modelCoolingModeNonIntegrated
Cooling mode controller in the chilled water system with a non-integrated waterside economizer
Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).
Information
Chilled water plant with a non-integrated waterside economizer (WSE) have two cooling modes: free cooling (FC) mode and fully mechanical cooling (FMC) mode. This model determines when to activate FC or FMC for a chilled water system with 2 chillers and 1 waterside economizer.
The FMC mode is activated when
- TWetBulb≥ TWetBulb,tran, or
- TCHWST≥TCHWSTSet + deaBan,
and the FC mode is activated when
- TWetBulb< TWetBulb,tran, and
- numOnChi<2,
where TWetBulb is the wet bulb temperature of the outdoor air, TWetBulb,tran is the wet bulb temperature transition point for switching between FC and FMC, TCHWST is the chilled water supply temperature, TCHWSTSet is the chilled water supply temperature setpoint,and numOnChi is the number of running chillers.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.TemperatureDifference | deaBan | Dead band width for switching waterside economizer off | |
| Modelica.Units.SI.Temperature | TSwi | Temperature transition to free cooling mode | |
| Modelica.Units.SI.Time | tWai | Waiting time |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.IntegerInput | numOnChi | Number of running chillers | |
| Modelica.Blocks.Interfaces.RealInput | TWetBul | Wet bulb temperature of outdoor air | |
| Modelica.Blocks.Interfaces.RealInput | TCHWSup | Temperature of leaving chilled water | |
| Modelica.Blocks.Interfaces.RealInput | TCHWSupSet | Temperature setpoint of leaving chilled water | |
| Modelica.Blocks.Interfaces.IntegerOutput | y | Cooling mode signal (1: free cooling mode, 3: fully mechanical cooling) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.StateGraph.InitialStepWithSignal | freCoo | Free cooling mode | |
| Modelica.StateGraph.StepWithSignal | fulMecCoo | Fully mechanical cooling mode | |
| Modelica.StateGraph.Transition | con1 | Fire condition 1: free cooling to fully mechanical cooling | |
| Modelica.Blocks.MathInteger.MultiSwitch | swi | Switch boolean signals to real signal | |
| Modelica.StateGraph.Transition | con2 | Fire condition 2: fully mechanical cooling to free cooling | |
| Modelica.StateGraph.StateGraphRoot | stateGraphRoot |
Revisions
-
July 30, 2017, by Yangyang Fu:
First implementation.