Contents - Index



R513A (also known as Opteon XP10) is an azeotropic mixture consisting of 56 weight% R1234yf and 44% R134a.  It has a molar mass of 108.4 kg/kmol.  Although it is a mixture, R513A exhibits no temperature glide between saturated liquid and vapor and therefore can be modeled as a pseudo pure fluid 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 for a pure fluid.  The model is applicable for temperatures between 240 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 were fitted to data provided by the manufacturer, available at


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



Fluid Property Information