THE THERMAL-CONDUCTIVITY OF R22, R142B, R152A, AND THEIR MIXTURES IN THE LIQUID-STATE

An experimental apparatus for measuring the thermal conductivity of liquids by the transient hot-wire method was constructed and tested with toluene as a standard liquid. Measurements were performed on R22, R142b, and R152a. The thermal conductivities of mixtures of R142b and R152a with R22 were also measured by varying the weight fraction of R22. Experiments were performed in the range from - 50 to 50-degrees-C and from 2 to 20 MPa and the measured data are analyzed to obtain a correlation in terms of temperature, pressure, and composition of the mixture. While the thermal conductivity of R22+R152a mixtures varies monotonously with composition, that of R22+R142b mixtures turned out to go through an extremum value. The accuracy of our measurements is estimated to be within 2%.