Heat Transfer Modeling on High-Temperature Charging and Discharging of Deep Borehole Heat Exchanger with Transient Strong Heat Flux

High-temperature charging and discharging by deep borehole heat exchanger is typical of a large exchange temperature difference transient strong flux. Simulation this problem not only computationally expensive, but it also challenging in terms robustness stability for numerical methods. This paper formulates generic efficient transfer model with two distinctive novelties: Firstly, highlights unsteady- quasi-steady-state modeling strategies outside inside borehole. Secondly, provides analytical solutions the front propagation flux density distribution unsteady-state rock zone. These formulations prove to be critical relieve computational effort face validated high-temperature storage case from literature, as well pilot demonstration project China. It was discovered that prediction error exists very short operation days during initial unsteady stages discharging. Both relative errors under phases are within 5% steady-state period. A comparison simulation cost OpenGeoSys software demonstrates its high efficiency. proves achieves an acceleration ratio 30 times fully method. In general, has four advantages: applicability, good accuracy, easy implementation, efficiency, limited single pure conduction.