Study on the simulation and optimization of the heat transfer scheme in a buried-pipe ground-source heat pump

To guarantee the sustainable development and utilization of shallow geothermal energy and avoid heat accumulation problems during the operating period of ground-source heat pump, a three-dimensional coupled numerical model of unsteady groundwater seepage and heat transfer was established. This model was applied to the demonstration project of the buried-pipe heat pump system in Danyang, Jiangsu Province. The model was based on the principles of groundwater seepage and heat transport and was combined with the future operating conditions of the ground-source heat pump system, to forecast the thermal equilibrium development trend of underground temperature field. A design scheme was determined on this basis. The district was divided into five development and utilization zones (I–V), and we changed the minimum heat transfer hole spacing from 5 to 14, 17, 18, 21, and 19 m. From the results, according to the actual situation we adopted, the simulation optimization scheme effectively slowed the heat transfer and resolved the heat accumulation problem, which can easily occur during the operation of a ground-source heat pump system. The three-dimensional coupled numerical model of unsteady groundwater seepage and heat transfer is an effective way to optimize and determine the sustainable development and utilization plan of a ground-source heat pump for shallow geothermal energy.