modelChillerStage
Chiller staging control logic
Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).
Information
This is a chiller staging control that works as follows:
- The chillers are all off when cooling mode is Free Cooling.
- One chiller is commanded on when cooling mode is not Free Cooling.
- Two chillers are commanded on when cooling mode is not Free Cooling and the cooling load addressed by each chiller is larger than a critical value.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Time | tWai | Waiting time | |
| Modelica.Units.SI.Power | QEva_nominal | Nominal cooling capaciaty(Negative means cooling) | |
| Modelica.Units.SI.Power | criPoiLoa | 0.55*QEva_nominal | Critical point of cooling load for switching one chiller on or off |
| Modelica.Units.SI.Power | dQ | 0.25*QEva_nominal | Deadband for critical point of cooling load |
| Modelica.Units.SI.Temperature | criPoiTem | 279.15 | Critical point of temperature for switching one chiller on or off |
| Modelica.Units.SI.TemperatureDifference | dT | 1 | Deadband width for critical point of switching temperature |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.IntegerInput | cooMod | Cooling mode signal, integer value of Buildings.Applications.DataCenters.Types.CoolingMode | |
| Modelica.Blocks.Interfaces.RealInput | QTot | Total cooling load in the chillers, negative | |
| Modelica.Blocks.Interfaces.RealOutput[2] | y | On/off signal for the chillers - 0: off; 1: on | |
| Modelica.Blocks.Interfaces.RealInput | TCHWSup | Temperature of leaving chilled water |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.StateGraph.Transition | con1 | Fire condition 1: free cooling to partially mechanical cooling | |
| Modelica.StateGraph.StepWithSignal | oneOn | One chiller is commanded on | |
| Modelica.StateGraph.InitialStep | off | Free cooling mode | |
| Modelica.StateGraph.StepWithSignal | twoOn | Two chillers are commanded on | |
| Modelica.StateGraph.Transition | con2 | Fire condition 2: partially mechanical cooling to fully mechanical cooling | |
| Modelica.StateGraph.Transition | con3 | Fire condition 3: fully mechanical cooling to partially mechanical cooling | |
| Modelica.StateGraph.Transition | con4 | Fire condition 4: partially mechanical cooling to free cooling | |
| Modelica.StateGraph.StateGraphRoot | stateGraphRoot | ||
| Modelica.Blocks.Tables.CombiTable1Ds | combiTable1Ds | ||
| Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger | booToInt | ||
| Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger | booToInt1 | ||
| Buildings.Controls.OBC.CDL.Integers.Add | addInt | ||
| Buildings.Controls.OBC.CDL.Conversions.IntegerToReal | intToRea |
Revisions
-
September 11, 2017, by Michael Wetter:
Revised switch that selects the operation mode for issue 921 -
July 30, 2017, by Yangyang Fu:
First implementation.