Datacenter Modeling must do - minimum inputs for ensuring accuracy
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Transcript of Datacenter Modeling must do - minimum inputs for ensuring accuracy
![Page 1: Datacenter Modeling must do - minimum inputs for ensuring accuracy](https://reader034.fdocuments.us/reader034/viewer/2022042716/55a9b10e1a28ab480c8b48f8/html5/thumbnails/1.jpg)
Modeling Must Do’s:
Minimum Inputs for Ensuring Accuracy
and
Using Simulation in Capacity Management
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Our Findings....The Devil is in the Detail!
3kW - Simple 3kW - Detailed
One Room, two different representations of 3kW
Completely Different Results
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Modeling Must Do’s –
Minimum CFD Inputs
• Accurate Representation of IT Devices
• Differences in cabinet modeling
• Buoyancy modeling
• Cooling unit discharge
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Modeling Must Do’s –
Minimum CFD Inputs
• Accurate Representation of IT Devices
• How does representation of air jets from high density servers, such as blades,
affect results?
• Differences in cabinet modeling
• Does the modeling of blanking plates matter?
• Do cabinet accessories such fans, vents, penetrations, etc. affect the results?
• Buoyancy modeling
• How much does buoyancy affect the flow field?
• Cooling unit discharge
• How do different fan types affect airflow?
• Uniform discharge
• Blower
• Plug fans
• Axial/Propeller fans
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Capturing Exhaust Jets
“Simple CFD” –
•Little or no capability to model multiple
outflows – lumped outflow is best way of
modeling…
• The outflow for this model is same height
and width of the device
RoomLite -
Outflows are modeled as per
specification i.e. width and
height
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Thermal Footprint
Both servers are the same power density
and same exhaust flow volume but have a
different thermal footprint
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Sample Room
• 7 Racks with IBM Blade Center
Chassis
• 2’ Raised Floor
• Single ACU
• 30% Perforated Grills
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Result of Modeling Details
With Accurate Thermal Footprint
of Blade Center Fans
With a Lumped Exhaust from
Blade Center
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Modeling Must Do’s –
Minimum CFD Inputs
• Accurate Representation of IT Devices
• How does representation of air jets from high density servers, such as blades,
affect results?
• Differences in cabinet modeling
• Does the modeling of blanking plates matter?
• Do cabinet accessories such fans, vents, penetrations, etc. affect the results?
• Buoyancy modeling
• How much does buoyancy affect the flow field?
• Cooling unit discharge
• How do different fan types affect airflow?
• Uniform discharge
• Blower
• Plug fans
• Axial/Propeller fans
![Page 10: Datacenter Modeling must do - minimum inputs for ensuring accuracy](https://reader034.fdocuments.us/reader034/viewer/2022042716/55a9b10e1a28ab480c8b48f8/html5/thumbnails/10.jpg)
Difference in Cabinet Modeling
Unblanked Rack Blanked Rack
Empty U-Slots
Open
Side Gap
Open
Gap Below
First U-Slot
Open
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Difference in Results
Temperatures are higher
in the cabinet with no
blanking
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Airflow Paths in Unblanked Cabinet
Open U-Slot
Recirculation
Side Gap Open
Recirculation
Under Cabinet
Recirculation
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Modeling Must Do’s –
Minimum CFD Inputs
• Accurate Representation of IT Devices
• How does representation of air jets from high density servers, such as blades,
affect results?
• Differences in cabinet modeling
• Does the modeling of blanking plates matter?
• Do cabinet accessories such fans, vents, penetrations, etc. affect the results?
• Buoyancy modeling
• How much does buoyancy affect the flow field?
• Cooling unit discharge
• How do different fan types affect airflow?
• Uniform discharge
• Blower
• Plug fans
• Axial/Propeller fans
![Page 14: Datacenter Modeling must do - minimum inputs for ensuring accuracy](https://reader034.fdocuments.us/reader034/viewer/2022042716/55a9b10e1a28ab480c8b48f8/html5/thumbnails/14.jpg)
Demonstration of Ducted Delivery and
Buoyancy
• Overhead ducted
Air delivery
system
• Return Vent in hot
aisle
• 3.5 kW per cabinet
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Demonstration of Ducted Delivery and
Buoyancy
Gravity Modeled Gravity Ignored
Buoyancy driven flow not captured when Gravity Ignored.
Hot air seems to sink!
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Demonstration of Ducted Delivery and
Buoyancy
Gravity ModeledGravity Ignored
Major Variation in Airflow Paths
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Demonstration of Ducted Delivery and
Buoyancy
Gravity Modeled Gravity Ignored
Results in Major Variation in Cabinet Inlet Temperature
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Modeling Must Do’s –
Minimum CFD Inputs
• Accurate Representation of IT Devices
• How does representation of air jets from high density servers, such as blades,
affect results?
• Differences in cabinet modeling
• Does the modeling of blanking plates matter?
• Do cabinet accessories such fans, vents, penetrations, etc. affect the results?
• Buoyancy modeling
• How much does buoyancy affect the flow field?
• Cooling unit discharge
• How do different fan types affect airflow?
• Uniform discharge
• Blower
• Plug fans
• Axial/Propeller fans
![Page 19: Datacenter Modeling must do - minimum inputs for ensuring accuracy](https://reader034.fdocuments.us/reader034/viewer/2022042716/55a9b10e1a28ab480c8b48f8/html5/thumbnails/19.jpg)
Fan Types
Centrifugal Fan
(Blower)
Radial Fan
(Plug Fan)
Axial Fan
(Propeller Fan)
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Airflow Patterns
Centrifugal Fan
Radial Fan Axial Fan
Uniform Discharge
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Pressure Distribution
Centrifugal Fan Radial Fan Axial FanUniform Discharge
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Grill Airflow Distribution
Centrifugal Fan Radial Fan Axial FanUniform Discharge