Simulating thermal pollution caused by a hypothetical groundwater heat pump system under different climate, operation and hydrogeological conditions

Thermal–hydraulic analysis was conducted to examine the propagation of temperature anomalies under different climatic, subsurface and operation conditions. A series of scenarios simulated by numerical modeling indicate that the injection rate, injection depth and anisotropy of the aquifer are important parameters that need to be properly estimated to avoid critical thermal interference in shallow subsurface areas. The potential impact due to climate change is predominant only in shallow subsurface areas, but the situation may become severe if thermal anomalies that propagate upward due to injection of warm water mix with climate change anomalies that penetrate downward. Groundwater recharge and horizontal groundwater flows retard upward migration of temperature anomalies. Therefore, a proper analysis of groundwater flow in the area would facilitate harvesting a large amount of geothermal energy while limiting its impact to acceptable levels. Furthermore, a set of type curves was developed to select operational conditions with a reasonable accuracy while maintaining thermal pollution in an acceptable range.