Prediction of thermodynamic properties of refrigerant fluids with a new three-parameter cubic equation of state

• A new predictive three-parameter equation of state (NEoS) is described.
• A good capacity of prediction is obtained with the NEoS for thermodynamic properties at and outside equilibrium.
• Better performances than PR-EoS and PT-EoS are obtained with the NEoS for density properties.
• A better prediction is obtained with the NEoS in the critical region.
• A very good prediction is obtained with the NEoS for thermodynamic properties of mixtures.

To describe the thermodynamic properties of refrigerant fluids, it is important to use a reliable thermodynamic model able to predict accurate results for both pure compounds and mixtures. In this study, a new three-parameter cubic equation of state is presented, based on the modification of the well-known Patel–Teja equation of state. The new equation of state is associated with the Mathias–Copeman alpha function.By only knowing the acentric factor ω and the experimental critical compressibility factor Zc of pure compounds, it is possible to predict the thermodynamic properties of both pure compounds and mixtures by means of the new equation of state. No binary interaction parameter kij is needed for the prediction of mixture properties.The results obtained with the new equation of state show a good agreement with experimental data for vapor–liquid equilibrium and density properties. The obtained results are particularly satisfying for liquid density, and in the vicinity of the critical point, by comparison with the results obtained using the Peng–Robinson and the Patel–Teja equations of state.