The PVTx properties of the refrigerant mixtures of R1234yf and R152a with a mass fraction of R1234yf from 0.600 to 0.900 were measured using the method of Burnett's isothermal expansions. The temperature range was from 288.15 to 328.15 K with a temperature interval of 10 K. The standard uncertainties of the experimental setup were estimated to be 8.1 mK for temperature and 1.73 kPa for pressure. The relative uncertainties were 0.0008 for the compressibility factor and 0.006 for density. According to the obtained experimental data of densities and compressibility factors for the mixtures, gaseous virial equations of state and their second and third virial coefficients were fitted. This would be helpful for the use of R1234yf/R152a mixtures as new environmentally friendly refrigerants.

The gaseous PVTx properties of 1,1,1,3,3-pentafluoropropane (R245fa) + trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) mixtures were measured at temperatures from 300.5 to 335.5 K and corresponding pressures from 144.1 to 598.8 kPa, and the composition of R245fa from 0.60 to 0.85 mass fraction used the Burnett isothermal expansion method. The uncertainties of the experimental device was estimated to be ±8.1 mK for temperature, ± 1.7 kPa for pressure and ±0.003 for mass fraction. The experimental results were corrected using the virial equation of state (EOS) and the second and third virial coefficients of the virial EOS were fitted. Good agreement in the pressures obtained by virial EOS with the experimental pressures was found with relative errors within ±0.8%.

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