Experimental Thermal Conductivity Measurements for the Hydrofluoroolefin R1225ye(Z)

Abstract

In the pursuit of a fourth generation of refrigerants characterized by zero Ozone Depletion Potential and remarkably low Global Warming Potential (GWP), as mandated by EU Regulation No 517/2014 and the Kigali Amendment to the Montreal Protocol, natural refrigerants and hydrofluoroolefins (HFOs) have emerged as the most promising long-term alternatives. Notably, the hydrofluoroolefin cis-1,2,3,3,3-pentafluoroprop-1-ene R1225ye(Z) and its isomers have been considered as environmentally friendly options to replace the widely used R410A in refrigeration applications, both in pure form and blends, due to their similar characteristic pressures and temperatures. However, despite its GWP being lower than 3, studies on the toxicological effects of R1225ye(Z) have prevented its applications in industrial contexts, discouraging the study of its thermophysical properties. To date, the available literature offers only a limited amount of experimental data on the thermophysical properties of R1225ye(Z), with none specifically addressing its thermal conductivity. Thus, this study addresses this gap by presenting a comprehensive dataset of 68 experimental thermal conductivity measurements, performed employing a double transient hot-wire apparatus along eleven isotherms spanning temperatures from 243.15 to 343.15 K, encompassing pressures ranging from close to vapor pressure up to 8 MPa. A simplified correlation for estimating the thermal conductivity at saturation state was developed using the extrapolation method. Then, the experimental thermal conductivity data were compared with a generalized model for liquid thermal conductivity in HFOs, demonstrating good agreement with calculated values (AAD 2.3%), in line with the declared model accuracy.