modelChillerWSEDynamicPipes
Example model of a simple liquid cooled data center with chiller and water-side economizer
Extends from ChillerWSE (Example model of a simple liquid cooled data center with chiller and water-side economizer).
Information
This model is identical to Buildings.Applications.DataCenters.LiquidCooled.Examples.ChillerWSE except that the supply and return pipes in each of the three fluid loops are modeled using a pipe model that has transport delay. Moreover, the IT power consumed is here modelled using a time table that alternates the load every 2 minutes between 50% and 70% of the design thermal power.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Power | PRac (from ChillerWSE) | 1E6 | Total rack design power |
| Real | fraWSE (from ChillerWSE) | 0.6 | Fraction of peak load covered by water side economizer |
| Real | fraChi (from ChillerWSE) | 1 - fraWSE | Fraction of peak load covered by chiller |
| Modelica.Units.SI.TemperatureDifference | dTRac_nominal (from ChillerWSE) | -5 | Temperature difference rack loop |
| Modelica.Units.SI.TemperatureDifference | dTPla_nominal (from ChillerWSE) | -5 | Temperature difference cooling plant loop |
| Modelica.Units.SI.TemperatureDifference | dTTow_nominal (from ChillerWSE) | dTPla_nominal | Temperature difference tower water loop |
| Modelica.Units.SI.Temperature | TRacSup_nominal (from ChillerWSE) | 273.15 + 45 | Supply coolant temperature to rack at design conditions |
| Modelica.Units.SI.Temperature | TRacRet_nominal (from ChillerWSE) | TRacSup_nominal - dTRac_nominal | Return coolant temperature from rack at design conditions |
| Modelica.Units.SI.TemperatureDifference | TApp_nominal (from ChillerWSE) | 3 | Approach temperature at heat exchangers |
| Modelica.Units.SI.Temperature | TPlaSup_nominal (from ChillerWSE) | TRacSup_nominal - TApp_nominal | Temperature from cooling plant to CDU at design conditions |
| Modelica.Units.SI.Temperature | TPlaRet_nominal (from ChillerWSE) | TPlaSup_nominal - dTPla_nominal | Temperature from CDU to cooling plant at design conditions |
| Modelica.Units.SI.Temperature | TTowRet_nominal (from ChillerWSE) | TPlaSup_nominal - TApp_nominal | Return temperature from cooling tower |
| Modelica.Units.SI.Temperature | TTowSup_nominal (from ChillerWSE) | TTowRet_nominal - dTTow_nominal | Supply temperature to cooling tower |
| Modelica.Units.SI.Temperature | TDryBul_nominal (from ChillerWSE) | 273.15 + 36 | Design dry bulb temperature if WSE is used exclusively (with fraWSE=0.9999) |
| Modelica.Units.SI.MassFlowRate | mRac_flow_nominal (from ChillerWSE) | PRac/(TRacRet_nominal - TRacSup_nominal)/MediumRac.cp_const | Rack mass flow rate at design conditions |
| Modelica.Units.SI.MassFlowRate | mPla_flow_nominal (from ChillerWSE) | PRac/(TPlaRet_nominal - TPlaSup_nominal)/cpChi_default | Cooling loop water mass flow rate at design conditions |
| Modelica.Units.SI.PressureDifference | dpVal_nominal (from ChillerWSE) | 20000 | Valve design pressure drop |
| Modelica.Units.SI.PressureDifference | dpHexChi_nominal (from ChillerWSE) | 80000 | Heat exchanger design pressure drop on chiller side |
| Modelica.Units.SI.PressureDifference | dPRac_nominal (from ChillerWSE) | 60000 | Rack design pressure drop |
| Buildings.Fluid.DataCenterEquipment.Racks.LiquidCooledSinglePhase.Data.OCP_1kW_OAM_PG25 | datRac (from ChillerWSE) | Performance data for IT rack | |
| Real | COPc_nominal (from ChillerWSE) | 5 | Chiller COP |
| Real | epsWSE_nominal (from ChillerWSE) | QWSE_flow_nominal/(min(mWSEPla_flow_nominal*cpChi_default, mWSETow_flow_nominal*cpTow_default)*(TPlaRet_nominal - TTowRet_nominal)) | Effectiveness of water side economizer |
| Modelica.Units.SI.HeatFlowRate | QCon_flow_nominal (from ChillerWSE) | (1 - fraWSE)*PRac*(1/COPc_nominal + 1) | Design heat flow rate of condenser |
| Modelica.Units.SI.HeatFlowRate | QWSE_flow_nominal (from ChillerWSE) | fraWSE*PRac | Design heat flow rate of economizer |
| Modelica.Units.SI.MassFlowRate | mEva_flow_nominal (from ChillerWSE) | mPla_flow_nominal | Nominal mass flow rate at condenser water, sized to circulate all water through it to meet set point when trim chiller is needed |
| Modelica.Units.SI.MassFlowRate | mCon_flow_nominal (from ChillerWSE) | -QCon_flow_nominal/dTTow_nominal/cpTow_default | Nominal mass flow rate at condenser water |
| Modelica.Units.SI.MassFlowRate | mWSETow_flow_nominal (from ChillerWSE) | -QWSE_flow_nominal/dTTow_nominal/cpTow_default | Nominal mass flow rate at WSE on tower side |
| Modelica.Units.SI.MassFlowRate | mWSEPla_flow_nominal (from ChillerWSE) | -QWSE_flow_nominal/dTPla_nominal/cpChi_default | Nominal mass flow rate at WSE on chilled water side |
| Fluid.DataCenterEquipment.CDUs.LiquidToLiquid.Data.Generic_2MW | datCDU (from ChillerWSE) | Data record for CDU | |
| Fluid.HeatExchangers.CoolingTowers.Data.DryCooler.Generic | datCooTow (from ChillerWSE) | Performance data for cooling tower |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| BoundaryConditions.WeatherData.Bus | weaBus (from ChillerWSE) | Weather data bus |
Components
Contents
| Name | Description |
|---|---|
 MyPlugFlowPipe |
Revisions
-
July 20, 2026, by Michael Wetter:
First implementation.