[Beowulf] 'liquid cooled' racks

Jim Lux James.P.Lux at jpl.nasa.gov
Wed Dec 6 06:23:42 PST 2006

At 04:20 AM 12/6/2006, Daniel Kidger wrote:
>In spite of many of the slides saying "ISR Propiatory and Confidential"

Hah.. they've published it on the web, so it's not proprietary and 
confidential any more.  Furthermore, if they really want trade secret 
protection, they've got to be a bit more careful about how they mark 
their stuff, or someone who DID steal their stuff could use the 
following defense: "How was I to know that this really was 
proprietary, they mark their stuff any old way, and lots of published 
information is marked as proprietary, even when it isn't, so the 
markings have no meaning."  been there, done that, sat in the depositions.

>I did find this presentation on the web:
>see slide 11 for a photo of what they are doing.
>Slide 18 implies there early market is for Defence systems - I guess getting
>rid of hot air on a submarine is a bit tricky?

And for land and portable apps.  Spray cooling in one form or another 
has been around for quite a while. It's really only useful when you 
can't afford to design a conduction cooled system (i.e. you 
absolutely, positively have to use some COTS widget, available in no 
other form, in sealed box).  It's a lot of complexity (pumps, 
sprayers, fluids, orientation sensistivity) compared to simple things 
like blowing cold air over the device.

>I am at a UK HPC Conference today (so is Greg L for that matter)
>One of the speakers said he was evaluating Spraycool to retrofit to his
>existing cluster.
>So if these guys spray *downwards* on the chip - what is the risk of a blocked
>tube causing the Flurinert to catch fire?

Fluorinert is, as the name implies, inert.  It doesn't 
burn.  Actually, it's pretty amazing stuff.  If you remember the 
photo from decades ago of the mouse breathing under the surface of a 
liquid.. that was Flourinert.

It IS quite pricey.  Back in the 80s it was in the hundred 
dollars/gallon range.

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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