[Beowulf] More about those underwater data centers

[Prentice Bisbal]

> . And serviceability is challenging. You need to pull the "wet" boards 
> out, or you need to connect and disconnect fluid connectors, etc.  If 
> you're in an environment where you can manage that (or are forced into 
> it by necessity), then you can do it.

I think everyone on this list already knows I'm no fan of mineral oil 
immersion (It just seems to messy to me. Sorry, Stu), but immersion 
cooling with other liquids, such as 3M Novec engineered fluid addresses 
a lot of your concerns. It as a low boiling point, not much above room 
temperature, and it was originally meant to be an electronic parts 
cleaner (according to a 3M rep at the 3M booth at SC a few years ago, so 
if you pull a component out of it, it dries very quickly and should be 
immaculately clean.

The low boiling point is an excellent feature for heat transfer, too, 
since it boils from the heat of the processor (ebullient cooling). This 
change of state absorbs a lot of energy, making it very effective at 
transferring heat away from the processor. The vapor can then rise and 
condense on a heat exchanger with a chilled water heat exchanger, where 
it again transfers a lot of heat through a change of state.

Prentice

On 11/05/2018 06:30 PM, Stu Midgley wrote:
> I refute both these claims.
>
> You DO want to run your boards immersed in coolant.  It works 
> wonderfully well, is easy to live with, servicing is easy... and saves 
> you almost 1/2 your power bill.
>
> People are scared of immersion cooling, but it isn't that difficult to 
> live with.  Some things are harder but other things are way easier.  
> In total, it balances out.
>
> Also, given the greater reliability of components you get, you do less 
> servicing.
>
> If you haven't lived with it, you really have no idea what you are 
> missing.
>
>
> Serviceability is NOT challenging.
>
>
>
>     You really do NOT want to run boards immersed in coolant - yeah,
>     there's folks doing it at HPC scale
>
>     Whatever the coolant, it leaks, it oozes, it gets places you don't
>     want it to go. And serviceability is challenging. You need to pull
>     the "wet" boards out, or you need to connect and disconnect fluid
>     connectors, etc.  If you're in an environment where you can manage
>     that (or are forced into it by necessity), then you can do it.
>
> -- 
> Dr Stuart Midgley
> sdm900 at gmail.com <mailto:sdm900 at gmail.com>
>
>
> _______________________________________________
> Beowulf mailing list, Beowulf at beowulf.org sponsored by Penguin Computing
> To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.beowulf.org/pipermail/beowulf/attachments/20181106/77917881/attachment.html>