Nearly Fanless verticle case - silent

[nzimmers]

building on some of my experience with my shallow HTPC/Server
http://www.qpkun.com/images/r13.gif
(I'll post some updated pics, it's really working out good)

I decided it would be nice to try and do something totally unique, a vertical tower that would act as a sort of thermal chimney (literally!) with only a fan on the power supply

here's a really awful 2D pic of my idea:




the neat thing about this design will be that the Motherboard will be mouted from corner to corner instead of against one side, this will mean I should be able to make the case 8'x8'x20' or close to that.

if I mount only 1 or 2 drives underneath the MB I could probably get away with 7.5x7.5x18 or less!!


any thoughts? anyone wanna take bets that I can do it *completely fanless* ???

[bonestonne]

i'm not sure how fanless that would be. where is the PSU fan blowing? i think that it would be very effective if you have two undervolted fans at the top, sucking air through the system. one on each side for exhaust, it would pull a slight amount of air through the system, which is most likely all it will need.

if the PSU fan blows upwards, maybe it'll work without any other fans, but i think that if you're going for a fanless system like that, the air needs to be guided somehow.

[nzimmers]

yes, at this time, I intend to reverse the PS fan so it blows upward. but I will have to run some tests with no PS fan to see if the thermal chimney can pull enough air on it's own to keep everything cool enough.

Certainly, a pair of 120mm low RPM fans (one on the bottom and one on near the top) would almost certianly be enough

I plan to cover the interior of the case in acoustic dampening foam

[bonestonne]

I should be able to make the case 8'x8'x20' or close to that

thats a really big case... why not just get a P182 and mod that? where would you even fit a computer 20 feet long?

[nzimmers]

I should be able to make the case 8'x8'x20' or close to that

thats a really big case... why not just get a P182 and mod that? where would you even fit a computer 20 feet long?

whups, got the ' and the " mixed up!

I was talking in inches

the P182 is a GIGANTIC case compared to what I am proposing

P182 Dimensions: 21.3'' x 8.1â€

[jaganath]

will be interesting to see if this works. I would prefer to have the top of the case completely open for best convectional airflow.

[McBanjo]

Change the direction of the PSU fan will most likely cause the PSU to overheat since the air will flow from "exhaust" to fan without cooling any/or few pieces. Might work with a duct tho

Intresting project

[nzimmers]

Change the direction of the PSU fan will most likely cause the PSU to overheat since the air will flow from "exhaust" to fan without cooling any/or few pieces. Might work with a duct tho

Intresting project

I'm not clear on how reversing the airflow will somehow mean nothing gets cooled.....the air will take the same path just in reverse, all the components will cooled just in the reverse order

[McBanjo]

I'm not clear on how reversing the airflow will somehow mean nothing gets cooled.....the air will take the same path just in reverse, all the components will cooled just in the reverse order[/quote]

For a 80mm fan type then yes but for 120mm fan I drawed a nice pic:
http://hem.bredband.net/gabsta/Blandat/reverse.JPG

I might ofcourse be wrong

[EndoSteel]

I agree with McBanjo, reversing the fan is generally not a good idea. You can give it a try though, with a thermocouple hooked to the hottest heatsink - just to be safe.

[EndoSteel]

I'd rather place the PSU at the top leaving the fan the way it is.

[nzimmers]

placing the PS at the top means it would get nothing but hot air, and even if the cooling from reversing the fan is 50% reduced, getting fresh cool air is a big difference than what a PS normally gets (the hot sloppy seconds of all the other components just before it leaves the case)

I'm pretty sure a PS would stay cool enough with no fan sitting outside the case with normal convection (assuming you removed the PS case and just had the components out on you desk)

with just a slight airflow at the bottom of the case the PS should be fine, I guess I will find out one way or another!

[IsaacKuo]

For everyone who says reversing the fan is a bad idea--have you actually tried it? I've reversed fans on many PSUs of various configurations, and haven't had a single problem with any of them.

For a 120mm fan PSU, there are essentially two options:

1. Reverse the fan and place in the original location. This will absolutely guarantee everything inside gets good airflow. There is so little space inside a 120mm fan PSU that turbulence from the 120mm fan alone will absolutely guarantee everything gets airflow. However, you have to be careful about wires and potentially other stuff being bumped into by the fan blades. Flipping the fan puts the "blade side" of the fan on the inner side--making it just that much more likely to bump into stuff.

or

2. Reverse the fan and place it OUTSIDE the PSU. This places the fan further from the internal components, so there's a risk that some components won't get airflow. However, this frees up a LOT of space and will make the airflow smoother, less restricted, and quieter. With this option, you have enough space to softmount the fan, for even more reduction in noise.

The latter is my preference for custom case builds. My main workstation uses such an external flipped fan: Single Fan Madness 6:Diskless Elegance

So, my advice on flipping the PSU fan is to just do it.

In contrast, I've killed PSUs by removing the fans altogether. I've done this several times with cheap spare PSUs. They may last a few months, but sooner or later they die. (OTOH, I never did this starting with a good quality PSU.)

Starting with decent PSUs, I've flipped fans and even jury rigged undervolted 80mm fans to 120mm fan PSUs. With just a little fresh cool airflow, they do fine.

I'm skeptical that you can get a pure passive chimney effect strong enough to keep everything cool and reliable--not with a PSU originally designed for fanned operation. If you start off with a fanless PSU and a large tower CPU heatsink, then your configuration definitely WILL work--but the hard drives will be cooking in warm PSU heated air. When you go from the low airflow of an undervolted 80mm fan to the extremely low airflow of totally passive operation, the PSU gets pretty hot and the air lazily flowing from it will also be hot.

From a thermal perspective, the best order would be intake->hard drives->PSU->CPU->exhaust. Unfortunately, this may require really long hard drive cables. Those pesky cables can really ruin an otherwise brilliant layout concept.

[nzimmers]

Issac, that's for a great post, lots of good advice !

From a thermal perspective, the best order would be intake->hard drives->PSU->CPU->exhaust. Unfortunately, this may require really long hard drive cables. Those pesky cables can really ruin an otherwise brilliant layout concept.

oh yes, here's a picture of a horizontal layout I did with the PS in the middle, was a pain in the aXX but in the end it worked out:





I thought about that order of components, but I'll probably be going with PS->HDDs-> CPU because the HDD's will probably be spun down (at least some of them) most of the time. Also having the PS on the bottom allows me to have the power cord down in the bottom along the floor. I'd preferr the HDD's on teh bottom to give the tower the lowest center of gravity, but in the middle should be okay for stability. Also I think from a silence perspective, HDDs mounted in the center and furtherst away from any opening would help reduce the noise.

I can do a bit of a combination of air sources, not all the air will come from the PS, the HDD's will get 50% fresh air as the venturi effect pulls in air from other channels.

Definately, one slow moving 120mm fan would almost certainly be enough

[ronrem]

If it's a Sempron/Ninja setup.I don't doubt it's possible to do it with just the flow of a 120mm PSU fan,though you might find tan you need a fixed speed-otherwise the PSU may slow,due to it being near the inlet while the CPU,not near the inlet is getting hot.

In my "chimney" the plan was have the mobo crosswise....horizontal and an internal "Big-Fan" between it and the exaust....an advantage of that is the I/O jacks are accessable

[nzimmers]

yes, i plan to make the jacks accessable but the I/O plate will be located at the corner (with the corner cut out and the I/O plate recessed in slightly.

[Brian]

If it's a Sempron/Ninja setup.I don't doubt it's possible to do it with just the flow of a 120mm PSU fan

Yeah, you should be able to. My 2.2GHz X2 was fine with just the case exhaust fan 10cm away and no duct.

NZimmer, you've drawn four hard drives. Won't that totally drown out the sound of any fans in the system anyway?

Regarding the vertical design. I'd love it see it work. Didn't Apple do something like that once upon a time?

Sticking the PSU right under the Ninja would suck cool air into the PSU, but really only a trickle of cool air. That PSU there doesn't look particularly breathable. You may have to go Pico.

Turn the mobo up side down to place the CPU where you want it.

[nzimmers]

apple did have something similar...the cube - it was a nearly fanless comptuer that drew in cold air from the bottom and exhausted out the top, with interior components along the inside of the walls although it used purpose made components



My idea would be something that is 2-3 times the height of the apple cube (and for that matter cooling components that are using 2-3 times what the apple cube used)

[CyberDog]

I have build one computer in the i-Tee case. http://www.lope.com.tw/i-tee-features.htm It's socket A sempron 3000+ based with slow passive graphic card and one samsung spinpoint. I replaced PSU with nearly silent 12cm fan PSU and cut a hole on the bottom for it. CPU heat sink is ZALMANs CPNS6000 with backup fan. Backup fan because its mostly off. Works great. The Samsung is soft mounted.

[MC FLMJIG]

Would like to see how this ends...

Kind of the idea I was thinking on my case. I'm resting a Mystique on the side and let hot air rise to a vmodded 120mm out.

[screenslave]

looks neat!

[aliasfox]

Actually, the cube's only "purpose built" components were the motherboard and heatsinks. The optical drive was simply a vertically mounted slot load unit, and the HD is any off the shelf 3.5" drive. The AGP slot is a tight fit for most cards, but it too is standard. Stock, the Cube came fanless and relied entirely on convection cooling for its vertically mounted components.

I have one on my desk - I've mounted an 80 x 80 x 15 Silenx fan (not many manufacturers make 15 mm thick fans) in the base - oddly enough, Apple included a mount just for this, but never used it.

The Cube is also seven years old and its power supply is separate from the main unit - maybe that could be a consideration if you want your tower to be silent - store the noisy PSU somewhere behind a bookshelf, and have a fanless tower on your desk?

[nzimmers]

well, my intentions with the design are to incorporate common (and therefore inexpensive) components while requiring the least amount of exotic items to make it work.

I've conducted some test already with a core 2 duo, and while at load things run a bit on the hot side, it seems as though fanless is totally do-able.

but to be on the safe side for now as far as cooling goes, a single slow moving 120mm fan is all that is required to keep everything well under control.