Numerical simulation of ground heat exchangers based on dynamic thermal boundary conditions in solid zone

Accurate calculation and prediction of solid zone (pipe, grout and soil) temperature variation caused by ground heat exchanger heat release or absorption are needed for evaluating performance of ground source heat pump system. For this purpose, according to energy conservation, one numerical simulation model with dynamic thermal boundary conditions is established and verified with experimental data. As to single borehole and array boreholes, temperature variations in soil zone are assessed with the present model. Meanwhile, limitations of constant temperature and adiabatic boundary conditions are found and can be overcome with dynamic thermal boundary conditions. This study achieves improvement of numerical solution on heat transfer of ground heat exchanger and provides one favorable method for analyzing the influence of ground heat exchanger operation on solid zone temperature.