[Beowulf] Servers Too Hot? Intel Recommends a Luxurious Oil Bath

[Joe Landman]

On 09/04/2012 09:16 AM, Robert G. Brown wrote:

> Helium, OTOH, has six times the thermal conductivity of air, and is
> relatively inexpensive.  The biggest downside I can think of is that it
> requires a pretty good seal and thick walls to keep the slippery little
> atoms from sliding right through to the outside, and of course the fact
> that systems techs would always be hitting up the helium tanks so that
> they could talk like Donald Duck.  And you'd still have to refrigerate
> the outside of the systems units.  But all of these things are still
> orders of magnitude easier than with oil, and even things like cooling
> fans work fine in Helium.  Maybe there are other problems -- lower heat
> capacity to match its higher conductivity -- but it seems like it is
> worth an experiment or two...

As someone who used to (way way back in the nether reaches of time ... 
when IBM PCs were still being sold/used) trace leaky helium gas returns 
... I'll say ....  no.

It readily leaks, very hard to seal (makes oil sealing look easy in 
comparison).  Last I checked, it was pretty expensive.  It is a 
suffocant, so you have to be very careful in enclosed spaces (but 
detecting concentrations is as easy as measuring pitch of a few sound 
waves).

LN2 OTOH is very cheap, easy to make, and there is a potentially 
limitless supply (think very large atomospheric reservoir of gaseous N2 
we could tap).  Just need to replace heat sinks with conduction plates, 
and have LN2 run through heat exchangers in bottoms of racks.  It won't 
short out electronics, though if you have moisture in the air, it will 
condense that.

Only real issue (apart from cryogenic liquid handling, suffocant, ...) 
is the tendency to enable forming LOx in metal containers directly 
cooled by LN2.  Yeah ... just what you want near electrial components ...


-- 
Joseph Landman, Ph.D
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