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Old 10-23-2009, 10:27 PM
datacenter_guru datacenter_guru is offline
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Join Date: Oct 2009
Posts: 1
Default Technical questions

Hi Amattson,

In order to properly answer your question you need to think of a couple of things?

1) What is the intended density/rack of your comptuer room?
2) How tight for space are you?
3) Will you be using inrow cooling or end of row?
4) Will you be using a raised floor?

I ask you these questions because a typical server rack receiving 100 CFM of air at a standard delta T of 5.5 degrees Celsius will have 5.3 kW heat dissipated from the rack. A 56% open perf tile will allow anywhere between 200 and 400cfm pass through it depending on the pressure differential above and below the floor. This being said, this air would be divided between two racks (one on each side of the perftile) and maybe only half of the air would actually enter the servers (some would go around the servers and some over the tops of the racks). So we would be doing well to get 50cfm actually through the server meaning you are looking at a density of 2.5kW/rack if your cold aisle is one tile wide (6 tile pitch) or two tiles wide 5kW/rack if your cold aisle is two tiles wide(7 tile pitch). If you are looking to increase densities further I strongly suggest using a 32" wide cabinet and 42" to 48" deep cabinet.

On another note if your design group is asking for a sqft estimation per rack they have absolutely no clue what they are doing. I see it all the time. Regular engineering groups think they can design a data center and try and use basic building principles like w/sqft and sqft/rack to do it. Those parameters worked 10 years ago but with the densities we are seeing today you will end up with an inoperable data center.

Hopefully this helps and hopefully I didn't scare you too much with that last statement. If you want to reach me directly for any additional questions please feel free to contact me directly through my corporate IT infrastructure consulting website.

Best of luck,

datacenter geek
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