论文部分内容阅读
The ChineseAcademy of Agricultural Sciences is working on improvements of the widespread Chinese Solar Greenhouse.Typically this greenhouse is heated by solar energy only and is therefore a sustainable way of growing vegetable crops in the off-season period.Due to the high insulation of the covering during the night and the bright sunny days, the diurnal mean inside temperatures are around 10℃ higher than the average outside temperature.Even on dull days the diurnal mean temperature in the greenhouse remains 5 to 6℃ higher than the ambient.In the Shouguang region this means that the Chinese Solar greenhouse enables a frost-free ambient so that crops like tomato, cucumber and sweet pepper can be grown without heating.However, the passive character of the Chinese Solar Greenhouse prohibits any control of the heating.During the day,solar heat is accumulated in the north wall and during the following night, this heat is released to the greenhouse air.This paper discusses the measurements and simulation results with a new design for the greenhouse, allowing for a controllable release of solar energy to the greenhouse.Moreover, the design comprises additional screening for a higher daytime insulation.The paper shows that some improvements can be made, but the total amount of intercepted solar radiation remains to be the limiting factor.