[Beowulf] watercooling

Vincent Diepeveen diep at xs4all.nl
Wed Dec 28 11:46:10 PST 2011

On Dec 28, 2011, at 8:17 PM, Lux, Jim (337C) wrote:

> On 12/28/11 11:00 AM, "Vincent Diepeveen" <diep at xs4all.nl> wrote:
>> Yeah Jim good comments,
>> I was thinking for my cluster to overclock, which is why i guess some
>> posted the overclocking sentences,
>> and wanted to do it a bit more cheapskate.
>> Latest idea now was to save costs by using for say a node or 16,
>> to order 16 cpu blocks and 16 small pumps and 2 cheap big reservoirs:
>> Coldreservoir ==> 16 minipumps ==> 16 cpu blocks ==> Hotreservoir
> Hmm.. Over the past few years I've been trying different schemes to  
> keep a
> bunch (a cluster?) of glass bottles full of 750ml of an 12-15% alcohol
> solution in water at a reasonable temperature (15C or thereabouts),  
> and
> I've gone through a wide variety of improvised schemes.  (aside from
> buying a purpose built refrigerator.. Where's the fun in that?)
> Unless you need small size with high power density, very quiet  
> operation,
> or sealed cases, BY FAR the easiest way is a conventional air  
> conditioner
> blowing cold air through the system.

> Schemes with pumps and radiators and heat exchangers of one kind or
> another have maintenance and unexpected problems (stuff grows in  
> almost
> any liquid, metals corrode, pumps fail, plastics degrade).
> A very inexpensive window airconditioner (US$99, 8000 BTU/hr = 2400  
> Watts)
> draws about 500-800 Watts (depending on mfr etc). The Coefficient of
> Performance (COP) of these things is terrible, but still, you ARE  
> pumping
> more heat out than electricity you're putting in.
> A "split system" would put the noisy part outside and the cold part  
> inside.
> The other strategy... Get a surplus laboratory chiller.  Put THAT  
> outside
> and run your insulated cold water tubes down to a radiator/heat  
> exchanger
> in your computer box.  At least the lab chiller already has the  
> pumps and
> packaging put together.  Run a suitable mix of commercial  
> antifreeze and
> water (which will include various corrosion inhibitors, etc.)
> But really, cold air cooling is by far and away the easiest, most  
> trouble
> free way to do things, unless it just won't work for some other  
> reason.

How about 2 feet thick reinforced concrete walls?


 From ease viewpoint we totally agree. yet that won't get even close  
to that 4.4-4.6Ghz overclock.

For that overclock you really need stable watercooling with low  

So those cooling kits are there anyway. Just i can choose how many  
radiators i put inside the room.

Good radiators that use the same tube system are expensive. Just a  
single big huge car radiator
that you put on the roof is of course cheaper than 16 huge ones with  
each 3 to 4 fans.

Realize that for home built clusters so much heat inside a room and  
burning that much
watts is a physical office limit. Like you can burn a watt or 2000  
without too much of a problem,
above that it gets really problematic.

This office has 3 fuses available. Each 16 amps. Practical it's over  
230 volt. In itself one fuse
can't be used as the washing machine is on it. So 2 left. Now on  
paper it would be possible to
  get 4 kilowatt from those 2. Yet that's paper.

All the airco's also consume from that.

With the 16 radiators and 3 to 4  fans a radiator we speak of a lousy  
48-64 huge fans just for cooling 16 cpu's.
Also eats space.

The airco here is rated using a 1440 watt maximum and uses practical  
a 770 watt or so when i measured.

The noise is ear deafening. Now for the switch i can build a case  
that removes a lot of sound from it,
also because switch isn't eating much, yet it's a different story for  
the machines.

So removal of noise sure is an important issue as well, as i sit the  
next room.

As for the nodes themselves, realize idea is mainboards with  
underneath say 0.8 cm of space, and 16 PSU's.

Next posting i'll try to do an email with a photo of current setup  
using an existing mainboard.

You'll see the constraints then :)


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