1043 0195-928X/03/0700-1043/0 © 2003 Plenum Publishing Corporation International Journal of Thermophysics, Vol. 24, No. 4, July 2003 (© 2003) Modeling of Gas Solubility Data for HFCs–Lubricant Oil Binary Systems by Means of the SRK Equation of State M. Teodorescu, 1, 2 L. Lugo, 1 and J. Fernández 1, 3 1 Laboratorio de Propiedades Termofísicas, Facultad de Física, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela, Spain. 2 Institute of Physical Chemistry ‘‘ I. G. Murgulescu,’’ Romanian Academy, Splaiul Indepen- dentei 202, 77208 Bucharest, Romania. 3 To whom correspondence should be addressed. E-mail: fajferna@usc.es Received August 29, 2002 The Soave–Redlich–Kwong (SRK) equation of state (EOS) is used to describe vapor-liquid ( VLE) and vapor-liquid-liquid ( VLLE) equilibria of mixtures con- taining environmentally friendly refrigerants (hydrofluorocarbons, HFCs) and lubricant oils ( polyalkylene glycols, PAGs and polyol esters, POEs) at high pressures. For refrigerants, pure component parameters are used as they were found in refrigerant properties computer program Version 6.0 of REFPROP. For the PAG and POE oils, they are either predicted by group contribution methods or obtained from thermodynamic data. Extension to mixtures is per- formed by using the conventional quadratic mixing rule with only one param- eter for each binary pair. The binary parameters are regressed from VLE exper- imental data available in the literature and subsequently used for prediction of VLLE. All results of the calculations are discussed, and the necessary param- eters for prediction of thermodynamic properties of these types of mixtures for the SRK EOS are presented. The computations were performed using phase equilibria software (PE2000). KEY WORDS: equation of state; HFCs; lubricants; refrigerants; solubility; vapor-liquid (liquid ) equilibria. 1. INTRODUCTION Modeling of the thermophysical properties and phase behavior of alterna- tive refrigerant (HFC)–lubricant oil (PAG and POE) mixtures is highly