Experimental investigation of the heating performance of refrigerant injection heat pump with a single-cylinder inverter-driven rotary compressor

Applying the refrigerant injection technology to air-source heat pump had been proved to be an effective access to acquire a better performance in the cold regions. In this paper, the test-bed of R410A single-cylinder rotary compressor vapor injection (SCRCVI) system with flash tank was built and measured by changing the compressor frequency f and injection pressure P inj under various ambient temperatures. The experimental results indicated that the effect of refrigerant injection became stronger as the ambient temperature decreased. So the SCRCVI showed a superior heating performance at lower ambient temperature, and the conventional single-stage vapor compression (CSVC) system would exhibit higher COP h , while the ambient temperature was beyond the critical value. Compared with the CSVC system, the Q h and COP h were improved by 9.1 ~ 29.5 and 5.35 ~ 7.89%, respectively, under the ambient temperature T od = − 10 °C. The injection pressure ratio R p under different operating conditions was varied in the range between 0.2 and 0.22. Specifically, the trend in variation of R p was reliably used to optimize the refrigerant injection system design and the control strategy.