# Information

The model ExpansionTank describes the storage of fluid in liquid phase in a closed volume filled with gas.

Pressure and enthalpy are selected as state variables.

The assumptions for this model are:

- The gas is considered ideal and using Boyle’s law: p_gas*V_gas = Const = pstart*V_gas
- The gas is considered at the same temperature of the fluid
- The model is based on dynamic mass and energy balances of the fluid
- The static pressure head due to the liquid level is taken into account
- Thermal energy transfer due to external air convection through the tank surface (lateral+top+bottom) is ensured by the TankWall connector. The actual heat flow is computed by the thermal energy model
- Minimum liquid level with respect to tank height= 0
- Maximum liquid level with respect to tank height= 0.5

The model is characterized by one flow connector.

The thermal energy transfer through the Tank surface is computed by the ConvectiveHeatTransfer model which is inerithed in the ExpansionTank model

# Modelling options

In the General tab the following options are availabe:

- Medium: the user has the possibility to easly switch Medium.
- HeatTransfer: selection between the different heat transfer models available in ThermoCycle