Thermodynamic study on working fluids for advanced air-conditioning systems

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The objective of this study is to find the new refrigerants wich can replace R-22, a present working fluid for air-conditioning systems, and to reveal the thermodynamic properties of the new refrigerants. The followings are the results fo this study through 1991 to 1995, which have been reported in 26 papers of academic journals.1. Regarding R-32, the PVT-properties, vapor pressures, densities of saturated liquid, specific heats, and the speed of sound were measured.2. Regarding R-125, the PVT-properties, vapor pressures, densities of saturated liquid, specific heats, and the speed of sound were measured.3. Regarding R-134a, the critical parameters were redetermined on the basis of the measurements with high purity sample fluids and the speed of sound in gaseous R-134a was also measured.4. Regarding R-143a, vapor pressures, densities of saturated liquid and the PVT properties in the gaseous phase were measured.5. Regarding refrigerant mixtures, the PVT properties of gaseous R-32/125, R-32/134a were measured in the extensive range and the bubble-point ressures and the densities at bubble point were measured for R-32/125, R-32/134a, R-125/143a, and R-32/125/134a.6. Based on the above measurements, the azeotropic compositions of R-32/125 and 125/143a were determined, ideal-gas-specific-heat values were derived from speed-of-sound measurements, and the compositions of mixtures were determined using the ideal-gas-specific-heat values.7. The thermodynamic equations of state are being developed and the thermodynamic characteristics of new refrigerants are being studied wich will be presented at the academic meeting to be held in April 1996.