Abstract

BoreSimSU is a C++ program that can simulate the thermal response of any single U-tube Borehole Heat Exchanger (BHE) in the short and medium term. It is based on the model illustrated in arXiv:2510.14421 [physics.app-ph], which combines the speed of Thermal Resistance Capacity Models (TRCMs) and the accuracy of finite-element simulations. The program yields, in a couple of seconds, the same results as those obtained by an accurate finite-element simulation requiring several hours of computation time. It provides the time evolution of the inlet, outlet and mean fluid temperature, of the mean BHE surface temperature, of the 3D and the effective borehole thermal resistance, and it can be easily connected to long-term simulation tools to obtain the full-time-scale thermal response of a bore field.