[Beowulf] liquid cooling for HPC

Lux, Jim (337C) james.p.lux at jpl.nasa.gov
Wed Dec 5 04:38:56 PST 2012

I can't figure out how they are transferring the heat from mobo/components
to the fluid. On the one hand, it looks like they're immersing the board
in a sealed container, but there's also what is identified as "water
channels" (page 2 of the pdf)

 They've got the usual sort of "liquid connector" things which probably
don't leak too much (and you're much better off than in, say, a hydraulic
system where inevitably, there's grit and such that gets stuck in the
valve built into the connector).

Liquids leak, always, but with decent design in the rack, at least the
drips don't go somewhere bad.

Using the "engineered fluids" seems like a typical approach.  Back in the
day, Fluorinert was popular (but expensive).  It looks like they're using
conduction for the heat transfer, as opposed to ebullient/condenser
strategies.  (but if they're using that, why do they reference "water
connectors and water channels"?)

Or do they have the board immersed in a suitable fluid filled box, and
there's a fluid/water heat exchanger built into each little module?  That
makes reasonable sense.  Seal the expensive oil/fluid in the module, use
water (with corrosion inhibiters mixed in) to circulate around.

On 12/5/12 1:50 AM, "Jörg Saßmannshausen" <j.sassmannshausen at ucl.ac.uk>

>Dear all,
>I am sure the subject has been covered a number of times, however, I have
>to the Machine Evaluation Workshop last week here in Liverpool and this
>company here
>done something which I found rather unusual. Rather then using pipes to
>the CPUs or dipping the whole node into silicon oil (messy) or water,
>they are 
>using a hydrofluoro carbon compound to move the heat from the motherboard
>to a 
>chilling plate. There are pros and cons of course. As the whole
>motherboard is 
>sealed into the box you cannot change it yourself. It needs to be send
>back to 
>them. On the flip side, it appears the the excess heat could be used a
>bit more 
>I was wondering whether somebody has some experiences with 'water'
>cooling in 
>HPC and would like to share it with me? I am thinking of getting
>like that or similar (no decision has been made right now) for the next
>I am getting. However, as that is new technology to me (the 'water'
>before I venture into that I would like to hear some first hand
>not necessarily with the company/product mentioned above which is only an
>example here.
>All the best from a wet London
>Jörg Saßmannshausen
>University College London
>Department of Chemistry
>Gordon Street
>WC1H 0AJ 
>email: j.sassmannshausen at ucl.ac.uk
>web: http://sassy.formativ.net
>Please avoid sending me Word or PowerPoint attachments.
>See http://www.gnu.org/philosophy/no-word-attachments.html
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