| Abstract |
Aquifers significantly alter the thermal response of geothermal heat exchangers. To capture this influence accurately, theoretical models must incorporate the convective transport of heat due to the flowing groundwater. While existing models effectively describe the two limiting regimes—creeping flows (low Peclet number) and strong flows (Peclet number of order unity)—no theoretical framework currently provides accurate predictions across the full spectrum of Peclet numbers. A general model applicable to all flow regimes would be highly valuable, as it would eliminate the need to classify the aquifer's flow regime during system design. In this work, the authors present a unified theoretical model developed using asymptotic expansion techniques, capable of describing the thermal interaction between single geothermal boreholes and aquifers for any Peclet number. The semi-analytical model demonstrates excellent agreement with high-fidelity numerical simulations, highlighting its robustness, accuracy, and broad applicability to real-world geothermal systems. |