Simulation Research About Performance Of Air-to-earth Heat Exchanger And Soil Temperature

The air temperature and humidity inside greenhouse with no heating devices can not meet the production needs of the agriculture in cold areas. Therefore,we need to seek a energy saving through to regulate the air temperature and humidity in the greenhouse. As a solar absorbing and releasing carrier, Soil can cooling and heating the air,even dehumidifying in the underground pipe efficiently. Therefore,it is important to energy saving that placing air-to-erath heat exchanger under the greenhouse soil.In this paper, after a full analysis of the HME process of moist air in the air Heat Exchanger. Through user-defined function to load the loss of quality of the source term and energy source terms during the process of condensation of water vapor. Established stratified soil model with different soil moisture. Simulated the heat transfer performance of air-to-erath heat exchanger under different wind speed conditions in sunny winter. Forecasted the heat transfer performance of air-to-erath heat exchanger under 7.5m / s, 10 m / s, 15 m / s wind speed conditions. And simulated the soil temperature of 4.5m / s wind speed condition.Simulation results show that the air-to-erath heat exchanger in the greenhouse can be effectively to achieve the process of dehumidification cooling at daytime and heating at night in winter. The outlet air temperature and humidity is affected greatly by the inlet air temperature and humidity if the air-to-erath heat exchanger with a great inlet velocity. For pipe diameter Φ110 heat transfer tubes, the heat transfer process of moist air in the heat transfer tubes occurred at the entrance to the heat transfer tubes 9m range if the air-to-erath heat exchanger with wind speed less than 4.5m / s. the best inlet speed of Φ110 heat transfer tubes for humid air heat and moisture treatment is within 4.5m / s ~ 7.5m / s range. The variation of soil temperature around heat exchanger was similar to the change of inlet temperature of heat exchange. The soil temperature of measuring point in vertical and horizontal direction with an equal distance were different because of the thermal properties of stratified soil. Along the direction of depth, the soil temperature around heat transfer tubes(Z≤450mm) is impact by the heat transfer tubes, near-surface(Z> 450mm) soil temperature is impact by thermal effect on soil surface.