Study On Thermal Performances of The Horizontal Ground Heat Exchanger Exploiting Shallow Geothermal Resources

Horizontal ground heat exchanger (HGHE) is always used to exploit the shallow geothermal resources. The climatic conditions including precipitation and radiation have significant impacts on HGHE performances, and effects of the key factors on thermal performances under the climatic conditions are still unclear. Hence, a 3D numerical model considering the atmosphere-soil-HGHE interaction and water content variation was constructed in this paper. The temperature contours around the HGHE and thermal performances during one year were analyzed. Then, effects of inlet temperature, HGHE length, soil types, material thermal conductivity and groundwater level on thermal performances were compared. The results indicated that the ground temperature was obviously affected by the HGHE operation, and the thermal performance in winter was superior to that in summer. Enlarging the temperature difference between inlet and ground could obtain a higher thermal power, but the outlet temperature was unsatisfactory. Increasing the HGHE length and thermal conductivity improved thermal performances, while the soil types and groundwater level had minor impacts on performances. The results are expected to provide suggestions for the HGHE operation and installation design.