Exergy Analysis of Transcritical Carbon Dioxide Refrigeration Cycle with an Ejector

The throttling loss is the major loss of the transcritical carbon dioxide refrigeration cycle, and the reason of low efficiency for performance. The study on the transcritical carbon dioxide refrigeration cycle with ejector and with throttling valve has been performed by the first and second laws of thermodynamics in theory. The effects of the injection ratio of ejector, heat rejection pressure, outlet temperature of gas cooler and evaporating temperature on the coefficient of performance (COP) and exergy loss were investigated in transcritical carbon dioxide refrigeration cycle with ejector and with throttling valve. It is found that ejector instead of throttling valve can reduce more 70% exergy loss and increases COP more 36%. In addition, optimal heat rejection pressure and outlet temperature of gas cooler affect COP greatly for the transcritical carbon dioxide refrigerating cycle with ejector.