THERMAL-CONDUCTIVITY OF HALOGENATED ETHANES, HFC-134A, HCFC-123, AND HCFC-141B

The gaseous thermal conductivity of three CFC alternatives, HFC-134a (1,1,1,2-tetrafluoroethane), HCFC-123 (1,1-dichloro-2,2,2-trifluoroethane), and HCFC-141b (1,1-dichloro-1-fluoroethane), has been measured in the temperature ranges 273-363 K (HFC-134a) and 313-373 K (HCFC-123, HCFC-141b) at pressures up to saturation. The measurements were performed with a new improved transient hot-wire apparatus. The uncertainty of the experimental data is estimated to be within 1 %. The gaseous thermal conductivity obtained in this work together with the liquid thermal-conductivity data from the literature were correlated with temperature and density by an empirical equation based on the excess thermal-conductivity concept. The equation is found to represent the experimental results with average deviations of 2.5 % for HFC-134a, 0.75 % for HCFC-123, and 0.55 % for HCFC-141b, respectively.