[Beowulf] small cluster cooling / beer fridges

Mark Kosmowski mark.kosmowski at gmail.com
Thu Sep 18 17:34:17 PDT 2008

On Thu, Sep 18, 2008 at 4:44 PM, Lux, James P <james.p.lux at jpl.nasa.gov> wrote:
>> -----Original Message-----
>> From: beowulf-bounces at beowulf.org
>> [mailto:beowulf-bounces at beowulf.org] On Behalf Of Mark Kosmowski
>> Sent: Thursday, September 18, 2008 12:19 PM
>> To: beowulf at beowulf.org
>> Subject: [Beowulf] small cluster cooling / beer fridges
>> >
>> > Questions (same RGB asked):
>> > What environmental conditions should such an office have?
>> > 1.5ton A/C?
>> > 4kW  capable wiring?
>> > Beer keg refrigerator?
>> > How many air vent and drip holes on the walls, ceiling and windows?
>> >
>> Assuming the physical dimensions work, would condensation (or anything
>> else) be a problem if someone, say a crazy grad student in
>> his non-AC basement, were to put a few desktop nodes in a
>> used, cleaned refrigerator?
> No big problem.  The condensation will tend to be on the cold coils. However, refrigerators don't move very much heat though. A 100W lightbulb would probably overpower the refrigeration capacity.  They're also optimized for a delta T of 30-40 degrees F (i.e. keep the insides at 40 when the room is at 75)
> If you're buying, you're much better off getting a small airconditioner, especially one of the ones that has a hot air outlet duct you can shove in a window.  Even small $100 room A/Cs move 5000 BTU/hr (1000 BTU is 1054 kJ... A 200W PC is dissipating 720 kJ/hr.. So a 5000 BTU/hr unit will just keep up with a 1kW load).  Even better would be a "mini split" AC, which puts the hot part outside, but they're pretty pricey.  The room AC is optimized for a smaller delta T, though.
So if I don't have ready window access / it's a really big basement
and I don't want to cool the whole thing, maybe a very small AC unit
with some sort of enclosure to hold the towers would be better.  I
hadn't thought of doing this - thanks!  I think I burnt a couple DIMMs
this summer due to heat and would like to avoid that next year.

Our dryer broke and we've been just hanging up the laundry - perhaps I
could re-task the dryer outlet for a hosed AC unit.  Said outlet is
conveniently located near the hole in the concrete pad where the
washing machine drains (I know this probably has a name, but am not
all that familiar with construction vocabulary).  Again, thanks for
the idea and explanation!

>  For power into the fridge, a
>> hole could be drilled into the hull and then filled in with
>> closed cell foam once the cords are poked through.
> Careful there.. They run wires and pipes in the walls, particularly on those 2-4 cu ft "dorm refrigerators"  and kegerators.  I did my part contributing to global warming by not knowing this.  A better solution is to cut a slit/notch in the door gasket.  The door is also usually less likely to have critical components imbedded in it.

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