My A/C Ducting Solution

Chewsmoka

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Jul 5, 2004
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So, I was bored last weekend, freezing my arse off in my small window air conditioned room ( which my girlfriend insists on run 24/7 ) so I thought, why not use the dang thing for cooling? Off I went to Home Depot, only to be disheartened at the 9$ price of metal ducting... Then, low and behold, a 4" x 25' box of insulated ducting for 18$ As I'm on my way out, I get on the cell phone to a good friend with a dremel to cut a hole in the side of my case ( waking him up on a sunday of course So, an hour and 3 bits later, I had made a 5" hole in the side of my case, directly over the CPU/Video Card area of the case. I left for home thinking of the next step... then walla - I made a make-shift cardboard gaskit on the A/C side of the ducting, and run my ducting around the back of my room ( which worked beautifuly ) and connected the ducting to my case... perfect fit.


Now that I had A/C pumping directly into my case, I waited for the results.

IDLE : Case: 14°C, CPU Socket: 24°C, CPU Diode: 30°C

LOAD : Case: 19°C, CPU Socket: 30°C, CPU Diode: 40°C

All this with a 20$ Coolermaster POS Heatsink!!!

I got my friend to take a couple pics so you can get the basic idea of what I got going.

http://justintox.servebeer.com:8080/AlexConditioner.jpg

http://justintox.servebeer.com:8080/alexcomputer.jpg

First pic is my handy work with the card board from the box the ducting came in and some duct tape with the 4" insulated duct running 25' into my case.

Which leads to pic two where a 5" hole was cut into the side of the case to accomidate the ducting. The hole is directly over the CPU/Video card area of the mother board, with 2 x 80mm fans blowing cold air out of the rear exhaust ports, and the PSU as well ( which is not pictured ).

Temps now are :

IDLE : Case: 7°C, CPU Socket: 19°C, CPU Diode: 26°C, Fan 1: 4963RPM

LOAD : Case: 12°C, CPU Socket: 25°C, CPU Diode: 37°C, Fan 1: 4963RPM

Not bad results

Now that I think about it, these temps beat some water cooled systems. Extreme air cooling >

By the way, CPU is AMD Barton 2500+ @ 2230 203 x 11
 
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OMG i thought about doing that to mine....my window air conditioning is literally 1 foot away from my computer......but my dad wouldnt let me :( and me living in his house i had no choice....so i just shut my door to my small room and watch the room temp fall to 50F .....my dad mentioned something about the air conditioning ionizing the air and that being bad for the computer......does that make any sense to you?
 

Chewsmoka

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xSyzygy666x said:
OMG i thought about doing that to mine....my window air conditioning is literally 1 foot away from my computer......but my dad wouldnt let me :( and me living in his house i had no choice....so i just shut my door to my small room and watch the room temp fall to 50F .....my dad mentioned something about the air conditioning ionizing the air and that being bad for the computer......does that make any sense to you?
Air conditioners that ionize the room actually help clean the air - " By combining an electrostatic filter with a plasma filter, the IAQ air conditioners “ionize” the contaminants to collect and neutralize irritants and odors, leaving only fresh, clean air."

Also, the air conditioner itself is a dehumidifer and leaves little moisture in the air that it pumps out, which reduces the chance of condensation inside of the case consiterably. Air is cycled out via 2 x 80mm exhaust fans and the exhaust fan on the Raidmax PSU.
 

Justintoxicated

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nice shit, now get your PC stable so I can come over and play some Desert Combat on your other machine...You need to run a duct to that one too :)
 

wedoe21

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nice bong. :cool: Is that a newcastle on the far left of the case? One of my fave beers.
 

Chewsmoka

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wedoe21 said:
nice bong. :cool: Is that a newcastle on the far left of the case? One of my fave beers.
heh, you know its a newcastle, justintoxicated brought over a 12 pack and we rigged up the A/C box. ( Blue moon belgium white ale not pictured :)
 

Chewsmoka

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Update : Last night my PC decided it wanted to shut it self off... it was clocked at 2000 when it happened, and the temps were very cold. Now, I don't know if condensation formed on any parts of the motherboard since I piped in the full A/C flow ( instead of about 1/3 before ). So at present, my machine boots up for about 5 seconds, then shuts off ( with normal air cooling ). I'm going to cut the intake box in half, in an attempt to lessen the cold air flow vs. ambient room tempurature effect in the box, and to lower the overall tempurature in the room as well.

I'm off to fry's to get a 2.8E Prescott and an MSI PT880-LSR motherboard and try again...

Anyone know about ideal air flow with cold air into a case?

Thanks,
Chewy
 

KoZLop

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Wow sorry about the cpu but,

I like what im am hearing. Trying again. :D
 
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My dad ended up being right....even though the air conditioner is a condenser the cold air is still picking up ALOT of moisture on its way....he said you should make a trap like in a drain that would let all the moisture pool.....like run the pipe from the air condioning...to the floor and back up....the water will collect down there...he also said you should make a valve of some sort to clear the water out of the line......thats what he said....the validity of it i do not know....i just know hes a very smart person
 

2Busy

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I had wondered about doing something like this, but was afraid of the condensation issue. If memory serves me correctly, condensation forms when you have warm moist air (inside your case?) meets cool dry air (from the ac?). This being the case, I dont know what you would have to do to correct the problem. When people run pelts they insulate and seal with silicone around the cpu and the back side as well to keep condensation away. Maybe if the whole rig was in a cardboard box and you piped the cold air to the whole box at a lesser rate? Intersting experiment, please keep us posted.
 
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Condensation appears when air is cooled down, making the relative water content go past 100.
Let's say you have 80% humidity in 30°C air on a bad day. Binging the air into contact with solid objects of *thinkthink* 24.7°C or less would cause condensation. Your air is colder, HOWEVER: Your air has, let's say, 10°C when entering the case. It's dehumidified, so we'll say it's got 10% relative moisture content... the median temp of 30 and 10 is twenty, assuming equal flows. The relative saturetion of the combined streams of air would be.. um... 50 something %, meaning no condensation whatsoever. bear in mind that your AC is pushing a lot mor air in there than is entering through vents etc, so you've probably got less.

This could only be a problem if you decide to cool the air don further _while it is in the case, which you are not doing. Ergo: No comndensation.
 

ehZn

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hahaha I've been thinking of doing that for so long. Sorry about the comp eating itself, though.

My solution at school in Cleveland, where it is usually butt fucken cold, is just to have my case on the floor and crack my window slightly. Cold air rushes in and drops to floor level, going right into my case! Not working in the summer though...
 

Super-b

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I was on my way to doing this once i allocated enough money to get a window a/c. But my approach was different. I already have duct running from the back of my case to directly ontop of the cpu, which is temporary fix for heat issues. That in itself cooled down the cpu (and in effect the case as well) by a few degrees.

My use for the a/c unit was going to be 100% strictly for the computer. I already knew of the condensation factor and knew the air surrounding the case needed to be cool as well. Not a problem in my current residence seems how i have central air and it's cool enough in here. With little condensation worries, i knew there's still a chance, factor in Murphy's Law. So i was set on putting a "U" in the duct from the a/c to the computer and adding a couple filters to slow down air flow into the computer. One at the a/c side, one at the computer side. I, however, didn't think of putting in a little drain like xSyz's dad suggested. That wouldn't be difficult to implement and make draining a lot less painless then pulling off the ducting and trying to get all the collected water to drain out.

I also had planned on modding the a/c unit in a few ways. One would be the vents that are blowing out. Seems how i have central air, i don't need air blowing everywhere else too. I'm planning on keeping this a/c unit under my desk so that would make my legs and feet cold...i don't want that, so i was gonna cut that up and put something else on there to direct all the air into the duct. The card board box is a great idea and would save a lot of work on that part. It's not eye catching but it gets the job done. I might opt for something like that instead.
The other thing was a pan under the unit to collect the water from the window unit. Seems how it'll just be sitting under my desk and not through a window, i need something to collect the water. That wouldn't be hard to accomplish either. And it's certainly something i don't want to forget seems how i don't want to walk around on wet carpet.

You've given me a few new ideas to work with when i do this, hopefully i've done the same for you for the next time u attempt this.
As they say, brilliant minds think alike. ...which just so happens to be insanely. ;)
 

Matt Woller

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I did something similar, only involved some aluminum ducting and the winter. Ducted outside air into my system, with the side off. Worked great, and I got 30c-ish temps with my 3.06Ghz OCed to 3.83Ghz, however after a few weeks of this, the board died. No idea why, but I'm contributing this to the ducting. I'm thinking something to do with condensation, possibly, but not sure. But hey, that's what RMAs are for, right? ;)
 

dark_mark

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If you are going to go to the trouble of putting the A/C under your desk you might consider mounting it to the side of your case. You could set it to recirculate instead of fresh so that it would pull warm air from the case and dump cold air back in. Although it would dump considerable heat into the room out the back of the A/C.

I wonder if you insulated the case if you could get the whole thing down to freezing temps using this method. Although this could be bad for the hard drives and cd's.

Speaking of bad for hard drives this could be Chewsmoka's problem. As someone else mentioned you get condensation from warm moist air hitting a cold object. Did you notice any condensation on the I/O panel or vid card? I can see water on either of those causing headaches.
 

tim_m

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i got a window ac unit because at one point i had 5 computers in my room. now it's down to 3. it does a decent job, right now it's 72 F. it can range anywhere from 70-77 or so. i closed the house's central air vent but i've noticed that if the house ac is not working temps in my room still get a bit higher. unfortunately my rather large desk is in between the window and the comps so it's a little warm down there by my feet. the ducting doesn't sound like a half bad idea. if i'm not lazy later maybe i'll try it.
 

debaucher

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Super-b....

YOu have to remember that you need a place to vent the hot air that is made from cooling the compressor on the AC... so if you have the AC unit under your desk, you need to vent out the hot air from the AC (usually out a window) otherwise, your room temps will skyrocket and if the AC compressor isn't being cooled enough then it will sieze and no more AC.

I have one of those portable AC units with ducting which you pipe out a window, so I can get mine kinda close to my computers, but I always worried about the condensation.
So.. I watercool my comps and the AC helps keep the room comfy.

D.
 

Chewsmoka

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Indeed, some very good points brought up, thanks for all the insight guys. Heres where I'm at now.

Last night I went and picked up a cheapy CPU/mobo combo to replace my 2500+/DFI board. So I stuck in the P4 3.0C and the cheese-ball ECS mobo and went at it again. I'll copy some some I posted last night on ocforums.

" been running @ 3222 ( 15 x 215 ) with Prime95 for 2 hours. Load temps have ranged from 47°C - 50°C with an ambient case tempurature between 18°C - 20°C and had to change my memory timings to 2-3-3-7 on my Kingston HyperX 3500 to make it stable. Going to see if I can take it a bit higher

::EDIT::

IDLE : 30°C CPU Core, 25°C Ambient Case Temp ( turned down the a/c a bit )

So 15 x 220 failed Prime95... so I back down to 218 which was running prime fine, then poof, reboot So it seems that this motherboard is limiting me right now on potential speeds. Hopefully soon I can grab up a nice one, unless any one knows of a way to change Intel vcore through software? ( no vcore adjustment on this board ) "

So now I'm sitting at 3222 with stock voltage stuck :( I know, I know I need a new mobo, but I got other bills that a a bit more pressing :mad:

I got to run to the phamacy, when I get back I'll post on my theory about A/C-Case condesation and the procedures to possibly avoid such moves as with my last system ( which the DFI mobo was definately the problem, some short somewhere as the machine would bootup for 5 seconds, then shut itself down. )

Peace.

Chewy
 

RagingSamster

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the reason ionization works so well is that it charges the particles in the air and they want to stick to whatever they can get their grubby little mits on - positively charged collectors, walls, computer components etc, that's why you get clean air and thats why after a while your walls will start to look discolored. this is the way it worked on the old ones, maybe the collector plates on the new ionizers do a better job of cleaning.
 

Chewsmoka

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Ok, after frying my DFI lanparty NFII Ultra ( which ran like a champ since I bought it ) twice I've come to some thoughts about the nature of cold air flow and pressure through a case. When I first hooked up the A/C duct to the actual A/C blower, I made a crude cardboard gasket with duct tape and stuck the ducting straight onto the grill of the A/C, which channeled *maybe* 1/5 of the total air coming out of the A/C. This produced desierable results :
IDLE : Case: 14°C, CPU Socket: 24°C, CPU Diode: 30°C

LOAD : Case: 19°C, CPU Socket: 30°C, CPU Diode: 40°C

Mysteriously, my on board nforce sound died... coincidence?... maybe I thought, so I threw in the good ole SB Live 5.1. I saw the temps and it was obvioius I could do better. So I grabbed up the box the ducting came in, some scissors, and a roll of duct tape ( no pun intended ;) and produced the air catcher that is pictured on the first page of this thread. So smart I thought I was, when MBM 5 read my Ambient case temp drop to 6°C and Idle temps of 24°C - Keep in mind this was with my 2500+ barton @ between 2000-2250Mhz O/C'd - With full A/C flow now, the Ambient case dropped to 6°C and the Idle temp to 25°C. I thought I had it licked when, poof, machine up and shut itself off, tryed to reboot, ran for 5 seconds - shut off... My heart sank as I knew something had gone wrong. The DFI had shorted again, and this time I knew it wasn't just coincidence, some type of condensation had occured in the case... but why? and how?

Lets try to analyze and see where I went wrong.

My theory is that in hooking up the A/C catcher and drawing ( or rather pushing ) all the air from the A/C that the tempurature and pressure varaients were incorrect ( that produced a 6°C case enviroment ). I have 2 x 80mm fans blowing air out of the exhaust of the case, as well as my RaidMax PSU which has a bottom 120mm fan, and an additional 80mm exhaust fan. Now, I think that ambient case temps withen 17°C - 25°C are acceptable with the amount of air flow coming into, and out of my case. If you start dropping below those numbers, the air temp and pressure start to effect components inside the case. I now have cut the air box in half, in what is so far a successful attempt to restrict air flow from the A/C, and increase the air cycle inside of the case. More info to come as I think of it or anyone wishes to add.
 

Jonsey

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I don't see how condensation could ever be a problem. The electronic parts of your computer will be far above the dew point of the dehumidified cold air from the A/C. Condensation would only be a concern if your CPU/Mobo/etc. were colder than the surrounding air. That's never going to happen with a ducted A/C, right?
 

Chewsmoka

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Jonsey said:
I don't see how condensation could ever be a problem. The electronic parts of your computer will be far above the dew point of the dehumidified cold air from the A/C. Condensation would only be a concern if your CPU/Mobo/etc. were colder than the surrounding air. That's never going to happen with a ducted A/C, right?
I agree Jonsey, but how to you explain my DFI crapping out all the sudden? Like I said, I think theres a certin air temp/pressure that would ensure no condensation, but then again, what do I know, I was just bored last sunday ;)
 

Sate

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I am going to try this as well.
Fortunately for me, I live in the desert so condensation isnt an issue. My freezer for example, has never had the tiniest speck of frost.

Im curious about why a custom system using a commercial AC unit costs so much less than the made-for-pc compressor cooling systems, like the ones from Asetek. The newest Vapochill is 820$(!!). I'll only spend about 100$ total for a brand new AC unit, ducts etc.., I mean, I understand the vapochill performs better and better avoids condensation issues.. but I cant imagine those components are anything but cheaply manufactured compressors and insulated tubing. By "cheaply" I mean "not 820$ freakin dollars". The lightSpeed offers useless performance, too. a hyper-OC'd Prescott at -11 C (according to http://www.extremeoverclocking.com/reviews/cooling/Asetek_VapoChill_LS_3.html) . That's no better nor more stable than if it was 20 or 30 degrees warmer.
 

Chewsmoka

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Sate : I live in an arid climate as well ( So Cali ) so its not really an issue for me either, but there is a connection with cold air into the case, and warmer air escaping at the propper rate. I learned this the hard way.. :p
 

Sate

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Chewsmoka said:
I agree Jonsey, but how to you explain my DFI crapping out all the sudden? Like I said, I think theres a certin air temp/pressure that would ensure no condensation, but then again, what do I know, I was just bored last sunday ;)
It is a puzzle. Let me offer an hypothesis.
Lets say you have surfaces in your case that are getting blasted by cold AC air on only one side. For example the motherboard itself. One surface is very cool, the other side is stagnant, uncooled air between the board and backplane. Thus you have a warm air contacting the cooler surface of the back of the board. Perhaps the airflow is not diffuse enough.
 

Jonsey

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I don't think it is physically possible to have a electronic component that is hotter than the surrounding air have condensation. If anything, you should be making the chance of condesation less because you are lowering the amount of humitiy in the air and increasing the temperture difference between the electronic components and the air.

I have fried a motherboard due to condensation, but the CPU was at -20 degrees, far lower than the surrounding air. Sometimes it helps to take the CPU out of the socket and let it dry for a day or two when you have condensation.
 

Jonsey

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Lets say you have surfaces in your case that are getting blasted by cold AC air on only one side. For example the motherboard itself. One surface is very cool, the other side is stagnant, uncooled air between the board and backplane. Thus you have a warm air contacting the cooler surface of the back of the board. Perhaps the airflow is not diffuse enough.
Wouldn't that only make condensation on the outside of the case?
 

Chewsmoka

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Sate said:
It is a puzzle. Let me offer an hypothesis.
Lets say you have surfaces in your case that are getting blasted by cold AC air on only one side. For example the motherboard itself. One surface is very cool, the other side is stagnant, uncooled air between the board and backplane. Thus you have a warm air contacting the cooler surface of the back of the board. Perhaps the airflow is not diffuse enough.
Good point, although I do think that at present, the cold is is curculating around every component in my case, as every metal part of it feels refidgerated, and I have plenty of fans blowing the air around.

Jonsey : I can't confirm that it was condensation that fryed the board, since I didn't see any, however, how much water does it take to fry an electronic component? ;)
 

Sate

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Jonsey said:
Wouldn't that only make condensation on the outside of the case?
Theoretically, it would make condensation on any exposed PCB that had one side cooled by the AC, but not the other. In my example I was thinking of the air inside the case, between the mothboard and the backplane/case wall. There is no flow to that air, and nothing cooling it. Thats just an example, it would apply to any component with substantially uneven cooling/flow on two different surfaces.

And Chew, the relative humidity here right now is 8%. I cant see having a condensation problem.. there just isnt enough moisture for it to be possible.
 

Chewsmoka

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Sate said:
And Chew, the relative humidity here right now is 8%. I cant see having a condensation problem.. there just isnt enough moisture for it to be possible.

Partly Cloudy Feels Like: 73°F

UV Index: 3 Moderate

Wind: From the West Southwest at 8 mph

Dew Point: N/A°F

Humidity: N/A%

From weather.com :)
 

Jonsey

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A week before my IS7 died, the onboard LAN died. Do you think that's coincidence? I have an AI7 now, much better board.
 

SJetski71

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Jonsey said:
Wouldn't that only make condensation on the outside of the case?
Yes, and how do i know that? From the former 3dmark record holder named DJ (old madonion forums). He had a mad AC unit and ducting setup to cool his P3 rig, the thing must have been a >15000 BTU unit. He oc'ed his hardware to insane levels and never had a problem with condensation (yes all his hardware was naked with nothing sprayed on to insulate it from condensation).

The one big thing he illustrated was the huge iceberg that formed on the outside of his case (mobo side). I imagine he had to peel that case door off when he powered the rig & AC down to avoid seepage. He had a big writeup with lots of pics...too bad the thread is so old that its probably deleted now.
 

Chewsmoka

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Jonsey said:
A week before my IS7 died, the onboard LAN died. Do you think that's coincidence? I have an AI7 now, much better board.
That maybe, but was it hooked up to A/C ducting as well? :)

SJetski71 : My digi is broke so I'm having to use a friends cam to take pics, or else I'd have a whole slew for you. He's coming over later tonight so I'll post a bunch of new pics
:D

::EDIT::
I'm not trying to take credit for a new idea, just looking for some insight on how to make it better :)
 

Jonsey

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Actually, it was hooked up to a window A/C. But I cut off the factory evaporator and put on a custom one that fit over only the CPU. The CPU got down to around -20 degrees idle, -11 under load.
 

Chewsmoka

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Jonsey said:
Actually, it was hooked up to a window A/C. But I cut off the factory evaporator and put on a custom one that fit over only the CPU. The CPU got down to around -20 degrees idle, -11 under load.
How was it ducted into your case? into the side, front, back. Was it connected directly to your HS/Fan? I'm confused as I'm not seeing temps that low.
 

Chewsmoka

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SJetski71 said:
Yes, and how do i know that? From the former 3dmark record holder named DJ (old madonion forums). He had a mad AC unit and ducting setup to cool his P3 rig, the thing must have been a >15000 BTU unit. He oc'ed his hardware to insane levels and never had a problem with condensation (yes all his hardware was naked with nothing sprayed on to insulate it from condensation).

The one big thing he illustrated was the huge iceberg that formed on the outside of his case (mobo side). I imagine he had to peel that case door off when he powered the rig & AC down to avoid seepage. He had a big writeup with lots of pics...too bad the thread is so old that its probably deleted now.
Does that dismiss the chance that the mobo was fryed due to condensation? Then again our setups are different as well.
 
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