Thermodynamic properties of pure hydrofluorocarbons by a perturbed hard-sphere-chain equation of state

This paper deals with the evaluation of thermodynamic properties of pure hydrofluorocarbons. A perturbed-hard-sphere-chain equation of state was adapted to these compounds and tested on a large database of refrigerants and hydrocarbons, with reference to both volumetric and equilibrium properties. The ability of the proposed model to reproduce experimental values is discussed and comparison with that of the PHCT equation of state is presented. The model contains three parameters, which are only slightly correlated with one another. Expressions for predicting the parameter values as a function of molecular quantities are proposed. The results obtained show that the proposed model can be reliably used for calculation of pure properties of refrigerants, starting from the Bondi volume and surface area values, plus a single vapour pressure value. The results are promising in view of application to mixtures of refrigerants and long-chain hydrocarbons. In this respect, the paper can be regarded as a necessary step toward the prediction of the mixture behaviour of refrigerants and the effect of the presence of the lubricant oil in the mixture.