Rapid Measurements of Thermodynamic Properties for Alternative Refrigerants with Vibrating-Tube Densimeter

More than 2000 PVT data in the liquid phase, vapor phase, and at saturation boundaries have been obtained for pure compounds of several alternative refrigerants. In addition, more than 1000 liquid-density data have been obtained for several binary and ternary mixtures. The alternative refrigerants measured in the present study include CF3OCH3 (trifluoromethyl methyl ether) and CF3CF2OCH3 (pentafluoroethyl methyl ether), which are hydrofluoroethers developed by RITE (the Research Institute of Innovative Technology for the Earth, Japan), and typical hydrocarbons, such as propane, n-butane, isobutene, and their binary and ternary mixtures. The measurement uncertainties are estimated to be 3 to 7mK for temperature, 0.26 kPa or 0.022% whichever is greater for pressure, and 0.07 kg ·m−3 or 0.024% whichever is greater for density. The present measurement system took only a few minutes to get one PVT datum, and one or two days to complete all the measurements for a single fluid at temperatures from 240 to 380K and at pressures up to 7MPa. In addition, an empirical equation of state (EoS) for the liquid phase was developed on the basis of the present data, and the EoS nicely reproduces not only the present data but also existing data reported by other researchers.