**Nomenclature**


#### *Energies* **2018**, *11*, 1915


#### **Appendix A. Compressor Coefficients**

The coefficients used for modelling each compressor are detailed in this appendix. They have been obtained from the real operating curves of the compressors provided by the manufacturers, both in transcritical and subcritical operation.

Using these coefficients with Equations (5)–(7), we can obtain the global and volumetric efficiency of each compressor used in this work for the entire operating range.


