Thermal resistor

Linear thermal resistance: ΔT = R·Q.

  • thermal
  • Modelica Standard Library
  • 2 ports
  • 1 parameter
BlockThermal resistorKindthermalResistorLibraryThermal

Description

Linear thermal resistance between two ports with no heat storage: the temperature difference is proportional to the heat flow. Equivalent to Thermal conductor with G = 1 / R.

Example

Cooling a hot part A 10 W part cools through a thermal resistance into a heatsink that convects and radiates to 20 °C.

10 WPart 100 J/KHeat flowR 2 K/WHeatsink 500 J/Kh·A 5 W/KConvectionAir 20 °CRadiationRoom 20 °CPart temperatureAcross R350 KHeld at 350 KG 1 W/KBody 100 J/K20 W at 1500 sHeaterBody temperature
In Gradara, select a Thermal resistor block and press F1, then choose Open example. It opens as a new model in My models, ready to run.

Also in this example:ConstantStepHeat capacitorThermal conductorConvectionRadiationFixed temperatureTemperature sourceFixed heat flowHeat flow sourceTemperature sensorHeat flow sensorTemperature difference sensor

Ports

Conserving terminals 2

  • aport_athermal

    Heat port a. Heat flow Q from a to b enters here.

  • bport_bthermal

    Heat port b. Q leaves here.

Parameters

  • ResistanceR1 K/W

    ≥ 0

    Thermal resistance, in K/W. Use a positive value.

Equations

Modelica
ΔT = port_a.T − port_b.T
ΔT = R · Q
port_a.Q_flow = Q, port_b.Q_flow = −Q

Implementation

Modelica Standard Library 4.1.0Modelica.Thermal.HeatTransfer.Components.ThermalResistor
MSL documentation

Assumptions and limitations

  • Constant resistance, independent of temperature. No heat storage.

Tips

  • Datasheet junction-to-case and case-to-ambient values in K/W can be entered directly and chained in series.

See also

Select a block in Gradara and press F1 to open its page offline.