Coexistence curve of HFC-134a and thermal conductivity of HFC-245fa

Abstract

The present paper deals with the experimental results for the refractive index of the saturated vapor and liquid of HFC-134a and the thermal conductivity of HFC-245fa in the liquid phase.The coexistence curve of the refractive index of HFC-134a up to the critical temperature has been measured. The density coexistence curve of HFC-134a in the critical region is calculated from the refractive index data by using the Lorentz–Lorenz equation. Assuming as the critical density ρC=511.0kgm−3, the critical temperature TC=374.107±0.020K and the critical index β=0.348±0.001 are obtained. The calculated density coexistence curve proved to be reasonable from the agreement with the directly measured values of density and the equation of state recently reported.The thermal conductivity of HFC-245fa in the liquid phase has been measured by using a transient hot-wire method. The nominal diameter of the long and short wires is 20μm and the effective length of them is around 60mm. Measurements are carried out in the range from 253 to 315K and up to 15MPa. The results for the thermal conductivity are correlated by the equation of temperature and pressure. The present results of HFC-245fa are compared with the predicted values of HFC-245fa as well as the experimental values of some propane series refrigerants.