modelCoolingTowerSpeed
Controller for the fan speed in cooling towers
Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).
Information
This model describes a simple cooling tower speed controller for a chilled water system with integrated waterside economizers.
The control logics are described in the following:
- When the system is in Fully Mechanical Cooling (FMC) mode, the cooling tower fan speed is controlled to maintain the condener water supply temperature (CWST) at or around the setpoint.
- When the system is in Partially Mechanical Cooling (PMC) mode, the cooling tower fan speed is set as 100% to make condenser water as cold as possible and maximize the waterside economzier output.
- When the system is in Free Cooling (FC) mode, the cooling tower fan speed is controlled to maintain the chilled water supply temperature (CHWST) at or around its setpoint.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Controller | |||
| Modelica.Blocks.Types.SimpleController | controllerType | Modelica.Blocks.Types.SimpleController.PI | Type of controller |
| Real | k | 1 | Gain of controller |
| Modelica.Units.SI.Time | Ti | 0.5 | Time constant of integrator block |
| Modelica.Units.SI.Time | Td | 0.1 | Time constant of derivative block |
| Real | yMax | 1 | Upper limit of output |
| Real | yMin | 0 | Lower limit of output |
| Boolean | reverseActing | false | Set to true for throttling the water flow rate through a cooling coil controller |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealInput | TCHWSupSet | Chilled water supply temperature setpoint | |
| Modelica.Blocks.Interfaces.RealInput | TCWSupSet | Condenser water supply temperature setpoint | |
| Modelica.Blocks.Interfaces.RealInput | TCHWSup | Chilled water supply temperature | |
| Modelica.Blocks.Interfaces.RealInput | TCWSup | Condenser water supply temperature | |
| Modelica.Blocks.Interfaces.RealOutput | y | Speed signal for cooling tower fans | |
| Modelica.Blocks.Interfaces.IntegerInput | cooMod | Cooling mode signal, integer value of Buildings.Applications.DataCenters.Types.CoolingMode |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Sources.Constant | uni | Unit | |
| Modelica.Blocks.Sources.BooleanExpression | pmcMod | Partially mechanical cooling mode | |
| Buildings.Controls.Continuous.LimPID | conPID | PID controller | |
| Modelica.Blocks.Math.IntegerToBoolean | fmcMod | Fully mechanical cooling mode |
Revisions
-
July 30, 2017, by Yangyang Fu:
First implementation.