Dual loop Watercooling/peltier concept

I've been thinking about this concept for some time, and can't find any good information on it.

I want to use an evaporative/bong type cooler, but don't like the idea of running tapwater through hundreds of dollars worth of water cooling equipment (or constantly paying for distilled water or additives). This problem is made worse by the fact that an evaporative cooler has to be open to air which constantly introduces contaminents.

The concept I've been toying with is to set up a normal watercooling loop (CPU/VGA/Bridge), but instead of running this straight to an evaporative cooler, using another waterblock to transfer heat out of this loop into a second loops which uses an evaporative cooler.

The first problem I came up with in this method is that using a waterblock/waterblock transfer would not be nearly efficient enough to transfer this amount of heat. The solution I've been considering is using a Peltier element for this junction, not really to get the water sub ambient so much as just to increase the heat transfer between these two loops.

I made a really ****ty MSpaint drawing in an attemp to illustrate:


Now for a few questions:
-Is there already a thread about this concept somewhere that I just couldn't find?

-Would the water in the waterblock on the cold-side of the peltier just freeze solid?

-Is there an effective antifreeze solution for PC WC systems that isn't corrosive?

-Would it be more efficient (or cost effective) to use a waterblock on waterblock junction, or use a passive aircooling heatsink in the reservor for the heat exchange into the evaporative loop?

-Is it possible to balance a peltier so that the cold side water temp is at or above ambient, or at least high enough that the CPU doesn't have to be insulated? I don't want to deal with heavily insulating everything if I can help it.

I know it's not the most direct/efficient method of cooling, but I think there are a few advantages to it which could make it worthwhile. Plus it would be fun to make and unique. Any ideas/feedback are welcome.

1) XS in pelt section, someones making one, though really aught to use more pelts
2) Don't use water, ipso facto.
3) Alcohol based, mixed with water
4) If the heat densitys small enough, air will do.
5) Yes.
6) It can be quite efficient if done proper.

Efficient and Peltier don't go together. Most pelts use about 1W of electricity to move 1W of heat.

So with 200W of CPU/GPU/NB you would need a 200W pelt to keep the secondary loop the same temp as the 'bong' loop.

This would put 400W of heat into your bong. My estiamate is that you will end up pulling about 600W out of the wall by the time your done.

If you pay $.10/KWh for electricity that is about $500 a year. NOT EFFICIENT


You might be able to have two loops without the pelt. Either a tube-in-tube heat exchanger. Or even a rad submerged in the bong water.

Or just a straight bong loop with an autorefilling system

http://www.ocforums.com/showthread.php?s=&threadid=168477
See the link, part of what you have in mind.
If you use multiple TEC at low voltage, you can achieve decent COP, better than the 1/1 ratio given by Zebkoolindc. Like NoL said, multiple TECs is a must. Not too sure on the alcohol/wate mis tho, depends how low temp wise you'r aiming.

Thanks for all the responses. I know most if not all of this information is available elsewhere, but bringing it together and considering it in terms of this specific aplication is a big help.

So from what you are saying, I ought to use several low wattage TECS in series instead of one high wattage TEC? Is this just for increased surface area for heat exchange?

I'm not aiming for extremely low temperatures, I really just want to keep it right around ambient. Just keeping my coolant temps from going up into the 50s (C) is what I'm really looking for. I'm trying to cool a HD3870 X2, E6600 @ 3.5ghz, and nforce 780i NB. My current setup just isn't keeping things low enough (DD DDC-12v 18w, MC-TDX, Stealth GTS 240)

Frizzaper said:

...really just want to keep it right around ambient.

Click to expand...

That will be really hard to do. You'll have to change the power supplied to the TEC (and hence how much it cools) as system load changes. And you don't shoot for ambient temperature, you shoot for remaining above the dew point temperature.

Frizzaper said:

So from what you are saying, I ought to use several low wattage TECS in series instead of one high wattage TEC? Is this just for increased surface area for heat exchange?

Click to expand...

Not, you use high wattage TEC (ie 226W), but run it at 40-50% of it's nominal voltage.
That being said, I'd try adding a bong to your existing setup and see how much you like it. I tried one ounce and couldn't stand the noise for more than 5 minutes.

Not, you use high wattage TEC (ie 226W), but run it at 40-50% of it's nominal voltage.
That being said, I'd try adding a bong to your existing setup and see how much you like it. I tried one ounce and couldn't stand the noise for more than 5 minutes.

Click to expand...

Not correct. You want many higher wattage TEC's, 6-10 or so for a 400W heatload, and then run those at lower voltages for increased efficiency, and tune it via voltage into the range you want.
As for bongs, ping pong balls or sponges will reduce noise

i believe this article will be helpfull.

http://www.procooling.com/index.php?func=articles&disp=46

I have a bong cooler that I havn't used in a few months, I switched back to my normal watercooling setup to make it easier to haul my computer around. (Moving back and forth between school and home). I have since gotten a laptop though, so mobility isn't a big issue anymore.

The bong cooler I made actualy isn't to bad in terms of noise. Instead of using a straight shower type drop I used a smaller PVC pipe as a core and ran fiberglass window screen around it in a spiral pattern with a very high number of passes. I only ever used it on an older system with a Brisbane 3600+ and 75gph pump, but it kept that at right around room temp.

The reason I don't want to use a staight evap/bong type cooler is that I don't think it would be a good long term option, after only a week or so mine had a whole bunch of dust in it, not to mention the deposits that you would get from running a bunch of evaporating tap water through your loop in the long term. Doing a dual loop I expect alot of wear on the evap loop pump and waterblock, but I don't have to worry nearly as much about the high end pump, 2x CPU blocks(one for heat xfer), NB block, or GPU block in the other loop.

I know that the second loop could be anything, but I am only thinking about this because of the reasons in the above paragraph. I don't see a good reason to use two loops for any other type of secondary cooler.

If you are pumping 600W of heat into the second loop, an evap is about the only real choice. Evaporative coolers scale very well with heat input because the higher the water temp, the more easily the water evaporates. Of course then you have to add water more often.

honisty i would forget the tec and setup a water-to-water intercooler type soution to pass the cold from the water on the bong side of the loop to the water in the component side of the loop. The tec would just get in the way and be an extra complication IMO.

Alright, for everyone saying avoiding peltiers is the way to go: What would you use to transfer heat that would cost less than peltiers? Just use a submerged rad? Could you just use an elaborate series of thin copper piping to transfer the heat?

Take a look at this guys setup with the heat exchanger ("intercooler"). Something like that would probably work great, or you could put a regular air radiator (thats attached to a closed loop) in the bong-water.

If you end up using only a regular air radiator, and water flow in your bong water isn't that good, you could buy a cheap (10-20$) "powerhead" pump to keep the water flowing. All depends on how big your bong is going to be. The Via Aqua line of pumps come with powerhead attachments, and are cheap and decent quality as well.

I would say have a submerged Thermochill PA 120.3 radiator in the bong water with something pushing water around in the bottom to have water flow through the fins of the radiator

lol, now THAT is a bong, that copper intercooler design is alot like what I was thinking about when I said "elaborate series of copper pipes". This brings me to anouther question though I have when ever I look at evaporative coolers; Why do people insist on building bigger and bigger drops? The the only thing that has any bearing on the efficiency of an evaporative cooler is the amount of air/water exposure you have. Having water resting on obstructions, a higher airflow, or a finer water spray ought to alter cooling effects just as easily as having twenty foot drop. (so long as the same amount of water is exposed to just as much air.)

Prandtl said:

Not, you use high wattage TEC (ie 226W), but run it at 40-50% of it's nominal voltage.
That being said, I'd try adding a bong to your existing setup and see how much you like it. I tried one ounce and couldn't stand the noise for more than 5 minutes.

Click to expand...

Sorry, I had to lol at the use of "bong" and "ounce" in the same line, while being 100% about overclocking. Skill.

Frizzaper said:

lol, now THAT is a bong, that copper intercooler design is alot like what I was thinking about when I said "elaborate series of copper pipes". This brings me to anouther question though I have when ever I look at evaporative coolers; Why do people insist on building bigger and bigger drops? The the only thing that has any bearing on the efficiency of an evaporative cooler is the amount of air/water exposure you have. Having water resting on obstructions, a higher airflow, or a finer water spray ought to alter cooling effects just as easily as having twenty foot drop. (so long as the same amount of water is exposed to just as much air.)

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The reason for that is just to be able run more heat producing devices in the loops and still be able to cool it all... and just to say

MY BONG HITS HARDER THAN YOURS!

Is it somehow more efficient to run one nine-foot drop rather than three three-foot drops though? Huge bongs (off all sorts) are awsome, but is there a huge advantage to having one huge drop instead of several small drops?

Frizzaper said:

Is it somehow more efficient to run one nine-foot drop rather than three three-foot drops though? Huge bongs (off all sorts) are awsome, but is there a huge advantage to having one huge drop instead of several small drops?

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Well the longer the water is expose to air the more heat exchange theoretically though there will be a point of diminishing returns. I don't think anything built on the scale for computer cooling would reach that point though unless you go crazy and build a thirty foot high six feet wide cooling tower that also cools your house as well as your computers.