The Research Of Thermal Property Of Greenhouse Covering Materials

Greenhouse industry has been grown up rapidly in the recent years. It has became thegrown point and roll booster of Modern Agriculture;it is the significant model anddevelopment direction of Modern Agriculture. Covering material, as part or all of themaintenance material, its thermal properties has remarkable effect on the lighting ofgreenhouse in daytime and keeping the temperature in night. Combined the theoriesand experiments, we made the research on the thermal properties of severalgreenhouse cover materials which are used frequently.Firstly, based on the conclusions of the acdemic journals, the current research statusof greenhouse covering materials has been summarized. Then according to solarenergy application theory, the light transmission property of covering materials wasinvestigated. The full radiation transmission rate of different materials was testedthough experiment. In some large-scale greenhouses, the experiments on the radiationand heat transfer properties of greenhouse were conducted. The solar radiationintensity of outside and inside greenhouse was simulated on the basis of experimentresults. Heat transfer coefficient of greenhouse was simulated by the application ofheat transfer theory and reasonable hypothesis. And the experiment layout of heattransfer coefficient of covering materials was designed on the foundation of somereferences. At last, heat supply load of different covering materials greenhouses ondifferent weather were computed by the application of greenhouse microclimatemodel.The lighting transmission and heat transfer properties are significant parameters ofgreenhouse microclimate model. The research of lighting transmission and heattransfer properties, the simulation of greenhouse outside and inside solar radiationintensity and materials' heat transfer coefficient provide the solid foundation for thelighting and heat supply of greenhouses design. The research results of the thermalproperties of covering materials will benefit for the optimum design of greenhouseand engineering application.