Thermodynamic analyses of the CFC-12 and HFC-134a refrigeration cycles

Dichlorodifluoromethane (CFC-12) is the major contributor to ozone depletion. The new refrigerant tetrafluorethane (HFC-134a), which is a leading candidate to replace CFC-12 in refrigeration and air-conditioning applications, has been investigated from the standpoint of thermodynamic performance. For this purpose, a computer program is written to calculate the thermodynamic properties of HFC-134a, which can be used as a reference for analyses. A comparison has also been made for CFC-12 and HFC-134a refrigerants, which indicates that CFC-12 may be replaced by HFC-134a without a significant loss in overall thermal performance. It is found that the volumetric refrigerating effect of HFC-134a is less than that of CFC-12 for the same operating conditions. Thus, a larger compressor will be required for the same refrigeration capacity with HFC-134a.