Light and Temperature Environment in PO and PVC Greeenhouses and Its Relationship With Condensation on the Films

The radiation and temperature environment of PO and PVC greenhouses were examined in this research. The main results are as follows: The highest transmittance of total solar radiation in PO greenhouse is 76.7 % and its aged deterioration is very little. The transmittance of PVC greenhouse dropped to 71.6 % from 88.9 % . Condensation on the film in PO greenhouse is very little with 40 g/m². It is up to 140 g/m² in the PVC greenhouse. And the performance of anti drop of PVC film decreased rapidly with ages. It was observed that the solar radiation transmittance of greenhouses declined 11% by 100g/m² of condensation on film. A ccording to the principle of heat budget, a new function was induced to evaluate the influence of condensation at the film on air temperature difference(in side-outside).