Measurements and modeling of the vapor-liquid equilibrium properties of low-global-warming-potential refrigerant R32/R1234yf/R1123 ternary mixtures

There is an urgent need to replace existing refrigerants that have significant greenhouse effects with next-generation, low-global-warming-potential refrigerants. Various multi-component refrigerant mixtures are potential candidates to reduce the flammability and/or toxicity and improve the compatibility with lubricating oils while preserving the refrigerant performance. In this study, for R1123/R1234yf/R32 ternary mixtures, we performed two types of accurate measurements of the vapor-liquid equilibrium properties and attempted to verify the reliability of two types of thermodynamic property models. Measurements were conducted at temperatures from 303.15 to 328.15 K and at saturation pressures of up to 3.7 MPa. The expanded uncertainties (k = 2) of the temperature, pressure, and composition measurements were estimated to be less than 0.03 K, 1.4 kPa, and 0.43 mol%, respectively. Two of the models used were the well-known and well-established Helmholtz free energy equations of state. We used these equations of state to predict the vapor-liquid equilibrium data of the ternary mixtures. The predicted values and measured results of the ternary mixtures were systematically compared, and the most reliable numerical values of the vapor-liquid equilibrium properties for these ternary mixtures and the necessity for improvement of the recent models were clarified. (C) 2022 Elsevier B.V. All rights reserved.