Numerical Modeling on the Performance of Aquifer Thermal Energy Storage System under Cyclic Flow Regime

Abstract

Coupled hydrogeological-thermal model for simulating the thermal energy storage system in aquifer is described. It is essential to provide an optimized configuration and operation schedule for wells on the site. This paper presents numerical investigations and thermohydraulic evaluation of two-well models of aquifer thermal energy storage (ATES) system operating under cyclic flow regime. A three-dimensional numerical model for groundwater flow and heat transport is used to analyze the thermal energy storage system in the aquifer. The model includes the effects of convection and conduction heat transfer, heat loss to the adjacent confining strata, and hydraulic anisotropy. The operation scenario consists of cyclic injection and recovery from two wells and four periods per year to simulate the seasonal temperature conditions. The model has been used to study performances under various operational and geometrical parameters of the storage system. The calculated temperatures at the producing well were relatively constant within a certain range through the year and fluctuating quarterly a year. Operation schedules, injection temperature, injection/production rate, and geometrical configuration of well and aquifer used in the model are shown to impact the predicted temperature profiles at each stage and the recovery water temperature. But aquifer thickness and hydraulic anisotropy have a minimal effect on the performance of ATES systems.