Performance analysis of ground-source heat pump variable flow rate system based on TRNSYS simulation

Establishes a simulation model for the variable flow rate water system of ground-source heat pump with TRNSYS, and validates it with the theoretical calculation and the measured data. Calculates the minimum flow ratio in considering the flow state of fluid, the pump head and the overall efficiency of pump. The pump frequency is controlled by indirectly controlling condensation temperature and setting minimum flow ratio. According to the simulation results, analyses the influence of variable flow rate on heat exchange of the buried pipe and soil temperature, and discusses the energy consumption and energy saving potential of the system. The results show that compared with constant flow rate system, energy consumption of both pump and air conditioning system decrease in variable flow rate system, where the EER of system increases, and the energy conservation rate reaches 6.94% in cooling period.