Operation performance analysis of middle-deep ground-source heat pump systems in high cold area

A study is conducted on the actual operation of the middle-deep ground-source heat pump centralized heating system in Gonghe county,Qinghai province.The actual operation performance of the heating system is comprehensively analysed through data such as indoor and outdoor temperatures,extraction and reinjection water temperatures,supply and return water temperatures,energy consumption,and coefficient of performance.The research results show that there is a decay rate of 0.078 ℃/d for the geothermal water outlet temperature.To maintain the geothermal dynamic balance,the upper limit flow rate of water extraction is 80 m3/h.In addition,when the weather warms up,an outdoor average temperature of 5 ℃ can be regarded as the start-stop node of the heat pump unit.Closing the ground-source heat pump unit and relying only on the plate heat exchanger for heat transfer can maximize the comprehensive coefficient of performance of the system to 8.7,and the system energy consumption can be reduced by 42.9%.This paper can provide a reference for the optimized operation and efficiency improvement of geothermal heating systems.