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CRAC (Computer Room Air Conditioner):

In

addition to proper maintenance, follow these tips:

Turn off re-heat in CRACs

(if possible).

Check glycol levels (freeze points):

water glycol

mix – often over time water is added diluting the

mixture in your glycol loop, which increases the risk

of freezing.

Cool servers per ASHRAE standards:

The latest

ASHRAE standards recommend higher setpoints,

allowing instant energy savings.

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Generators:

Standby Power systems need routine

maintenance to ensure reliable operation when a

utility failure occurs. In addition to proper

maintenance, consider these additional steps.

• Frequently check the starting batteries and block

heaters.

• Frequently check and maintain the belts and hoses.

• Frequently check and maintain all fluids.

• After every PM activity, be sure the technician has

returned the operating switch to “Auto”.

• Implement a program to annually sample and test

coolant, fuel and oil for breakdown or

contaminants.

• Automatic Transfer Test – Using Building Load

• Implement a program for annual load bank testing

(more often if possible).

• Implement a program for fuel polishing if the fuel

will be idle for long periods of time.

ROOM LAYOUT AND AIRFLOW

MANAGEMENT:

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Block the holes:

This will eliminate air loss,

promoting proper air flow and improving static

pressure:

• Install blanking panels.

• Seal cable cutouts with brush sealed floor

grommets.

• Block off the voids/holes in drywall below raised

floor and above drop ceiling.

• Seal all voids under doors leading into DC rooms and

support areas.

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Perform a Computational Fluid Dynamics (CFD)

analysis:

This will simulate the airflow through your

data center and identify problems that can lead to

overheated servers. This is generally the first step in

understanding issues and identifying opportunities for

improvement.

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Hot aisle/cold aisle layout:

This layout enables cool

air to flow to air intakes on the front of the rack and

hot air to exhaust out the back, then return to the

(CRAC) return ducts. You will reduce hot spots and

you could lower your power consumption significantly.

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Use existing drop ceilings as a return plenum and

install return air plenums on CRAC units:

This will

direct the hot air exhaust from the back of the server

racks to the return on the CRAC, reducing

recirculation of hot air.

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Use the proper floor tiles:

• Replace missing floor tiles.

• Put floor grates or perforated tiles in cold rows,

especially in front of the hottest racks. If necessary,

rearrange or change to different floor grates to

match the airflow to the heat load.

• Avoid placing floor grates too close to the CRACs,

this will “short circuit” the airflow, sending it right

back into the CRACs and rob the rest of the

room/row of sufficient cool air.

• Install solid floor tiles in hot rows to prevent cold

air from coming through the floor.

• If you still have data center hot spots, consider

installing directional or fan assisted floor tiles to

move the underfloor cooling air exactly where it is

needed.

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Remove under floor obstructions in raised floors:

Unused cables beneath the raised floor tend to build

up over time, thereby reducing or blocking airflow. Be

sure to remove them to ensure high quality airflow to

your servers.

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Install variable speed fans or variable speed

drives:

These devices are designed to automatically

speed up or slow down as needed to manage air flow

and reduce energy usage.

7X24 MAGAZINE SPRING 2015