rotary compressor, end-plate injection, experiment, simulation
The refrigerant injection technology can improve the performance of heat pump in low ambient temperature. Traditional end-plate injection of rotary compressor controls the injection by the rotation of the piston, which leads to some drawbacks such as small injection area and bad adaptability to variable working condition. By adopting a check valve system, a novel end-plate gas injection structure for rotary compressor had been put forward to increase injection port area and enhance the adaptability to variable working condition in previous research. In this paper, a vapor-injected rotary compressor prototype is manufactured and tested compared to single stage and two stage rotary compressor. The experimental results indicate that the vapor-injected compressor can enhance the heating capacity by 23.8~42.3% and COP by 4.0~11.8% compared to single stage compressor, which is close to two stage compressor. But the power consumption increases because of the huge back-pressure volume which related to the area and location of the injection port. The influence of the parameters of the injection port on the compressor is researched based on a numerical model verified by experimental results. The results show that the smaller injection port can decrease the power consumption obviously and increase COP. The heating capacity doesn’t change significantly when the injection area is over 20.1mm2 in this compressor but decreases if the injection area is too small. So the injection port scenario should consider heating capacity and COP synthetically.