modelSprayHumidifier
Extends from AixLib.Airflow.AirHandlingUnit.ModularAirHandlingUnit.Components.BaseClasses.PartialHumidifier (partial model of a humidifier).
Information
This model provides a idealized spray humidifier. The output air humidity is calculated either using the input air humidity and the mass flow rate of water:
mair,in Xair,in + mwat,in ηB = mair,out Xair,out
or it is calculated using a set point for the humidity at the outlet if the parameter use_X_set is set to true. Note: If the relative humidity with the givin set-point or mass flow rate of water would exceed saturation the humidification is reduced to reach saturation as maximum. Additionally a warning will be thrown.
The energy balance is formulated using the enthalpy of the air streams and the enthalpy of the water:
mair,in hair,in + mwat,in hwat,in ηB = mair,out hair,out
The humidifying degree ηB is calculated using the water to air ratio E:
ηB = 1 - exp(-k E)
E = mwat,in ⁄ mair,in
If the boolean variable simplify_m_wat_flow is set to true, the mass flow rate of the water is not considered for the mass balance. Moreover the enthalpy of the water is neglected for the energy balance.
The equations are based on [1].
References
[1]: Baumgarth, Hörner, Reeker (Hrsg.): Handbuch der Klimatechnik, Band 2, 5. Auflage, VDE Verlag GmbH, 2011 (pp.304-306)
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | use_X_set (from PartialHumidifier) | false | if true, a set humidity is used to calculate the necessary mass flow rate |
| Modelica.Units.SI.Temperature | TWatIn (from PartialHumidifier) | temperature of liquid water added to humidifier | |
| Real | k | 500 | exponent for humidification degree |
| Advanced | |||
| Modelica.Units.SI.SpecificHeatCapacity | cpAir (from PartialComponent) | 1006 | specific heat capacity of dry air |
| Modelica.Units.SI.SpecificHeatCapacity | cpSteam (from PartialComponent) | 1860 | specific heat capacity of steam |
| Modelica.Units.SI.Density | rhoAir (from PartialComponent) | 1.2 | Density of air |
| Modelica.Units.SI.SpecificHeatCapacity | cpWater (from PartialHumidifier) | 4180 | specific heat capacity of liquid water |
| Nominal conditions | |||
| Modelica.Units.SI.MassFlowRate | m_flow_nominal (from PartialComponent) | nominal mass flow rate | |
| Modelica.Units.SI.PressureDifference | dp_nominal (from PartialComponent) | pressure drop at nominal mass flow rate | |
| Modelica.Units.SI.MassFlowRate | mWat_flow_nominal (from PartialHumidifier) | 0.05 | nominal water/steam flow rate of humidifier |
Connectors
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.SpecificEnthalpy | hAirIn (from PartialComponent) | specific enthalpy of incoming air | |
| Modelica.Units.SI.SpecificEnthalpy | hAirOut (from PartialComponent) | specific enthalpy of outgoing air | |
| PartialPressureDrop | partialPressureDrop (from PartialHumidifier) | ||
| Modelica.Units.SI.SpecificEnthalpy | hWatIn | specific enthalpy of incoming water | |
| Real | etaHum | humidification degree | |
| Utilities.Psychrometrics.SaturationPressure | pSat | ||
| Utilities.Psychrometrics.X_pW | humRat |
Revisions
- April, 2019, by Martin Kremer:
First Implementation. - April 2020, by Martin Kremer:
Extended from PartialHumidifier. - January 2022, by Martin Kremer:
Implemented maximum limit for saturation.