A modified Carnahan-Starling-de Santis equation of state to compute thermodynamic properties of refrigerants

The knowledge of accurate thermodynamic properties of refrigerants is of great importance in modern design and simulation of heat pumps, refrigeration systems, etc. The objective of this work is to present a new equation of state with highly accurate pvT results without the need to use additional empirical equations. The new equation arose by a modification of the two-parametric Carnahan-Starling-de Santis equation of state. The reason for elaboration of a new modification was the lack of accuracy of the majority of up to now known equations of state in the liquid phase, because of which additional empirical equations were used for the liquid volume. The new equation was tested on 30 fluids for which experimental thermodynamic data were available. The obtained relative standard deviation of pvT results from ASHRAE experimental data was within the limits of 0.05-0.6%. This work deals with application of the new equation of state in the vapor-liquid equilibrium computations of pure substances. (C) 1997 Elsevier Science Ltd and IIR.