# HeatCapacitor

Lumped thermal element storing heat

# Information

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

This is a generic model for the heat capacity of a material. No specific geometry is assumed beyond a total volume with uniform temperature for the entire volume. Furthermore, it is assumed that the heat capacity is constant (independent of temperature).

The temperature T [Kelvin] of this component is a state. A default of T = 25 degree Celsius (= SIunits.Conversions.from_degC(25)) is used as start value for initialization. This usually means that at start of integration the temperature of this component is 25 degrees Celsius. You may, of course, define a different temperature as start value for initialization. Alternatively, it is possible to set parameter steadyStateStart to true. In this case the additional equation 'der(T) = 0' is used during initialization, i.e., the temperature T is computed in such a way that the component starts in steady state. This is useful in cases, where one would like to start simulation in a suitable operating point without being forced to integrate for a long time to arrive at this point.

Note, that parameter steadyStateStart is not available in the parameter menu of the simulation window, because its value is utilized during translation to generate quite different equations depending on its setting. Therefore, the value of this parameter can only be changed before translating the model.

This component may be used for complicated geometries where the heat capacity C is determined my measurements. If the component consists mainly of one type of material, the mass m of the component may be measured or calculated and multiplied with the specific heat capacity cp of the component material to compute C:

```   C = cp*m.
Typical values for cp at 20 degC in J/(kg.K):
aluminium   896
concrete    840
copper      383
iron        452
silver      235
steel       420 ... 500 (V2A)
wood       2500
```

# Parameters (1)

C Value: Type: HeatCapacity (J/K) Description: Heat capacity of element (= cp*m)

# Connectors (1)

port Type: HeatPort_a

# Used in Examples (19)

 HeatingMOSInverter Modelica.Electrical.Analog.Examples Heating MOS Inverter HeatingNPN_OrGate Modelica.Electrical.Analog.Examples Heating NPN Or Gate HeatingPNP_NORGate Modelica.Electrical.Analog.Examples Heating PNP NOR Gate HeatingRectifier Modelica.Electrical.Analog.Examples Heating rectifier DCPM_Cooling Modelica.Electrical.Machines.Examples.DCMachines Test example: Cooling of a DCPM motor EddyCurrentBrake Modelica.Mechanics.Rotational.Examples Demonstrate the usage of the rotational eddy current brake EddyCurrentBrake Modelica.Mechanics.Translational.Examples Demonstrate the usage of the translational eddy current brake SimpleCooling Modelica.Thermal.FluidHeatFlow.Examples Simple cooling circuit ParallelCooling Modelica.Thermal.FluidHeatFlow.Examples Cooling circuit with parallel branches IndirectCooling Modelica.Thermal.FluidHeatFlow.Examples Indirect cooling circuit PumpAndValve Modelica.Thermal.FluidHeatFlow.Examples Cooling circuit with pump and valve PumpDropOut Modelica.Thermal.FluidHeatFlow.Examples Cooling circuit with drop out of pump ParallelPumpDropOut Modelica.Thermal.FluidHeatFlow.Examples Cooling circuit with parallel branches and drop out of pump OneMass Modelica.Thermal.FluidHeatFlow.Examples Cooling of one hot mass TwoMass Modelica.Thermal.FluidHeatFlow.Examples Cooling of two hot masses TwoMasses Modelica.Thermal.HeatTransfer.Examples Simple conduction demo ControlledTemperature Modelica.Thermal.HeatTransfer.Examples Control temperature of a resistor Motor Modelica.Thermal.HeatTransfer.Examples Second order thermal model of a motor GenerationOfFMUs Modelica.Thermal.HeatTransfer.Examples Example to demonstrate variants to generate FMUs (Functional Mock-up Units)

# Used in Components (2)

 DirectCapacity Modelica.Thermal.HeatTransfer.Examples.Utilities Input/output block of a direct heatCapacity model InverseCapacity Modelica.Thermal.HeatTransfer.Examples.Utilities Input/output block of an inverse heatCapacity model