From: Bill Burns (bburns@racktimerentals.com)
Date: Thu Apr 12 2007 - 00:56:42 ART
Hi Brad,
Whenever I have build out computer rooms, I usually go by the formula 1/4 to
1/3 of what the manufacturer say the BTUs or the amps pulled. This isn't
limited to Cisco gear but all computer components. It has worked for me so
far but this estimate is far from being accurate. I was told this many
years ago from a "sparky" I knew and he stated that the information on
electrical components is usually a stated max and it will happen only at
startup. Maybe that's why they made the 2800 router so loud at start up..we
got to reach 580 so rev this baby up! Im sure there are electrical
engineers out there that can elaborate on that but this is what I have done
in the past and those companies are still talking to me. : )
Thanks,
Bill Burns
CCIE #12464, CCSI
Rack Time Rentals
www.racktimerentals.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Brad
Ellis
Sent: Wednesday, April 11, 2007 7:57 PM
To: Cisco certification
Subject: actual BTUs vs. Cisco's listed BTUs
We're seeing a huge discrepency in our rack room HVAC calculations. We're
showing cisco's mfg listed 2811 router btu's to be 580. However, when we
actually check the power the router is using, we're getting closer to
123BTUs. Since we have over 400 of these devices, this is a HUGE difference
in the amount of cooling needed for our rack room. I've typically done HVAC
calcs in the past using the manufacture #s, but with the difference being
this big, it means the $$ difference between $15k additional cooling and
$100k additional cooling. Is this a typical discrepency with Cisco devices?
(Yes, I understand it depends on what modules are in the devices, the fan
speed of the router, etc). Just was looking for other's thoughts.
thanks,
Brad Ellis
CCIE#5796 (R&S / Security)
CCSI#30482
Network Learning Inc - A Cisco Sponsored Organization (SO)
YES! We take Cisco Learning credits!
brad@ccbootcamp.com
www.ccbootcamp.com (Cisco Training and Advanced Technology Rental Racks)
Voice: 702-968-5100
FAX: 702-446-8012
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