The impact of mixed non-azeotropic working fluids on refrigeration system performance

The use of non-azeotropic mixed refrigerants is becoming of greater interes t due to the phase-out of CFC's, and the lack of suitable environment-frien dly pure alternatives. Refrigeration systems may use either pool- or flow-b oiling evaporators. Whilst the use of mixtures in how-boiling systems has b een the subject of a significant amount of research, Little attention has b eer, paid to pool-boiling systems. This article considers this issue, and i dentifies a reduction in efficiency that occurs as a result of using mixtur es in place of pure fluids. The cause of this problem is examined, and a nu mber of alternative system configurations are evaluated. It is concluded th at, in a pool-boiling cycle, a mixed refrigerant will always result in a po orer efficiency than is obtainable with a pure fluid. (C) 1998 Elsevier Sci ence Ltd and IIR. All rights reserved.