HFC+HC blends as refrigerants

The blends formed mixing hydrofluorocarbons (HFC) and hydrocarbons (HC) can be classified as semi-natural refrigerants since, by optimizing the composition, it is in principle possible to adapt basic features such as GWP, TEWI and flammability to the industrial and environmental requirements. However, the energetic efficiency must be competitive with the traditional refrigerants. To evaluate the efficiency, it is necessary to know the actual thermodynamic properties. VLE measurements allow to regress the interaction parameters for selected equations of state so to calculate with good accuracy the thermodynamic properties. For this reason, VLE measurements were performed at the CNR-ITC for several of HFC+HC blends. The present paper summarizes the results obtained for VLE measurements and discuss the possibility to apply the mixtures studied in HVAC&R applications by analyzing their performance in ideal cycles, calculated on the base of selected models, in comparison with the traditional refrigerants.