**R452B**

R452B (also known as DR-55 and Opteon XL55) is a zeotropic mixture consisting of 67 weight% R32, 7% R125 and 26% R1234yf. It has a molar mass of 63.5 kg/kmol. R452B exhibits a small temperature glide between saturated liquid and vapor. It has been modeled as a pseudo-pure fluid based 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 model provided by EES was generated by fitting mixture data from the REFPROP program to a fundamental equation of state with separate correlations for the bubble and dew point pressures. The model is applicable for temperatures between 180 K and 420 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 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