Measurements of vapor pressure, vapor-liquid coexistence curve and critical parameters of refrigerant 152a.

Abstract

Forty-four vapor pressures of Refrigerant 152a (CH3CHF2: 1, 1-difluoroethane) between 273 K and 386 K have been measured in the range of pressures from 0.26 MPa to 4.48 MPa. Ten saturated liquid densities and eleven saturated vapor densities near the critical point have also been measure in the range of temperatures from 370 K to the critical temperature which corresponds to a density variation of 153 kg·m-3 to 635 kg·m-3. The experimental uncertainties of temperature, pressure and density measurements have been estimated within 10 mK, 0, 8 kPa and 0.55%, respectively. On the basis of these results, the critical temperature, critical pressure and critical density of R 152a have been determined to be 386.44K, 4.5198 MPa and 368 kg·m-3, respectively, in consideration of the meniscus disappearing level as well as the intensity of the critical opalescence. In addition, the correlation of vapor pressure and the vapor liquid coexistence curve have also been proposed.