In this study, taking an office building in Xiâ€™an city as the research object, the heat load of the office building has been simulated using DeST. The rate of heat extraction from a 2000 m closed-loop geothermal well has also been simulated using COMSOL. The influences of the mass flowrate on the heat extraction rate and the average outlet temperature have been discussed. Combined with the downhole heat exchanger model, the heat pump model, and the thermal energy storage model, an integrated numerical simulation model for office building heating is established. The model is used to investigate the influence of different energy storage ratio on the system total cost, based on which the optimal energy storage ratio is determined. The results obtained from this study provide theoretical basis for improving geothermal energy utilization.
Keywords geothermal heating system, integrated model, thermal energy storage, heat pump, closed-loop heat extraction, energy storage ratio