Model for a steam humidifier with a prescribed outlet water vapor mass fraction in kg/kg total air.
This model forces the outlet water mass fraction at
port_b to be no lower than the input signal
X_wSet, subject to optional limits on the maximum
water vapor mass flow rate that is added, as described by the
parameter mWatMax_flow. By default, the model has
unlimited capacity.
The output signal mWat_flow ≥ 0 is the moisture
added to the medium if the flow rate is from port_a to
port_b. If the flow is reversed, then mWat_flow
= 0. The outlet specific enthalpy at port_b is
increased by the enthalpy of steam at 100°C times the mass
of steam that was added. Therefore, the temperature of the leaving
fluid is slightly above the inlet temperature.
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 model that uses a control signal u ∈ [0, 1] and multiplies this with the nominal water mass flow rate, use Buildings.Fluid.Humidifiers.Humidifier_u
This model only adds water vapor for the flow from
port_a to port_b. The water vapor of the
reverse flow is not affected by this model.