Effect of greenhouse design parameters on conservation of energy for greenhouse environmental control

A mathematical model was developed and used to study the effect of various energy conservation measures to arrive at a set of design features for an energy efficient greenhouse. The Simulation results indicated that under cold climatic conditions of northern India, a gothic arch shaped greenhouse required 2.6% and 4.2% less heating as compared to gable and quonset shapes. An east-west oriented gothic arch greenhouse required 2% less heating as compared to a north-south oriented one. North wall insulation of an east west oriented gothic arch greenhouse saved 30% in heating costs. The use of night curtains reduced the night time heating requirement by 70.8% and daily requirement by 60.6%. By replacing the single cover on the southern side with air inflated double wall glazing, the heating requirement was reduced by 23%. The combination of the design features for an energy efficient greenhouse suitable for cold climatic conditions was found to reduce the greenhouse heating needs by 80%. An internal rock bed thermal storage/retrieval system met the remaining heating energy requirements of the energy-conserving greenhouse. (C) 2002 Elsevier Science Ltd. All rights reserved.