MEASUREMENT OF VAPOR PRESSURE, VAPOR-LIQUID COEXISTENCE CURVE AND CRITICAL PARAMETERS OF REFRIGERANT 152a.

Forty-four vapor pressures of Refrigerant 152a (CH//3CHF//2: 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 measured in the range of temperatures from 370 K to the critical temperature which corresponds to a density variation of 153 kg multiplied by (times) m** minus **3 to 635 kg multiplied by (times) m** minus **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. 44 K, 4. 519 8 MPa and 368 kg multiplied by (times) m** minus 3, respectively, in consideration of the meniscus disappearing level as well as the intensity of the critical opalescence.