Wood case: Straight airflow with a 22cm fan - Comments?

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marp
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Wood case: Straight airflow with a 22cm fan - Comments?

Post by marp » Thu Nov 19, 2009 3:17 pm

After reading some comments on the different Aplus and Xclio style cases (those with 22cm side fans), I came to this conclusion: While the fans themselves aren't necessarily that bad, side fans cannot offer much improvement to the old ATX case design.

And why? My guess is because they blow on the motherboard, but not past it. On the side of the graphics card, not past it (and not through the fins). On the top of the CPU tower cooler, again not through the fins. Overall, they tend to simply pressurize the case, partly disrupting "normal" front-to-back airflow. Turning/removing the front fan will create a T-junction airflow path: intake on the side, exhaust at the front and back. This isn't necessarily bad, but in such a case you are still likely to need spot cooling on CPU and graphics card.

So what did I do? I opted for the simplest possible case design: straight front-to-back airflow. High airflow, minimal turbulence, low noise. Positive pressure coupled with a dust filter. Indeed, this seemed like a good idea (in theory). A MATX board, 24cm wide, should be the perfect size for two 12cm fans (or possibly 14cm). But I figured a single 22cm might work as well.

Now, to get the most benefit of the relatively low-pressure low-velocity airflow, large heatsinks with wide fin spacing should be used. For the CPU that means Ninja or Mini Ninja. For the graphics card, well... an Accelero S1 will have to do. If it turns out the airflow through the S1 fins is not enough, some ducting or mounting an extra fan should fix it.

Ok, time to turn theory into practice. Make a sketch and get to work. Unfortunately it turned out that I'm not a very handy person, so it took quite a long time to make a rather ugly case. :oops: Still, here is the result:

Image The front of the case. Size: 300x325x400 mm (WxHxD) The dust filter may not be noticable, but it is there. At the bottom, the included rheobus fan controller. At the top, a flip panel that covers the optical. Beside it a 3.5" fan controller may be placed if I need one. At the left, the power button literally sticks out. :D

Image Backside of the case. Scrap hardware, but should give an idea on how the airflow goes. You have to picture a Mini Ninja on the CPU, and above it a graphics card with an S1 mounted. The PSU covers about 20% of the area, the Mini Ninja about the same. The HDD gets less than 10%. The rest of the airflow goes to the graphics card, the motherboard, and to waste. Hopefully in that order.

Image Top-down view. Notice how short the mb is compared to the case (though 40cm isn't that long for a case). The real mb will probably be shorter still (<20cm). The foam holding the fan takes quite some space, but not enough to be a problem. Actually I'd prefer to move it a bit into the case to get more distance between the filter and the fan. PSU can be moved back if needed. The crossing plates at the back holds a suspended harddrive. Maybe I will try some other solution for that. The plate near the front will hold an optical drive in place.

Image The Bzerk fan. I recall someone identified it as the fan from the original Xclio, but i'm not sure. It's not a very good fan, then again not that bad either, and replacement 22cm fans are quite hard to find. There is a high-pitched "ringing" noise to it, which decreases slowly with speed, and remains to some extent even at low rpms when the regular hum and whoosh sounds are gone. At first I thought this was the ball bearing ringing, but it might as well be the motor whining. :? It would probably be annoying as a desktop, but not as a HTPC. Standing 3m away the fan is just barely audible. Hopefully the other parts will be too...

Speaking of which, which PSU should I go with? Yes, a subject never discussed before. :wink: My needs are modest: 2 s-ata, 1 or 2 pcie, a minimum of molex, and I would prefer really short cables (or modular, if the cables are still short). Power consumption should be around 70-80W idle, and max out at 200 or 250W depending on GPU.

Skimming through the shop I'm considering, these stand out (in price order):

Mushkin EP 400w - half-modular (no major benefit), 2 pcie, but not very efficient (haven't found more than 2 reviews though, not enough)
Be Quiet L7 350w - efficient, possibly silent (where are the reviews?)
Seasonic S12II 330W - efficient, should be quiet below 200W, lots of cables though
Corsair CX400W - should be good upto 250W, but again lots of cables
Xigmatek 400W - nah, hardly better than Corsair
SilverPower 400w - hardly better than Corsair
Arctic Cooling 500W - 2pcie, and this is interesting for the front-to-back airflow alone, but 8 cables may be too much to handle
Tagan Superrock, Corsair VX, yada yada...
Enermax LibertyECO - finally a modular, but nothing special, and costly

Ah well, better stop now, as I'm probably not willing to pay more.

Alrighty then... comments? Suggestions? Please?

xan_user
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Post by xan_user » Thu Nov 19, 2009 3:34 pm

looks nice.

did you consider;
having the mobo flat, so when the ninja is installed there are no issues with cantilevered weight?

how about this for vga? http://www.thermalright.com/new_a_page/ ... tfire.html

it has rather tight fin spacing, which is a drawback, but you might be able to orient it better, and end up with more airflow than a S1. -If you dont plan on having any add on cards.

PS -it might only need a pico. :D

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Post by BillyBuerger » Thu Nov 19, 2009 7:21 pm

That's awesome that you're trying this. I've got a case idea that's half-built and been half-built for a couple years now. It looks like a fun and possibly efficient idea. Definitely better than the big fan on the side. Keep us posted on your results.

marp
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Post by marp » Fri Nov 20, 2009 10:05 am

xan_user wrote:looks nice.
Yeah, right...I mean, thanks! :)
xan_user wrote:did you consider;
having the mobo flat, so when the ninja is installed there are no issues with cantilevered weight?
At first I did, but then I figured I don't have a good way to hang the PSU securely. Really didn't want to risk it crashing down on anything. Besides, it should be easier to deal with cables with the PSU in the low corner. As for the Mini Ninja (not so heavy anyway), if needed, I could let it rest on some soft foam.
xan_user wrote: how about this for vga? http://www.thermalright.com/new_a_page/ ... tfire.html
it has rather tight fin spacing, which is a drawback, but you might be able to orient it better, and end up with more airflow than a S1. -If you dont plan on having any add on cards.
That one could actually work pretty well in a side fan case. Pity about the tight fins though. Still, with the airflow parallel to the fins, I think the only way to improve upon the S1 would be wider fins, like 3cm or so. Either that, or strap a Ninja on. :D
xan_user wrote:PS -it might only need a pico. :D

Uh, no. A PW-200 with a 220W brick might just work, but would leave little to no leeway for overclocking. And costs (Ebay, incl. shipping to Europe) is $100 or more. Not sure if I'm willing to pay that for a low-power PSU without any warranties. It's perfect (even required) for a smaller case though.

Shobai
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Post by Shobai » Fri Nov 20, 2009 8:24 pm

i think you've started out with the right idea - grab a fan which moves a large amount of air while spinning at low speeds, ideally reducing noise. if i may make a suggestion; have a look at Bluefront's work, IsaacKuo's work.

at the moment you've got a certain amount of air moving, and it moves most easily in the most unrestrictive paths. you've got a large cross sectional area, and only a little amount of that is heatsink - your air is going to move through the unimpeded open space on the whole, very little will want to move over your heatsinks.

what you might like to try is directing the air over the places you want. Isaac called this compartmentalising the air, if i recall correctly. basically, you'll want to direct the air as much as you can, otherwise it's going to have marginal effect in comparison to it's potential.
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Post by Fayd » Fri Nov 20, 2009 11:16 pm

something like this, i think you might be better served by turning the air column on end. blow the hot air up.

might make a nicer looking case too. then vertically mount the CD drive to one side of the front of the cabinet...

with regard to the oversized fans, when you undervolt a very large fan, even if it puts out quite a bit of air, its static air pressure is minimal. thus, for anything of reasonably high wattage, you're still gonna need spot cooling.

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Post by xan_user » Sat Nov 21, 2009 8:22 am

Fayd wrote:turning the air column on end. blow the hot air up.
We just call that a Bluefront special. :D

marp
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Post by marp » Sat Nov 21, 2009 10:13 am

Shobai wrote:at the moment you've got a certain amount of air moving, and it moves most easily in the most unrestrictive paths. you've got a large cross sectional area, and only a little amount of that is heatsink - your air is going to move through the unimpeded open space on the whole, very little will want to move over your heatsinks.
Good point, although I think the relative proximity to the fan will have some spot-cooling effect. The Ninjas with their unrestrictive fin spacing have a reputation for being excellent for semi-passive cooling, and that's usually without a big fan blowing towards it from 15cm away. Not that any currently available low-cost CPU would output much heat anyway.

The major point if this quite open case design is to have good airflow through the case (duh!). Overall case temperature should be pretty much the same as ambient, as there are no pockets of dead air that will heat up. Actually there is one, right before the PSU, but without any heat sources.

The drawbacks are obvious: no containment of internal noise, no EMI shielding at the open areas.
Shobai wrote:what you might like to try is directing the air over the places you want. Isaac called this compartmentalising the air, if i recall correctly. basically, you'll want to direct the air as much as you can, otherwise it's going to have marginal effect in comparison to it's potential.
About 50% of the exhaust area are covered by the PSU, the CPU heatsink and the HDD compartment. Any heat sources on the motherboard should get their fair share of airflow, being in close proximity to the fan.

This leaves the area above the expansion slots. Unfortunately the Accelero S1, only covers a small portion of it. I think about 11x1 cm, not at all unrestricted due to the heatpipes. Some have reported success with semi-passive cooling with less airflow, but it remains to be seen what kind of temps I would get. Some ducting to direct more air through the fins might be a good idea. Or just attach a low-rpm 12cm fan on. Or both.

marp
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Post by marp » Sat Nov 21, 2009 11:24 am

Fayd wrote:something like this, i think you might be better served by turning the air column on end. blow the hot air up.

might make a nicer looking case too. then vertically mount the CD drive to one side of the front of the cabinet...
I did consider it when starting out. Apart from aesthetics, the benefits are better noise containment, and the bonus of natural convection. Points against:

1. How to attach the PSU securely? Probably easy to solve.
2. How many tray optical drives will function vertically? Slim ones with caddy, and slot-in of course, but others?
3. The effects of (non-local) convection should be marginal compared to froced airflow. Right?
Fayd wrote:with regard to the oversized fans, when you undervolt a very large fan, even if it puts out quite a bit of air, its static air pressure is minimal. thus, for anything of reasonably high wattage, you're still gonna need spot cooling.
Could be. Not worried about the CPU, but the S1 could probably use a fan. About the pressure, it's interesting to see how the air velocity increases when the dust filter is removed, though it's unclear by how much, or how much is caused by increasing rpm. The basic paper roll test is the best I can do. :)

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Post by xan_user » Sat Nov 21, 2009 11:56 am

Check out some of Bluefront's builds- He doesn't come around anymore, but he played with the bottom up airflow and filter pressure differences quite a bit.

here's a rather elaborate 2 fan one. (he had single fan ones too)
viewtopic.php?t=44406&highlight=

marp
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Build complete

Post by marp » Mon Feb 15, 2010 12:46 pm

In case someone reads this... Finally got around to ordering the parts:

Biostar G31-M7 TE
2x2GB DDR2-800 mushkin CL5
Intel DC E6300
Scythe Ninja mini Rev.B
Club3D Radeon HD5770 1GB
Accelero S1 rev.2
1TB SpinPoint F3 HD103SJ
BE Quiet L7 350W
CoolerMaster MegaFlow 20cm

So, obviously this is hardly a high-power build, but I wasn't keen on spending much.
Will overclock the CPU a bit, but with moderate voltages.

About the fan... the previous one, (22cm Bzerk) produced a high-pitched "ringing" noise,
which to some extent persisted even below 5V. The Megaflow at 5V is practically inaudible
to me (tested with 5V brick) Putting the ear next to the hub reveals a low humming sound,
then again my ears will be elsewhere when I use the computer. Obviusly it produces less
airflow, but for this half-open case design it should be enough. If not, 7V may work.

The PSU is the cheapest bronze-rated I could find with enough connectors. The german site
Technic3d called it inaudible even under full load, but this is of course false. At idle
(with no other sources of noise connected) it is far from noisy, but not silent either.
Unfortunately I discovered that my case transfers vibrations really well, even creating
resonance, which is not what I intended. So the BeQuiet while reasonably quiet on its own
makes the case noisy. This is indeed a pity, especially considering how quiet the case fan
is, and how well it probably would cool a passive PSU. How to suspend the PSU in such a
small available space? Perhaps I should have bought that Fusion 550R after all, unplugging
the fan would have been so much easier on that one. Ah well. For now, some thin foam around
the PSU and under the case lid reduces the noise somewhat.

The F3 is not annoyingly loud. It does produce a typical hizzing sound which is clearly
audible up close but fades away quickly. If the hizzing ever becomes a problem, I suppose
I could make a tiny foambox to hold it. As for vibration, there's not enough room in the
case for a proper horizontal suspension. At present it's resting on foam on top of the PSU,
secured by slightly elastic string. Mounted this way, vibration seems negligible compared
to what the PSU produces. Hard to tell though, because it won't spin down for more than a
few seconds.

The 5770 is obviously the loudest part at present. Its custom fan is quite noisy at default
speeds. Turning it down to the minimum 20% makes it bearable, and by then from about 3m away
most of the noise drowns in ambience. But while gaming 20% is not enough. Fortunately I have
an S1 waiting for the card.

Of course, installation of the S1 turned out a bit complicated. The heatsinks was the easy part,
all the chips were already clean so thee tape stuck easily. The cooler however needed some work.
First of all the mounting area on the card was only 5cm square (42mm hole distance), too small
for the S1 base. That was easy to fix though, just remove the plastic and cut the corners on the
mounting bracket. After that 19 of the fins on the back needed some cutting. Luckily, the Club3d
card doesn't have any dual connectors, just a single backplate with 3 connectors. So after some
fiddling with the distances and the screws the card was ready for testing. Or so I thought.

Oh no, 50°C at idle passive! Oh no, why did I start Furmark - it's already up at 110! :shock: Better shut
down and add a fan. Booting up again. Oh no, Windows displays no picture! Shut down. Reboot.
Oh no, Windows enters a 30 min uninterruptible recover because I shut down with the power button!
Shut down. Reboot. Oh no, Windows displays no picture! Better give up and retry tomorrow.


However, after reinstalling with shorter spacers and less thermal paste, the S1 worked fine.

Temps (°C) at idle / load (Furmark 1.8.0 default settings)

Stock fan (auto speed) 35 73
First accelero mount 48 110 (aborted!)
Second accelero mount 35 85 (10 min)
+ 80 mm Ninja fan 32 66 (20 min)
+ 140 mm Revoltec AirGuard 31 59 (20 min)

The fans listed above were centered over the GPU and blowing upwards, away from the card.
They were connected to an external 12 brick through a resistor. The Revoltec was a bit loud
but probably less than the stock fan at idle. Since then I have put some foam between the S1
and the Revoltec fan, and attached it to the 2pin fan connector on the card. It is now quiet
at idle (fan speed at 85%), and reasonably quiet when spinning at 100%. Can't say for sure
how much voltage the card produces at 100%, best guess is around 8V. MSI Afterburner is used
for automatic fan control, and the GPU rarely goes above 55°C during gaming.

Overall I'm satisfied with the noise level of this build. Though to be fair, it is currently
hidden away next to the sofa, which dampens the noise somewhat. In practice it is barely
audible over the ambience in the quiet room. With headphones on, the reciever buzz is louder.
With any sound playing at low volume, no noise can be heard. Of course, noise level is very
subjective, and I doubt any hardcore SPCR member would call it silent.

As for the temps, they are neither great nor terrible. The gpu temps should be ok, since they
are a lot better than with the loud stock cooler. The cpu is semipassively cooled by the large
intake fan blowing through the Mini Ninja. It idles exactly at body temperature, while Prime95
brings it up to 55°C. Although it runs at 3.34GHz (1.1375V, 10x FID) both temps are higher than
expected. The silent front fan running at 5V may provide too little airflow (or air velocity),
but I may also have used too much paste during installation. However, during typical load it
rarely reaches 45°C, which is acceptable.

The northbridge (FSB at 334MHz) is a different matter. Idle temp at 35°C is fine, but Prime95
brings it up to 65°C which is not healthy. Even at typical load it often reaches 55°C. The tiny
heatsink, hidden behind the DIMMs, probably recieves very little airflow. I tried during the
build to direct more air towards it with some cardboard, but couldn't notice any difference
at the time, may have to try again. Installing a taller heatsink (like a Zalman ZM-NBF47)
should otherwise solve the problem.

Meanwhile the Samsung F3 at 27°C is possibly a bit too cool. But I have not foamed it yet.


Pictures will come later, if anyone is interested.

mark19891989
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Post by mark19891989 » Mon Feb 15, 2010 1:36 pm

Looks nice :)

If it was my case i would want it about half the hight , wth 2 120mm fans on the front, my wood work skills suck, so it would be better to see if i could find a big project box.
specs:[email protected],4gb ddr2 1066, DFI LP jr p45-t2rs,Super talent 64gb ssd,8800gts @ 513/792/1674, 8800gt @ 555/800/1782 corsair tx650
Cooling:XSPC Acrylic top, MCP355, D-TEK FuZion v2,XSPC RS360 Black,swiftech MCW60,D-TEK FuZion GFX+uni sink,EK-NB S-MAX
Server/htpc: Zotac GeForce 9300-ITX-I-E - E5200 - 4gb ddr2 800 - 2* 1.5tb f2 drives- Pico PSU - minja

Fayd
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Post by Fayd » Mon Feb 15, 2010 2:37 pm

xan_user wrote:Check out some of Bluefront's builds- He doesn't come around anymore, but he played with the bottom up airflow and filter pressure differences quite a bit.

here's a rather elaborate 2 fan one. (he had single fan ones too)
viewtopic.php?t=44406&highlight=
i thought bluefront died. 0.o

marp
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Post by marp » Tue Feb 23, 2010 10:02 am

mark19891989 wrote:Looks nice :)

If it was my case i would want it about half the hight , wth 2 120mm fans on the front, my wood work skills suck, so it would be better to see if i could find a big project box.
Yeah, with a low-profile graphics card and a Pico that would be a nice compact design. However, if you want an Accelero in there, it will rise about 17-18 cm above the motherboard tray. This means the case would need to be 18cm high, so two 18cm fans might be the natural choice, and there would be room for a full size Ninja and ATX PSU on the side of the otherboard. In the end, the result would be the size of typical mini-tower case, but with dual 18cm fans on the front. Nothing wrong about that, but not very original.

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