Pseudo-Pure Fluid Equation of State
Pseudo-pure fluid equation of state is the term used when the thermodynamic properties of a mixture of fixed composition are represented by a generalized Helmholtz free energy equation of state for a pure fluid, as detailed by Lemmon.
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
Pseudo-pure equations of state are used in EES to provide property data for most of the R4xx and R5xx refrigerant mixtures. In most cases, the property estimates resulting from the pseudo-pure fluid equation of state provide acceptable accuracy. The uncertainty of the results increases in the vicinity of the the critical point, particularly for the specific heat. EES will issue a warning if the specific heat calculation is not considered to be reliable.