Thermal properties and heat transfer characteristics of ternary alternative refrigerant mixtures for HCFC22.

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The purpose of this study is to clarify the thermal properties and heat transfer characteristics of ternary mixture of HFC 32/125/134a, which is assumed a promising alternative refrigerant for HCFC22.1. In order to determine the binary interaction parameters in the Peng-Robinson equation of states, vapor pressure of the mixtures and composition in vapor were measured using a strain gauge type of pressure transducer and a gas chromatography, respectively. The temperature ranged from-10 to 50 degrees. Accuracy of the pressure measurement was checked by comparing measured and published saturation pressures of HFC134a, and was within 0.25%. Based on the obtained data, the binary interaction parameters in the Peng-Robinson equation of states were determined, and a program code for the ternary mixtures was developed.2. Evaporation and condensation heat transfer coefficients of various kinds of refrigerant including HFC32, HFC125, HFC134a, HFC32/134a and HFC32/125/134a, were measured inside a horizontal smooth tube. Effects of heat flux, mass flux, quality and temperature glide of the mixture on the heat transfer characteristics were examined. Evaporating and condensing temperature were 20 and 40 degrees, respectively. The heat transfer coefficients of mixtures were about, 30% lower than the single component fluids with similar thermopysical properties to the mixtures. A predictive model of evaporation heat transfer for HFC32/125/134a was presented. It was concluded that the principal mechanism of heat transfer degradation of the ternary mixtures was the same with the binary mixtures.