R424A
R424A (also known as RS-44) is a zeotropic mixture consisting of 50.5 weight% R125, 47.0% R134a, 0.9% isobutane, 1.0% n-butane and 0.6% isopentane. It is considered to be a drop-ion replacement fluid for R22. It has a molar mass of 108.41 kg/kmol.
Property data for R424A are provided using a generalized equation of state fitted by F-Chart Software using thermodynamic property data generated by REFPROP. The model is applicable for temperatures between 180 K and 470 K with pressures up to 20 MPa. The reference state is saturated liquid at 0 C for which specific enthalpy and entropy are 200 kJ/kg and 1.0 kJ/kg-K, respectively.
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