Exergy Analysis of Transcritical CO2 Air-Source Heat Pump with Honeycomb Gas Cooler

Abstract

In order to build an efficient and energy-saving CO2 heat pump system and to improve the heat transfer efficiency of the gas cooler, a novel honeycomb gas cooler with a compact structure, high heat transfer efficiency, and high pressure-bearing capacity was proposed in our previous work. To clarify the components in the system that need further optimization and to improve its performance, an exergy analysis of a transcritical CO2 air-source heat pump system with the novel honeycomb gas cooler is studied in this paper. Based on the second law of thermodynamics, the exergy model of each component in the heat pump system is established, and the irreversible loss of each component is analyzed. In addition, the degree of energy loss of the honeycomb gas cooler is clarified, and the possibility and direction of system optimization are pointed out. The results show that the exergy efficiency of the system is 35.33% under nominal operating conditions, and there is a lot of room for improvement in its energy utilization. The three components with the largest exergy destruction percentage are the compressor, throttle valve, and evaporator in the order of 36.13%, 22.90%, and 19.51%, respectively. These components with high exergy destruction percentages are the main reasons for the large irreversible losses of the system.