Investigation and Potential Evaluation of Shallow Geothermal Energy Resources in Haikou City

Shallow geothermal energy is an important component of geothermal resources, and its rational development and utilization are of great significance for optimizing the energy structure. This study focuses on the regional characteristics of Haikou City, through multiple approaches including data collection, thermal property testing of rock and soil masses, pumping and reinjection tests, and on-site thermal response tests, it systematically reveals characteristics for shallow geothermal energy. The index method and analytic hierarchy process (AHP) were adopted to construct a suitability evaluation index system for the development and utilization of shallow geothermal energy in Haikou area, and the suitability zoning and resource evaluation of shallow geothermal energy were carried out, filling the research gap in this field in Haikou City. The results show that the constant temperature is 27.5 ℃, and the self-pressure reinjection/pumping ratio for groundwater ranges from 4.03 % to 11.1 %, indicating that the ground-coupled ground source heat pump system is suitable for exploitation. The total thermal capacity of shallow geothermal energy reaches 179.873×10¹² kJ/℃. The total summer cooling heat exchange power is 20.61×10⁸ W, which can meet a cooling demand of 22.9×10⁶ m². Based on the occurrence characteristics of shallow geothermal energy and the urban planning layout, the study area is divided into three zones: encouraged exploitation zone, controlled exploitation zone and restricted exploitation zone, covering areas of 217.88 km², 77.07 km² and 13.12 km² respectively. This study provides theoretical basis and technical support for the large-scale and scientific planning and utilization of shallow geothermal energy in Haikou City.