Sub-ambient water-cooling

Jimbo Mahoney · 7 May 2006 at 21:58

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

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

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 · 7 May 2006 at 22:00

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!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Cyanide · 7 May 2006 at 22:07

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

Martynt74 · 7 May 2006 at 22:16

Jabo on another forum who did the whole underground thing and documented it really well think he called it Project Medusa.

The bong type cooling is nice and old school dont think i've read anyone do that recently though which is a shame.

If your after a quick fix you've always got the option of ice cubs into the res like i used to on my gfx loop while benching

Drazic · 7 May 2006 at 22:18

I like the sound of putting copper pipe under the gorund....will be cool when it rain or is winter...heheheh

I say stick a coper coil in you cold water tank in the loft or toilet!!!

My toilent in my new house gets used a lot i know that as all the doors here are fire ones and slam shut....so that much use and water chnaging is gonna be good and cold

Jimbo Mahoney · 7 May 2006 at 22:49

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!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

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?

Zefan · 7 May 2006 at 22:51

I still reckon you'd get condensation, remember even if it's just a little it really matters.

Jimbo Mahoney · 7 May 2006 at 22:53

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

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

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

Jimbo Mahoney · 7 May 2006 at 22:53

Zefan said:
I still reckon you'd get condensation, remember even if it's just a little it really matters.

Why?

You don't get condensation above dew point - that's what dew point is.

Zefan · 7 May 2006 at 22:55

Jimbo Mahoney said:
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

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

Drazic · 7 May 2006 at 22:55

Think it's 16c is the safest coldest temps you can have so don;t get any condenstaion on anyhting

Zefan · 7 May 2006 at 22:56

Ah, for some reason I thought you meant -16. Silly me

Jimbo Mahoney · 7 May 2006 at 22:58

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

I've done similar for some benches

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

NightmareXX · 7 May 2006 at 23:20

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

WOW. What an idea! I so have to try that one winter day.......damnit. Gotta wait half year now. Don't think my mum'll be very pleased either

fatty1 · 8 May 2006 at 12:46

Just get a mini water chiller with a fridge controller on them
I have modded up a few of these units

***F1ZZY*** · 8 May 2006 at 12:59

Jimbo

I was thinking of this a while back and came up with the following method of the evaporative bong cooling.

Rather than have 1 loop close to the PC which uses lots of water (expensive distilled). Have 2 loops with the bong bit in outhouse or loft or whatever.

Let me explain.
LOOP 1 - BONG
Have a freezerbox or insulated loft tank (maybe only 1 -3 cubic foot or so)somewhere out of the way with a ball **** inside to keep volume up. Have a baffle in the middle (creating 2 sections in the water tank) and an old rad in it (so only way to pass from section 1 to section 2 is through the rad)
Then use pump 1 to go from section 1 up to shower head and back to section 2 -> creates cold water flow through rad.

LOOP 2 - PC cooling
Uses a second pump and the rad in the baffle. Then piped to your PC for silence and sub-ambient water to your choice of water blocks. This loop uses de-ionised/distilled plus your choice of additive.

Should be good heat transfer in rad. Water > air

Tips
1 vent the bong vent to outside so no dampness/high humidity.
2 change bong water occaisionally [he he not done that for a while]

(esp if in hard water area as it will increase its mineral content as water evaporates and get replaced from ball ****.)
3 Insulate as much of the tubes in loop 2 as possible.
4 can chuck ice or TEC in for extra fun

Make sense..??

/edit - wouldn't get you 12 degC below ambient without tip #4/

SteveOBHave · 8 May 2006 at 13:14

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!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Yeah - we love Minifridges

***F1ZZY*** · 8 May 2006 at 14:31

Saw a doco on TV where they generate tons of ice in South Africa gold mines to pump down to cool air in the mine. They could generate enough to make a 40 foot ski run in the blazing sun. ie tons of the stuff.

Uses no refrigerants or CFC nasties.

Basically just by putting water in a near vacuum you have some thing called Triple point This is where ice, water and steam can co-exist.
If you let the steam off, the latent heat of evaporation means you get stacks of ice. 1 part steam to 7 parts ice. IIRC

This got water temps to like 5 degC or so.

If you can get a vacuum pump (bit noisy) maybe you could create a small version of this.

Extreme cooling anyone?

Jimbo Mahoney · 8 May 2006 at 18:09

***F1ZZY*** said:
Triple point

LOL

Now all I need is 0.01'C and 0.006 atm and I'm away!

Thanks matey!

malcolm · 9 May 2006 at 12:31

I read an article on the web a few years back about a guy who water cooled his K7 with a reservoir buried in the garden. He just used a standard pond pump and his reservoir was an old oxygen cylinder or such like. Once you get about 6 feet down the ground temp is about 8 degrees all year round in the UK. Problem is the PC is no longer portable. No noise though, specially with water blocks now available for everything. Al you would be left with would be the hard drives.