Performance analysis of a dual ejector enhanced vapor injection high-temperature heat pump.

The traditional vapor injection high-temperature heat pump cycle (VIHPC) has the shortcomings of high compression ratio and limited make-up gas volume for vapor injection, in order to make up for this shortcoming, this paper proposes a dual ejector enhanced vapor injection high temperature heat pump cycle (DEHPC), in which dual ejectors are used, in which the function of ejector 1 is to enhance the refrigerant pressure at the compressor inlet, while the function of ejector 2 is to enhance the make-up gas volume for vapor injection. R1233zd(E) was used as the working fluid for energy analysis and exergy analysis of the two heat pump cycles. The simulation results show that the heating coefficient of performance (COPh), exergy efficiency (ηex), and make-up gas volume for vapor injection (mi) of DEHPC are better than those of VIHPC. Specifically, the COPh, ηex, and mi of DEHPC are improved by 8.8 %-13.4 %, 8.5 %-13.6 %, and 50 %-74.5 %, respectively, compared with VIHPC. In this paper, the performance of VIHPC is enhanced by the reasonable arrangement of double ejectors in the heat pump, which provides a new idea for the research of heat pump system and proposes a novel and
efficient high-temperature heat pump system for factories that need high-temperature heat source.