Heat and moisture migration in soils around ground heat exchangers under heating operation of ground source heat pump

An in-site observation station for soils around the ground heat exchanger (GHE) in the operating process of ground source heat pump (GSHP) is installed to monitor the operation performance of GSHP as well as heat and moisture migration in soils with the heat exchange. Through a heating experiment of GSHP, the effect of heat and moisture migration in soils is revealed. The experimental results show that the GSHP under heating condition has a stable running performance and good heating effect, and its coefficient of performance (COP) is 3.58. The change of temperature fields of soils is affected by the heat exchange of GHE and atmospheric environmental change, but their influence scope and degree are different. Meanwhile, the variation range of temperature field of soils decreases progressively with the increasing distance to the GHE. Therefore, the heat influencing radius of vertical and horizontal GHE is 2.0, 1.0 m, respectively. Finally, the impact of heat exchange of GHE on moisture field of soils is in-apparent. However, there are two obvious impact factors, the surface water infiltrating caused by rainfall and change of the groundwater table on the variation of moisture field of soils.