Abstract: The reasonable layout of well group for ground-source heat pump system is studied in the purpose of improving the efficiency of ground-source heat pump and in the meantime avoiding heat penetration during refilling and pumping. A 3D model of the pumping and recharging system for ground-source heat pump is established using COMSOL Multiphysics software to simulate the water temperature in wells of three different layouts (aligned, staggered, and cross-row layouts) with different well spacings. The optimal layout of well group is selected according to the degree of heat penetration. Results demonstrate that: no matter how the well spacing changes, the temperature in the central well changes the most drastic, subject the most to thermal penetration; in the same layout, a wider spacing between pumping wells results in a smaller change of water temperature and a slighter heat penetration. When the pumping and recharging wells are arranged in alignment, heat penetration during the operation of the system occurs the latest with the least impact. When the well spacing is 100 m, the water temperature of well No.4 under both working conditions changed by 0.03 K, whereas that in well No.5 climbed by 0.07 K and dropped by 0.06 K respectively in the two working conditions, and well No.6 raise by 0.02 K and fell by 0.03 K, respectively. In conclusion, a spacing of 100m is recommended to be the optimal.

Key words: ground-source heat pump, pumping and recharging system, heat penetration, optimal layout, numerical simulation