Experimental Study Of Water Source Direct Thermal Heat Pump Water Heater Using R290 As The Refrigerant

Today, energy issues become more prominent, energy conservation has become a major theme of production and life in our country. In terms of energy consumption, it occupies a large proportion of building energy consumption, and the application of heat pump technology can effectively promote the implementation of building energy saving. However, due to the heat pump refrigerants damaging the atmosphere, the international community have reached a consensus on the issue of the banning use of those harmful refrigerants and the traditional refrigerants will be eliminated soon. Thus, the new environmentally friendly refrigerants researches are imminent.As the above problems, the hydrocarbon refrigerants attract the attentions again. In the heat pump water heater nominal operating conditions, make a calculation of the thermodynamic cycle in theory of the four candidate refrigerants(R290、R600、R600a and R1270)of the R22. Then analyze the dates of the system and the results show that the R290 is the best. The heating performance coefficient and the heating capacity for per unit mass of the R290 are 5.573 and 418.0 kJ/kg, which are 2.6% and 81.1% more than the R22 respectively; The compression ratio, the condensing pressure and the discharge temperature are 2.996, 1.907 MPa and 73.22℃ accordingly, which are 6.2%、12.3% and 20.5% less than the R22.According to the calculation results, set up the heat pump system experiment device and research the direct thermal heat pump water heater using R290 as the refrigerant by experiments. The results of the variable charging mass experiments show that the optimum charging masses of the R22 and the R290 are 1.6kg and 0.7kg respectively. The mass of the R290 is 43.8% of the R22. Under the optimum charging mass, for the R22 and the R290, the heating performance coefficients are 3.87 and 2.88; the condensing pressures are 2.01 MPa and 1.83MPa; the compression ratios are 3.02 and 2.88; the discharge temperatures are 84.1 and 69.8℃ ℃; the power consumptions are 1.24 KW and 1.05KW; the heating capacities are 4.75 KW and 4.21 KW. Besides, the refrigerant charging mass varies and the system performance is impacted obviously. As the R290 charging mass adding, the heating performance coefficient, the condensing pressure and the power consumption are monotone increasing, and the pressure ratio and the heating capacity increase firstly and then decrease, and the discharge temperature is monotone decreasing.Finally, set the temperatures of the heat exchange outlet as 45℃、55 and 65℃ ℃. In the case of the optimum refrigerant charging, with the heat sink outlet temperature rising, the heating performance coefficient is decreasing, and the heating capacity increases firstly and then decreases, and the condensing pressure, the pressure ratio, the discharge temperature and the power consumption are increasing.