Background Image
Previous Page  68 / 80 Next Page
Information
Show Menu
Previous Page 68 / 80 Next Page
Page Background

68

7X24 MAGAZINE SPRING 2015

Throughout this process, it is

important to utilize the “4Rs” in their

proper sequence:

1: RAISED FLOOR

The first step is to seal all unmanaged

openings in the horizontal plane of the

raised floor. A thorough effort is

required to identify and seal all raised-

floor penetrations. Electrical

equipment such as power distribution

units often have large openings that

need to be sealed. This task must be

seen to completion because as each

hole is sealed, the remaining holes

release increasing volumes of valuable

conditioned air. In some cases cable

openings indirectly provide cooling by

reducing the temperature of exhaust

air flowing from the hot aisle through

openings in cabinets such as missing

blanking panels or open spaces

between mounting rails and sides of

the cabinet. In this condition, sealing

cable openings may cause IT intake

temperatures to increase. This can be

easily remedied by sealing the

openings in the cabinet. Adjust

perforated tile and grate placements

to make all IT equipment intake air

temperatures as low and even as

possible. This will include replacing

perforated tiles or grates with solid

tiles in areas where excess conditioned

air is being provided, and adding

perforated tiles to areas where intake

temperatures are the highest. All

perforated tiles and grates located in

dedicated hot aisles and open spaces

should be replaced with solid tiles.

2: RACK

The second step is to seal the vertical

plane along the face of IT equipment

intakes. Blanking panels that seal

effectively (no gaps between panels)

need to be installed in all open spaces

within cabinets. The space between

cabinet rails and cabinet sides need to

be sealed (if not sealed by design).

And open areas above the highest U

spaces and below the lowest U space

must also be sealed.

3: ROW

The third step is to manage airflow at

the row level. Spaces between and

under cabinets need to be sealed to

retain conditioned air at the IT

equipment face and prevent hot

exhaust air from flowing into the cold

aisle. Any locations where cabinets are

missing in the row due to structural

columns or decommissioning need to

be filled. For high-density rooms and

rooms with layout challenges (e.g. low

ceilings, cabinet and/or cooling unit

placement), partial or full containment

strategies may be warranted. Doors on

the ends of the rows are the first

element of aisle containment to install.

4: ROOM

A common misconception is that AFM

initiatives reduce operating expenses.

In most cases, even with high

percentages of excess cooling

capacity running, the first three

fundamental steps of AFM must be

implemented before changes can be

made at the room level to reduce

operating expenses. Improving AFM

will improve IT equipment reliability

and free stranded capacity. However,

to realize operational cost savings and

defer capital expenditure of additional

cooling capacity, changes must be

made to the cooling infrastructure,

such as raising cooling unit set-points,

raising chilled water temperatures,

turning off unnecessary cooling units,

or reducing fan speeds for units with

variable speed drives (VSD).

CONCLUSION

Improving AFM is fundamental to

maximizing cooling efficiency and

improving IT equipment reliability in

data centers. If your site has no IT

equipment intake air temperature

problems then determining your

Cooling Capacity Factor will reveal if

efficiency improvements and cost

savings are possible. If your site does

have intake air temperature problems,

then calculating your CCF will reveal if

problems are a result of a lack of

capacity or a lack of AFM. By starting

with CCF, you can understand the

potential benefits and data center cost

savings before investing in cooling

solutions and/or AFM initiatives,

helping to avoid the possibility of

implementing an expensive solution

that won’t fit your needs.

Lars Strong is the Senior Engineer at Upsite Technologies. He can be reached at

lstrong@upsite.com

1

$24,000 from turning off 4 cooling unit fan motors + $8,000 from reduced maintenance

costs for the 4 units.