Study On Thermal Performance In Three Kinds Of Composite Wall Of Sunlight Greenhouse

This experiment to produce three kinds of composite wall(the brick-and-clay greenhouse,the brick-and-cinder greenhouse,the brick-and-polystyrene greenhouse)of the sunlight greenhouse as the research object,the paper measured wall,soil and air temperature and humidity indoor and outside greenhouses and the analyzed the heat preservation and insulation property of three kinds of greenhouse by theoretical analysis and experimental verification.Main conclusions are as follows:The brick-and-polystyrene greenhouse heat storage property was best,the brick-and-clay greenhouse heat preservation is the best.In the horizontal direction,the brick-and-clay wall temperature difference is bigger,the brick-and-cinder wall is smaller;in the vertical direction,the brick-and-polystyrene wall temperature difference is smaller,another is bigger.In the heating stage,the brick-and-clay wall heat storage property is best;in the cooling storage,the brick-and-clay greenhouse heat storage property is best,however,the brick-and-polystyrene greenhouse heat dissipation is biggest.Greenhouse soil heat from center to all round.In the heating stage,the heat of soil from the deep soil flow to the shallow in the brick-and-clay greenhouse and the brick-and-cinder greenhouse,but the brick-and-polystyrene greenhouse 10 cm soil layer heat flow to shallow and deep soil layer.In the cooling stage,the heat from deep soil layer to shallow soil layer.In summer,the soil heat flux is mainly two-way heat conduction;in winter,the heat flux is one-way.In the continue cloudy days the rate of the brick-and-cinder wall heat storage is fastest,and the brick-and-polystyrene heat storage is worst.The difference of 3 kinds of structural greenhouses is little in cloudy day,but the humidity is lowest in the brick-and-clay greenhouse,the brick-and-cinder greenhouse’s humidity is highest.The brick-and-clay greenhouse’s soil temperature is higher than others,its temperature stability is better than others,but the brick-and-polystyrene greenhouse’s soil temperature is lowest and stability is worst.