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 modelled 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 10 MPa.


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