Adding a compressor to basic in-counter-series triple-effect lithium bromide absorption refrigerating cycle is an effective solution to reduce the temperature of high pressure generator and slow down the corrosion situation. Exergy analysis based on thermodynamic analysis shows that the compressor placed between the low pressure generator and the condenser is the best, which help the system get the highest energy efficiency.

The application of natural refrigerant CO2 is of great significance to reduce the greenhouse effect and ozone depletion. Transcritical CO2 refrigeration cycle is presently an important aspect of natural refrigerant alternatives research. In this paper, the transcritical CO2 refrigeration cycle system is experimentally studied, effect on performance of heat rejection pressure, gas-cooler outlet temperature and evaporation temperature is analyzed. The experimental results show that there is an optimum high pressure to achieve the maximum COP, the evaporation temperature and gas-cooler exit temperature have great impact on the COP. Increase of gas-cooler outlet temperature led to a rapid increase in the optimal high pressure, but effect of evaporation temperature is not obvious. So in order to obtain the optimum performance, the influence of heat rejection pressure, evaporating temperature and gas-cooler outlet temperature should be considered during the designing and operating CO2 refrigeration cycle system.