Equations of State for the Ozone-Safe Refrigerants R32 and R125

Equations of state for gaseous and liquid difluoromethane (R32) and penta- fluoroethane (R125) were developed. The coefficients of the equations were determined using experimental density data and heat capacities cv and cs . The equations satisfy Maxwellʹs rule. The equations describe the thermodynamic properties of R32 and R125 at temperatures from 140 to 433 K and from 178 to 480 K, respectively, and at pressures up to 70 MPa within the experimental uncertainties. In particular, the root-mean-square deviations of the calculated values of density from the most reliable experimental data are equal to 0.100 for R32 and 0.120 for R125.