水平埋管热作用下周围土壤热湿特性实验研究

Soil heat and moisture properties under thermal effect of heat transfer of horizontal ground-coupled heat exchanger

土壤含湿量的不同是影响土壤导热系数的主要因素之一,进而影响地埋管地源热泵系统地下埋管换热器的换热性能。沙箱实验结果显示,水平埋管周围土壤水分迁移现象有可能受到地下埋管换热器热作用的影响,土壤温度梯度是土壤水分迁移的主要动力。取热工况下,埋管周围土壤水分迁移现象可以忽略;排热工况下,埋管与周围土壤间热湿作用相互耦合,水平及竖直方向上均呈现土壤水分由管壁处向埋管远端迁移的现象。

The different soil moisture content is one of the major factors influencing on the thermal conductivity of soil and further impacting on the efficiency of ground-coupled heat exchangers （GCHE）. Sandy soil container experiment results show that soil water migration is impacted by heat transfer of the horizontal GCHE. The temperature gradient is the driving force. Under the heat extraction condition, water transfer can be neglected. Under the heat rejection condition in summer, heat and water transfer is coupled and water migrates from the tube wall towards the far field along the horizontal and vertical direction.