An Overview Of Cold And Hot Aisle Containment

Cold Aisle Containment An overview of cold and hot aisle containment

Containment is about isolating hot air from cold air

No sealing above and around racks allows mixing and lets cold air escape without doing any work

Containment seals above and around racks and prevents mixing

Air mixing and air escaping is costly

Change from 19⁰ to 32⁰ Delta-T improves CRAH capacity 49%

Hot spots cause failures and shorten equipment life

Typically, a chiller will operate 1% more efficiently for every 1°F increase in the chilled water supply temperature

Set points kept low to assure cold air at top of racks

14°F to 20°F temp differential in chill water increases piping capacity by 43%

Containment Options Depend on ceiling type and fire safety constraints

Cap •Panels rest on racks or hang from cables •Ceiling open grid or too tall for curtains

Stovepipe/Open Top •Curtains or Panels go partially up to ceiling •Ceiling is over 15’ but capping is too difficult or not allowed

Walls •Curtains hang from drop ceiling •OK for ceilings 12’ or under

After Cold Aisle or Hot Aisle Containment Savings and benefits Immediate Energy Savings •Energy savings from increased CRAH efficiency •Lower demand on chilled water plant Next Step Energy Savings •Raise set points (can do this now that inlet temperatures are more uniform) •Turn off CRAH units •Raise chilled water temperature •Increase number of hours of economizer usage (again, with more uniform inlet temperatures, cab bring in warmer air) Reliability •More uniform inlet temperatures •Reduced heat related failures Capacity •Can add more servers •Defer capital expenditures

Cap Design Sample Cold Aisle Containment, Panels, Open Grid Ceiling

Uniform racks

Panels held by racks

Strip curtain doors connected directly to racks

Stovepipe/Open Top Design Sample Cold Aisle Containment, Panels, Open Grid Ceiling, Slab Floor Uniform racks, containment connected directly to racks Overhead cooling ducts drop into stovepipe containment

Slab floor

Wall Design Sample Curtains Hung from Drop T-Bar Ceiling

Curtains connect to drop ceiling

Single sided cold aisle

Fire Safety – Containment’s Biggest Issue Fuse Links - Curtains Hanging curtains could obstruct sprinkler coverage zones •It is costly to move and add sprinkler heads, especially in a dry type system •Fuse links let curtains drop prior to sprinkler head activation, avoiding the need to move or add sprinkler heads •BUT, not every fire marshal or insurance company is signed on for this approach •SO, check first. •PLUS, the are other containment solutions that meet more stringent requirements.

Typical Cold Aisle or Hot Aisle Containment Project Each project has these three key steps

BASELINE • Rack Temperatures • Delta-T’s

CONTAIN • • • •

Barriers above racks Doors on aisle ends Blanking panels Filling floor gaps

TUNE • CRAH on/off • Change set points

Polargy Containment Case Study Site:

Savings: CRAC reduction 1 CRAC turned off, 2 put in standby

2000 square foot, high density site Problem: High energy bills, hot air recirculation under racks. Containment: Cold aisle containment with panels and strip curtains on aisle ends. Contained two cold aisle. Blanking panels and Air Dam Foam under racks. Cooling: Available cooling: 200 tons Average cooling load: 150 tons Average IT load: 350 kW Cooling required for 330kW: Excess cooling: 47 tons

103 tons

Annual Savings: Investment: Rebate:

$30,000 validated by PG&E $30,000 $15,000 rebate from PG&E

Payback Period:

6.0 months

Containment ROIs Are Compelling Compelling ROI • Energy savings from increased CRAH efficiency • Lower demand on chilled water plant saves energy • Reduced heat related failures • Power utility rebates • More data center capacity

www.polargy.com

Polargy, Inc. 256 Gibraltar Drive, Suite 155 Sunnyvale, CA 94089 888.816.8338