A novel approach for delineating the suitability zone of ground coupled heat pump system and geothermal resource potential in a seasonally frozen region

Accurate delineation and assessment of the suitability zone and geothermal resource potential are crucial for the utilization of shallow geothermal energy resources, particularly in seasonally frozen regions. In this study, the field experiments were conducted to delineate and assess the suitability zone and geothermal resource potential for the ground coupled heat pump (GCHP) system in a seasonally frozen region by adopting a novel approach of entropy-based Fuzzy Analytic Hierarchy Process (FAHP) method and trapezoidal fuzzy number-based Monte Carlo method. The results showed that the suitable and moderately suitable area of GCHP systems was 359.182 km2 and 648.196 km2, accounting for 96.28 % of the study area. The western part of the study area exhibited greater development potential for GCHP system than the other areas due to its superior hydrogeological, geological and geothermal conditions. The borehole field data indicated that the heat capacity of rock and soil mass in the vadose zone was 54.38 × 1011 kJ/°C, that of water was 70.645 × 1011 kJ/°C, and that of air was 7.963 × 1011 kJ/°C. The heat capacity of overall study area at 200 m and 100 m was 5.55 × 1014∼5.94 × 1014 kJ/°C and 2.72 × 1014∼2.84 × 1014 kJ/°C, respectively, with a 90 % probability. When the land use coefficient was considered, the heat transfer capacity was 6.64 × 106 kW in summer and 1.49 × 106 kW in winter, and geothermal resource potential was 8.24 × 104 m2/km2 in summer and 2.47 × 104 m2/km2 in winter, suggesting that geothermal resource potential is greater in summer than in winter due to the larger available temperature difference. This study provides novel insights into the delineation and assessment of suitability zone and geothermal resource potential for the GCHP system, which can improve the sustainable utilization of shallow geothermal energy in seasonally frozen regions.