Effect of Insect-Proof Screen on Solar Greenhouse Ventilation

Convective transfers determine, for a large part, the energy and mass balances, which regulate the microclimate inside a greenhouse. In order to improve the standard of microclimate management and structure design of solar greenhouse, one of the most common greenhouses in China, it is necessary to study the effect of insect proof screen on solar greenhouse ventilation so as to raise productivity of green products in greenhouse. The objective of this work is to determine and model the air exchange rate of solar greenhouse with insect proof screen over the vents. Experimental study using tracer gas technique and decay rate method were conducted in solar greenhouse with two types of ventilation openings, one with sheet parting roof vent and the other with rolling up roof vent. It was found that rolling up vent has a higher ventilation rate (1.4 times) than the sheet parting vent, in the case of both with or without the insect proof screen. And experiments have confined a significant reduction in the ventilation rate when an insect proof screen is fitted to the vent (about 50%).