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# Data Center Toolbox "Watts per Square Foot of What"?

Posted by John Musilli in IT Peer Network on Oct 1, 2007 11:09:00 PM

Things You Need to Operate a Successful Data Center Infrastructure.

This is number 2 in a series of Toolbox topics.

If you have spent more than 3 months in data center operations someone has asked, "What is your Watts per Square Foot (W/sq.ft) Data Center design"?

Odds are your room design is somewhere between 40 watts per sq.ft and 100 watts per sq.ft This value is most likely the room envelope, Wall to Wall area including staging, telecom, tape storage, PDU,s (Power Distribution Units) and CRAC units (Computer Room Air Conditioner) See diagram below. Although this is the correct answer from the architect's perspective and the electrical,mechanical capacity construction designs, it causes great confusion in the industry. What we really want to describe and reference is the area or space the work is being performed in. In other words where the POWER (Heat) is delivered, and COOLING, (heat removal), is required. To better understand this concept and use this knowledge to communicate with others, please review the drawing below. This is an example of the possable interpretations of Watts per Square Foot data center design. Note as you are going through the exercise that I started out with a 50w/sq.ft room and by re-evaluating my environment I created a room design at 130w/sqft without spending a dime! The point is Do Not be Confused by The Facts you may have a 50w/sqft room but you can produce 130w/sqft of capacity

bq.

Data Center Math

Watts Per Square Foot Of What?

• Room Envelope = Gross Raised Floor sq.ft. This is the wall to wall space of the entire room including ramps, tape storage, PDU,s CRAC's staging area

• Production Area= Servers Plus Support Equipment (Traditional Layout) This area is represented in blue and is the actual recommended space access (48in front 36in rear) PLUS the direct support equipment CRAC's that need to be near the heat loads

• Equipment Footprint or Work Cell = Racks + Required Access Space (~16sq.ft. per rack) this is the recommended space for access (48in front 36in rear) and average rack size (24x40in)*

• Server Rack Load The actual electrical load of the installed server base in Kw (kilo watts)

Please see my earlier blog Data Center Toolbox for Power and Cooling. Please comment on and rate this Blog. New topics coming soon:

• "Use of a Hand Held IR (Infra Red) Gun for a Data Center Health Check"

• "Generic Data Center Racking, Cost and Space Benifits"

• "Data Center Layer One and Structured Cabling Designs, Without Costly Patch Panel Installations"

• "Server Power Cord Management"

Disclaimer

• The opinions, suggestions, management practices, room capacities, equipment placement, infrastructure capacity, power and cooling ratios are strictly the opinion and observations of the author and presenter.

• The statements, conclusions, opinions, and practices shown or discussed do not in any way represent the endorsement or approval for use by Intel Corporation.

• Use of any design practices or equipment discussed or identified in this presentation is at the risk of the user and should be reviewed by your own engineering staff or consultants prior to use.