Phase change water chiller CPU cooling build

Hello World so to speak!!

This is my first post on any forum regarding this type of subject matter. So bare with me as I try my best to explain my thoughts and build.

For my first build I didn't want to go straight into a Direct die single stage phase cooling system (for some reason I was scared lol). I currently water cool my PC and achieve 4.5 ghz completely stable with 36 degC idle and 83 degC full load with a i7 3770K CPU. This is fine but I really want to take the next step. Plus, I love to DIY and have projects.

I would like to build a water chiller phase change system. I also do not want to battle condensation (I know I will more than likely have to, but with this build I am going to try very hard not to). I would like to regulate my chiller to keep the system above dew point at all times (under load be able to compensate and engage to keep water temperatures down and then not over chill at ideal). this is my end game goal so-to-speak.

currently I have started the fabrication of my aluminum water tower reservoir. See the picture below. I have moved past this picture, but wanted to give an idea of where I am going ( I will soon post some diagrams of how I want to put it all together ). I have purchase a new 5,000 BTU window unit to source out for parts. I plan to take the compressor, condenser, May use their dryer not sure, and some of the electronics. See pictures.




My build Ideology

I want to say with this being my first build I'm probably going to say stuff that you will laugh at and say " this guys is way over is head" or "that is just not going to work". so I digress, My "tower" as you can see is made from aluminum and I am brazing ( yes you can braze aluminum just have to have the right stuff. If you have questions about this please let me know). the tower is 6x6x24 so a 6 inch square that is 2 feet high. The top foot will be the reservoir and where the evaporator will go. The bottom part will be a area put in for the water pump and such. Possibly plans for a PSU at the very bottom depending on what kind of controls I end up putting in. The water reservoir will hold 1.8 gallons of liquid going by pure volume, but I will have acrylic windows for the sides and tops, the evaporator tubing, and a water loop. So the volume after all this will probably be at like 1.5 gallons at best. *** I do plan to coat the aluminum that might come in contact with water. I do not want to run the risk of corrosion*** any advise is much appreciated.

Here is my first question to the masses. for the type of system that I am shooting for, do you believe this volume to be adequate? I don't want the water to heat up to much during a cycle. I will be running the computer pretty much all the time. My goal is not to go sub ambient, but to really cool the water down well at loads (no condensation!!! ). I know this is going to be tricky and a under-use of the cooling power I have, but this is also learning for me and when I'm not so scared to insulate my board I can go much cooler.

Moving on to the next thing I would like to discuss, the Compressor. The A/C window unit had a rotary r410a compressor. I am unsure of the HP as there is not much information that I can find on the thing online. The brand is a QinGan and model yzg-a050ay2d2. It is r410a compressor so should be able to handle some pretty high pressures. the oil is POE. I didn't want this but this is all I could find. I really wanted to find an old r22 compressor using mineral oil. I know I can change it to one by changing refrigerant and all, but I am really trying to not change the oil out of this thing. It is charged but I will have to empty the coolant to put in my evaporator and new capillary system.

so question here, what is your opinion on if I can achieve this without having to redo my oil?

I will be keeping the fan and the condenser set up and just attaching it to my tower build along with compressor and electronics.

a Major question here, What length and size of capillary tube would you advise? Keep in mind that I really have no need to bring temperatures down extremely much, nor do I want to because of evil condensation.

I am planning to use 1/4" OD copper tubing to make up the evaporator. Any advise on how long to make the evaporator for my desired goal?

I feel like I am rambling on now. This is not suppose to be a complete overview of my system but a starting point of my project to bring in the CPU cooling community into. Also to get much needed guidance and advise. As I will need plenty . I will give pictures and updates as I go. Any advise on what I have stated above. even the stuff I didn't ask questions on would be much appreciated.

Thanks in Advance, Torn

Update!! I have just about finished the Tower and base. I have also finished my evaporator. All pictures attached. Don't be scared to comment. Ask a question or even better give some advice . I know there has to be some more interest in phase cooling and or water cooling (which this is a combination of both).

Next step I plan to start work on getting everything in the reservoir. All connections will be coming in from the bottom. I will have my suction and capillary line coming from the phase change unit (I still have to mount and then charge the system). I will have my out for the liquid in the reservoir. This will also have a "T" coming off of it for a drain with a valve. Inlet for the Liquid returning form the CPU. the inlet will be a copper pipe coming from the very bottom where the pump plate is and reaching to just a few inches from the top. this will allow for the hotter return water to inter from the top and travel through the evaporator before exiting the reservoir, but allowing for all connection coming in from the bottom. there will also be a temperature prob entering the reservoir here.

I plan to use the A/C window units own temperature control to achieve my goal. the A/C units control should turn off at 65 degF or so ( I can adjust this if this is not the bottom limit, but it will be close). So theoretically I should be able to maintain a reservoir water temperature above the dew point of my house. thus not allowing for condensation to form. the controller should also allow for the unit to really kick in once the water starts to heat up because the computer is under load.

I have also thought about a fail safe to help insure that the water going to the CPU is as close to ambient as possible. Adding a radiator between the water pump and the CPU. I though about placing it on the side of the tower near the water pump to help cool it, or I have also thought about putting it near the compressor and condenser unit. I do plan on enclosing the phase change system (with condenser coils not being enclosed of course) along with some sound proofing. there will be vents for fresh air, but with most of the high pressure side of the unit being in this en closer, my fear is the condenser might not be able to add the super-cooling I am looking for or worse not get it to a liquid at all. So having the radiator in this area blowing cooler air on the system would help out tremendously, but currently not have this planed in my build. It is an idea if I run into issue with condensation even with the controller working properly. any thought here?

Drew!
Thanks for the reply and input. I have read many of your post on forums. I don't have much time but wanted to talk about the Evaporator real quick. The evaporator coil I made if roughly 20ft to 25ft in length. i do plan to put to "U bends before the compressor. My POE oil might have been open to air more than I wanted too. Any advise on this point? I would like not to have to change out the oil. I will comment more later, but I have to go. Once again thanks for the reply.

What is your recommendation on the length of 1/4" to use. I want to stick with 1/4" for space issues getting the coil in my reservoir. I could ways make a 3/8 OD ft, but would like to stick with 1/4". What is the draw back if the pressure drop is to much? over working the compressor. I have a huge filter dry that I plan to braze into the system as well. I mean not to huge it is still 1/4" in and out, but it is a good size.

Well we are both thing the same on the capillary tube. I allready have purchased 10ft of 0.04" which I was going to use 6ft for R134a for this application. I will try and reduce it down a bit until that range. It might be a little longer thant 15ft. Might have to readjust some design if that just is not going to work. I just wish it wasn't so damn HOT in louisiana this time of year.