modelVariableSpeedPumpStage
Staging control for variable speed pumps
Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).
Information
This model implements a simple staging control logic for variable speed pumps.
- When the mass flowrate in each pump is greater than a threshold, and the speed signal is greater than a threshold, then activate one more pump;
- When the mass flowrate in each pump is less than a threshold, or the speed signal is smaller than a threshold, then deactivate one more pump.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Time | tWai | Waiting time | |
| Modelica.Units.SI.MassFlowRate | m_flow_nominal | Nominal mass flow rate of the identical variable-speed pumps | |
| Real | minSpe | 0.05 | Minimum speed ratio required by variable speed pumps |
| Modelica.Units.SI.MassFlowRate | criPoiFlo | 0.7*m_flow_nominal | Critcal point of flowrate for switch pump on or off |
| Modelica.Units.SI.MassFlowRate | deaBanFlo | 0.1*m_flow_nominal | Deadband for critical point of flowrate |
| Real | criPoiSpe | 0.5 | Critical point of speed signal for switching on or off |
| Real | deaBanSpe | 0.3 | Deadband for critical point of speed signal |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealInput | masFloPum | Total mass flowrate in the variable speed pumps | |
| Modelica.Blocks.Interfaces.RealInput | speSig | Speed signal | |
| Modelica.Blocks.Interfaces.RealOutput[2] | y | On/off signal - 0: off; 1: on | |
| Modelica.Blocks.Interfaces.BooleanInput | on | On signal of the plant |
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 | Determine which pump should be on - rotation control is not considered here | |
| Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger | booToInt | ||
| Buildings.Controls.OBC.CDL.Conversions.BooleanToInteger | booToInt1 | ||
| Buildings.Controls.OBC.CDL.Integers.Add | addInt | Outputs how many pumps are to be commanded on | |
| Buildings.Controls.OBC.CDL.Conversions.IntegerToReal | intToRea | Comparison from integer to real signal for number of pumps |
Revisions
-
December 30, 2022, by Kathryn Hinkelman:
Added anoninput for a plant-level override to turn pumps off. -
September 11, 2017, by Michael Wetter:
Revised switch that selects the operation mode for issue 921 -
July 30, 2017, by Yangyang Fu:
First implementation.