Development of Helmholtz Equation of State for Thermodynamic Properties of R-1233zd(E)

Abstract

The application of refrigerants from the Hydro Chloro Fluoro Olefins (HCFO) group, namely R-1233zd(E), in addition to the Hydro Fluoro Olefins (HFO), is a solution to environmental problems. A thermodynamic equation of state for R-1233zd(E), which can predict all thermodynamic properties over a wide-range fluid phase, is proposed in a function of the Helmholtz free energy. Three ancillary equations support the development and application. A genetic algorithm method combined with a weighted least squares regression was applied. The Helmholtz equation of state has an average absolute deviation of 0.12% for the liquid density, 2.0% for the vapor density, 1.4% for the vapor pressure, 0.16% for the saturated liquid density, 4.1% for the saturated vapor density, 3.6% for the isobaric specific heat, and 0.15% for the speed of sound in the liquid phase, and 0.18% for the speed of sound in the vapor phase. The deviation of the isochoric and saturated specific heats was not evaluated yet due to unavailable experimental data. The reasonable behavior of its extrapolation and ideal characteristic curves confirm its reliability. The Helmholtz equation of state can predict thermodynamic properties from the triple point to 1000 K and 100 MPa.