blockMerkel
Model for thermal performance of Merkel cooling tower
Extends from Buildings.Obsolete.BaseClasses.ObsoleteModel, Modelica.Blocks.Icons.Block.
Information
Model for the thermal peformance of the Merkel cooling tower.
For the documentation, see Buildings.Obsolete.Fluid.HeatExchangers.CoolingTowers.Merkel.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Obsolete.Fluid.HeatExchangers.CoolingTowers.Data.UAMerkel | UACor | ||
| Modelica.Units.SI.HeatFlowRate | Q_flow_nominal | -m_flow_nominal*cpWat_nominal*(TWatIn_nominal - TWatOut_nominal) | Nominal heat transfer, (negative) |
| Modelica.Units.SI.ThermalConductance | UA_nominal | NTU_nominal*CMin_flow_nominal*Buildings.Utilities.Psychrometrics.Constants.cpAir/cpEqu_nominal | Thermal conductance at nominal flow, used to compute heat capacity |
| Real | eps_nominal | Q_flow_nominal/((TAirInWB_nominal - TWatIn_nominal)*CMin_flow_nominal) | Nominal heat transfer effectiveness |
| Real | NTU_nominal | Buildings.Fluid.HeatExchangers.BaseClasses.ntu_epsilonZ(eps = min(1, max(0, eps_nominal)), Z = Z_nominal, flowRegime = Integer(Buildings.Fluid.Types.HeatExchangerConfiguration.CounterFlow)) | Nominal number of transfer units |
| Nominal condition | |||
| Modelica.Units.SI.MassFlowRate | m_flow_nominal | Nominal mass flow rate of water | |
| Real | ratWatAir_nominal | Water-to-air mass flow rate ratio at design condition | |
| Fan | |||
| Modelica.Units.SI.MassFlowRate | mAir_flow_nominal | m_flow_nominal/ratWatAir_nominal | Nominal mass flow rate of air |
| Real | yMin | Minimum control signal until fan is switched off (used for smoothing between forced and free convection regime) | |
| Heat transfer | |||
| Modelica.Units.SI.Temperature | TAirInWB_nominal | Nominal outdoor (air inlet) wetbulb temperature | |
| Modelica.Units.SI.Temperature | TWatIn_nominal | Nominal water inlet temperature | |
| Modelica.Units.SI.Temperature | TWatOut_nominal | Nominal water outlet temperature | |
| Real | fraFreCon | Fraction of tower capacity in free convection regime | |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealInput | y | Fan control signal | |
| Modelica.Blocks.Interfaces.RealInput | m_flow | Water mass flow rate | |
| Modelica.Blocks.Interfaces.RealInput | TWatIn | Inlet water temperature | |
| Modelica.Blocks.Interfaces.RealInput | TAir | Entering air wet bulb temperature | |
| Modelica.Units.SI.Temperature | TAirOut | Outlet air temperature | |
| Modelica.Units.SI.MassFlowRate | mAir_flow | Air mass flow rate | |
| Modelica.Units.SI.MassFraction | FRWat | Ratio actual over design water mass flow ratio | |
| Modelica.Units.SI.MassFraction | FRAir | Ratio actual over design air mass flow ratio | |
| Real | eps | Heat exchanger effectiveness | |
| Modelica.Units.SI.SpecificHeatCapacity | cpWat | Heat capacity of water | |
| Modelica.Units.SI.ThermalConductance | CAir_flow | Heat capacity flow rate of air | |
| Modelica.Units.SI.ThermalConductance | CWat_flow | Heat capacity flow rate of water | |
| Modelica.Units.SI.ThermalConductance | CMin_flow | Minimum heat capacity flow rate | |
| Modelica.Units.SI.HeatFlowRate | QMax_flow | Maximum heat flow rate into air | |
| Modelica.Units.SI.ThermalConductance | UAe | Thermal conductance for equivalent fluid | |
| Modelica.Units.SI.ThermalConductance | UA | Thermal conductance | |
| Modelica.Blocks.Interfaces.RealOutput | Q_flow | Heat removed from water |
Contents
| Name | Description |
|---|---|
| Medium | Medium in the component |
| Airprotected | Package of medium air |
Revisions
-
April 27, 2026, by Michael Wetter:
Moved toObsoletepackage due to new cooling tower implementation.
This is for issue 4567. -
April 17, 2025, by Michael Wetter:
Corrected computation of nominal UA value, which also needs to include the correction forcpEqu_nominal.
This is for #4189. -
January 20, 2020, by Michael Wetter:
First implementation during refactoring of Buildings.Obsolete.Fluid.HeatExchangers.CoolingTowers.Merkel.