recordGoogleProjectDeschutes_2MW
Data record for a Google Project Deschutes CDU
Extends from Buildings.Fluid.DataCenterEquipment.CDUs.LiquidToLiquid.Data.Generic_epsNTU (Generic data record for a CDU that uses the epsilon-NTU method to compute the thermal performance).
Information
This data record is for the 5th generation CDU unit of Google, named Project Deschutes. This unit is specified for the following data (OCP, 2026):
| Description | Value | Unit |
|---|---|---|
| IT Loop flow | 31.48 | kg/s |
| Facility Loop flow | 32.30 | kg/s |
| IT Loop dP available | 80-90 551,581 - 620,528 |
psi Pa |
| Facility Loop dP | 15-27 103,421 - 186,159 |
psid Pa |
| Thermal load | 2000 | kW |
| Approach temperature | 3 | °C |
| Facility Loop entering temperature | 26.8 | °C |
| Power consumption | 74 | kW |
| Liquids | DI water, PG25 |
References
OCP 2026. Open Compute Project meeting, CDU Information WP. March 24, 2026.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Temperature | TPlaIn_nominal (from Generic_epsNTU) | TRacOut_nominal - TApp_nominal | Inlet temperature from cooling plant loop |
| Modelica.Units.SI.Temperature | TPlaOut_nominal (from Generic_epsNTU) | TPlaIn_nominal - Q_flow_nominal/CPla_flow_nominal | Outlet temperature to cooling plant loop |
| Modelica.Units.SI.Temperature | TRacIn_nominal (from Generic_epsNTU) | TRacOut_nominal - Q_flow_nominal/CRac_flow_nominal | Inlet temperature from IT rack loop |
| Modelica.Units.SI.DynamicViscosity | etaPla_default (from Generic_epsNTU) | Buildings.Fluid.DataCenterEquipment.CDUs.LiquidToLiquid.Data.BaseClasses.dynamicViscosity_TX_a(medium = medPla, X_a = XGlyPla, T = TRacOut_nominal) | Dynamic viscosity for plant-side performance data |
| Modelica.Units.SI.SpecificHeatCapacity | cpPla_default (from Generic_epsNTU) | Buildings.Fluid.DataCenterEquipment.CDUs.LiquidToLiquid.Data.BaseClasses.specificHeatCapacityCp_TX_a(medium = medPla, X_a = XGlyPla, T = TRacOut_nominal) | Specific heat capacity at constant pressure for plant-side performance data |
| Modelica.Units.SI.ThermalConductivity | kPla_default (from Generic_epsNTU) | Buildings.Fluid.DataCenterEquipment.CDUs.LiquidToLiquid.Data.BaseClasses.thermalConductivity_TX_a(medium = medPla, X_a = XGlyPla, T = TRacOut_nominal) | Thermal conductivity for plant-side performance data |
| Modelica.Units.SI.PrandtlNumber | PrPla_default (from Generic_epsNTU) | Buildings.Fluid.DataCenterEquipment.CDUs.LiquidToLiquid.Data.BaseClasses.prandtlNumber_TX_a(medium = medPla, X_a = XGlyPla, T = TRacOut_nominal) | Prandtl number for plant-side performance data |
| Modelica.Units.SI.DynamicViscosity | etaRac_default (from Generic_epsNTU) | Buildings.Fluid.DataCenterEquipment.CDUs.LiquidToLiquid.Data.BaseClasses.dynamicViscosity_TX_a(medium = medRac, X_a = XGlyRac, T = TRacOut_nominal) | Dynamic viscosity for rack-side performance data |
| Modelica.Units.SI.SpecificHeatCapacity | cpRac_default (from Generic_epsNTU) | Buildings.Fluid.DataCenterEquipment.CDUs.LiquidToLiquid.Data.BaseClasses.specificHeatCapacityCp_TX_a(medium = medRac, X_a = XGlyRac, T = TRacOut_nominal) | Specific heat capacity at constant pressure for rack-side performance data |
| Modelica.Units.SI.ThermalConductivity | kRac_default (from Generic_epsNTU) | Buildings.Fluid.DataCenterEquipment.CDUs.LiquidToLiquid.Data.BaseClasses.thermalConductivity_TX_a(medium = medRac, X_a = XGlyRac, T = TRacOut_nominal) | Thermal conductivity for rack-side performance data |
| Modelica.Units.SI.PrandtlNumber | PrRac_default (from Generic_epsNTU) | Buildings.Fluid.DataCenterEquipment.CDUs.LiquidToLiquid.Data.BaseClasses.prandtlNumber_TX_a(medium = medRac, X_a = XGlyRac, T = TRacOut_nominal) | Prandtl number for rack-side performance data |
| Modelica.Units.SI.Density | rhoRac_default (from Generic_epsNTU) | Buildings.Fluid.DataCenterEquipment.CDUs.LiquidToLiquid.Data.BaseClasses.density_TX_a(medium = medRac, X_a = XGlyRac, T = TRacOut_nominal) | Mass density for rack-side performance data |
| Buildings.Fluid.Movers.BaseClasses.Characteristics.efficiencyParameters | pumpEfficiency (from Generic_epsNTU) | Total pump efficiency vs. volumetric flow rate | |
| Modelica.Units.SI.ThermalConductance | CPla_flow_nominal (from Generic_epsNTU) | mPla_flow_nominal*cpPla_default | Capacity flow rate at nominal conditions on cooling plant side |
| Modelica.Units.SI.ThermalConductance | CRac_flow_nominal (from Generic_epsNTU) | mRac_flow_nominal*cpRac_default | Capacity flow rate at nominal conditions on rack side |
| Modelica.Units.SI.TemperatureDifference | dTPla_nominal (from Generic_epsNTU) | -Q_flow_nominal/CPla_flow_nominal | Fluid temperature difference at nominal conditions on cooling plant side |
| Modelica.Units.SI.TemperatureDifference | dTRac_nominal (from Generic_epsNTU) | Q_flow_nominal/CRac_flow_nominal | Fluid temperature difference at nominal conditions on rack side |
| Nominal thermal performance | |||
| Modelica.Units.SI.HeatFlowRate | Q_flow_nominal (from Generic_epsNTU) | Nominal heat flow rate (negative as it is for cooling) | |
| Modelica.Units.SI.TemperatureDifference | TApp_nominal (from Generic_epsNTU) | Approach temperature on IT loop size (to cooling minus from rack) | |
| Modelica.Units.SI.Temperature | TRacOut_nominal (from Generic_epsNTU) | Outlet temperature to IT rack loop | |
| Nominal condition | |||
| Modelica.Units.SI.MassFlowRate | mPla_flow_nominal (from Generic_epsNTU) | Nominal mass flow rate on cooling plant side | |
| Modelica.Units.SI.MassFlowRate | mRac_flow_nominal (from Generic_epsNTU) | Nominal mass flow rate on rack side | |
| Modelica.Units.SI.PressureDifference | dpHexPla_nominal (from Generic_epsNTU) | Heat exchanger design pressure drop at plant side | |
| Modelica.Units.SI.PressureDifference | dpHexRac_nominal (from Generic_epsNTU) | dpHexPla_nominal | Heat exchanger design pressure drop at rack side |
| Modelica.Units.SI.PressureDifference | dpFilRac_nominal (from Generic_epsNTU) | 65000 | Clean filter design pressure drop at rack-side |
| Flow resistance › Medium 1 | |||
| Real | deltaMPla (from Generic_epsNTU) | 0.1 | Fraction of nominal flow rate where flow transitions to laminar on cooling plant side |
| Real | nPla (from Generic_epsNTU) | 2 | Flow exponent, n=1 for laminar, n=2 for turbulent |
| Flow resistance › Medium 2 | |||
| Real | nRac (from Generic_epsNTU) | 2 | Flow exponent, n=1 for laminar, n=2 for turbulent |
| Real | nFilRac (from Generic_epsNTU) | 1.76 | Flow exponent for filter on rack-side, n=1 for laminar, n=2 for turbulent |
| Real | deltaMRac (from Generic_epsNTU) | 0.1 | Fraction of nominal flow rate where flow transitions to laminar on rack side |
| Plant-side medium for performance data | |||
| Fluid.DataCenterEquipment.CDUs.Types.Media | medPla (from Generic_epsNTU) | Buildings.Fluid.DataCenterEquipment.CDUs.Types.Media.Water | Media for which performance data are specified |
| Real | phiGlyPla (from Generic_epsNTU) | 0 | Glycol volume fraction for which performance data are specified |
| Modelica.Units.SI.MassFraction | XGlyPla (from Generic_epsNTU) | if medPla == Buildings.Fluid.DataCenterEquipment.CDUs.Types.Media.Water then 0 elseif medPla == Buildings.Fluid.DataCenterEquipment.CDUs.Types.Media.EthyleneGlycol then Buildings.Media.Antifreeze.Functions.EthyleneGlycolWater.volumeToMassFraction(phi = phiGlyPla, T = TRacOut_nominal) else Buildings.Media.Antifreeze.Functions.PropyleneGlycolWater.volumeToMassFraction(phi = phiGlyPla, T = TRacOut_nominal) | Glycol mass fraction for which performance data are specified. Set to 0 if only water is used. |
| Rack-side medium for performance data | |||
| Fluid.DataCenterEquipment.CDUs.Types.Media | medRac (from Generic_epsNTU) | Media for which performance data are specified | |
| Real | phiGlyRac (from Generic_epsNTU) | Glycol volume fraction for which performance data are specified. Set to 0 if only water is used. | |
| Modelica.Units.SI.MassFraction | XGlyRac (from Generic_epsNTU) | if medRac == Buildings.Fluid.DataCenterEquipment.CDUs.Types.Media.Water then 0 elseif medRac == Buildings.Fluid.DataCenterEquipment.CDUs.Types.Media.EthyleneGlycol then Buildings.Media.Antifreeze.Functions.EthyleneGlycolWater.volumeToMassFraction(phi = phiGlyRac, T = TRacOut_nominal) else Buildings.Media.Antifreeze.Functions.PropyleneGlycolWater.volumeToMassFraction(phi = phiGlyRac, T = TRacOut_nominal) | Glycol mass fraction for which performance data are specified |
| Valve | |||
| Modelica.Units.SI.PressureDifference | dpValve_nominal (from Generic_epsNTU) | dpHexPla_nominal | Nominal pressure drop of fully open valve on chiller plant side |
| Dynamics › Valve | |||
| Modelica.Units.SI.Time | strokeTime (from Generic_epsNTU) | 120 | Time needed to fully open or close actuator |
| Dynamics › Pump | |||
| Modelica.Units.SI.Time | riseTime (from Generic_epsNTU) | 30 | Time needed to change motor speed between zero and full speed |
| Pump | |||
| Modelica.Units.SI.PressureDifference | dpPumpExt_nominal (from Generic_epsNTU) | Pump head available for flow network that is connected to the CDU on the rack-side at m_flow_nominal | |
| Buildings.Fluid.Movers.BaseClasses.Characteristics.flowParameters | pumpExtHead (from Generic_epsNTU) | Pump head available for flow network that is connected to the CDU on the rack-side | |
| Buildings.Fluid.Movers.BaseClasses.Characteristics.flowParameters | pumpHead (from Generic_epsNTU) | Actual head of the pump, composed of external pump head, and head used for heat exchanger and filter | |
| Advanced › Heat transfer coefficients | |||
| Real | r_nominal (from Generic_epsNTU) | (kPla_default*(mPla_flow_nominal/etaPla_default)^nConPla*PrPla_default^(1/3))/(kRac_default*(mRac_flow_nominal/etaRac_default)^nConRac*PrRac_default^(1/3)) | Ratio between convective heat transfer coefficients at nominal conditions, r_nominal = hAPla_nominal/hARac_nominal |
| Real | nConPla (from Generic_epsNTU) | 0.8 | Exponent for convective heat transfer coefficient, h~m_flow^nCon |
| Real | nConRac (from Generic_epsNTU) | nConPla | Exponent for convective heat transfer coefficient, h~m_flow^nCon |
| Advanced › Expansion vessel | |||
| Modelica.Units.SI.Volume | VExp (from Generic_epsNTU) | -0.056/2E6*Q_flow_nominal | Size of expansion vessel on IT loop side |
Revisions
-
April 13, 2026, by Michael Wetter:
First implementation.