New Thermodynamic Equation of State for Refrigerant HFO-1243zf

R-1243zf is a new refrigerant that could replace R-134a. Its thermodynamic properties represented in the equation of state (EOS) play an essential role in analyzing and designing thermal systems. The EOS exists without including caloric property data due to unavailable data during the development time. New EOS was developed explicitly in Helmholtz free energy and optimized to represent the experimental data accurately and maintain thermodynamic consistency. The optimization process undergoes using a genetic algorithm and weighted-least squares regression. The experimental data used in the optimization have a range of 233–430 K and 0.106–34.6 MPa and were validated from the extrapolation and consistency to confirm the reliability. The average absolute deviation from the data is 0.48% for the ideal gas isobaric specific heat, 1.7% for the isochoric specific heat, 0.33% for the speed of sound, 0.22% for the liquid density in single-phase, 0.49% for the vapor density in single-phase, 0.96% for the vapor pressure, 2.2% for the saturated liquid density, and 3.2% for the saturated vapor density. The EOS has a reasonable extrapolation behavior from the triple point up to 700 K and 100 MPa.