Comparative energy and exergy analysis of an ejector-enhanced vapor injection transcritical CO2 refrigeration system integrating with subcooler and flash tank

Key Words:HEAT-PUMP CYCLE; COMPRESSION REFRIGERATION; THERMODYNAMIC ANALYSIS; PERFORMANCE ANALYSIS; EXPANSION; OPTIMIZATION

Abstract:To enhance the performance of transcritical CO2 refrigeration system, an ejector-enhanced vapor injection transcritical CO2 refrigeration system integrating with subcooler and flash tank is proposed, which utilizes an ejector to entrain the saturated refrigerant vapor from the flash tank and injects the vapor into compressor. The performance of the proposed system is theoretically analyzed from the viewpoints of energy and exergy in terms of the key parameters of vapor injection and compared with the basic subcooler vapor injection transcritical CO2 refrigeration system (SCRS) and flash tank vapor injection transcritical CO2 refrigeration system (FCRS). The results demonstrate that system performance can be improved due to the lower flash pressure and large subcooling degree by using ejector. There exists an optimal relative intermediate pressure factor and discharge pressure to make the system performance maximum. Ejector-enhanced vapor injection system outperformed the basic subcooler and flash tank vapor injection systems in COP and exergy efficiency. The COPmax of ejector-enhanced vapor injection system improvement is 8.4 %similar to 9.9 % and 6.6 %similar to 10.4 % respectively compared with subcooler and flash tank vapor injection systems at different outlet temperature of gas cooler. In addition, the exergy efficiency of new system is improved by 8.4 %similar to 9.9 % and 6.7 %similar to 10.4 % at the same conditions. Overall, this study confirms the performance improvement potential of the proposed hybrid cycle and provides theoretical support for its practical application.

Volume:64

Issue:-

Translation or Not:no