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

[Rubycon]

Originally posted by: thilan29

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

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[QueBert]

I have to watch this thread, anyone undertaking such a hard ass project and doing the illustrations in MS Paint is awesome in my eyes.

 

[aigomorla]

Originally posted by: Rubycon

Originally posted by: thilan29

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

Affirmative. Text

seriously.... she sometimes leave me speachless in the amount of info she knows.

too bad for you she's on a ship most of the time... i think...

 

[thilanliyan]

Originally posted by: Rubycon

Originally posted by: thilan29

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

Affirmative. Text

Lol, good to know

 

[Orwellian]

I can't believe I came late to this party...

EM field... house compressor in faraday cage (not as complicated as it sounds)

Condensation- seal off all your ductwork to make it a closed air loop. then dry out your air with dessicant. If you don't want to buy a big dessicant sock you can make your own by breaking up chunks of sheetrock and baking them in the oven for a few hours.

Does anyone know if he could have a static build up problem if he dries out the air inside his case that much?

The biggest problem with a closed air loop would be cooling too much. If you aren't carefull the return air gets so cold that there isn't enough heat to cause phase change in the refrigerant. No phase change and you get liquid freon back to compressor. Compressors cant compress liquid and bad things happen when they try.

That said you will prolly be stuck cooling outside(room) air to pump into the case which brings you back to condensation. The evap removes some moisture (draining it outside case I assume?) and your climate is pretty dry so stick a humidistat next to your case air thermometer and keep an eye on how close you are to dew point. You can still use the dessicant as well.

Do you have gauges and a source of r-22? you cant just go out and buy that stuff

 

[Orwellian]

you are gonna have a heck of a time adjusting the freon charge for this. I think I saw you can braze? if so get a sight glass installed on the liquid line of the compressor somewhere before the expansion point (I can't tell from the picture if that AC has a TXV or simple orifice) was this a window unit?


I have a feeling you might run into problems with being over sized. I'm not sure you are going to be moving the same amount of air across the evap coil as the old fan unit did.

EDIT: I remember reading something about defeating EM fields by just alternating a conductive insulation thats grounded with a non-condutive insulation. (read: build a box around compressor with 2 layers of thin styrofoam with tin foil in between them and ground the foil)

 

[DerwenArtos12]

Hello again, sorry to go missing for so long. I went and got myself sick. Ate some bad pizza and some food poisoning seeped through my ulcer into blood poisoning, or so the hospital said. I've basically thrown up everything i've EVER eaten in the last 24 hours and finall went to the hosipotal about 3 am with 103 fever. Broke the fever and now I just feel like I've been run over by a truck.

I'm very familiar with faraday cages. Aluminum window screen is probably the cheapest and least effective version I've found. I was able to buy some woven copper through a friend of mine in tucson fairly cheaply, I'll see if I can still get some.

This thing is atleast a 1/2hp so I was going to cool room air and then push/pull it through the case with the condensor at/as the exhaust. I was planning on having about 360CFM(open air rating so more like 300cfm) on the intake at the evaporator and run the condensor passively to help it self-regulate temperatures. I'll see if I can finish the diagram today.

EDIT:
Apparently I was almost done before I got sick night before last so I just had to label a few things and the new version is ready to go.

 

[DerwenArtos12]

Originally posted by: 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.

But, it's built from a standalone AC Unit. So you're actually saying I should have just stuck it in a window, built a shroud and ducted the air from the outlet of the AC unit into the front of my case and called it a day. Where's the fun in that?

 

[Orwellian]

looks like you will have 5100 btu of cooling or ~1500watts of cooling capacity and that unit only needs 140CFM across the evap, if you run higher you could cut down the size of the evap coil (dangling the carrot of alot more work to save some space)

what did you mean by leaving the condenser passive? I assume its gonna have at least most of that CFM going through it...

 

[DerwenArtos12]

Originally posted by: Orwellian
looks like you will have 5100 btu of cooling or ~1500watts of cooling capacity and that unit only needs 140CFM across the evap, if you run higher you could cut down the size of the evap coil (dangling the carrot of alot more work to save some space)

what did you mean by leaving the condenser passive? I assume its gonna have at least most of that CFM going through it...

The only two openings in the case are going to be the intake at the evaporator and teh exhaust at the condensor so essentially all of the air is going to be going up and across teh condensor that's brought in across the evaporator, with the exception of the power supplies but, thats fairly minimal. What I meant by passive is that it won't have any fans of it's own directly mounted to it.

The evap coil really isn't the space hog here, the entire size of the case is basically being dictated by the size of the condensor coil/radiator, it's gargantuan.

 

[aigomorla]

Originally posted by: DerwenArtos12
Hello again, sorry to go missing for so long. I went and got myself sick. Ate some bad pizza and some food poisoning seeped through my ulcer into blood poisoning, or so the hospital said. I've basically thrown up everything i've EVER eaten in the last 24 hours and finall went to the hosipotal about 3 am with 103 fever. Broke the fever and now I just feel like I've been run over by a truck.


EDIT:
Apparently I was almost done before I got sick night before last so I just had to label a few things and the new version is ready to go.

Man... i hope you have a speedy recovery. Looks like you went though hell.

 

[Rubycon]

A spot cooler is more efficient because any heat generated by your refrigeration system is not added to the overall load. You could make a plenum that the system sits on with the cold air supply pressurizing the system from the bottom and the warm air venting from the top. The air conditioner's condenser can be vented in the room in the winter and outdoors in the summer.

There's no need for a Faraday cage around a hermetic (tin can) compressor. The back EMF comes up the line and dips in the voltage can challenge the hold times of some PC power supplies particularly if the unit is run at the end of a long 14AWG leg. LRA = locked rotor amps. That is what the compressor draws when starting. That is why it's common to see a flicker in the lights when an a/c unit starts up. Larger units may have LRA's over 100A!

Good luck on recovering from your illness!

 

[Orwellian]

Originally posted by: Rubycon
A spot cooler is more efficient because any heat generated by your refrigeration system is not added to the overall load. You could make a plenum that the system sits on with the cold air supply pressurizing the system from the bottom and the warm air venting from the top. The air conditioner's condenser can be vented in the room in the winter and outdoors in the summer.

While I wouldn't worry about adding to the heat load of the AC system I do like her idea about separating the condenser. While it makes things a bit messier, it would also give you some cooling in the room as well then. Also with that route, you could get rid of 80% of your space concerns by setting the compressor with the condenser and a seperate condenser fan (just use the window unit motor). You would then just have 2 freon lines to the case. with a little research you could find some flexible lines that could handle the freon pressure (with very good fittings) and even be able to shift the case around a bit to get at things.

Most importantly you could tell people "My computer has central air conditioning"

you could set the entire condenser outside just like a house AC unit. this would get rid of the VERY noisy compressor rattling around in your case. The vibration isn't good for your drives anyways. no matter how well the compressor is mounted it will still vibrate the case. You would have to set a fan cycling switch on the outside unit for when temps get too low at night and during the winter (at low temps you can have issues with good phase change and oil seperation inside the compressor leading to damage) If you set the condenser inside you would get heat in the room during winter, but would have to duct it out during the summer.

just an idea

 

[DerwenArtos12]

As it stands, the closest window to my computers desk is about 12 feet and above my kitchen sink. I do have an exhaust pipe in the wall pretty close that's for my clothes drier that I could probably tap into for exhausting the condenser if need be. I gotta say though, with the fan on the condenser un-plugged the evaporator side still freezes over inside about 10 minutes and the condenser side never gets above maybe 26-27C. I have to say I'm just not worried about the evap adding load to the system. I have been a little worried about the EM and vibration from the compressor though. Let me re-think the design. I'm probably making the whole thing a lot more complicated than it needs to be by making it two motherboards.

I guess I could try and get a smaller condenser to make fitiment easier but, I can more or less run it without any airflow and the system runs fine, it's surprising. I suppose I could use that last design and just remote mount the compressor. That would give me a bunch of space back for the drives and power supplies but, where to mount it? I guess the other option would be to use my current case since it works really really well and just assemble the AC unit separately and pipe the cool side into the case front and let it exhaust out the rear, right next to the condenser, but into the room, and reverse the fan blades on the condenser side so it intakes across the condenser and exhausts across the condenser then into the case.

 

[Orwellian]

I assume you don't have fans blowing across the evap when it freezes up?

once your rig is complete as you described it, you will get a decent amount of heat out of the condenser. You have not only the heat of you computer components, but also the heat the compressor creates through compression. I would bet there is more heat generated by your refrigeration system than by your computer.

You would prolly have a hard time operating the coil at sub freezing temperatures for your alchohol setup in the future. R-22 is most efficient with evap temps of 40-60f

One of you big concerns is that your evap coil will start to frost up during operation. This can be caused by freon charge too low, or not enough air flow. Once it starts to frost, it very quickly will turn into a big block of ice. The you get back to the problem of liquid freon getting back to compressor (not to mentiopn very little cooling). Your best case scenario will be an evap coil that is at ~40f when your house is ~75-80f or so. Unless the evap had a TXV (thermostatic expansion device) you have to set the charge so you are above 32f when the room ambient air is at its coldest.