Thermodynamlcs properties of HCFC133a were studied by using experimental method by means of opalescence intensity method, critical temperature and critical density of HCFC133a were measured. By means of constant volume method, saturated density of liquid and vapour,saturated vapour pressure were measured. Furthermore, critical pressure and critical index were determined according to experimental data, and vapour pressure equation with high accuracy was presented.
Based on thermodynamic and statistical physical analysis, a new mixing equation of state (EOS) for calculating properties of mixed substitutes only with critical parameters of pure substitutes and without experimental data of the mixture was established in this paper. The new method use EOS of pure substitutes to calculate thermal properties of mixed working substitutes. It has a higher degree of accuracy than Peng-Robinson EOS with reckoned interactive coefficient Kij given only critical thermodynamic properties of the working substances.