Study of High-temperature CO₂ Transcritical Heat Pump with Recuperator and Ejector

In this study,the thermodynamic optimization of the high-temperature CO₂ transcritical heat pump was carried out.The recuperator and ejector were used to improve the COP_h.How effectiveness of recuperator,outlet temperature of gas cooler and outlet pressure affect system performance were analyzed by parameter calculation.The analysis results showed that with the effectiveness of recuperator increasing,the system COP_h continues to increase,when the effectiveness of recuperator is 30%,40% and 50%,the optimal outlet pressure is 14 MPa,when the effectiveness of recuperator is 60%,70% and 80%,the optimal outlet pressure is 13 MPa;with the temperature of the gas cooler outlet increasing,the system COP_h continuously decreases,corresponding to the optimal outlet pressure continuously increasing.When the outlet temperature of gas cooler is 60℃,the optimal outlet pressure is 13 MPa,and the COP_h can reach 3.01;The effectiveness of recuperator and the outlet temperature of gas cooler affect the choice of outlet pressure.