Radiator chiller using second pump.

[jasonruiz]

I have a small 80gph pump I was thinking uf using in the following way. Hooking up a system somehow where it would pump water to one or several nozzles that would spray water through the fins of the radiator. Basically this would work on the same principle as the bong cooler. THe smaller pumpwould just recyle a small amount of water that would be sprayed though the fins of the heatercore, this would help cool it off, and at the same time by the time the water collects atthe bottm of the resevoir it would be chilled off itself. I'd just have to figure out a way to mount the radiator inside a resevoir. What I was thinking of was an external resevoir...something like this


I think I could make it a pretty effiecient cooler, my only concern is whther or not I could get it down to an accpetable size. If I could waterproof the fan, that would probably increase the cooling even more.

[Player0]

It's like a bong, only it wont work as well. Why not just do a bong?

[Drake]

I agree. Isn't adding the radiator in there just another medium for heat to transfer through?

[illmatik]

I am considering doing the same thing, except running the return from the rad thru a large metal pipe w/ a bunch of mesh to break up the water in the top of a 20mm army ammo case.

[illmatik]

Will bongs work sealed, so that anticorrosive agents can be used? I'm considering using the above mentioned ammo can which has a watertight gasket w/ maybe a capped 12" metal pipe @ the top w/ stainless mesh to break up the water into droplets. I'd try to dissipte the water w/ a low flow showerhead or something similar to retain maximum flow, or running a HUGE submersible pump to make up for it.

I figure a box this size would be pretty good for it, and the metal would act as a second radiator.

http://www.factory51.com/pc/pc-Pages/Image12.html

[Player0]

Bongs cant be sealed.

[illmatik]

Grrrrrrrrrrrr..

U think one of those ammo cases full to the brim w/ coolant would do the trick or is too much coolant in the loop a bad thing?


I would build a chiller to help the pelts out, but power is a problem in my building in the summer and 2 pelt cooled systems and 2 conventional systems is about all my current setup will handle unless some extra cash flow comes in to run a 220V circuit for my A/C, and I'll have a dedicated circuit for more gear.

[Player0]

More coolant only slows the rise and fall of temperatures, it doesnt add to cooling.

[Denovin]

coolant isnt really made for computers, or low temperatures, except to keep the water from freezing so early. I read a few articles on using coolant, and the best they found would be 50/50 water/coolant.

[dicki]

the other problem is that system will need to be open to the atmosphere (like a bong) otherwise you won't benefit from the evaporative effect because there won't be any evaporation...

[illmatik]

Yeah, nyc is humid enough during the warmer months, and I don't want to add to it. I think I might try to chill the water instead.

If I modify a lab chiller that can drop 75 gallons of water 15 degrees, what do you think I can expect to see on a gallon or less of water? Obviously the law of diminishing returns will apply a good deal, but I would figure that water would get pretty friggin' cold. In turn, the cooler the hot side of the pelt gets, the better the pelt performs, no?

Do you think that with a 226w and 80w loop my cpu can hit maybe 0-2C under load?

Better yet, the unit I'm looking at can remove 1500btu/hr. The only problem is, I have no idea how much fluid will be in the system yet, so it would be hard to use a canned calculation to figure it out, wouldn't it?

On another note, the smallest intake fitting my via aqua has is a 3/4" barb. The chiller I'm considering rigging for this project uses 3/4" tubing standard. Could I use a 3/4" from chiller out to intake, and 1/2" ID for the blocks to output to the chiller? How badly would that mess up my flow? The pump is rated (i know take 40% off any mfg ratings in most cases) for 970gph or max head of 11feet. Would this be enough flow for this system?

[Player0]

If I modify a lab chiller that can drop 75 gallons of water 15 degrees, what do you think I can expect to see on a gallon or less of water?

Cant answer that. You need to know the chillers wattage rating. Gallons has nothing to do with it really, thats a more complex equation. Those are designed to work on 0 load. And, they simply aren't going to work as good as you think they will. Is it phase change chiller or pelt chiller?

In turn, the cooler the hot side of the pelt gets, the better the pelt performs, no?

No. The peltiers performance will remain the same. Its delta T is determined by the pelts QMax and the input wattage. So if the peltier has a worknig delta T of 15 degrees, that will never increase. It will however decrease as temperatures decrease because they loose efficiency. However, 40c water and 15 dT means 25c CPU, while 20c water and 10dT means 10c CPU, so there will still be more cooling.

Better yet, the unit I'm looking at can remove 1500btu/hr. The only problem is, I have no idea how much fluid will be in the system yet, so it would be hard to use a canned calculation to figure it out, wouldn't it?

Id have to convert BTU to watts. But it has nothing to do witht he amount of fluid at all. Thats simply a timing issue.

On another note, the smallest intake fitting my via aqua has is a 3/4" barb. The chiller I'm considering rigging for this project uses 3/4" tubing standard. Could I use a 3/4" from chiller out to intake, and 1/2" ID for the blocks to output to the chiller? How badly would that mess up my flow?

The larger the tubing the better. Having thicker runs of tubing at some points in the system can help flow.

The pump is rated (i know take 40% off any mfg ratings in most cases) for 970gph or max head of 11feet. Would this be enough flow for this system?

Who can answer what 'enough' is? Yes, it will work. There are better and worse pumps. All of them will work to some extent.

[illmatik]

Thanks for the quick response Tom!

Judging by BTU/hour to watts calculation I found

1500BTU/h * 0.239 = 439.5Watt-hours

So do I figure theres 306W for the pelts, but how do I factor the cpu and gpu wattages under those pelts?

[Player0]

I think your talking about chilling the water that will flow over your CPU and GPU pelt blocks.

And saying that there will be no radiator on the chiller loop (because this would be silly).

And say your running the pelts at 12v.

So first your 226w peltier. 226w is the QMax, the amount of heat the peltier can move from the cold side to the hotside.

This number has NOTHING to do with the heat the peltier produces. To find that, multiply its voltage and amper usage together. In your case, 12v x 19a = 228w. Add 100w for your CPU (this can be more or less depending), so 338w for that block to cool.

Same with the GPU, which should come out to about 100w itself.

So you have roughly 450w of heat input that the chiller needs to deal with. Say you're goal is to achieve 0c water temperatures. Well, theres some complex math to figgure this out. In my experience, you need AT LEAST 2x the cooling wattage as the input heat.

So you need a chiller capable of 800-900w of heat, AT LEAST.

With that said, there are huge inefficiencies to consider. Thermal bleeding, thermal interfaces, can be 10% to 30% of your cooling power right there.

That 1500BTU cooler? Well you'd need two of them :)

Chilling water is tough. Its tougher than it lets itself look. Check out my gallery and my Cube projects. In the end, I *was* able to do what you're trynig to do (in fact, im selling the chiller if you want it lol). It took a 700w chiller to effectively cool a 226w pelt running at 12v 19a, and the GPU. A little underpowered, but it was all I could squeeze in a tight space (this was all self contained, lets see someone else try that!) In the end, I did get my 2800+ down to -20c :)

[illmatik]

I can get a 4500btu/hr unit as well for maybe $25 more, but its rather bulky and I would have to de-ugly it before my lady lets me bring it in the house. The one advantage of this one however is that its prefitted w/ 1/2" barbs and comes w/ a nice length really nice low temp, reinforced hose. I need to go see it though, to make sure its not 220v as I believe it to be.

[Spazzonater]

Do it just see what happends maybe it will work just put a fan on the outside between the sprayers to get the bong effect. do man do it!