modelCoolingMode
Mode controller for integrated waterside economizer and chiller
Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).
Information
Controller that outputs if the chilled water system is in Free Cooling (FC) mode, Partially Mechanical Cooling (PMC) mode or Fully Mechanical Cooling (FMC) mode.
The waterside economizer is enabled when
- The waterside economizer has been disabled for at least 20 minutes, and
- TCHWR > TWetBul + TTowApp + deaBan1
The waterside economizer is disabled when
- The waterside economizer has been enabled for at least 20 minutes, and
- TWSE_CHWST > TWSE_CHWRT - deaBan2
The chiller is enabled when
- The chiller has been disabled for at leat 20 minutes, and
- TWSE_CHWST > TCHWSTSet + deaBan3
The chiller is disabled when
- The chiller has been enabled for at leat 20 minutes, and
- TWSE_CHWST ≤ TCHWSTSet + deaBan4
where TWSE_CHWST is the chilled water supply temperature for the WSE, TWetBul is the wet bulb temperature, TTowApp is the cooling tower approach, TWSE_CHWRT is the chilled water return temperature for the WSE, and TCHWSTSet is the chilled water supply temperature setpoint for the system. deaBan 1-4 are deadbands for each switching point.
References
- Stein, Jeff. Waterside Economizing in Data Centers: Design and Control Considerations. ASHRAE Transactions 115.2 (2009).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Time | tWai | Waiting time | |
| Modelica.Units.SI.TemperatureDifference | deaBan1 | Dead band width 1 for switching chiller on | |
| Modelica.Units.SI.TemperatureDifference | deaBan2 | Dead band width 2 for switching waterside economizer off | |
| Modelica.Units.SI.TemperatureDifference | deaBan3 | Dead band width 3 for switching waterside economizer on | |
| Modelica.Units.SI.TemperatureDifference | deaBan4 | Dead band width 4 for switching chiller off |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealInput | TCHWRetWSE | Temperature of entering chilled water that flows to waterside economizer | |
| Modelica.Blocks.Interfaces.RealInput | TCHWSupWSE | Temperature of leaving chilled water that flows out from waterside economizer | |
| Modelica.Blocks.Interfaces.RealInput | TCHWSupSet | Supply chilled water temperature setpoint | |
| Modelica.Blocks.Interfaces.RealInput | TApp | Approach temperature in the cooling tower | |
| Modelica.Blocks.Interfaces.IntegerOutput | y | Cooling mode signal, integer value of Buildings.Applications.DataCenters.Types.CoolingMode | |
| Modelica.Blocks.Interfaces.RealInput | TWetBul | Wet bulb temperature of outdoor air |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.StateGraph.Transition | con1 | Fire condition 1: free cooling to partially mechanical cooling | |
| Modelica.StateGraph.StepWithSignal | parMecCoo | Partial mechanical cooling mode | |
| Modelica.StateGraph.InitialStepWithSignal | freCoo | Free cooling mode | |
| Modelica.StateGraph.StepWithSignal | fulMecCoo | Fully mechanical cooling mode | |
| 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.MathInteger.MultiSwitch | swi | Switch boolean signals to real signal |
Revisions
-
July 24, 2017, by Yangyang Fu:
First implementation.