A fundamental equation for chlorodifluoromethane (R-22)

• Published in: Fluid phase equilibria 1992-11, Vol.80 (pt 4), p.71-85
• Main Authors: Kamei, A., Beyerlein, S.W., Lemmon, E.W.
• Format: Article
• Language: English
• Subjects: Chemical thermodynamics; Chemistry; Chlorodifluoromethane; Elements, mineral and organic compounds; equation of state; Equations of state; Exact sciences and technology; Freons; General and physical chemistry; Mathematical models; Ozone layer; R-22; Thermodynamic properties
• ISSN: 0378-3812; 1879-0224
• DOI: 10.1016/0378-3812(92)87056-S

A new thermodynamic property formulation which is explicit in 4 dimensionless Helmholtz energy has been developed for Chlorodifluoromethane (R-22). This equation of state is applicable for temperatures from 200 to 550 K, and at pressures up to 60 MPa. Temperatures are given on the new International Temperature Scale of 1990 (ITS-90). New pressure-density-temperature data and velocity of sound data in the liquid region have been incorporated to improve the accuracy of properties predicted by this formulation over that of prior correlations for R-22. Newly correlated ancillary functions representing the vapor pressure, saturated liquid density, saturated vapor density, and ideal gas heat capacity were used to insure proper behavior of the equation of state at phase equilibrium. The accuracy of the new formulation is estimated to be ±0.2% in density, ±1.0% in heat capacities, and ±0.5% in velocity of sound. These estimates are based on comparison of calculated properties to experimental measurements.