An equation of state for a new working fluid HCFC-123

An equation of state for environmentally acceptable refrigerant, HCFC-123, has been developed, based on the available thermodynamic property data. It is a non-dimensionalized virial equation of state which has 21 coefficients and effective in the entire fluid phase of pressures up to 15 MPa, temperatures from 270 K to 550 K, and densities from 0 to 1600 kg m³, respectively. The equation represents the reliable PVT measurements within ± 0.5 % in pressure for the superheated gaseous and supercritical fluid phase, while within ± 0.5 % in density for the compressed liquid phase. The vapor pressures and other essential thermodynamic properties have been derived from the present modeling. Detailed discussions on the results compared with other measured data are also reported. As a typical example, the isobaric specific heat data(Nakagawa et al., 1991)in the liquid phase have been reproduced within ± 3 % by the present equation of state, while the existing best equation of state has reproduced them with the maximum deviation of 12 %.