modelAirLiquidRearDoorHexActive

Example model for hybrid liquid-cooled and air-cooled rack with active rear door heat exchanger
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Extends from Buildings.Fluid.DataCenters.Racks.Hybrid.Examples.AirLiquidRearDoorHexPassive (Example model for hybrid liquid-cooled and air-cooled rack with rear door heat exchanger).

Information

Example model of a hybrid IT rack with liquid-cooled, air-cooled, and active rear door heat exchanger components.

This model is identical to Buildings.Fluid.DataCenters.Racks.Hybrid.Examples.AirLiquidRearDoorHexPassive except that the rear door heat exchanger has a built-in fan.

Parameters

TypeNameDefaultDescription
Modelica.Units.SI.PowerPLiq_nominal (from AirLiquid)48*13200Design power for liquid-cooled IT
Modelica.Units.SI.PowerPAir_nominal (from AirLiquid)0.1*PLiq_nominalDesign power for air-cooled IT
Modelica.Units.SI.TemperatureDifferencedTLiq_nominal (from AirLiquid)7Design temperature difference of liquid coolant
Modelica.Units.SI.TemperatureTLiqIn_nominal (from AirLiquid)273.15 + 42Supply coolant temperature to rack at design conditions
Modelica.Units.SI.MassFlowRatemLiq_flow_nominal (from AirLiquid)PLiq_nominal/dTLiq_nominal/cpLiq_defaultNominal mass flow rate for liquid cooling at design conditions
Modelica.Units.SI.SpecificHeatCapacitycpLiq_default (from AirLiquid)MediumLiq.specificHeatCapacityCp(state = MediumLiq.setState_pTX(T = MediumLiq.T_default, p = MediumLiq.p_default, X = MediumLiq.X_default[1:MediumLiq.nXi]))Heat capacity of liquid coolant
Modelica.Units.SI.PressureDifferencedpValve_nominal (from AirLiquid)5000Nominal pressure drop of fully open valve
Buildings.Fluid.DataCenters.Racks.Liquid.Data.OCP_1kW_OAM_PG25datLiq (from AirLiquid)Liquid-cooled rack performance data
Buildings.Fluid.DataCenters.Racks.Air.Data.GenericdatAir (from AirLiquid)Air-cooled rack performance data
Buildings.Fluid.DataCenters.Racks.Hybrid.Data.AirLiquid.Genericdat (from AirLiquid)
Modelica.Units.SI.TemperatureTAirDatHal (from AirLiquid)303.15Air temperature in data hall
Modelica.Units.SI.SpecificHeatCapacitycpAir_default (from AirLiquid)MediumAir.specificHeatCapacityCp(MediumAir.setState_pTX(T = MediumAir.T_default, p = MediumAir.p_default, X = MediumAir.X_default[1:MediumAir.nXi]))Specific heat capacity of air
Modelica.Units.SI.TemperatureTReaDooCooIn_nominal (from AirLiquidRearDoorHexPassive)273.15 + 25Rear door heat exchanger coolant supply temperature
Modelica.Units.SI.TemperatureTReaDooCooOut_nominal (from AirLiquidRearDoorHexPassive)273.15 + 35Rear door heat exchanger coolant return temperature
Modelica.Units.SI.TemperatureTAirReaDooIn_nominal (from AirLiquidRearDoorHexPassive)TAirDatHal + (datAir.TOut_nominal - datAir.TIn_nominal)Nominal air temperature entering the rear door heat exchanger
Modelica.Units.SI.MassFlowRatemReaDoo_flow_nominal (from AirLiquidRearDoorHexPassive)(PAir_nominal + datAir.PFan_nominal)/((TReaDooCooOut_nominal - TReaDooCooIn_nominal)*Buildings.Utilities.Psychrometrics.Constants.cpWatLiq)Nominal mass flow rate for rear door heat exchanger at design conditions
Buildings.Fluid.DataCenters.Racks.RearDoorHeatExchangers.Data.Passive.GenericdatReaDooHex (from AirLiquidRearDoorHexPassive)

Components

TypeNameDefaultDescription
Buildings.Controls.OBC.CDL.Reals.Sources.TimeTableutiLiq (from AirLiquid)Utilization of liquid-cooled hardware
Buildings.Controls.OBC.CDL.Reals.Sources.ConstantutiAir (from AirLiquid)Utilization of air-cooled hardware
Modelica.Blocks.Math.GainPITLiq (from AirLiquid)Power consumption by the liquid-cooled IT equipment
Modelica.Blocks.Math.GainPITAir (from AirLiquid)Power consumption by the air-cooled IT equipment
Buildings.Fluid.DataCenters.Racks.Hybrid.AirLiquidrac (from AirLiquid)
Buildings.Fluid.Movers.Preconfigured.SpeedControlled_ypum (from AirLiquid)Pump for liquid cooling loop
Buildings.Fluid.Sources.Boundary_pTbouLiq (from AirLiquid)Pressure boundary condition for liquid loop
Buildings.Fluid.Sources.Boundary_pTdatHal (from AirLiquid)Temperature and pressure of air in data hall
Fluid.Sensors.TemperatureTwoPortsenTLiq_a (from AirLiquid)Liquid inlet temperature to rack
Fluid.Sensors.TemperatureTwoPortsenTLiq_b (from AirLiquid)Liquid outlet temperature from rack
Fluid.Sensors.TemperatureTwoPortsenTAir_a (from AirLiquid)Air inlet temperature
Fluid.Sensors.TemperatureTwoPortsenTAir_b (from AirLiquid)Air outlet temperature
Buildings.Controls.OBC.CDL.Reals.PIDconPI (from AirLiquid)PI controller for pump speed to maintain constant pressure across rack
Actuators.Valves.TwoWayLinearval (from AirLiquid)Valve
Controls.OBC.CDL.Reals.Sources.ConstantTSetRet (from AirLiquid)Temperature setpoint for return water
Controls.OBC.CDL.Reals.PIDconVal (from AirLiquid)PI controller for valve to control return temperature
Buildings.Controls.OBC.CDL.Reals.Sources.ConstantdpSet (from AirLiquid)Pressure drop setpoint across rack
Buildings.Fluid.HeatExchangers.SensibleCooler_Tcoo (from AirLiquid)Cooler to maintain supply temperature
Buildings.Controls.OBC.CDL.Reals.Sources.ConstantTSetCoo (from AirLiquid)Temperature setpoint for cooler
Fluid.Sensors.RelativePressuresenRelPre (from AirLiquid)Relative pressure sensor across rack
Buildings.Fluid.Sources.Boundary_pTsouReaDoo (from AirLiquidRearDoorHexPassive)Rear door heat exchanger coolant supply at elevated pressure
Sources.Boundary_pTsinReaDoo (from AirLiquidRearDoorHexPassive)Sink rear door heat exchanger coolant
Sensors.TemperatureTwoPortsenTReaDooLvg (from AirLiquidRearDoorHexPassive)Coolant outlet temperature from rear door heat exchanger

Revisions

  • September 17, 2026, by Michael Wetter:
    First implementation.