.Buildings.Fluid.HeatExchangers.Heater_T

Information

Model for an ideal heater that controls its outlet temperature to a prescribed outlet temperature.

This model forces the outlet temperature at port_b to be no lower than the temperature of the input signal TSet, subject to optional limits on the capacity. By default, the model has unlimited heating capacity.

The output signal Q_flow is the heat added to the medium if the mass flow rate is from port_a to port_b. If the flow is reversed, then Q_flow=0.

The outlet conditions at port_a are not affected by this model, other than for a possible pressure difference due to flow friction.

If the parameter energyDynamics is different from Modelica.Fluid.Types.Dynamics.SteadyState, the component models the dynamic response using a first order differential equation. The time constant of the component is equal to the parameter tau. This time constant is adjusted based on the mass flow rate using

τeff = τ |ṁ| ⁄ ṁnom

where τeff is the effective time constant for the given mass flow rate and τ is the time constant at the nominal mass flow rate nom. This type of dynamics is equal to the dynamics that a completely mixed control volume would have.

Optionally, this model can have a flow resistance. Set dp_nominal = 0 to disable the flow friction calculation.

For a similar model that is a sensible cooling device, use Buildings.Fluid.HeatExchangers.SensibleCooler_T. For a model that uses a control signal u ∈ [0, 1] and multiplies this with the nominal heating or cooling power, use Buildings.Fluid.HeatExchangers.HeaterCooler_u

Limitations

If the flow is from port_b to port_a, then the enthalpy of the medium is not affected by this model.

Validation

The model has been validated against the analytical solution in the examples Buildings.Fluid.HeatExchangers.Validation.PrescribedOutlet and Buildings.Fluid.HeatExchangers.Validation.PrescribedOutlet_dynamic.

Revisions


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