A combined-cycle refrigeration system using ejector-cooling cycle as the bottom cycle

A combined-cycle refrigeration system (CCRS) that comprises a conventional refrigeration and air-conditioning system using mechanical compressor (RAC/ MC) and an ejector-cooling cycle (EJC) is proposed and studied. The EJC is driven by the waste heat from the RAC/MC and acts as the bottom cycle of th e RAC/MC. A system analysis shows that the COP of a CCRS is significantly h igher than a single-stage refrigeration system. Improvement in COP can be a s high as 18.4% for evaporating temperature of the RAC/MC T, at -5 degreesC . A prototype of the CCRS was built and tested in the present study. Experi mental results show that at T-e = -4.5 degreesC, COP is improved by 14% for a CCRS. For T-e at 5 degreesC, COP can be improved by 24% for a CCRS with higher condensing temperature of the RAC/MC. The present study shows that t he CCRS using the ejector-cooling cycle as the bottom cycle of the RAC/MC i s viable. Further improvement in COP is possible since the prototype is not designed and operated at an optimal condition. (C) 2001 Elsevier Science L td and IIR. All rights reserved.