Chilled water with Pelt - Necessary?

[Flybye]

If I were to use a chiller to bring the water down near freezing, would it be worth while to use a pelt on the GPU and CPU?

[Player0]

Yes, but the chiller would have to be massive.

[tripodal]

See the gallery for the system Player0 built, doing what you suggest.

[Flybye]

Well, the compressor looks like it might be a 1/6hp unit. I'm still not sure how long of an evaporator to make just yet. It all depends how big the unit is.....assuming I get it. If the deal goes through, I'll post pics when I get it. :)

I would like to simply not use pelts if possible. Make the installation of everything a bit more neater with less wiring, plus the headaches of wondering if my PSU will be up to the task or not.

[tripodal]

1/6th hp is probably too small anyways.
So you should be good.

[Flybye]

Originally posted by tripodal
1/6th hp is probably too small anyways.
So you should be good.
So I should be good not using pelt or using pelts? :confused:

The unit I'm looking at was used to cool down a laser diode via a 2"x2"x4" copper block. This copper block cools down to 0f So I'm thinking.....this is just a damn 2x2x4 block. What about changing it out for a full sized evaporator or several feet of copper tubing and mating it to either the right sized capillary tube or an expansion valve? The condensor that comes with this unit allready has a VERY nicely sized fan attached to it.

I've been reading a lot on the net, and I think a 1/6hp unit would be just perfect. Then again, I don't know for sure. This is where you supposed experts come in ;) :D

[Flybye]

Actually, the guy selling it IS a Mechanical Engineer. I told him my application, probable wattage (with a nice little wattage calculator thanks to dicki), amount of h20 I'll be using, and he said this unit should be fine.

[tripodal]

How much heat is a setup like that capable of removing? being 1/6hp?

[Flybye]

Originally posted by tripodal
How much heat is a setup like that capable of removing? being 1/6hp?
I keep reading that a 1/6 unit can support anywhere between 20f-55f on the evaporator or between 1000-1500btus. This guy is rating his unit at about 1000btus.

This guy tested the unit by sticking a 300watt heating element in front of the block, and the block stayed at a constant 80f. I did a quickie chart in excel using 30watts as ambient when the copper block made it to 0f. A P4 3ghz pumps out about 100watts, The GPU and CPU will prolly pump out about 200watts. At 200watts, the unit (as per the chart) was at about 50f. Again, this is a calculation made by a little 2x2x4 copper block being used as an evaporator!!

Of course, this is pure guestimation with a little bit of internet help :D

IF I get the unit, I'm hoping a MUCH larger evaporator and making sure the capillary tube is of correct length (or maybe even an expansion valve) will be able to keep water temps around 30-40f since it will cover a larger area.

What do you guys think?

[Flybye]

Here are some of the compressor sizes commonly found in units...

Full size frige: Compressor probably about 1/8 - 1/6hp

Full size friger/freezer combo: Compressor typically 1/6 - 1/3hp

Chest freezer: Compressor typically 1/4 - 1/2hp

Full size freezer: Compressor typically 1/5 - 1/3hp

Mini fridge: Compressor range 1/20 - 1/8hp

Mini freezer: Compressor range 1/10 - 1/6hp

Dehumidifier: Compressor range from 1/8 - 1/4hp

Window AC unit: Compressor range 1/6 - 3/4 hp

So yeah, if most people are finding compressors from these units, hopefully this one will do me some good.

[Player0]

1/6th is small compared to what most people use. If your using it to chill water, your going to loose a ton of efficiency. If you mounted it directly to the CPU, it would probably cool okay.

HP rating really doesnt say much. If you knew the wattage the cooling system could remove. Theres too many variables involved here to really say how well it will work. If your using it to chill water though, your talking like a 60-80% efficiency loss easily.

[Flybye]

Originally posted by Player0
.... Theres too many variables involved here to really say how well it will work......
Tell me about it :(
A programmer here should come up with a little program to calculate it all for us. Punch in your CPU, GPU, total gallons of water in system, your ambient air temp, size of hosing, GPH of pump, your desired water temp, and .................................BAM here's the compressor you'll need, the size condensor, length of capillary tube, and size evaporator! Ok, let me wake up now :P

I've also read the better cooling capacity the condensor has, the better it will have the capability of liquifing the refrigerant? This unit comes with, what appears to be, a 10x16xlike 1.5 or 2" condensor, and the fan looks huge to be almost like a 10" fan with a crazy pitch blade.

Hey here's something else I was thinking.....

Generally, the more GPH the better, but what about with chilled units? Isn't it better for the water to actually take longer to stay around the evaporator to aborb more of the cold? Or is this just another one of those experimentation things we all need to go through :D

[Player0]

Yeah. Ideally for a good chiller you want an agitator as well as a pump. If you have a lot of water around the chiller and you mix it thoroughly, and your only pumping a small bit of it away, then its getting a lot of contact time. The key here is water circulation around the condensor. You coulld do it with a smaller pump.

The reason this is innefficient however is that water freezes at 0c. The evaporator will probably get well below that. The coldest water is going to freeze to your evaporator which isnt very helpful. You could use glycol, but that starts reducing performance. Some other guys have used certain types of oil or goo which works well, but you wouldnt want to really PUMP too much of that with a normal hobby pump :)

[Flybye]

Originally posted by Player0
.....The reason this is innefficient however is that water freezes at 0c. The evaporator will probably get well below that. The coldest water is going to freeze to your evaporator which isnt very helpful. .....
Well of course :)
I'm a newbie but not stupid :D

I'm planning to use a bit of antifreeze, or something to keep it from freezing. I can be as boring as dipping a small evaporator in a reservoir, or as creative as custom pluming the copper tubing through it.

The nice thing about this kit I'm looking at is that it's self contained. It's all in one neat little package. All I would basically need to do is attach a tank to its lower plate and plumb a new evaporator through it. It's even neat enough to almost fit perfectly under the tower :)

I'm actually planning to do a few experiments. One of them will be to set a pot of water on low (and try to maintain around 90f or so), have the unit sitting right next to it, and have a water pump circulate the water through.