Simulation And Experimental Study On The Direct-expansion Ground Coupled Heat Pump System

Ground-Source Heat Pump (GSHP) technology is clean and high-efficiency. Because of lack of the middle heat exchanger, the efficiency of DX-GCHP(direct expansion ground coupled heat pump) is higher than the SL-GCHP(secondary loop ground coupled heat pump)'s. Refrigerant flows in the buried pipe of DX-GCHP and the anti-freeze fluid is not required when DX-GCHP system works in winter. DX-GCHP is more and more attracting many scholars'attentions.Temperature field of buried U-tube heat exchanger is achieved by the CFD software Fluent. The heat transfer coefficient of natural convection in the well water is calculated. Based on the component model the DX-GSHP system model is built. COP and quantity of exchanged heat is calculated. The results are verified by experiment.Conclusions are made:(1) Refrigerating capacity,heating capacity and COP of the DX-GCHP system increased with the flux of cooling water, while the power of compressor decreased. (2) Refrigerating capacity,heating capacity and COP of the DX-GCHP system decreased with the inlet temperature of cooling water, while the power of compressor increased. (3) The COP of DX-GCHP is higher than ASHP's.