low energy greenhouse, Triple thermal screen, 80 % saving at night energy partition at day energy partition at night
Energy Saving Potential www.efficiency-from-germany.info
Energy Saving Potential (values are examples) The technical realisation of the Low Energy Greenhouse is possible!
Conclusions • The realisation of the Low Energy Greenhouse is a challenge! • anApproach 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