Saturated liquid densities and bubble-point pressures of binary HFC 152a + HFC 134 system

Forty-eight sets of saturated liquid densities and bubble-point pressures of the binary HFC 152a + HFC 134 system were measured by a magnetic densimeter coupled with a variable volume cell. The results of four different compositions of 20, 40, 60, and 80 wt% HFC 152a cover a temperature range from 280 to 380 K. The experimental uncertainties in temperature, pressure, density, and composition measurements were estimated to be not greater than ±15 mK, ±20 kPa, ±0.3 %, and between -0.11 and +0.01 wt%, respectively. The modified Rackett equation proposed by Spencer and Dannar and the Hankinson-Brost-Thomson equation were discussed on the basis of the present measurements. Vapor-liquid equilibrium calculations based on the Peng-Robinson equation of state were also compared with the present measurements. In this paper it should be noted that such an analysis suggests the possible existence of a new azeotrope among the present binary refrigerant mixtures