Simulation Model for Borehole Heat Exchangers

Seasonal thermal energy storage (STES) offers a solution to address the mismatch between production and consumption by storing the produced excess heat for later use. Borehole heat exchangers (BHEs) are one of the sensible STES technologies. In this paper, a longterm simulation model for BHEs was developed. A finite line-source model for the heat transfer outside the borehole and a quasi-3D model for the heat transfer inside the borehole were applied in two region simulation approach. Fast Fourier transformation technique together with a cubic spline interpolation method were used for faster simulation time with time varying loads and longer simulation periods. The simulation method was validated using experimental data. Results showed that the simulation model is able to accurately model ground and fluid temperature evolution.