Measurements of liquid densities of the binary HFC-32 + HFC-134a system

Thirty measurements of saturated-liquid density and bubble-point pressure, and twenty-two Pρ{variant}Tx data in the liquid phase of binary HFC-32 + HFC-134a systems have been obtained over a temperature range of 280-340 K. using a magnetic densimeter coupled with metallic bellows. The measurements were performed at compositions of 20, 25, 40, 60 and 80 wt% HFC-32, and pressures up to 3 MPa. The experimental uncertainties of the temperature pressure and density measurements were estimated to be not greater than ±15mk, ±15kPa and ±0.2%, respectively. The uncertainty of composition determination was estimated to be within ±0.30 wt% HFC-32. The purity of the sample was 99.998% for HFC-32 and better than 99.8% for HFC-134a. Comparisons of the measurements with properties calculated from the modified Hankinson-Brobst-Thomson equation proposed by Maezawa et al., and the Peng-Robinson equation of state are also discussed.