Comparative Study on Heat and Moisture Transfer in Soil Heat Charging at High Temperature for Various Soils

Abstract

To investigate the mechanism of heat and moisture transfer in soil heat charging for solar-soil source heat pump system, a testing rig of one-dimension soil heat charging is constructed. Two different soils, sand and loam, are used for the testing. The soil temperature distribution and volumetric water content (VWC) variations are studied under different heat source temperature and soil initial VWC, and the difference between these two soils is analysed as well. The coupled and mutual effect of heat and moisture transfer is discussed. The study shows that sand is better than loam in soil heat charging. The heat source temperature has an obvious impact on soil VWC distribution. Higher heat source temperature leads to higher peak VWC. The initial VWC has a slight impact on soil temperature distribution.