抄録
A set of reliable PVTx property data for the binary 1,1,1,2-tetrafluoroethane (R 134a) + isobutane (R 600a) mixtures in two-phase and gas-phase regions are presented. The mixture is expected to be an alternative candidate of high temperature heat-pump working fluids. The experimental PVTx properties of the binary R 134a + R 600a system have been measured at three different compositions by a constant-volume method coupled with expansion procedures. The apparatus was newly developed in the present study. Temperature is measured by a standard PRT placed inside the aluminum block. Pressure is directly measured by a diaphragm-type pressure gauge. the measurement range of temperature is from 340 K t0 400 K, pressure up to 3.5 MPa and density up to 110 kg・m-3, respectively. The experimental uncertainties of the present measurements are estimated to be within±0.06 K in temperature, ±5.4 kPa in pressure and 0.34 % in density, respectively. PVTx properties for dew-points were also obtained from the intersections of the isochores for the two-phase and the single-phase measurements. Measured results were compared with mixture models by Lemmon and Jacobsen[1] employed in REFPROP 9.0, together with thermodynamic models for pure R 32[2] and R 600a[3].
