Effects of cooling, dehumidification and transpiration water recycling of closed micro-environment in greenhouse

In this study, temperature and humidity inside closed micro-environment were regulated through setting completely closed pot in greenhouse, dehumidifying, cooling air and recycling transpiration water within the closed pot based on energy exchange due to temperature disparity. The results showed that effects of dehumidifying and cooling were remarkable based on water-air temperature disparity. Compared to the closed check pot, the temperature of treated pot decreased by 3℃ and relative humidity decreased by 7% around 12:30. In other time, effect of dehumidifying and cooling was not so significant. However, temperature, relative humidity decreased on average by 2.4℃ and 5% in the daytime, respectively, with transpiration water gathered in a U-tube. Based on energy exchange due to soil-air temperature difference, air was pushed through soil using air pump to dehumidify, cool air and recycle transpiration water in the closed micro-environment. During the experiment, cooling effect was not significant at night, compared to the closed check pot, temperature and relative humidity decreased meanly by 2.5℃ and 10%, respectively, in the daytime. Around 12:30, dehumidifying and cooling were very significant; with temperature decreased 5℃ compared to the check pot, temperature difference inside and outside the micro-environment was only 1.5℃, relative humidity reduced by 15%. Condensed water from cooling was pushed by high speed air flow to the pot. In general, cooling and dehumidifying can be realized through utilization of temperature difference between water-air and soil-air in the micro-environment and transpiration water could be recycled as well.