modelWatersideEconomizer
Waterside economizer
Extends from Buildings.Applications.DataCenters.ChillerCooled.Equipment.BaseClasses.PartialPlantParallel, Buildings.Fluid.Interfaces.LumpedVolumeDeclarations, Buildings.Applications.DataCenters.ChillerCooled.Equipment.BaseClasses.ThreeWayValveParameters, Buildings.Applications.DataCenters.ChillerCooled.Equipment.BaseClasses.PartialControllerInterface.
Information
This module impliments a waterside economizer model that consists of a heat exchanger and a shutoff valve on each medium side. This waterside economizer model can be used in two different control scenarios:
- The temperature at
port_b2is controlled by a built-in PID controller and a three-way valve by setting the parameteruse_controllerastrue. - The temperature at
port_b2is NOT controlled by a built-in controller by setting the parameteruse_controllerasfalse. Hence, an outside controller can be used to control the temperature. For example, in the free-cooling mode, the speed of variable-speed cooling tower fans can be adjusted to maintain the supply chilled water temperature around the setpoint.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Efficiency | eta | constant effectiveness | |
| Dynamics › Time needed to open or close valve | |||
| Real | yThrWayVal_start | 1 | Initial value of output from the filter in the bypass valve |
| Real | yValWSE_start | 1 | Initial value of output from the filter in the shutoff valve |
| Dynamics › Nominal condition | |||
| Modelica.Units.SI.Time | tauThrWayVal | 10 | Time constant at nominal flow for dynamic energy and momentum balance of the three-way valve |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealInput | TSet | Set point for leaving water temperature | |
| Buildings.Applications.DataCenters.ChillerCooled.Equipment.HeatExchanger_TSet | heaExc | Water-to-water heat exchanger |
Revisions
-
April 9, 2021, by Kathryn Hinkelman:
Moved nominal pressure differences todpFixed_nominalat isolation valves to avoid redundant declarations and algebraic loops. -
June 30, 2017, by Yangyang Fu:
First implementation.