Implementing Hot and Cold Air Containment in Existing Data Centers

Implementing Hot and Cold Air p gContainment in Existing D t C tData CentersSchneider ElectricSchneider Electric Data Center Science Center White Paper 153

Schneider Electric – Data Center Science Center WP 153 Presentation – July 2014

Containment solutions can eliminate hot spots and provide energy savings over traditional uncontained data center designs. The best containment solution for an existing facility will depend on the constraints of the facility. While ducted hot aisle containment is preferred for highest efficiency cold aislecontainment is preferred for highest efficiency, cold aisle containment tends to be easier and more cost effective for facilities with existing raised floor air distribution. This paper investigates the constraints reviews all available containmentinvestigates the constraints, reviews all available containment methods, and provides recommendations for determining the best containment approach.


Introduction

Improve predictability and efficiency

Containment benefits include increased• Reliability

R k d it• Rack power density• Cooling capacity• Cooling system energy savings


Containment Methods

Hot Air and Cold Air

Containment methods

Contain hot air Contain cold air

Ducted rackDucted hot

aisle containment

Row-cooled hot aisle

containment

Rack air containment

Cold aisle containment

Row-cooled cold aisle

containmentcontainment containment containment


See White Paper 55, “The Different Types of Air Distribution for IT Environments”, for more information.

Assess the Facility

Essential to choosing the right containment solution

• Assessment should be done in advance• Note constraintsNote constraints

• Constraints – obstacles that cannot be overcome or only changed at great expense or with unacceptable consequences

• Determine cost or consequence of constraintsDetermine cost or consequence of constraints• Constraints include

• Facility limitations• Regulatory limitations• Regulatory limitations• Unchangeable business requirements


Assess the Facility -- Constraints

IT equipment arrangement

• Lack of hot/cold aisle arrangement limits choice of containment solution

• Proper aisle widths also essential for aisle containment deployment



Ceiling height

• Need room to install drop ceiling• Used as air return plenumUsed as air return plenum

• Essential for ducted hot aisle containment or ducted rack solutions



Raised floor plenum depth

• Insufficient depth will not provide sufficient cooling air volume to higher density racksg y

• Due to• Poor design• Resistance caused by cabling conduit and pipingResistance caused by cabling, conduit, and piping

• Limits ability to adopt cold aisle containment solution



Column location

• Two main locations• Two main locations• Within row of racks• Aligning with rack aisle

M i t f b t l• May cause interference between columns and aisle containment panels



Cabling

• Overhead cabling can interfere with ducted containment panelsp

• May eliminate ducted hot aisle containment or ducted rack solutions

• Cabling routed across aisle in single locationCabling routed across aisle in single location may allow ducted solutions



Air distribution type

• Critical to determining investment level and complexity of containment methodEasy and cost effective to deploy• Easy and cost effective to deploy

• hot air containment for data centers with targeted return and flooded supply

• cold air containment for data centers with targeted supply and• cold air containment for data centers with targeted supply and flooded return.

Targeted return and flooded supply Targeted supply and flooded returnTargeted return and flooded supply Targeted supply and flooded return



Considerations for lighting

• Creating containment space can cause poor lighting• Transparent or translucent ceilings only partially effective

P l t di t• Panels can get dirty



Considerations for fire detection and suppression system

• Air containment directs high air volume t IT i t d b k t li itat IT equipment and back to cooling units• Can dilute smoke

• Makes detection and suppression more diffi ltdifficult

• Detector affected by local airflow patterns, smoke dilution

• Suppression agent dispersion affected• Suppression agent dispersion affected by airflow volume, obstructions



Considerations for a cooling outage

• Air containment solutions influence ride through time during cooling outage


See White Paper 179, “Data Center Temperature Rise During a Cooling System Outage”, for more information.

Assess the Facility -- ConstraintsConsiderations for working conditions around IT equipmentq p

• Containing cold air makes rest of room same temperature as hot aisleaisle

• Can become uncomfortable for personnel in data center

• IT equipment on data center• IT equipment on data center perimeter may be negatively affected

• May also violate OSHA• May also violate OSHA regulations or ISO 7243 guidelines for exceeding wet-bulb globe temperature


globe temperature

Review All Potential Solutions

Likely solutions

All solutions• Allow for higher rack power densities

All f i d li• Allow for increased cooling system energy savings

• Eliminate hot spots• Increase cooling unit capacity

• Hot and cold air containment types should ypnever be mixed

• Lowers cooling system efficiency



Cold aisle containment system (CACS)

Raised floor cooling distribution system• Encloses cold aisle, making rest of room large hot-air return plenum

R d d h• Recommended when• Racks and IT equipment are in a hot aisle/cold aisle arrangement• Data center uses a raised floor and flooded return air distribution method• There are no stand-alone IT devices on the data

center perimeter• High density racks can’t draw or pull enough

cool air from the raised floorcool air from the raised floor• Containment project must be completed quickly


See White Paper 135, “Impact of Hot and Cold Aisle Containment on Data Center Temperature and Efficiency”, for more information.


Ducted hot aisle containment system (Ducted HACS)

Used with either raised floor- or hard floor-based air distribution system• Encloses hot aisle, allowing rest of data center to become a large cold-

air plenumair plenum• Recommended when

• Racks and IT equipment are in a hot/cold aisle arrangementarrangement

• There is a drop ceiling hot air return plenum• There are stand-alone IT devices on data center

perimeterperimeter• Data center is frequently occupied by personnel

• Will not create a hot working environment in the uncontained area)


See White Paper 182, “The Use of Ducted Air Containment Systems in Data Centers ”, for more information.


Ducted rack

Best in environments with scattered high density racks with front-to-back airflow pattern

• Duct mounted to back of rack contains hot exhaust air and ducts it into drop iliceiling

• Recommended when• Data center has a drop ceiling, air return plenum• Data center has scattered high density racks• Data center has scattered high density racks• Rack rows have unequal length• Rack uses front-to-back airflow pattern• No hot aisle/cold aisle arrangement and it’s impractical to g p

migrate to it• Data center is frequently occupied by personnel • Building columns interfere and prevent aisle containment solutions


See White Paper 182, “The Use of Ducted Air Containment Systems in Data Centers ”, for more information.

Review All Potential SolutionsRow-cooled hot aisle containment system (Row-cooled HACS)

Best in data centers with existing row-based cooling units; also for data centers with perimeter cooling unit

• With existing in-row cooling units, containment by adding ceiling panels over aisle• With existing perimeter cooling, cooling units added between racks • Recommended when

• Data center has a drop ceiling, air return plenumI li it l d d l d• In-row cooling units already deployed

• Racks and IT equipment in hot aisle/cold aisle arrangement• Cold aisle containment and ducted hot aisle containment are poor choices• Higher density racks are being added to existing lower density data centerHigher density racks are being added to existing lower density data center• Where floor space must be conserved• Data center is frequently occupied by personnel• Containment project must be completed quickly


See White Paper 134, “Deploying High-Density Pods in a Low-Density Data Center”, for more information.


Rack air containment system (RACS)

Best in data centers with very high-density racks• Integrates rack-based cooling units with racks to keep air circulation within

containment

Single rack

Multiple racks


See White Paper 130, “Choosing Between Room, Row, and Rack-based Cooling for Data Centers”, for more information.


Rack air containment system (RACS) – cont.

Recommended when• Data center has a drop ceiling, air return

plenump• There are scattered high density racks,

or sound attenuation is required• Complete isolation is required, such asComplete isolation is required, such as

stand-alone open data center environments, or mixed layouts, or to prevent exposure to hot aisles.

• Wiring closets lack any form of cooling, exposing high density equipment to high temperatures


Review All Potential SolutionsRow-cooled, cold aisle containment system (Row-cooled CACS)

Best in data centers with perimeter cooling units, and all racks are in some form of cold aisle containment

• Encloses cold aisle; containment system deployed as a pod

( )

Encloses cold aisle; containment system deployed as a pod• Recommended when

• Racks and IT equipment are in a hot/cold aisle arrangement

• All IT racks can be configured with some form of cold aisle containment to avoid exhaust hot air to the fronts of uncontained racks

• Raised floor cooling has reached maximum airflowRaised floor cooling has reached maximum airflow capacity due to height and/or congestion

• More perimeter cooling units cannot be added to increase cooling capacity• Containment project must be completed quickly


See White Paper 137, “Energy Efficient Cooling for Data Centers: A Close-Coupled Row Solution”, for more information.

Comparison of Air Containment MethodsContainment method Pros Cons

Cold air containment

Cold aisle containment system

Easy and cost effective for raised floor applications; cooling capacity can be shared with other racks within two rows; fastest deployment time of all containment types

Lower number of free cooling hours; creates uncomfortable working environment in uncontained areas

Row-cooled cold In-row cooling units increase cooling capacity of existing CACS Higher first capital cost; need toRow-cooled, cold aisle containment system

In-row cooling units increase cooling capacity of existing CACS environment with perimeter cooling units; prepackaged solution can save deployment time

Higher first capital cost; need to move IT racks to insert row-based cooling units within row

Hot air containment

Ducted rack Easy to deploy for scattered HD racks; Don’t require a hot aisle / cold aisle arrangement; can be deployed piece by piece to reduce upfront capital cost; offers higher number of free cooling hours

May cause pressure imbalance inside of drop ceiling or between nearby racks; increased labor time; longer deployment timetime; longer deployment time for each rack

Ducted, hot aisle containment system

Creates comfortable work environment in uncontained areas; cooling capacity can be shared with other racks within two rows; offers higher number of free cooling hours

High temperature in the hot aisle may create uncomfortable work environment in contained area, longer deployment time for each rackrack

Row-cooled, hot aisle containment system

Low-cost option for data centers with existing row-based cooling. Thermally neutral to the existing room-based cooling system; cooling capacity can be shared with other racks within two rows; prepackaged solution can save deployment time

In data centers with existing perimeter cooling units: Higher upfront capital cost; need to move IT racks to insert row-based cooling units within row.

i i iHigh temperature in hot aisle may create uncomfortable work environment in contained area

Rack air containment system

Almost immune to the constraints of existing facility; easy to plan for any power density; isolated from the existing cooling system; attenuates noise

In data centers with existing perimeter cooling units, has the highest first cost because more


cooling units are needed; cooling capacity can’t be shared with other racks; containment will add the depth of rack which will consume more floor space

Select Containment Methods

Based on physical constraints

• Acceptable to implement both types of cold air containment or multiple types of hot air containmentp yp

• Hot and cold air containment types should never be mixed• Leads to lower cooling system efficiency


Select Containment MethodsSelect containment according to common air distribution methods. X means not recommended or impractical

Air distribution method

Type 1 Type 2 (perimeter cooling units)Type 2 (row-based cooling

units)

Cold air containment

Cold aisle containment system Preferred Selected when fast

deployment is required xRow-cooled cold aisle containment

Used when additional capacity is unattainable from existing perimeter cooling

Used when additional capacity is unattainable from existing perimeter cooling x

systemexisting perimeter cooling units or raised floor limitations

existing perimeter cooling units or raised floor limitations

xDucted rack x Only recommended for

scattered high density racks xDucted hot aisle x Preferred x

Hot air containment

containment system x Preferred xRow-cooled hot aisle containment system x

Used when additional capacity is unattainable from existing perimeter cooling units or raised floor limitations

Preferred


units or raised floor limitations

Rack air containment system Only recommended for scattered high density racks or to contain a single rack row

Select Containment MethodsSelect containment according to less common air distribution methods. X means not recommended or impractical

Air distribution method

Type 3 Type 4 Type 5 Type 6

r

ent

Cold aisle containment x x x Preferred

Col

d ai

rco

ntai

nme system

Row-cooled cold aisle containment system

x x xUsed when additional capacity is unattainable from existing perimeter cooling units

men

t

Ducted rack x xOnly recommended for scattered high density racks

xDucted hot aisle containment x x Preferred x

ot a

ir c

onta

inm containment

system

x x x

Row-cooled hot aisle containment

Selected when new high density racks need to be added in a traditional low density

Selected when new high density racks need to be added in a traditional low density

Used when additional capacity is unattainable from existing perimeter cooling nits

x


Ho system

ydata center

ydata center cooling units

Rack air containment system

Only recommended for scattered high density racks or to contain a single rack row

Selecting Containment Hardware

Considerations when deploying

• Customized containment solutions may be required if different kinds of IT racks exist

• Look for FLEXIBILITY, containment solutions that• Adapt to varying aisle widths, rack heights and depths to support

either hot or cold aisle containment, or single rows• Easy over aisle access means individual panels can be removed,

providing above-aisle access for cabling and maintenance




• For aisle containment or ducted rack, additional lighting fixture may be requiredy q

• Look for LIGHTING, containment solutions that• Specify overhead panels that

transmit up to 90% of lightp g• Use high efficiency LED lighting

with on/off motion sensors




• Fire suppression may be required by authority having jurisdiction (AHJ) inside of the aisle containment

• Look for FIRE SUPPRESSION, containment solutions that• Alert personnel• Drop ceiling panels based on temperature or smoke detectors• Emergency break-away sliding doors to exit aisle quickly in an

emergency

Normal Detect the fire Drop the ceilingNormal Detect the fire Drop the ceiling


Ongoing Air Management Maintenance

Monitor airflow patterns and temperature

• For cold aisle containment• Control air flow based on pressure differential of aisle• Monitor non-rack IT equipment in the uncontained area to insure

adequate cool supply air• For ducted hot aisle containment

• Mitigate high temperature in hot aisle by temporarily opening aisle doors to let in cooler aircooler air


Conclusion

● Two containment methods – hot air and cold air● Cold aisle containment and ducted hot aisle containment -- two most

common solutions for data centers with existing perimeter cooling units● Cold aisle containment preferred for facilities with raised floor as a p

supply air plenum● Ducted hot aisle containment preferred for facilities with drop ceiling as

the hot air return plenump● Row-cooled hot aisle containment is preferred for data centers with

existing row-based cooling units

These conclusions are for existing data centers. For new data centers, please see


These conclusions are for existing data centers. For new data centers, please see White Paper 135, “Impact of Hot and Cold Aisle Containment on Data Center Temperature and Efficiency”.

ResourcesImpact of Hot and Cold Aisle Containment on Data Center Temperature and Efficiency White Paper 135

The Different Types of Air Distribution for IT EnvironmentsWhite Paper 55White Paper 55

Data Center Temperature Rise During a Cooling System OutageWhite Paper 179

The Use of Ducted Air Containment in Data CentersWhite Paper 182

Energy Efficient Cooling for Data Centers: A Close-Coupled Row SolutionWhite Paper 137

Choosing Between Room Row and Rack-based Cooling for Data Centers

p

Deploying High-Density Pods in a Low-Density Data CenterWhite Paper 134

Browse all APC white papers whitepapers.apc.com

Choosing Between Room, Row, and Rack based Cooling for Data CentersWhite Paper 130


Browse all APC TradeOff Tools™tools.apc.com

Technology

Implementing Hot and Cold Air Containment in Existing Data Centers