The GERG-2008 equation of state is implemented in Refprop and available via the options. Although the default equations of state in Refprop are slightly superior to the GERG-2008 model, some applications require the use of the standard natural gas equation provided by GERG-2008. These standards are given in AGA8 (American Gas Association Report #8) and ISO-20765. With the GERG equation, industrial applications will always return identical values. The default equations in Refprop are updated as we develop new and better fits, both for the pure fluids and for mixtures, and thus one has to be careful to specify which equation of state or mixture model was used when reporting calculated values.
Additional information is available in the other issues on this github website, and further information will be added to this issue as questions arise.
The GERG-2008 mixture model can be obtained from:
Kunz, O. and Wagner, W.
The GERG-2008 Wide-Range Equation of State for Natural Gases and Other Mixtures: An Expansion of GERG-2004.
J. Chem. Eng. Data, 57(11):3032-3091, 2012.
The GERG-2008 equation of state is implemented in Refprop and available via the options. Although the default equations of state in Refprop are slightly superior to the GERG-2008 model, some applications require the use of the standard natural gas equation provided by GERG-2008. These standards are given in AGA8 (American Gas Association Report #8) and ISO-20765. With the GERG equation, industrial applications will always return identical values. The default equations in Refprop are updated as we develop new and better fits, both for the pure fluids and for mixtures, and thus one has to be careful to specify which equation of state or mixture model was used when reporting calculated values.
Additional information is available in the other issues on this github website, and further information will be added to this issue as questions arise.
The GERG-2008 mixture model can be obtained from: Kunz, O. and Wagner, W. The GERG-2008 Wide-Range Equation of State for Natural Gases and Other Mixtures: An Expansion of GERG-2004. J. Chem. Eng. Data, 57(11):3032-3091, 2012.
The TM-15 document can be downloaded here without charge: https://www.gerg.eu/wp-content/uploads/2019/10/TM15.pdf
Please open a new issue if you have questions.