A Variable Heat Flux Line Source Model For Boreholes In Ground Coupled Heat Pump

Line heat source model is a type of classical heat transfer analysis model for modeling the heat transfer process of ground heat exchanger(GHE) in ground-coupled heat pump system (GCHPs). In this paper, considering the disadvantage of the classical constant heat flux line heat source model, a variable heat flux line source model is developed to simulate the heat transfer of GHE of GCHP operated in variable heat flux by quoting the idea of superposition principle, step load and borehole resistance. The validation on the updated line source model was undertaken by analysis and comparison with the improved and validated cylindrical source model. The results indicate that the developed variable heat flux line source model can simulate the heat transfer process of ground heat exchanger effectively and can be used as a reliable calculation model for vertical U-tube GHE.