5. Conclusion

This article reviews the various models that can be used to represent the phase equilibria of pure compounds under pressure. These models vary in complexity, and require either a thorough knowledge of the physico-chemical aspects between the molecules, or experimental data to adjust the various parameters.

It should be noted that industry very rarely uses pure fluids, but often mixtures. This is the case in the refrigeration industry: in the past, chlorofluorocarbons (CFCs) were used, but energy and environmental considerations led to the use of substitute fluids such as hydrofluorocarbons (HFCs) and nowadays, because of the very high global warming power of HFCs, hydrofluoroolefins (HFOs) or so-called natural working fluids (such as ammonia or carbon dioxide, depending on the intended application). The use of certain HFCs, HFOs and pure natural fluids has shown...