modelDataCenter

Primary only chiller plant system with water-side economizer
Diagram of DataCenterOpen the diagram

Information

This model is the chilled water plant with discrete time control and trim and respond logic for a data center. The model is described at Buildings.Examples.ChillerPlant.DataCenter.

Parameters

TypeNameDefaultDescription
Modelica.Units.SI.MassFlowRatemAir_flow_nominalroo.QRoo_flow/(1005*15)Nominal mass flow rate at fan
Modelica.Units.SI.PowerP_nominal80E3Nominal compressor power (at y=1)
Modelica.Units.SI.TemperatureDifferencedTEva_nominal10Temperature difference evaporator inlet-outlet
Modelica.Units.SI.TemperatureDifferencedTCon_nominal10Temperature difference condenser outlet-inlet
RealCOPc_nominal3Chiller COP
Modelica.Units.SI.MassFlowRatemCHW_flow_nominal2*roo.QRoo_flow/(4200*20)Nominal mass flow rate at chilled water
Modelica.Units.SI.MassFlowRatemCW_flow_nominal2*roo.QRoo_flow/(4200*6)Nominal mass flow rate at condenser water
Modelica.Units.SI.PressureDifferencedp_nominal500Nominal pressure difference
Fluid.HeatExchangers.CoolingTowers.Data.YorkCalc.GenericdatTowPerformance data for cooling tower

Connectors

TypeNameDefaultDescription
BoundaryConditions.WeatherData.BusweaBus

Components

TypeNameDefaultDescription
Buildings.Fluid.Movers.FlowControlled_m_flowfanFan for air flow through the data center
Buildings.Fluid.HeatExchangers.DryCoilCounterFlowcooCoiCooling coil
Modelica.Blocks.Sources.ConstantmFanFloMass flow rate of fan
BaseClasses.SimplifiedRoomrooRoom model
Buildings.Fluid.Movers.FlowControlled_dppumCHWChilled water pump
Buildings.Fluid.Storage.ExpansionVesselexpVesCHWExpansion vessel
Buildings.Fluid.HeatExchangers.CoolingTowers.YorkCalccooTowCooling tower
Buildings.Fluid.Movers.FlowControlled_m_flowpumCWCondenser water pump
Buildings.Fluid.HeatExchangers.ConstantEffectivenesswseWater side economizer (Heat exchanger)
Buildings.Fluid.Actuators.Valves.TwoWayLinearval5Control valve for condenser water loop of chiller
Buildings.Fluid.Actuators.Valves.TwoWayLinearval1Bypass control valve for economizer. 1: disable economizer, 0: enable economizer
Buildings.Fluid.Storage.ExpansionVesselexpVesChi
Buildings.Examples.ChillerPlant.DataCenter.BaseClasses.Controls.WSEControlwseCon
Modelica.Blocks.Sources.RealExpressionexpTowTAppCooling tower approach
Buildings.Fluid.Chillers.ElectricEIRchi
Buildings.Fluid.Actuators.Valves.TwoWayLinearval6Control valve for chilled water leaving from chiller
Buildings.Examples.ChillerPlant.DataCenter.BaseClasses.Controls.ChillerSwitchchiSwiControl unit switching chiller on or off
Buildings.Examples.ChillerPlant.DataCenter.BaseClasses.Controls.LinearPiecewiseTwolinPieTwoTranslate the control signal for chiller setpoint reset
Modelica.Blocks.Sources.ConstantTAirSetSet temperature for air supply to the room
Modelica.Blocks.Math.BooleanToRealchiConControl signal for chiller
Buildings.Fluid.Actuators.Valves.TwoWayLinearval4Control valve for condenser water loop of economizer
Buildings.Fluid.Sensors.TemperatureTwoPortTAirSupSupply air temperature to data center
Buildings.Fluid.Sensors.TemperatureTwoPortTCHWEntChiTemperature of chilled water entering chiller
Buildings.Fluid.Sensors.TemperatureTwoPortTCWLeaTowTemperature of condenser water leaving the cooling tower
Modelica.Blocks.Sources.ConstantcooTowFanConControl signal for cooling tower fan
Buildings.Fluid.Actuators.Valves.TwoWayEqualPercentagevalBypBypass valve for chiller.
Buildings.Examples.ChillerPlant.DataCenter.BaseClasses.Controls.KMinusUKMinusU
Buildings.Fluid.Actuators.Valves.TwoWayLinearval3Control valve for economizer. 0: disable economizer, 1: enable economizer
Buildings.Fluid.Sensors.TemperatureTwoPortTCHWLeaCoiTemperature of chilled water leaving the cooling coil
Buildings.BoundaryConditions.WeatherData.ReaderTMY3weaData
Modelica.Blocks.Math.Gaingain
Modelica.Blocks.Math.Feedbackfeedback
Modelica.Blocks.Logical.GreaterThresholdgreaterThreshold
Modelica.Blocks.Logical.Oror1
Modelica.Blocks.Math.BooleanToRealmCWFloMass flow rate of condenser loop
Modelica.Blocks.Sources.RealExpressionPHVACPower consumed by HVAC system
Modelica.Blocks.Sources.RealExpressionPITPower consumed by IT
Modelica.Blocks.Continuous.IntegratorEHVACEnergy consumed by HVAC
Modelica.Blocks.Continuous.IntegratorEITEnergy consumed by IT

Contents

NameDescription
MediumAMedium model
MediumWMedium model

Revisions

  • April 27, 2026, by Michael Wetter:
    Refactored for new cooling tower implementation.
    This is for issue 4567.
  • December 6, 2021, by Michael Wetter:
    Changed initialization from steady-state initial to fixed initial.
    This is for issue 2798.
  • November 18, 2021, by Michael Wetter:
    Set dp_nominal for pumps and fan to a realistic value.
    This is for #2761.
  • September 21, 2017, by Michael Wetter:
    Set from_dp = true in val6 and in valByp which is needed for Dymola 2018FD01 beta 2 for Buildings.Examples.ChillerPlant.DataCenter.DiscreteTimeControl to converge.
  • January 22, 2016, by Michael Wetter:
    Corrected type declaration of pressure difference. This is for IBPSA, #404.
  • January 13, 2015 by Michael Wetter:
    Moved model to BaseClasses because the continuous and discrete time implementation of the trim and respond logic do not extend from a common class, and hence the constrainedby operator is not applicable. Moving the model here allows to implement both controllers without using a replaceable class.
  • January 12, 2015 by Michael Wetter:
    Made media instances replaceable, and used the same instance for both water loops. This was done to simplify the numerical benchmarks.
  • December 22, 2014 by Michael Wetter:
    Removed Modelica.Fluid.System to address issue #311.
  • March 25, 2014, by Michael Wetter:
    Updated model with new expansion vessel.
  • December 5, 2012, by Michael Wetter:
    Removed the filtered speed calculation for the valves to reduce computing time by 25%.
  • October 16, 2012, by Wangda Zuo:
    Reimplemented the controls.
  • July 20, 2011, by Wangda Zuo:
    Added comments and merge to library.
  • January 18, 2011, by Wangda Zuo:
    First implementation.