Investigation of pρTx properties for R1234ze(E) + R134a mixtures in the gas phase

- Gaseous pρTx data for R1234ze(E) + R134a were measured.
- Measurements were performed by a compact single-sinker densimeter.
- Experimental results were correlated with the PR and truncated virial equations of state.

In this work, 101 gaseous pressure-density-temperature-mole fraction (pρTx) measurements for trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) + 1,1,1,2-tetrafluoroethane (R134a) binary mixtures were measured along with seven isotherms from 270.351 to 300.276 K by using a compact single-sinker densimeter. The mixtures consisted of four mole fractions of R1234ze(E) from 0.4338 to 0.6356, corresponding to mass fractions of R1234ze(E) from 0.4613 to 0.6610. The experimental standard uncertainties in temperature, pressure, mole fraction, and density were estimated to be less than 5 mK, 200 Pa, 0.0003, and 0.05%, respectively. The Peng-Robinson (PR) equation of state with vdW one-fluid mixing rules and a truncated virial equation of state were employed to correlate the experimental data. The correlated results from different models are consistent with each other, and the virial model gives the best description of the experimental pρTx data with average absolute relative pressure and density deviations of 0.088% and 0.093%, respectively.