4. Conclusion

There are several models and approaches for determining the thermodynamic properties of fluid mixtures. These models need to take account of the non-ideality of mixtures and perform well over a wide temperature and pressure range. These models can be more or less empirical and more or less predictive (ab-initio calculation, group contributions). All the models mentioned in this article can be used to calculate the thermodynamic properties of pure substances and mixtures. In most cases, the parameters are adjusted on the basis of experimental data. As a result, for heat pump or refrigeration applications, it is possible to select the best working fluid and perfectly size the system.