Evaluation of ejector supported supermarket refrigeration systems

摘要

To meet the criteria of a sustainable use of energy in future, the development of refrigeration plants using CO_2 as working fluid is of great importance. Especially integrated cycle layouts, covering a heat recovery for warm water supply and space heating, can contribute to increase the energy efficiency of supermarkets. Further, the utilization of ejectors for work recovery can enhance the energy efficiency. This paper deals with the analysis of different operation modes. The comparison of a combi ejector operation and an operation with expansion valve shows an improved energetic efficiency at higher ambient temperatures. The analysis also reviled a significant utilization of heat recover during ambient temperatures >15°C for the combi ejector operation compared to the HPV - operation. Comparison of fist law efficiency (COP) based on the high side pressure/gas cooler pressure of the plant reveals an COP increase for the combi ejector operation of 10.6 % at 80 bar.