Phase change cooling-just for fun

Hey guys. so I've been bored, and I was going to add water cooling to my gaming rig. As I was looking at price and other considerations, I decided a single-stage phase changer would be much more cost effective. My target temperature is -40° Celsius. (yes, negative forty) This will include ovedocking my Q6600 to 4.5 Ghz as well. Cost should stay in the $400 to $500 range. For those unfamiliar with the concept, here's a diagram.
http://img217.imageshack.us/img217/9...echangezq2.jpg

Basically, the compressor (a 1hp for me) forces a gas such as propane, (or R134a in this case) into the condenser, which cools and compresses it to a liquid. The liquid flows down a tiny tube (.03 inches or less in diameter)eventually coming to the evaporator. In the evaporator, the liquid expands quickly into a gas, absorbing heat from the processor to overcome the enthalpy of vaporization. The coolant then flows back into the compressor as a gas.

Anyway, I'll start building two weeks from this Friday (next payday).

This should be interesting to see, you may want to consider wearing a t-shirt should it engulf the room, you wouldn't want to freeze :wink:

Best of luck with it though, good to see you back also, i know we didn't talk much, but you will always be the guy who i thought was ranma :D

My biggest concern is the semi-hazardous gasses I'll have to store. I think I might have to get a permit, but R134a isn't too bad. Oxy/Acetyl torches are worse. If I was building a double cascade, you'd be right to worry. :P

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Originally Posted by Tsen

My biggest concern is the semi-hazardous gasses I'll have to store. I think I might have to get a permit, but R134a isn't too bad. Oxy/Acetyl torches are worse. If I was building a double cascade, you'd be right to worry. :P

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:shock:

Wow... you're actually gonna have to get a permit for a computer cooler. Damn... lol. Is this a gaming rig, or is it simply computing the meaning of life? :D

I want to see pictures when you're done... this sounds freaking amazing!

ps. -40 celcius... wow. That's about -52 Fahrenheit for those who aren't very keen on the conversion rates. Dayum...

It's a sort of gaming rig. I mean, it can run Crysis at medium-high settings. But to be honest, I game maybe two hours a week, tops. I used to game more, but I don't have time or desire anymore. So it's mostly to say I can. And, as always, to one up the script-kiddie computer science majors who think they're 1337.

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Originally Posted by Tsen

So it's mostly to say I can. And, as always, to one up the script-kiddie computer science majors who think they're 1337.

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hahaha... damn. That's funny, and always a good reason.

"Just 'cause I can." :D

I wanna hear how it turns out.

I order the compressor tomorrow. Also picking up a mapp gas torch and some copper pipe. I think the insulation I need isn't stocked at Lowe's, but I hope so. I might be able to squeeze in the condensor on this pay check, but it'll be close. And I still need to find somebody with a milling machine to make the evaporator for me.

Awesome! :D

I just did a bit of googling because I was curious as to what it would look like. I found this page where a guy has made (what I think to be) the setup you are talking about. He gives a pretty good step-by-step on the whole setup, so you might find it helpful.

Here's the link for it.

http://gomeler.com/pic/Articles/Vapo...nishedunit.jpg

That's not quite what I'm doing, but I already have all the plans laid out, and I know what steps and precautions I need to take. Also, I won't be needing a permit for R134a (though any Brits out there would), but as it turns out, I'm going to be switching to R404a, which is a higher pressure, more powerful and more environmentally friendly refrigerant. Hell of a lot more expensive though. I can't find anywhere that sells it in less than 30lb tanks, and those run anywhere from $200-$300 dollars for an empty tank alone. All things considered, seeing as how I'm going to have to buy more than I need no matter how I do it, I'm probably going to build multiple units and sell a few once they're finished.
My budget has increased significantly, too.
I'm looking at $150-200 for the compressor, $50-80 for the condensor/shroud/fan assembly, $80 for the evaporator, $50-100 on copper piping and flexlines, $400 or more for coolant, $200 for a vacuum pump and another $100-200 on misc. small items (drier filter, MAPP gas torch, valves, swaging tools, etc).
Not cheap, but it should be worth it, seeing as how after I've built the first one, I'll have all the tools and most of the supplies to build more at little cost--maybe $300 per unit, and then I can sell those for quite a bit of profit to cover the expense.

Anyway, I'm making it more compact, something like this:
http://img72.imageshack.us/img72/4579/img1386em4.jpg

Only problem being, wheres the motherboard or anything? XD

That comes later. Insulating the motherboard is a pain in the arse, because you have to prevent condensation on any electric components. Basically, a whole friggin' ton of neoprene and dielectric grease, and a little liquid electrical tape. It'd be worse if I was doing a cascade cooler--they get down to -100C and lower, and often times, virtually every single circuit has to be protected against moisture. I'll only have to insulate about a three or four inch square around the processor.

Ah, that sounds like a serious pain.

Well, one piece of advice. If you're gonna be taking people's computers and adding this on.. be sure to get insurance to cover your ass. Too many things can go wrong and you don't wanna be paying to replace parts of some kid's $4000 rig.

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Originally Posted by arby

Ah, that sounds like a serious pain.

Well, one piece of advice. If you're gonna be taking people's computers and adding this on.. be sure to get insurance to cover your ass. Too many things can go wrong and you don't wanna be paying to replace parts of some kid's $4000 rig.

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I think he's talking about just selling his parts to the person. That way there's no liability and the person is the one that has to take care of everything. :D

No, actually I was going to sell the complete unit. Not to just anybody, though. On Xtremesystems forums there's quite a few buyers who have the knowledge on how to run a system, but lack the tools to make one.

As it turns out, my dad has a vacuum pump for work on A/C units, and there's a few compressors I have access to as well, but I'm not sure if I'm going to use one with a little wear and tear on it, or if I'll spend some extra just to be sure it's in good shape.