Numerical Study of Greenhouse Nocturnal Heat Losses

In this study we quantify and analyze different components of nocturnal losses from a heated greenhouse with the presence of vegetation for typical winter weather conditions in Marrakesh-Morocco, using a non linear model, based on the greenhouse heat and mass balance. It was found that 12% of the total input heat was dissipate as a sensible and latent leakage losses, 66% was lost by convective exchange through air-inner cover. This gain of energy at the inner-cover is dissipated at the outer-cover by radiation (66%) and convection (34%). This results point toward some practical measures to reduce heat losses: increasing air tightness, using covering materials with low-emissivity in the long wave band or putting up an external thermal curtain should provide significant energy savings.