THERMODYNAMIC ANALYSIS ON TRANS-CRITICAL R744 VAPOR-COMPRESSION/EJECTION HYBRID REFRIGERATION CYCLE

摘要

In the process of trans-critical R744 vapor-compression cycle, the operating pressure is about 10MPa, and the pressure differential is 7MPa between evaporator and gas cooler. This leads to a large throttling loss. A new vapor-compression/ejection hybrid refrigeration cycle has been proposed. This cycle needs a little modification compared with a standard vapor-compression refrigeration cycle and is easy to realize. In this cycle, an ejector is used instead of a throttling valve to recover some of the kinetic energy of the expansion process. Through the action of the ejector the compressor suction pressure is higher than it would have been in a standard cycle. Thus the compressor does less work, resulting in energy savings. The theoretical analysis and simulation of this cycle have been carried out. The comparison between the new cycle and the standard vapor-compression cycle are made under the same operating conditions. The effects of ejector's entrainment ratio and efficiency on the cycle performance have also been discussed. The results indicate that the new cycle can improve the performance of the trans-critical CO{sub}2 cycle effectively.