**R454B**

R454B (also known as Opteon XL41) is a zeotropic mixture consisting of 68.9 weight% R32 and 31.1% R1234yf. It is considered to be a replacement fluid for R410A. It has a molar mass of 62.6 kg/kmol.

Thermodynamic and transport property data for R45B are provided using a generalized equation of state fitted using thermodynamic property data provided by REFPROP. The reference state for enthalpy and entropy is the IIR recommendation in which the specific enthlapy and entropy of saturated liquid are 200 kJ/kg and 1.0 kJ/kg-K, respectively. The model is applicable for temperatures between 180 K and 500 K with pressures up to 100 MPa..

Transport properties are estimated based 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

The data provided by EES should be considered to be approximate. Use of REFPROP property data (with the EES_REFPROP interface) is recommended for applications requiring high accuracy.