[Beowulf] 'liquid cooled' racks

Jim Lux James.P.Lux at jpl.nasa.gov
Tue Dec 5 19:23:05 PST 2006

At 03:45 PM 12/5/2006, Richard Walsh wrote:
>Greg Lindahl wrote:
>>On Tue, Dec 05, 2006 at 12:11:07PM -0600, Richard Walsh wrote:
>>>One of the key innovations on the Cray X1 is that the circuits are 
>>>"on the ceiling"
>>>so to speak and sprayed from below.  The fluid is gravity 
>>>collected and cycled up again.
>>This technology predates the X1 by a while.
>    Mmm ... I did not know that ... in a reasonably successful 
> commercial product (i.e. an innovation, rather
>    than a mere invention)?   What was/is/were/are the product(s)?
>Perhaps outside of HPC ...

This has been around for quite a while (decades at least).  It was in 
a Fluorinert brochure back in the mid 80s that I recall.  There's 
also versions with ebullient (boiling) cooling.  There might even be 
high power vacuum tubes cooled this way, although I think they either 
tend to use a cooling jacket or a boiler, as opposed to spraying).

And, of course, it's been mentioned on this list, several years ago, 
at least, as a potential solution for cooling a sealed box portable 
cluster that uses off the shelf mobos designed for convection cooling)

As far as spray cooling of things goes, that's been around since 
Newcomen invented his steam engine, predating James Watt.  Watt's big 
advance was realizing that the temperature changes in the engine 
cycle didn't all have to occur in the same place (i.e. you could keep 
the cylinder hot, and condense the steam somewhere else).  Spray type 
heat exchangers are also fairly standard devices (a notable example 
being the "swamp cooler" familiar to those in dry desert climates)

So, a decent idea, been around for a while, all it takes to make it a 
good *business* idea is the convergence of a need and a decent 
execution that is reliable and works.


James Lux, P.E.
Spacecraft Radio Frequency Subsystems Group
Flight Communications Systems Section
Jet Propulsion Laboratory, Mail Stop 161-213
4800 Oak Grove Drive
Pasadena CA 91109
tel: (818)354-2075
fax: (818)393-6875 

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