Three R744 supermarket refrigeration systems are compared

including conventional booster system (CB)

booster system with parallel compression (PC) and multi-ejector booster system with parallel compression (EJ). The parallel compressors in PC and EJ systems work under lower pressure ratio and consequently the energy of compressors decreases. In EJ systems

expansion valves are substituted by ejectors

so that the irreversible loss in the system could be lower. The air-conditioning system integrated with PC and EJ system are also discussed respectively. The optimal high side pressure of each system is confirmed. The value of high side pressure becomes larger when the outdoor temperature increases. When the ambient temperature is fixed

the multi-ejector system features the lowest high side pressure. The power consumption of each system is obtained by the simulation models. The results indicate that the power consumption of PC could be decreased

ranging from 6.8% to 12.3% compared to CB. And for EJ

the power consumption is even smaller

where the gap is 6.3% to 17.5%. Compared with HFC (hydrofluorocarbon)

such as R404a

the R744 supermarket refrigeration system is of great energy saving potential in warm climates.