Cooling Effects with Fan-Pad Ventilated in Plastic Greenhouse

It is very important to know the cooling effect and temperature distribution with wet pad and fan system in agricultural production greenhouse in hot weather summer in Jiaxing region. An experiment was conducted to measure the related factors such as solar radiation，temperature inside and outside in a multi-span plastic greenhouse with an area of 3 072 m2 and equipped with 8 fans.Results indicates that in the situation of 62% relative humidity of outside the fan and pad system had a significant cooling effect with combination utilization of solar shading screens，and the mean temperature inside the greenhouse could be cooled down 4.8 ℃.As to temperature distribution，there was a temperature gradient of 0.063 ℃m and around 2.5 ℃ difference horizontally from pad to fan. Vertical temperature gradient also occurred in greenhouse center location with a temperature difference of 2.6 ℃ between two temperature sensors in 2 m height difference.