Mechanism And Performance Optimization Of Compression-ejector Heat Pump System

The thermodynamic model of the performance of the compression-ejector heat pump system was established.With R410 A as the refrigerant,the compression ejector heat pump cycle was analyzed under various condensing temperatures and evaporation temperatures.The results show that compared with the ordinary refrigeration cycle,the COP of the ejector refrigeration cycle increases by 11.63%-19.44%,the total exergy loss decreases by 1.34kW-4.67 kW,the second law efficiency increases by 1.79%-5.73%,and the exergy loss of each component decreases.Among them,in the cooling mode,the reduction of the throttling loss is the most obvious,and the reduction range is 53.26%-63.44%.The two-phase flow ejector was preliminarily designed,and the flow characteristic of internal R410 A refrigerant fluid was analyzed by numerical simulation.The geometry of the ejector was optimized.It was found that the position of the secondary inlet,the area ratio of the mixed constant section to the main nozzle outlet,the main nozzle position,and the ratio of the length of the mixed constant section to the diameter have effects on the performance of the ejector.The ejector has the best performance when the secondary inlet is in the tapered section of the main nozzle.When the area ratio of the mixed constant section to the main nozzle outlet is 0.11,the mass entrainment ratio reaches a maximum value;when the distance between the main nozzle outlet and the mixed constant section inlet is 17 mm,the ejector performance is optimal;When the ratio of the length of the mixed constant section to the diameter is 10,the ejector mass entrainment ratio reaches a maximum value.Then,according to the difference between the heat and cold conditions of the heat pump,the four-way reversing valve is designed and simulated by numerical simulation.The values of heat transfer temperature difference,heat transfer loss,the pressure difference between inlet and outlet and pressure loss in the simulated cooling and heating mode were compared and analyzed.It was found that the heat transfer loss of the fourway reversing valve is the highest on the high temperature and high pressure side,followed by the low temperature and low pressure side,and the heat transfer loss of the valve seat is small.The performance of four-way reversing valve designed under the cooling condition was found to perform superior to the one designed under the heating condition.Figure 45;Table 7;Reference 93.