Modeling and Simulation of Solar Seasonal Underground Thermal Storage in a Solar-Ground Coupled Heat Pump System

This paper presents a three-dimensional unsteady state fluid-solid coupling mathematical model of multiple ground heat exchangers (GHE) used in a solar-ground coupled heat pump system (SGCHPS). The model was developed with the commercial computational fluid dynamics (CFD) software FLUENT. To simulate the long-term performance of solar seasonal underground thermal storage in SGCHPS, the mathematical models of solar collector and plate heat exchanger were dynamically loaded into the GHE model as User-Defined Functions (UDF). From the simulation results, the model can better reflect the operating conditions of solar seasonal underground thermal storage, and more accurately analyze the dynamic characteristics of system. This method provides a new idea for the research of SGCHPS.