modelAirRearDoorHexPassive
Extends from Buildings.Fluid.DataCenters.Racks.Hybrid.BaseClasses.PartialAirRearDoorHex (Partial model for air-cooled rack with a rear door heat exchanger).
Information
Model of an air-cooled IT rack with a passive rear door heat exchanger.
This model extends Buildings.Fluid.DataCenters.Racks.Hybrid.BaseClasses.PartialAirRearDoorHex and adds a rear door heat exchanger using Buildings.Fluid.DataCenters.Racks.RearDoorHeatExchangers.Passive.
The rear door heat exchanger is connected between the air outlet of the
air-cooled rack component air.port_b and the top-level air outlet
port portAir_b.
It cools the warm rack exhaust air using a liquid coolant loop connected
through portReaDooHex_a (inlet) and portReaDooHex_b (outlet).
The medium for the rear door heat exchanger coolant is MediumReaDooHex.
The model has separate fluid ports for each cooling loop.
For the rear door heat exchanger coolant, portReaDooHex_a and portReaDooHex_b
serve as the inlet and outlet ports.
If the fan of the air-cooled IT is controlled based on the rack outlet temperature, then the temperature between the rack and the rear door heat exchanger is used as the measurement signal; otherwise, the IT load is used as an input for the fan controller
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Performance data | |||
| Buildings.Fluid.DataCenters.Racks.Hybrid.Data.AirRearDoorHexPassive.Generic | dat (from Air) | Performance data | |
| Dynamics › Air cooling | |||
| Modelica.Fluid.Types.Dynamics | energyDynamicsAir (from Air) | Modelica.Fluid.Types.Dynamics.DynamicFreeInitial | Type of energy balance for air-cooled component: dynamic (3 initialization options) or steady state |
| Modelica.Units.SI.Time | tauAir (from Air) | 2 | Time constant of air outlet temperature at nominal flow |
| Initialization › Air cooling | |||
| Modelica.Units.SI.Temperature | TAir_start (from Air) | 293.15 | Start value of air temperature |
| Fan controller | |||
| Buildings.Fluid.DataCenters.Racks.FanControllers.Types.Strategy | fanControl (from Air) | Buildings.Fluid.DataCenters.Racks.FanControllers.Types.Strategy.Load | Type of fan control strategy |
| Real[:,:] | fanSpeed (from Air) | [0.0, 0.0; 1.0, 1.0] | Load and fan speed matrix (1st column normalized IT load, 2nd fan speed), e.g., fanSpeed=[0, 0; 0.5, 0.7; 1, 1]) |
| Modelica.Units.SI.Temperature | TAirOut_set (from Air) | dat.air.TOut_nominal | Set point temperature for rack outlet air |
| Real | k (from Air) | 1 | Gain of fan PI controller |
| Modelica.Units.SI.Time | Ti (from Air) | 60 | Integrator time constant of fan PI controller |
| Assumptions | |||
| Boolean | allowFlowReversal (from Air) | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Boolean | allowFlowReversalCoo (from PartialAirRearDoorHex) | true | = false to simplify equations, assuming, but not enforcing, no flow reversal for rear door heat exchanger coolant |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | portAir_a (from Air) | Air cooling inlet port | |
| Modelica.Fluid.Interfaces.FluidPort_b | portAir_b (from Air) | Air cooling outlet port | |
| Modelica.Blocks.Interfaces.RealInput | PAir (from Air) | Power consumed by air-cooled IT | |
| Modelica.Blocks.Interfaces.RealOutput | PAirTot (from Air) | Electric power consumed by air-cooled IT, including fan energy | |
| Modelica.Blocks.Interfaces.RealOutput | PAirFan (from Air) | Electric power consumed by fan for air-cooled IT | |
| Modelica.Fluid.Interfaces.FluidPort_a | portReaDooHex_a (from PartialAirRearDoorHex) | Rear door heat exchanger coolant inlet port | |
| Modelica.Fluid.Interfaces.FluidPort_b | portReaDooHex_b (from PartialAirRearDoorHex) | Rear door heat exchanger coolant outlet port |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Fluid.DataCenters.Racks.Air.Rack_P | air (from Air) | Air-cooled rack component | |
| Buildings.Fluid.DataCenters.Racks.RearDoorHeatExchangers.BaseClasses.PartialRearDoorHeatExchanger | reaDooHex (from PartialAirRearDoorHex) |
Revisions
-
September 29, 2026, by Michael Wetter:
First implementation.