Liquid cooling?

Robert G. Brown rgb at
Thu Apr 25 01:01:52 EDT 2002

On Wed, 24 Apr 2002, Velocet wrote:

> Anyone ever sell the heat generated from the clusters to someone else? :)

Step right up, folks, I gotcher heat right here, yes ma'am, packaged to
go.  How about you, sir, couldja use some heat?  Whatzat?  It's hot
enough outside already today?  Snark snark snark -- every crowd's got
one, folks, a JOKER!  THIS heat is special, Geuuwiiiine Beowulf Cluster
heat, imported from one of the O-riginal beowulf clusters, you can't
find heat like this any more, it's practically antique heat.

No, now stop that.  Quit walking away.  And don't shake your head like
that, sir, why, one day you'll be LACKING some heat and NEEDING some
heat and then you'll be sorry indeed you didn't take advantage of this
special offer, never mind that it is midsummer and hotter than H*** out
here... well, OK then.  I guess I'll just keep my heat.  Have to dump it
outside again, or worse, pay to have it hauled away.  Don't nobody seem
to WANT heat anymore, and a few months ago everybody was begging me for

Sigh.  That didn't go too well.  The problem with heat is one or t'other
of those darned laws of thermodynamics -- always making more of it when
it is waste, can't get enough of it when it is an energy source, can't
(generally speaking, although there are specific exceptions) take waste
heat and use it to make more organized energy without an ever-cooler
reservoir to ultimately dump it in.  Otherwise, by the time you run your
cluster hot enough for the heat to be "useful" (which requires a
signficant temperature differential relative to ambient) you're frying
the cluster's innards.

On a modest scale, of course, sure.  In the winter, I recycle my home
cluster's heat.  In the summer, I probably pay more than I gained in the
winter to remove it and dump it outdoors, but at least I break (more)
APPROXIMATELY even.  The same cycle probably holds elsewhere -- where it
is already cold, you can probably reuse the heat IF you can get it from
here to there (heat actually being pretty difficult and expensive to
pack up and ship from where you make it to where you MIGHT want it).
Where it is already hot, folks just look at you funny when you try to
sell them your garbage.


Robert G. Brown	             
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at

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