Experimental Compressed Liquid Density Measurements and Correlation of the Binary Mixture {n-Pentane (R601) + Trans-1-chloro-3,3,3-trifluoro-1-propene (R1233zd(E))}

Abstract Regulations like the F-gas Regulation (EU) 2024/573 and the Kigali Amendment to the Montreal Protocol, along with efforts to mitigate climate change, drive research into alternatives to fluorinated greenhouse gases for high-temperature heat pumps and power generation. Ideal refrigerants should have low GWP, high efficiency, non-flammability, non-toxicity, material compatibility and cost effectiveness. HCFOs have emerged as promising candidates, both as pure fluids and in mixtures with HCs. These blends show efficiency and potential non-flammability for high-temperature applications, but experimental data on their thermophysical properties remain scarce. This study presents the first experimental measurements on the {n-pentane (R601) + trans-1-chloro-3,3,3-trifluoro-1-propene (R1233zd(E))} binary system. In particular, the compressed liquid density of three mixture compositions have been measured employing a vibrating tube densimeter within the temperature range from 283.15 K to 423.15 K and at pressures ranging from 1 MPa to 12 MPa. A novel technique was applied to ensure a combined uncertainty ( k =2) not greater than 0.0003 mol $$\cdot$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>·</mml:mo> </mml:math> mol $$^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:mmultiscripts> </mml:math> in the mixture composition, leading to final combined uncertainty ( k =2) on the liquid density of no more than 0.2%. Finally, a new mixture model based on the Helmholtz-energy-explicit Equation of State has been developed from such experimental data. This model accurately represents the behaviour of the binary mixture, enhancing the available understanding of its thermodynamic properties.