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

Lux, Jim (337C) james.p.lux at jpl.nasa.gov
Tue Sep 4 09:54:04 PDT 2012


Hydrogen is cheaper than He and works even better.  Just make sure you don't have any air leaks in (i.e. keep a bit of positive pressure).  For the "server farm in a container" model, this would work just fine.. leaks would just float up into the atmosphere.

@ 300K
Air 26.2 mW/m*K
He 156.7
H2 186.9  !!!
Ar  17.9
CH4 34.1

He also is hard to come by.. 


Jim Lux

-----Original Message-----
From: Robert G. Brown [mailto:rgb at phy.duke.edu] 
Sent: Tuesday, September 04, 2012 6:16 AM
To: Lux, Jim (337C)
Cc: Eugen Leitl; beowulf at beowulf.org
Subject: Re: [Beowulf] Servers Too Hot? Intel Recommends a Luxurious Oil Bath

On Mon, 3 Sep 2012, Lux, Jim (337C) wrote:

> I'll bet they have to change it more often than that.  This isnt 
> something like a pole transformer.

Absolutely. Think of what you can do with a big vat of hot oil handy in the workspace.  Buffalo Wings.  French Fries.  Chicken.  Fish.  The reason nobody does this is because OSHA prohibits it -- it is a huge health hazard.  Not even Jolt Cola can keep you thin in a sedentary profession with your own personal deep frier as close as your server room.  Although you do have to change the oil pretty often, as otherwise shrimp tails and bits of overcooked tempura crust gunk up the memory and CPU.  Systems people were dying like pudgy little flies of advanced cardiovascular disease before the practice of using computers to heat deep fat was banned.

On a more serious note, one wonders why nobody has tried helium instead.
No, silly, not liquid helium, helium gas.  The reason they fill windows with argon is that it has around 2/3 the thermal conductivity of air, and hence is a better insulator.  This, in turn, is because it is more massive -- conductivity is tightly tied to mass and hence the speed of the molecules when they have kT sorts of energies.

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...

    rgb

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




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