Evaluation of supplementary/retrofit refrigerants for automobile air-conditioners charged with CFC12

In this study, thermodynamic performance of supplementary/retrofit refriger ant mixtures for CFC12 used in existing automobile air-conditioners was exa mined. A thermodynamic computer analysis of an automobile air-conditioner w as carried out for the initial screening of possible mixture candidates, an d refrigerant mixtures composed of HCFC22, HFC134a, HCFC142b, RE170 (dimeth ylether), HC290 (propane), and HC600a (iso-butane) were proposed to supplem ent CFC12. Also a breadboard type refrigeration test facility was manufactu red to verify the performance of the alternative refrigerant mixtures propo sed through the computer analysis. Test results showed that HFC134a/RE170 m ixture with zero ozone depletion potential is the best long term candidate to supplement CFC12. On the other hand, HCFC22/HFC134a/RE170 and HCFC22/HFC 134a/HCFC142b mixtures are good only as short term supplementary/ retrofit alternatives since they contain HCFC22. A hydrocarbon mixture of HC290/HC60 0a showed a good performance but its use in existing automobile air-conditi oners should be carefully considered due to its flammability. (C) 1999 Else vier Science Ltd and IIR. All rights reserved.