An Equation of State for a New Working Fluid HFC-134a

On the basis of the PVT, specific heat, and saturated-liquid-density data measured by our group, and other available experimental data, an equation of state for HFC-134a (1,1,1,2-tetrafluoroethane, CH₂FCF₃ was developed. It is a nondimensionalized virial equation of state which has 25 terms and is effective in the range of pressures up to 15 MPa, temperatures from 240 to 480 K, and densities from 0 to 1400 kg/m³. The equation represents reliable PVT measurements within ± 0.5% in pressure in the superheated gaseous and supercritical fluid phases, while within ± 0.5% in density in the compressed liquid phase. The reliability of the derived properties from the equation of state including specific heats, speed of sound, and so on, was confirmed by comparison with reliable experimental data. Speed-of-sound data in the gaseous phase reported by Goodwin and Moldover are reproduced within ±0.1%, and most of the isobaric specific heat data by Saitoh et al. are reproduced within ± 1% by this equation of state.