From Scratch, Dual ATX, Air conditioned Case *PICS*

[DerwenArtos12]

I'm working on the exact design in my favorite program(paint) so I'll get an image up ASAP but, here's the general idea. It will be a one on top of the other design with the cold side of the air conditoner on the intake in the bottom chamber and the hot side on the exhaust at the top. I've already dis-assembled a spare window A/C unit I had sitting in storage to get all the measurements and make sure it worked well. The cold side frosted over in ~2 minutes with the fan taken off the cold side but, still operating on the warm side. I also disabled the fan motor all together and the cold side took about 7 minutes to frost over and the warm side was warm to the touch but, not warm enough to do anything really, not even warm enough to keep the cats from sticking their noses on it to figure it out. Testing with the stock fan it's going to take about 400cfm to keep the cool side from frosting over on it's lowest setting. The A/C unit I dis-assembled has an integrated temperature monitoring and control system, though not digital I have a couple of VERY acurate temp probes I can use to map out the analog switch's activation and shut off temps in a couple spots. I also have an identical second one for spare parts if it comes to that. I was really impressed with the fan and motor on the warm side and I may just steal the fan off the warm side of the second unit for my intake. The fan that came on the cool side of the unit moves probably near 800CFM or more but, it's helaciously noisy and it's designed to pull through the condenser and output to the sides or top so that probably wouldn't work well in my application without some heavy modifications or an overly complicated design.

Any thoughts?

First Paint sketch of idea from 3 angles.

Let me offer a little insight into the reasoning here. It can easily be explained with one very short sentance. I live in Arizona. It's so damn hot here I have to give my computers their own air conditioners. I'm only really hoping to get this done before summer gets here and i have to choose between HUNDREDS of dollars a month cooling the entire house by 50 degrees or give the computers their own A/C. Right now I have the window open with the nose of my computer sticking out and my ambients in the middle of the day are still in the 50's-60's. At night I get to have fun though. It's been getting below freezing.

EDIT/UPDATE:
After doing a lot of research I feel a lot more comfortable modifying the coolant loop. My original design was made attempting to preserve, intact, the loop exactly as I removed it from the AC unit. This was for two reasons. Primarily I was quite un-familiar with the inerworkings of HVAC stuff and still am, just not quite as much, and secondarily because it was working fine and why fix what's not broken. My main problem and main reason for changing my mind was airflow. This is still going to be an air-cooled case with air cooled components so air-flow is a key. I've never built an air-cooling case without hooking up my fog machine and very thouroughly testing the flow. From doing that more times than i'd like to count I know a bit about how air likes to act and doesn't like to act. I'd have to say it's flow is about halfway between how water flows and how light flows, it can be made to make corners but, not without a lot more disturbance than water. My previous design was horrble for airflow, I tried to draw and balance it as best I could with some rear fans but, it was just going to be sh!t no matter how I played with it.

Well I was at work this morning just stewing over it and something I had thought of a while ago when it hit me. I could save a ton of space, better the airflow, centralize the main heat sources and passively cool the condensor. Want to know how? I get off work in half an hour, will be in paint in an hour and it'll be up by 11m mountian time. (dun-dun-dun)

 

[DerwenArtos12]

First Sketch done and linked. It looks like total size is going to be roughly 28.5" tall, 10" wide and 19" deep. It's a monster, no doubt. This will replace my main rig and my file server/HTPC all in one. I have a sceptre 19" LCD that I could use to switch back and forth between the two and my desk will be about 4 feet from my living room TV so no problem running video to it. Should be an interesting project.

 

[aigomorla]

LMAO!

this should be interesting. Make sure your temps dont get too low so you start condensending on the side pannels

 

[DerwenArtos12]

Originally posted by: aigomorla
LMAO!

this should be interesting. Make sure your temps dont get too low so you start condensending on the side pannels

The entire case is going to be silicone sealed .220 plexiglass with an aluminum exoframe so it would have to get really cold inside for it to start to condense. I just wish I could get it short enough to fit under my desk but, the only way I can see to do that would be to move both of the power supplies into the top chamber and I'm just slightly worried about heat up there. I may have to put a fw more 120mm fans up there to help out.

 

[DerwenArtos12]

Ok, got an updated version of the pain planning. I've highlighted the hot and cold sides with red and blue respecively and instead of circles I have actual pictures of the fans I've decided to use. They're going to be Scythe Ultra Kaze's. Mediums up front moving 88 cfm and low in the rear moving 44 cfm. I've also added a second hard drive cage so I can have all of my drives in the bottom as I was having a hard time finding room in the top. That will probably change as I get closer to a final design. I'm actually considering one at the bottom of the lower chamber and one at the top of the lower chamber. make for shorter runs and would keep things pretty tidy.

EDIT: oh, and i labeled everything.

 

[Bluefront]

Interesting, but complicated looking project. If I were attempting a dual computer, I'd stand the boards vertical, with the airflow between them.

And I'm curious why you would build the refrigeration unit into the computer, rather than just install a window AC unit, to keep the single room cooler?

 

[DerwenArtos12]

Originally posted by: Bluefront
Interesting, but complicated looking project. If I were attempting a dual computer, I'd stand the boards vertical, with the airflow between them.

I thought about that and just making it a cube but, I needed a way to isolate the hot and cold sides of the compressor so ideally i would either need a seperate area off to the side or above and I figured, since I'm building above, why not throw a motherboard up there with it, kill two birds with one stone. The only reason the case is this large is to house the two radiators, it would be notably smaller where it not for that. I'm still trying to work on a way to shrink it some.

And I'm curious why you would build the refrigeration unit into the computer, rather than just install a window AC unit, to keep the single room cooler?

Thats too easy and not nearly as much fun....

yeah thats about it.

Well, and i'll be able to drag the temperatures down further by cooling a smaller area. The room their in is a combination of kitchen, office, living room and dining room all open to each other.

 

[Old Hippie]

This is gonna be great! :thumbsup:

 

[Rubycon]

What about condensate removal? You will need to have a pan beneath your evaporator with a drain going somewhere.

 

[DerwenArtos12]

Originally posted by: Rubycon
What about condensate removal? You will need to have a pan beneath your evaporator with a drain going somewhere.

If you look in the second picture I'll be building a trough by adding a piece of plexiglass inside the case that will go up about 1.5" from the bottom of the evaporator to not only catch it but to prevent it from getting sprayed into the case. Condensation is actually the only reason it's going to be running four central fans instead of six that would cover the whole radiator. Keep them coming though, I'm sure I've missed something.

EDIT:
Just double checked the picture and it's in the picture from the front but not in the picture from the side, it's being added now.

 

[Rubycon]

Noise control both acoustic and electrical?

The hermetic compressor has a high inrush current with lots of back EMF that can cause problems if not isolated from the circuit that is feeding the PC SMPS. A dedicated circuit for the a/c or a ferroresonant transformer based UPS/conditioner on the same circuit will work. Also short cycling of the compressor has to be avoided to prevent the motor's klixon from engaging. This will result in no cooling for up to 5 minutes or so when the pressures equalize and the compressor can finally start. Of course internal temperatures should not warm that fast to present a danger unless you're overclocking on razor thin margins which is not recommended for daily use.

Rather simple control safeguards can prevent these things from happening and are easy to obtain and implement into your design if you are familiar with HVAC stuff.

 

[DerwenArtos12]

Originally posted by: Rubycon
Noise control both acoustic and electrical?

The hermetic compressor has a high inrush current with lots of back EMF that can cause problems if not isolated from the circuit that is feeding the PC SMPS. A dedicated circuit for the a/c or a ferroresonant transformer based UPS/conditioner on the same circuit will work. Also short cycling of the compressor has to be avoided to prevent the motor's klixon from engaging. This will result in no cooling for up to 5 minutes or so when the pressures equalize and the compressor can finally start. Of course internal temperatures should not warm that fast to present a danger unless you're overclocking on razor thin margins which is not recommended for daily use.

Rather simple control safeguards can prevent these things from happening and are easy to obtain and implement into your design if you are familiar with HVAC stuff.

I'm actually not very familiar with HVAC stuff to be honest. I do have a heavy duty UPS/conditioner though I don't know for sure if it's ferroresonant transformer based, I will check, thanks. In bench testing I did quick(3-5 minute) power ups with 2-3 minute power downs in between and didn't see any problems with the cooling falling flat. I've been really really amaized at the temps this little compressor is making I'll have to get a 12v source over there to do some temp readings but, it's getting too cold to touch and icing over inside 5 minutes with no airlfow and with the hot side fan sucking air across it and to the hot side it's actually icing faster due to the cooling the hot side is getting. I'll take some pictures when I get a temp probe over there to play with it.

 

[Rubycon]

Sounds like a rotary compressor which is tolerant of short cycling due to fast equalization time after shut down.

 

[DerwenArtos12]

Originally posted by: Rubycon
Sounds like a rotary compressor which is tolerant of short cycling due to fast equalization time after shut down.

It may be, there is no separate coolant pump and I can literally hear the equalization and the mass of it is done within 45-60 seconds of shutting the pump off depending on cycle time.

 

[aigomorla]

Originally posted by: Rubycon
Noise control both acoustic and electrical?

The hermetic compressor has a high inrush current with lots of back EMF that can cause problems if not isolated from the circuit that is feeding the PC SMPS. A dedicated circuit for the a/c or a ferroresonant transformer based UPS/conditioner on the same circuit will work. Also short cycling of the compressor has to be avoided to prevent the motor's klixon from engaging. This will result in no cooling for up to 5 minutes or so when the pressures equalize and the compressor can finally start. Of course internal temperatures should not warm that fast to present a danger unless you're overclocking on razor thin margins which is not recommended for daily use.

Rather simple control safeguards can prevent these things from happening and are easy to obtain and implement into your design if you are familiar with HVAC stuff.

rubycon... sometimes you really suprise me in how much stuff you know. :T

 

[DerwenArtos12]

What do you folks think about using one of These on my intake in place of the four 88cfm 120x38 fans. Open air CFM is not as good but, with the density of the fins on this radiator I'm worried that even the Scythe Ultra-Kaze's won't have enough static pressure and this fan has .51" H2O. It's really reall thick though so i would have to make a custom mount for it inside the case which may interfere with hard drive placement.

I also just saw a review of the new Zalman ZM-F3 over at xtremesystems that speaks very highly of it so I may try them out on the front of this monster instead.

Whatcha think?

 

[DerwenArtos12]

I jsut got a really stupid idea. In a few months when I decide this isn't cooling well enough, I can seal up the evaporator core completely and turn that front section into a resevior and run alcohol through my loop. Turn it from a sub-ambient air cooler into a sub freezing liquid cooling rig in one easy step. Well two, I'd have to insulate the hell out of it or my case would be a giant condenser.

 

[DerwenArtos12]

Ok, I took some pics fo those of you curious of what I'll be working with.

Not 56K friendly, like anyone actually still uses dial-up.

AC Label
Disassembled Unit
Compressor Label

I'm no HVAC guy but I know enough to know that R22 is not bad stuff and 530 watts of continuous cooling capacity at 5150BTU's an hour should be more than enough to keep my computers cooler than ambient. The label for the compressor says 1PH, I'm kinda hoping someone's dislexic and this means 1 horsepower but, it seems kinda small to 1hp. I can't find the model of compressor on LG's website but, I did find an almost identical model of GE AC on their site, though alas, no horsepower rating and no details of any kind on the compressor in the parts section.

EDIT: ok, found some calculations online and if they're acurate and I know how to multiply and divide then this is a 3/4hp motor. SUHWEET!

 

[Rubycon]

1PH means it runs on single phase power. At most that's a 1/2hp compressor. Still should be plenty to cool a PC case!

 

[DerwenArtos12]

Whilst designing the new case I thought of a problem that might just be really major, the electric motor inside the compressor. Electric motors create EM fields and all kinds of electric noise. Should I just consider brazing fairly long lines and mounting the compressor externally? As it stands, with everything crammed in there, some things in odd spots, it's down to 20" deep, 25" tall and 7 inches wide with both the evaporator and condeser side mounted but, to opposite sides with the top motherboard inverted.

 

[DerwenArtos12]

Originally posted by: Rubycon
1PH means it runs on single phase power. At most that's a 1/2hp compressor. Still should be plenty to cool a PC case!

But, it says right on the GE label says that it inputs 4.9 amps at 115 volts, 530 watts input. Thats .71 hp so for it to be a 3/4hp motor it would be 94% efficient. My electrical knowledge is pretty limited to DC so I may be way off here.

 

[Rubycon]

That's the nameplate input. You also have a fan motor that uses some power. A rough guide is about 1 compressor hp per ton of a/c. A ton is 12,000 btu/h.

 

[DerwenArtos12]

Originally posted by: Rubycon
That's the nameplate input. You also have a fan motor that uses some power. A rough guide is about 1 compressor hp per ton of a/c. A ton is 12,000 btu/h.

ok. makes sense.

any thoughts on the em problem?

 

[Rubycon]

Modify that into a unit that can supply a cool channel of air to your PC enclosure - aka spot cooler. The condenser can be ducted outdoors in a similar manner. Basically you would be converting that unit into a standalone a/c unit.

Another option is to convert it to a chiller but this would require you to install water blocks on everything that needs active cooling.

 

[thilanliyan]

Originally posted by: Rubycon
Noise control both acoustic and electrical?

The hermetic compressor has a high inrush current with lots of back EMF that can cause problems if not isolated from the circuit that is feeding the PC SMPS. A dedicated circuit for the a/c or a ferroresonant transformer based UPS/conditioner on the same circuit will work. Also short cycling of the compressor has to be avoided to prevent the motor's klixon from engaging. This will result in no cooling for up to 5 minutes or so when the pressures equalize and the compressor can finally start. Of course internal temperatures should not warm that fast to present a danger unless you're overclocking on razor thin margins which is not recommended for daily use.

Rather simple control safeguards can prevent these things from happening and are easy to obtain and implement into your design if you are familiar with HVAC stuff.

I hope you're a girl Rubycon cause I'm so attracted to you after reading that post!! Hehehe, j/k.