Jon Mitchiner jon at
Tue Apr 23 19:32:47 PDT 2002

The other consideration to have is some kind of monitoring/alerting system
for the room.  A client has a dedicated cooling equipment for a beowulf
cluster for 52 machines.  Recently the A/C broke one morning and they did
not find out till the afternoon when someone walked into the small network
room and found the room was in excess of 100 degrees.

I dont want to think about what could have happened if it happened on a
friday evening and nobody found about it until Monday. :)

Jon Mitchiner

----- Original Message -----
From: "Bob Drzyzgula" <bob at>
To: "Robert B Heckendorn" <heckendo at>
Cc: <beowulf at>
Sent: Tuesday, April 23, 2002 9:54 PM
Subject: Re: cooling

> If the new load requires the installation of new
> chillers, it could indeed cost a pile-o'-money. Even
> if each node burned electricity at 100 Watts, you
> are looking at 50 kW of power consumption, or about
> 170,000 BTU/hr, requiring about 14 tons of cooling to
> remove -- your facilities folks may well be looking
> at installing something like one or more Liebert
> chillers such as these:
> There could well be additional shortfalls in external
> heat exchanger capacity, pipe capacity out to the
> heat exchangers, electric power for the computers
> and for the chillers, etc. If you don't already
> have the raised floor space, that could also add
> quite a bit to the cost to cool all those nodes.
> As to how we are making the A/C for our systems "affordable",
> we do it by virtue of the HVAC budget belonging to
> a different division, :-) although that also means
> that we don't have *control* over that budget, and
> when we hit the ceiling on cooling we kind of have
> to just stop installing new equipment until the whining
> and begging and pleading might eventually get us
> a new chiller -- and even then we might have to give
> up some rack space so there'd be a place to put it. :-(
> --Bob
> On Tue, Apr 23, 2002 at 05:41:35PM -0700, Robert B Heckendorn wrote:
> >
> > We are looking at the facilities issues in installing a beowulf on the
> > order of 500 nodes.  What facilities is telling us is that it is going
> > to almost cost us more to buy the cooling for the machine than to buy
> > machine itself.  How are people making the air conditioning for their
> > machines affordable?  Have we miscalculated the HVAC loads?  Are we
> > being over charged?
> >
> > thanks for any guidance.
> >
> > --
> > | Robert Heckendorn                        | We may not be the only
> > | heckendo at                   | species on the planet but
> > |       | we sure do act like it.
> > | CS Dept, University of Idaho             |
> > | Moscow, Idaho, USA   83844-1010          |
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