**R423A**

R423A is a near-azeotropic blend of R134a and R227ea with mass percentages of 52.5% and 47.5%, respectively. It has a molar mass of 125.96 kg/kmol.

Thermodynamic data for R423A are provided using a pseudo-pure fluid model in the manner described by:

E. Lemmon

"Pseudo-Pure Fluid Equations of State for the Refrigerant Blends R-410A, R-404A,R-507A, and R-407C"

International Journal of Thermophysics, Vol. 24, No. 4, July 2003

The generalized equation of state was fitted by F-Chart Software using thermodynamic property data provided by the REFPROP 10 program. The reference state for enthalpy and entropy is the IIR recommendation in which the specific enthalpy and entropy of saturated liquid are 200 kJ/kg and 1.0 kJ/kg-K, respectively. The model is applicable for temperatures between 200 K and 420 K with pressures up to 20 MPa.

Transport properties are estimated using a corresponding states approach as suggested in:

Klein, S.A., McLinden, M.O., and Laesecke , A., "An improved extended corresponding states method for estimation of viscosity of pure refrigerants and mixtures", Int. J. of Refrigeration, 20, pp. 208-217, 1997

McLinden et al., "An extended corresponding states model for the thermal conductivity of refrigerants and refrigerant mixtures", Int. J. of Refrigeration, 23, pp. 43-63, 2000