4. Conclusion

Although software packages for calculating fluid properties are becoming increasingly widespread, thermodynamic diagrams continue to play an essential role.

By highlighting the transformations undergone by these fluids and making it possible to calculate them, at least approximately, diagrams are indeed among the basic tools of the thermodynamicist.

Different coordinate systems are used depending on the case, the most commonly used for pure bodies being the entropy diagram (T, s), the so-called refrigeration diagram (h, ln P) and the Mollier diagram (h, s).

The technological changes taking place in refrigeration and heat-to-mechanical-energy conversion are leading to the development of more environmentally-friendly thermodynamic fluids and a continuing need for thermodynamic diagrams.

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