A fast numerical approach for the horizontal ground heat exchanger

A fast thermal response numerical (TRN) approach for horizontal ground heat exchanger (HGHE) was developed and verified. The shape equivalence method was used to process the shapes of pipe cross section and elbows, reducing the meshing difficulty and the grid quantity of HGHE. A series of geometric equivalent quantization values were presented. Meanwhile, a semi-analytical equation was derived to reduce the sensitivity of the TRN model to the time step. The simulation results show the calculation speed of the TRN model is 38.98 times that of the Fluent model in the same case. Furthermore, long-term operations of HGHE were simulated, revealing that the soil around HGHE has good heat recovery capacity.