This information is part of the Modelica Standard Library maintained by the Modelica Association.

Planned changes for version 3.1

Several changes are planned for version 3.1 of Modelica.Media. In order to have an easy transition, the current version is moved to the ObsoleteModelica-package and current users can continue to use it for many years. The goal for the new version is to cover many more fluids, be easier to use for users and less for implementers that want to include their own models. A beta-version of the new media library will be available in the first quarter of 2009.

The main user-visible changes are:

• No distinction between pure fluids and mixtures on the interface level: pure fluids are mixtures with 1 component
• Compressibility will in the future be a flag that can be set for those media where it makes sense. It will thus be possible to treat an ideal gas as incompressible, which is adequate for certain applications, and also use the same medium model for thermal-only applications, and thermal-hydraulic ones.
• All functions will have derivatives to enable analytic Jacobians.
• Mole-fraction based media for process applications

For further information on the upcoming version, please contact the Author

Forward compatibility

In order to simplify transition to the upcoming version of Modelica.Media for Modelica 3.1, a new enumeration has been introduced: IndependentVariables with the entries ph, pT, pTX, phX and dTX. Users are advised to use this enumeration to determine the independent variables of a medium. If they are going to use the function based interface of the current Modelica.Media (and not use the BaseProperties from Modelica.Media), they should not have any trouble using the next version without any need for changes in their code.