# Slightly OT: Calculating HVAC requirements for server rooms

Sat May 2 08:50:09 CDT 2009

```   Just knowing your spacing and were to places perforated tiles is very
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Establishing a Floor Plan

[1]http://www.apcmedia.com/salestools/VAVR-6KYMZ7_R0_EN.pdf
May 2, 2009 08:41:50 AM, [2]alex at corp.nac.net wrote:

Calculating heat load in a datacenter is pretty easy. That's not the
hard part.
> I am curious what formulas/equations folks use to figure out
required
> cooling for small datacenters in offices.
The simplest equation to use assumes that you know how much power is
going into the room.
Btu/hr = watts * 3.412
This further assumes that a typical IT load is very inefficient
(which they are).. meaning that, for every watt that goes to a
computer / server / router, a significant portion is converted to
heat (we assume 100% for design purposes).
So, if you have a datacenter consuming 100kw, you'd need 341,200
btu/hr of cooling, or 28 tons of HVAC. Of course, there are other
issues (like leakage, windows, doors, humans, lights) but these tend
to be a little bit of line noise in a modern datacenter. Also
outside environment (is this Quebec or is this Cuba), insulation,
design delivery temperature, humidity requirements -- all play a
part.
> Translation: Hire a f***ing professional.
>
> And that's exactly what you need to do. Qualified HVAC installers
Two comments on this... first of all, the last thing you want is an
HVAC 'installer' to design your HVAC system in a datacenter.
Secondly, if you find an HVAC engineer who *really* knows datacenter
dynamics, that could be a help. But, frankly, there aren't a lot of
them.
If you need some help with this, let me know. There are a
significant amount of questions that need to be asked to give a
qualified answer. The cooling capacity question is secondary to the
delivery and extraction method.
I also submit that any good datacenter operator, who has had years
of experience of trial and error, years of engineers who say they
know something and don't, and had scores of contractors who say they
know something and don't, is in a much better position to talk about
this than a PE who designs comfort cooling systems.
"Question everything, assume nothing, discuss all, and resolve
quickly."
-- Alex Rubenstein, AR97, K2AHR, [3]alex at nac.net, latency, Al Reuben
--
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