Scaling theories for predicting the viscosity of binary and ternary refrigerant mixtures

Modeling the viscosity of potential replacements for refrigerants like hydrofluorocarbons (HFCs) and hydrofluoroolefins (HFOs) is important because this information can be used to determine which refrigerants are suitable for use in different refrigeration systems and to guide decisions about system design, operation, and maintenance. In this work, the viscosities of four selected refrigerants, two HFCs and two HFOs, and their mixtures were calculated using two similar approaches, namely entropy scaling and Helmholtz scaling. In both cases, the polar perturbed-chain statistical associating fluid theory (PPC-SAFT) EoS provides the molecular parameters and the entropy or Helmholtz energy dependency required. Results indicate good predictive capabilities for both models, with comparable error to the available experimental data. Even so, the Helmholtz scaling exhibits superior overall robustness, given its extra adjustable parameter. However, predictive results tend to be the same or less quality than those given by the entropy scaling approach.