AixLib.Fluid.HeatExchangers.Heater_T

# .AixLib.Fluid.HeatExchangers.Heater_T

Heater with prescribed outlet temperature

## 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 ṁ and τ is the time constant at the nominal mass flow rate ṁnom. 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 AixLib.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 AixLib.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 AixLib.Fluid.HeatExchangers.Validation.PrescribedOutlet and AixLib.Fluid.HeatExchangers.Validation.PrescribedOutlet_dynamic.

## Revisions

- September 10, 2018, by Michael Wetter:
  Corrected missing propagation of initial conditions.
  This is for AixLib, #1016.
- May 3, 2017, by Michael Wetter:
  First implementation.
  This is for AixLib, #763.

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