modelChilledWaterPumpSpeed
Controller for two headered variable speed chilled water pumps
Information
This model implements the control logic for variable speed pumps. The staging of pumps is implemented through an instance of Buildings.Applications.BaseClasses.Controls.VariableSpeedPumpStage.
The pump speed is controlled to maintain the pressure difference setpoint through a PI controller.
The model inputs are the measured chilled water mass flow rate
masFloPum and the pressure difference dpMea at a
reference point from the demand side. The output y is a vector
of pump speeds.
The model currently only supports the control of two variable speed pumps.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | dpSetPoi | Pressure difference setpoint | |
| Real | tWai | Waiting time | |
| Real | m_flow_nominal | Nominal mass flow rate of single chilled water pump | |
| Real | minSpe | 0.05 | Minimum speed ratio required by chilled water pumps |
| Real | criPoiFlo | 0.7*m_flow_nominal | Critcal point of flowrate for switching pump on or off |
| Real | 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 |
| Speed Controller | |||
| Buildings.Controls.OBC.CDL.Types.SimpleController | controllerType | Buildings.Controls.OBC.CDL.Types.SimpleController.PI | Type of pump speed controller |
| Real | k | 1 | Gain of controller |
| Real | Ti | 60 | Time constant of Integrator block |
| Real | Td | 0.1 | Time constant of Derivative block |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput | on | On signal of the plant | |
| Buildings.Controls.OBC.CDL.Interfaces.RealInput | masFloPum | Total mass flowrate of chilled water pumps | |
| Buildings.Controls.OBC.CDL.Interfaces.RealInput | dpMea | Measured pressure difference | |
| Buildings.Controls.OBC.CDL.Interfaces.RealOutput[numPum] | y | Pump speed signal |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Controls.OBC.CDL.Reals.Multiply[numPum] | pumSpe | Output pump speed | |
| Buildings.Applications.BaseClasses.Controls.VariableSpeedPumpStage | pumStaCon | Chilled water pump staging control | |
| Buildings.Controls.OBC.CDL.Reals.PIDWithReset | conPID | PID controller of pump speed | |
| Buildings.Controls.OBC.CDL.Reals.Sources.Constant | dpSetSca | Scaled differential pressure setpoint | |
| Buildings.Controls.OBC.CDL.Reals.MultiplyByParameter | gai | Gain for mesaured dp value | |
| Buildings.Controls.OBC.CDL.Reals.GreaterThreshold | twoPum | Two pumps are on | |
| Buildings.Controls.OBC.CDL.Reals.MultiSum | totPum | Total number of pumps on | |
| Buildings.Controls.OBC.CDL.Logical.Or | orRes | Or block for controller reset |
Revisions
-
August 9, 2023, by Hongxiang Fu:
Restricted this block to a two-pump configuration as intended.-
Set
final totPum.nin = numPum. - Corrected the "up to two pumps" language in documentation.
-
Set
-
December 30, 2022, by Kathryn Hinkelman:
Added anoninput for a plant-level override to turn pumps off. -
December 14, 2022 by Kathryn Hinkelman:
Normalizedu_sandu_mbydpSetPoi. Added reset for PI controller based on the number of pumps that are on.
This is for #2912. -
August 6, 2020 by Jing Wang:
First implementation.