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View Full Version : CPU Water Chiller - Help Needed







deltatechx
28-03-2010, 09:47 PM
Here's where I stand, I've custom built a PC with a water cooling system and I want to take it a step further by actively dropping the water temp below ambient for 24/7 operation with the ability of chilling the water (water/glycol or alcohol/glycol) below 0c. I love DIY projects and this is more for fun than practicality, my system currently stays under 50c during full load which is well within limits (70c is the CPU's limit). I already have a compressor from a 22 cubic ft deep freeze running r-22 and a condenser from a GE HotPoint. I'm currently working on the evaporator coils, I'm using two double helix coils made of 1/4" OD ACR copper tubing in two separate reservoirs. For the expansion valve, I'm wanting to use a thermostatic expansion valve. This is one area I need help with is choosing the expansion valve to use and the size of the orifice. I also need help in figuring out how much oil and refrigerant (R-134a, unless there's a better replacement for R-22) and what pressure the system should run at.

I've done some research online and on forum boards but can't find much on specifics, I understand the general operation of phase change systems, how they are put together, and copper brazing. I just need a little help hammering out the specifics. Any links to existing threads that could help on this or other forums would be welcome and any suggestions/criticism (be gentle, I'm a noob, lol) are also welcome.

Thanks in adavance.

Brian_UK
28-03-2010, 10:11 PM
Hi and welcome.

Sounds like you have a lot of learning to do and fast. :)

TEV info for a starter...
http://www.sporlanonline.com/tevs.shtml

Details of your compressor are needed before more advice/help can be given.

I have also moved this thread to the relevant section.

deltatechx
28-03-2010, 10:16 PM
Hi and welcome.

Sounds like you have a lot of learning to do and fast. :)

TEV info for a starter...
**removed url so I could quote**

Details of your compressor are needed before more advice/help can be given.

Thanks, I'll post more info on the compressor once I get it back from the shop that I had remove it from the deep freeze, hopefully tomorrow.

deltatechx
28-03-2010, 10:23 PM
also, I'm not in a huge hurry to get this done. I want to do it right the first time (filling a/c systems is a pain, I've done it on my car a few times). Where is a good place to purchase copper fittings for a/c use, I need a few short 90* bends, 2 x 1/4" OD to 3/8" OD t-fittings, and a y-fitting for one 1/4" OD to two 1/4" OD.

deltatechx
29-03-2010, 07:42 PM
The compressor is a MATSU****A D123LGAA 1/4hp R-12 unit (not R-22 as I mentioned above). Is R-134a the only refrigerant I can use with this pump? What do I need to do to switch over to R-134a? The ambient temp in the room this unit will be operating in will be between 60 F and 75 F.

Toosh
29-03-2010, 09:31 PM
also, I'm not in a huge hurry to get this done. I want to do it right the first time (filling a/c systems is a pain, I've done it on my car a few times). Where is a good place to purchase copper fittings for a/c use, I need a few short 90* bends, 2 x 1/4" OD to 3/8" OD t-fittings, and a y-fitting for one 1/4" OD to two 1/4" OD.

Your local refrigeration wholesaler

deltatechx
30-03-2010, 06:55 AM
Your local refrigeration wholesaler

I've been calling local businesses for the past couple days, most don't sell components and don't know where I can buy them, others direct me to other businesses but when I call them they tell me they only sell to contractors. I finally found someone that can sell me the parts I need but he wants to charge me $90 for 4x short 90's, 2x T-fittings, and 2x Y-fittings. I know copper prices are going up, but that's a bit too much right? Is there anywhere online I can purchase these parts?

Toosh
30-03-2010, 08:48 PM
I've been calling local businesses for the past couple days, most don't sell components and don't know where I can buy them, others direct me to other businesses but when I call them they tell me they only sell to contractors. I finally found someone that can sell me the parts I need but he wants to charge me $90 for 4x short 90's, 2x T-fittings, and 2x Y-fittings. I know copper prices are going up, but that's a bit too much right? Is there anywhere online I can purchase these parts?

Here you go

http://www.pexsupply.com/Copper-90-Degree-Elbows-For-HVAC-1711000

Tesla
31-03-2010, 12:10 AM
Hi deltatechx
One concern of mine would be the probability of condensation onto your cpu or other components. When you drop the temp of your cooling medium below ambiant, especaily on a humid day. there would need to be sufficient insulation of the cooling tubes to prevent this. Also an alarm (hi temp) for the cooling medium would be a good idea.

deltatechx
31-03-2010, 07:34 AM
Hi deltatechx
One concern of mine would be the probability of condensation onto your cpu or other components. When you drop the temp of your cooling medium below ambiant, especaily on a humid day. there would need to be sufficient insulation of the cooling tubes to prevent this. Also an alarm (hi temp) for the cooling medium would be a good idea.

When I updated my system to water cooling I sprayed the front and back of the motherboard, graphics card, and ram with silicone conformal coating (4 coats), packed the cpu socket, ram slots, and pci slots with silicone dielectric grease, and pooled potting compound around and behind the cpu and gpu. I also put closed cell foam padding between the motherboard and case (left over from sound deadening my car :D). I'm hoping that will be enough to protect the boards from condensation. I'm also installing a control board from Koolance that will monitor the coolant flow and temp and will also be used to control the chiller.

deltatechx
31-03-2010, 07:39 AM
Here you go

**removed url so I could quote**

sweet, that's exactly what I needed. Thanx

Tesla
01-04-2010, 12:08 AM
Hi deltatechx
Just an idea, personally I would use some sort of icebank hold over like an old coke pot mix machine. This would give plenty of time in the event of a failure. Perhaps this idea might be a little overkill. Or you could use your compressor and put the cooling coil into a bucket, use an icestat switch, and add an adjetator to achive the same above. You could still use glycol and get below 0.degC. Please keep us posted on how you go and any more questions. I'm just waiting for a core i7 980x in a reliable laptop to upgrade this year.