Best way to cool a room

The server room at my work has quite a number of computers(quite big
machines) and gets heated up inspite of the central airconditioning.
The room has glass walls and the only opening is a door. A fan with
about 4 feet tall stand, type which you typically get at Sears or
Walmart, is kept at the door and is working throughout the day.
I am wondering which position will cool the room better, when the fan
is throwing air in the room, or it's throwing out of the room. Fan is
kept at the threshhold of the room.
Thanks for your ideas.

Gen

i'd have to say (i'm not know physics expert or anything) the best way is to
have the air blowing out with the A/C cranked so you wont get any hot air
input....

DJ TecThreat

"Gen" <[Only registered users see links. ]> wrote in message
news:4d70acbb.0309111145.508a9a21@posting.google.c om...

Dear Gen:

"Gen" <[Only registered users see links. ]> wrote in message
news:4d70acbb.0309111145.508a9a21@posting.google.c om...

Fans increase mass flow by drawing from a cool source. You just need to
make sure the outflow from the room does not get sucked back down into the
fan...

Now the reason these rooms are isolated (among other things) is to prevent
dust contamination of the computer parts, especially hard drives (which are
exposed to ambient air). If the room does not have its own refrigeration
unit and/or thermostat, it is time to get one. The next hard drive crash
will have "we were keeping the room cool" written on it.

David A. Smith

"[Only registered users see links. ] (formerly)" <dlzc1.cox@net> wrote in message
news:Lw78b.51260$Qy4.38019@fed1read05...
are

Hard drives are hermetically sealed and their manufacturing process is in an
extremely high degree of air cleanliness, if they weren't they would fail
very rapidly.

Joe

On 11 Sep 2003 12:45:37 -0700, [Only registered users see links. ] (Gen) wrote:


As I recall, it has been found that maximum air movement occurs
with those kind of open (not mounted duct exhaust type) when the
fan is located about one to one and half fan blade diameter away
from an opening about twice the blade diameter. This presupposes
incoming air does not interfere with the outgoing stream as when
there is a separate inlet opening and no back pressure..

The practical position would seem to be as high a possible within
about one "normal" door distance away from the door. inside the
room, which will keep blown in detritus to a minimum ( low
incoming air speed at floor level) while, maximizing hot air
exhaust, A large fan generates its own heat too, maybe more
than a server, so the more efficient but dustier method is floor
level outside

Hard drives are not sealed but have a filtered opening to allow pressure
equalisation.

MikeC

"Phaedrus" <[Only registered users see links. ]> wrote in message
news:3f625c9d$0$251$[Only registered users see links. ].pipex.com.. .
the
prevent
refrigeration
crash
an

"MikeC" <[Only registered users see links. ].uk> wrote in message
news:KP49b.314$[Only registered users see links. ].uk...

I stand corrected.

Joe

fan
is
to
(which
in
fail

Dear Phaedrus:

"Phaedrus" <[Only registered users see links. ]> wrote in message
news:3f625c9d$0$251$[Only registered users see links. ].pipex.com.. .
to
the
prevent
refrigeration
crash
an

Sorry, I didn't see your post until just now. Older hard drives may have
been hermetically sealed, but current production has a little hole in the
case, with a very fine filter on it. Just as MikeC says. As barometric
pressure alters, and/or the drive heats up and cools down, the case
"breathes". It is important to keep this air as free of particles as
possible.

All the manufacturers mention 3rd party labels over breather filter or
holes as a source of failure.

David A. Smith

"[Only registered users see links. ] (formerly)" <dlzc1.cox@net> wrote in message
news:Rb79b.56185$Qy4.13211@fed1read05...
fan
is
(which
in
fail

Hello David,

Yes I certainly thought they were sealed, the ones I have seen may have
been, but I searched on the web and found conflicting statements about this,
some mentioning the hermitical seal and others mentioning the filtered
breathing. It does make sense to have some form of so as to maintain a
fairly constant air pressure inside the drive, as I know the reading head
flys over the drive platter on a cushion of air.

Joe

Dear Phaedrus:
"Phaedrus" <[Only registered users see links. ]> wrote in message
news:3f6715f8$0$247$[Only registered users see links. ].pipex.com.. .
....
this,

There are hermetic seals *and* filters on all the drives. The hermetic
seal allows access to the drive components for the assemblers, and people
who don't believe "do not tamper" stickers.

The filter is strictly a cost-saving measure. They could have packaged the
drive in a pressure vessel, and sealed a fixed amount of argon (or
nitrogen) inside. I guess they felt that the variation in gas density in
allowing altered "fly height" was less expensive than a ¼ or ½" thick
pressure vessel.

Especially considering hard drives go through pretty radical pressure
swings in a matter of hours... like laptops on aircraft, for example.

I wonder if you could infer barometric pressure with data from the
operations of your hard drive...

David A. Smith