Numerical simulation of the thermal interaction between pumping and injecting well groups

In the thermal energy utilization of a closed loop groundwater system of a groundwater source heat pump (GWHP) and an aquifer thermal energy storage (ATES), thermal breakthrough always occurs. This problem causes a gradual variation in the temperature of the pumping water and impacts the efficiency of the GWHP. In particular, a large scale GWHP system requires many wells; thus, the well location and arrangement become a considerable technological challenge. The aim of this study is to develop a numerical model for groundwater systems to obtain a fair comparison of the energy efficiency between different well locations and arrangement modes. In this study, four typical modes are studied to determine the thermal interaction influences, and the numerical model was verified with test data by using an artificial rock/soil test system. The comparisons show good agreement between the numerical date and the measured data. It is shown that the temperature variation is related to the well arrangement mode, and the row arrangement of well groups may be a better choice. Therefore, a suitable spacing well pattern in the limited area is helpful and can potentially decrease the intensity of the thermal interaction and resist the occurrence of thermal breakthrough.