RE: DATACENTER: Datacenter HVAC requirements

["Metcalf, Andrew \(ATL\)" <AMetcalf@ixl.com>]

 We have about total 15 full racks of equipment (we are at about 15Kva (out
of 70) on the UPS now) and a 20 ton cooling unit and everything is fine...I
have about 20 more racks to fill...looking at the MRTG of the temp sensor
there is no fluxuation (temp or humidity) and it stays in the temp range I
told it too....so i don't think i'm even close to stressing it.
I don't have any formulas...but thats whats happening in the data center
here.

andrew

-----Original Message-----
From: Robert Szarka
To: datacenter@shorty.com
Sent: 6/14/99 10:47 PM
Subject: Re: DATACENTER: Datacenter HVAC requirements

At 07:36 PM 6/14/99 , Mark Smith wrote:
>
>Ok, so if I look in my cool little master converter program it tells me
>that 1 watt = 3.4120962 BTU/hr. So my questions is how much cooling do

Actually, the rule of thumb I've seen is 1 watt = 3.5-3.7 BTU/hr.

>I need for my datacenter? Is it as simple as:
>
># racks * 20 amps a rack * 3.4120962 / 12,000 (BTUs in a ton) = tons of
>HVAC required?

But an amp isn't a watt!  It's been a couple of years, but I think since
Ohm's Law gives P = I x E (power = current x voltage), and assuming 120
volts, you get something on the order of 2.4 kva if the circuit were
fully
loaded.  So if your hypothetical rack on a 20 amp circuit were
generating
2.2 kva you'd need something on the order of .7 tons of cooling per
rack.
Now, I am definitely *not* the HVAC guy (or the electrical engineer)
here,
so that could be way off, but that's how it looks to me.

Of course, a quick peek says my server room is sucking up only a little
over a kilowatt right now, so if you have more routers than hard drives
in
that rack, I'd guess you'd be overbuying cooling quite a bit.  Given the
weather, that doesn't seem like a bad thing, but...  :)


-- 

Robert Szarka
Managing Partner, Operations
DownCity, LLC
+1 860 823 3000