Sub-ambient water-cooling

Jimbo Mahoney

Jimbo Mahoney

Jimbo Mahoney

Soldato
Joined
18 Oct 2002
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First, a disclaimer - I don't want to know if something is worth doing, just whether it's possible. Let's face it, a lot of computing is not good value, but it's all good fun :D

I currently have a watercooling system that I don't believe could get any better without reducing the water temps below ambient.

I'd love to get cooler water, BUT, without the hassle of condensation. I was thinking 5 - 10'C water would be ideal.

The question is, what options are there to do that?

I'm aware of four:

1) Evaporator:

Drop water down a tube using a shower head or similar. Some water evaporates, taking some energy.

Advantages - cheap

Disadvantages - making the room humid / noisy (water sounds!), not very effective

2) Chiller - air conditioner.

I have an aircon unit from Homebase, which was £150. I have NO experience of compressors though...

Advantages - medium cost

Disadvantages - condensation. How could I control the unit so it cooled the water to dew-point ONLY?

3) Chiller - peltier

Advantages - easy to control water temp (I'd imagine), given the fact you could turn the pelts up / down

Disadvantages - power required - I have a lot in my loop. 2nd water loop required, although I could use my rad for the pelt loop...

4) Underground loop

Burying some copper pipes a few feet underground and passing the water through that.

Advantages - cheap

Disadvantages - requires a garden :D

Any other ideas?

Estimates on my current loop:

CPU = 118 watts (Opty 146 @ TDP of 55watts, 3.05Ghz, 1.65v)
Gfx card = 60 watts (X1900XT @ 750Mhz, 1.575v, 38A)
Nbridge = 10 watts?
HDDs = 18 watts
Mosfets = 10 watts?
Pumps = 23 watts

Total = 239 watts

Currently, my rad can do 3'C over ambient with that lot. (Typically 20'C ambient, 23'C water).

I'd be after a 15'C drop in the water temp somehow...
 
Zefan said:
I'm thinking that will still result in condensation, however little it may be it'll still be there.

OH and you forgot the last idea...










a mini fridge!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Click to expand...

Looking here:

http://www.wunderground.com/global/Region/I_UK/2xDewpoint.html

Dew Point in Belfast (my current location) is ~ 8'C, so that's what I would be aiming for.

And yeh, mini fridge, wonder why I didn't include that one? :D
 
Cyanide said:
Pelts are awful at cooling water in a loop, they tend to only work on direct heat transfer (ie, slapped straight on the chip)

Underground stuff wouldn't work either, as you'd need one heck of a meaty pump!

Air con could work, as it'd cool everything around to to a certain temp (make some ducting around it and your comp) thus there'd be no condensation as the ambient temps would drop too :D
Click to expand...

Re: pelts - I don't see why they'd be any worse at cooling water than a CPU.

Re: underground stuff - I have 2 x AQX 50z's in series - I think they could handle it ;) I'll put them on their own 13.8V PSU soon. They'd do 24 feet of head then :D

Re: aircon - this could well be my best bet. Put the PC in a small room and leave the aircon on 24/7. The electricity company would love me, but I'd get ambient temps ~ 16'C and water ~ 18'C. Still not that much of a drop though :(
 
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Zefan said:
You'd get bloody cold if you were in the room. I left my window open for hours on a winters day and got cpu temp of 17 degrees. It was fun though, with my ski gear, gloves and a hat on :D
Click to expand...

I've done similar for some benches :D

I wouldn't be in the room - it'd be remote like a server room.
 
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