**Package with models for gases where pressure and temperature are independent of each other**

### Information

Medium models in this package use a constant mass density.

The use of a constant density avoids having pressure as a state variable in mixing volumes. Hence, fast transients
introduced by a change in pressure are avoided.
The drawback is that the dimensionality of the coupled
nonlinear equation system is typically larger for flow
networks.

Note that models in this package implement the equation for the internal energy as

u = h - p ⁄ ρ_{stp},

where
*u* is the internal energy per unit mass,
*h* is the enthalpy per unit mass,
*p* is the static pressure and
*ρ*_{stp} is the mass density at standard pressure and temperature.
The reason for this implementation is that in general,
h = u + p v,

from which follows that
u = h - p v = h - p ⁄ ρ = h - p ⁄ ρ_{std},

because *ρ = ρ*_{std} in this medium model.
Extends from Modelica.Icons.MaterialPropertiesPackage (Icon for package containing property classes).

### Package Content

Name | Description |

MoistAir
| Package with moist air model with constant density |

MoistAirUnsaturated
| Package with moist air model that decouples pressure and temperature and that has no liquid water |

SimpleAir
| Package with dry air model that decouples pressure and temperature |

Examples
| Collection of models that illustrate model use and test models |

Automatically generated Thu Dec 8 16:35:30 2011.