Comparative analysis and optimization of theoretical models for predicting refrigerant vaporization enthalpies.

Accurate calculation of the vaporization enthalpy is essential in engineering fields that involve phase transitions, energy transfer, and thermodynamic processes. Due to the complexity of experimental measurements and the high cost of data acquisition, combining theoretical prediction models with experimental data is a mainstream method to predict vaporization enthalpy. However, the different theoretical methods have various systematic deviations, which can be amplified for assessing systems’ cycle efficiency, so researching the deviation in the different prediction methods for refrigerants is vital. In this paper, the five theoretical prediction methods are compared: (1) The Clausius-Clapeyron equation, (2) The thermodynamic relationship equation of enthalpy, (3) The Helmholtz equation, (4) The corresponding state principle equation, (5) The PCP-SAFT equation. Sixteen refrigerants are selected as working mediums. The reasons for the systematic deviations of the theoretical prediction models are deeply analyzed, and the parameters of equations are modified to improve the vaporization enthalpy prediction accuracy. Utilizing the optimization method proposed in this paper, the average absolute
relative deviation (AARD) of hydrocarbons decreased from 1.35 % to 0.43 % in the best case. This study provides a universal and flexible method for the prediction of vaporization enthalpy, achieving an accurate prediction with the total average AARD of 0.981 %.