myths of data center containment:whats's true and what's not

Myths of Data Center Containment: What’s True and What’s Not

Lars Strong, P.E., Upsite Technologies

Airflow Management Awareness Month

June 8, 2016

Why Airflow Management

© Upsite Technologies, Inc.05/02/2023 2

Total Load

IT LoadPUE =

Mechanical plant + cooling fans: 35% of total load, 73% of non IT Load

2002 Uptime Institute Research

Bypass Airflow* 60%

Hot Spots 10%

Cooling Capacity 2.6x

2013 Upsite Technologies Research

Bypass Airflow* 48%

Hot Spots 20%

Cooling Capacity 3.9x

*More accurately, “Raised Floor Bypass Open Area” in today’s terminology.

The State of Airflow Management


Raised floor

area (sq ft)

# of running cooling units

Raised floor

bypass open

area (%)

Hot spots (%

of cabinets

)

Cold spots (%

of cabinets) (Data from 6 sites)

Proper perforated tile

placement (%)

Cooling Capacity Factor (CCF)

Averages 7,527 8 48% 20% 35% 77% 3.9Minimum 720 2 13% 0% 0% 7% 1.2Maximum 37,00

040 93% 86% 86% 100% 32.0

Recommended

n/a n/a <10% 0% 0% 100% 1.2Conclusion: Inefficient cooling configuration / airflow management is the problem; capacity is not the problem.

Research


Large unsealed cable openings can release ¼ of a cooling units capacity.

Raised Floor Open Area


Raised floor openings sealed with KoldLok brush grommets

Raised Floor Open Area


IT Intake Air Temperatures are Paramount


Airflow is invisible Cooling capacity is difficult to quantify Mixed messages in the market Vendor influence Lack of education

Why are Myths Prevalent


• Money

• OpEx Savings• CapEx Savings

• Capacity• Cooling Capacity

• IT Reliability

• Green Initiatives• CO2 Reduction

A 4,000 Sq. Ft. data center could reduce its operating expense by $60,000 annually, simply by improving airflow management.

AFM Problems Are an Opportunity


“Containment eliminates bypass airflow”

• Bypass airflow – any conditioned air that does not pass through IT equipment before returning to a cooling unit.

Myth #1


Bypass Airflow Clarified

Typical existing conditions

© Upsite Technologies, Inc.© Upsite Technologies, Inc.05/02/2023 11


After raised floor AFM improvements



With Containment



Optimized


“Containment improves efficiency / reduces costs”

• Only true if reduction of hot spots reduce IT equipment fan speeds

• Creates the opportunity to improve efficiency and reduce costs

Myth #2


Stranded Capacity of low temperature set pointsLiebert DX Model VH267W 20-Ton Cooling Unit

Environmental Condition

Total(kW)

Latent(kW)

Sensible(kW)

72°F, 45% Rh 67.0 0 67.070°F, 48% Rh 64.5 4.8 59.7Stranded 2.5 4.8 7.3Stranded (%) 4% 11%

Stranded Capacity


Stranded Capacity from low temperature set pointsLiebert Chilled Water Model 600C CRAH Unit

Cooling capacity increase from 7°F return air increase

Environmental Condition

Total(kW)

Latent(kW)

Sensible(kW)

72°F, 45% Rh 98.0 0 98.065°F, 45% Rh 70.0 0 70.0Stranded 28.0 0 28.0Stranded (%) 40% 40%

Stranded Capacity


“When containment is deployed, perforated-tile placement doesn’t matter”

•There can be too many perforated tiles or grates in a cold aisles

Myth #3


Misplaced/Excessive Supply Tiles


“Containment increases the return air temperature to cooling units”

•Thermostat controls return air temperature

•Same flow rate and heat load so same average delta T

Myth #4


Bypass Airflow Revealed


“Full containment is essential, partial containment doesn’t work.”

• Doors alone can produce significant benefits• Sealing rack openings can make an impact• A few baffles can eliminate isolated hot spots

Myth #5


Full containment didn’t solve intake air temperature problems

Hot and cold spots are still present

Myth #5


Rack AFM is crucial to any aisle level solution

Myth #5


No Containment


Baffles and Doors


Modular Containment

Modular Containment

Cold Aisle Application

Hot Aisle Application


Modular Containment

Angled Rack Top Baffles (Cold Aisle)

Adjustable Rack Gap Panel

Vertical Rack Top Baffles (Hot Aisle)

Modular Containment


Identify Your Opportunity


There are two types of computer rooms

1. Those without IT equipment intake air temperature problems

• Improving AFM enables them to be more efficient

2. Those with IT equipment intake air temperature problems

• Improving AFM solves intake air temperature problems (hot

spots and cold spots) and enables them to be more efficient

• More efficient results in: lower OPEX, deferred CAPEX,

increased cooling capacity

A metric Upsite Technologies developed to estimate the utilization of computer room cooling infrastructure.

CCF is a ratio of the total rated cooling capacity to estimated heat load.

The Cooling Capacity Factor (CCF)


Convert the total rated (stated) cooling capacity to kW, divide by 110% of the IT critical load (kW)

7 – 30 ton cooling units (210 tons) UPS load 235 kW

Total rated cooling capacity (210 tons x 3.52) = 739 kW

110% of the IT critical load (235 x 1.1) = 259 kW

CCF = 2.8 (739/259) Running cooling capacity is 280% of the load

CCF: How It’s Calculated


CCFTons x 3.52 = kWcCooling unit capacityRated capacity at standard conditions (75 deg F, 45%Rh)Capacity goes up with increase in return temperatureCapacity goes down with decrease in return temperature

At 80% fan speed80% airflow volumeOnly 50% of fan energy

Identify Your Opportunity


Relationship BetweenFlow rate : Delta T : Heat load

CFM =

q = amount of heat transferredCp = specific heat of airΔT = temperature rise of air across the heat source W = mass flow

CFM = cubic feet per minute of airflow through the server3.16 = factor for density of air at sea level in relation to F⁰ΔT = temperature rise of air through the server in F⁰

q = Cp x W x ΔT

3.16 x W Delta T

Heat Transfer Equation


Relationship BetweenFlow rate : Delta T : Heat load

“Blade” servers at 35 F ⁰ ΔT consume 90 CFM / kW

“Pizza box” servers at 20 F ⁰ ΔT consume 158 CFM / kW

UPS load (kW) x CFM/kW = Total IT CFM

Typical IT Cooling Airflow Rates


Key Airflow Management Metrics

AFM Metrics

IT Equipment Intake Air Temperature Cooling Capacity Factor (CCF) Raised Floor Open area Supply Tile Placement (perforated tiles and grates) Blanking Panel Utilization Bypass Airflow

A holistic approach An iterative process ‘Check in’ at the room level

after making any AFM improvements

Watch video at:upsite.com/resources/airflow-management/

Upsite’s 4 R’s of Airflow Management™


http://www.upsite.com/resources/airflow-management/

http://www.upsite.com/resources/airflow-management/

05/02/2023 © Upsite Technologies, Inc. 38

June 15: How IT Decisions Impact Facilities: The Importance of Mutual UnderstandingPresented by Ian Seaton and Lars Strong, P.E.

June 22: The 4 Delta T’s of Airflow ManagementPresented by Lars Strong, P.E.

Register at upsite.com/airflow-management-awareness-month

Upcoming Webinar Schedule

http://www.upsite.com/airflow-management-awareness-month/

Thank you!

@UpsiteTech

blog.upsite.com

On LinkedIn

Lars Strong, P.E.Senior Engineer, Upsite [email protected]

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myths of data center containment:whats's true and what's not

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