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while true
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PostPosted: Wed Aug 07, 2013 7:09 am    Post subject: fan system to cool pc [SOLVED] Reply with quote

hello there,

aaah, in such record heat that we have,
I decided to treat my box with two additional 12cm fans.

box:
http://www.thermaltake.com/products-model.aspx?id=c_00001579

motherboard has 4 connections for fans,
I already used two, one for cpu and one for original back fan.

I am interested in placing two new fans,
I will put one on top to take out air,
and as I found something on that matter:
http://www.xoxide.com/computer-cooling.html
I think I should put one to force air in,
but where to put it,
in the front or on the botton of the case?

If in front, the air will flow over ssd to psu and up over motherboard,
if on bottom, the air goes directly over motherboard (gpu and cpu),
but will it get enough air from the bottom of the case?

Thank you
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Last edited by while true on Fri Aug 16, 2013 10:29 pm; edited 1 time in total
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Navar
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PostPosted: Wed Aug 07, 2013 10:56 am    Post subject: Reply with quote

Dust (particularly coupled with humidity) is not your friend on cooling and adds noise (oscillation) and excessive wear on your fans over time. I prefer to build a case with slight positive pressure versus negative. That looks like a very well vented case without good filtering. Negative pressure in that case from extra exhaust instead of slightly more intake will bring dust in every opening but can otherwise cool well initially.

Try to balance it out with 2 120mm low rpm quiet front fans with good dust filters for intake with one exhaust fan in back rear/top of case. If you don't mind the noise and your ambient heat is a big concern then you can add a side panel fan and an additional exhaust fan to match. After that and ensuring you've got the 'best' (large) heatpipe coolers for your CPU and GPU, you're left with water cooling as the next route. Mostly bottom vents/fans are coupled to help cool today's style of bottom mounted power supplies. If you have plenty of clearance on the bottom of the case this may work ok, otherwise I'd avoid, but here again it can depend on the power supply you're using and how it's set up for exhaust cooling. The design intent was to allow larger cooling clearance for the CPU area and to help remove that immediate heat source from the power supply being nearby. This had a side effect of allowing quality power supplies to run cooler and quieter too.

My setup involves the initial 3 120mm case fans (2 front intake 1 exhaust) and my temperature inside the case is only a few degrees C above ambient at high load and barely audible. My ambient temp is kept at 22C so this is easily sufficient.
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PostPosted: Wed Aug 07, 2013 9:38 pm    Post subject: Reply with quote

oi Navar,

so more in than out? cool, ok, I will get dust filters for intake, thanks.
the main problem now is hardware, since the cable appears to be too short for front intake, which is not funny, kheh heh,
and also in front there is place just for one fan, so the other intake fan should go on bottom or on the side.

power supply unit has bottom intake, but lets air out at back of box (so air from psu does not go inside of case),
is this the case in which would be ok to have bottom intake fan (there is clearance),
or is it better to put it on side to push the air in directli over gpu and up to cpu?

I saw a picture that I can mount two fans one after the other, so I can put both in that manner on front side of box,
or is this too 'mounty'?

thank you
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PostPosted: Fri Aug 09, 2013 11:58 am    Post subject: Reply with quote

If no mounting option for two fans pushing in from front, then one on side panel at GPU/expansion slots would work fine. Since you say you have good clearance, you could try the bottom mount instead of side and compare over time. It is possible to have too much positive pressure which will cause some heat buildup and possible dead spots but you're less likely to suffer from that without fans rated for high positive pressure push than simple CFM output.

Or a simpler way to think about it, get all the same type/model case fans. As long as intake count > outtake you should have some positive pressure. This will also avoid odd oscillation noise. You'll still get dust buildup eventually, just a lot less of it and it'll tend to be a much finer grade due to filters used.

The L flow for the power supply keeping exhaust heat away from interior of case is ideal, so you're good there.

And don't forget good cable management for better airflow and reduced noise. ;)
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PostPosted: Fri Aug 09, 2013 3:04 pm    Post subject: Reply with quote

ola Navar,

Thanks for conformation, will do it that way, but right now I am seriously annoyed since in our little country I can not seem to get cable extension nor 12cm filters!!!
As it is now I can not reach front (and I did buy two same fans, with 30 cm cable) but painfully as it is, I also detached fan cable from corner of the fan to get extra 1/2 inch, but just shamefully short...
so I have one on side and one on the bottom for in-take.

and this bottom clearance, I take that everything should be away from case at least 4-5 inches (10-12 cm)?

I do know my new fans cfm, but I could not get specs on built in fan. In bios I can see built in runs usually on slower rpm,
so what I am thinking is replacing built-in out-take and place it in in-take position, guess side is the place,
one new one should be placed at back for out-take,
and one new one at the bottom for in-take.
Since 'original' runs on slower rpm there should be a bit pressure inside the case.

I hope that during next week I will find at least filters, since those cable extensions are a bit hard to came by...

Thanks man for now, I will be in touch
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PostPosted: Fri Aug 09, 2013 9:58 pm    Post subject: Reply with quote

while true,

You can check for positive pressure in your case with home made water manomoter.

This a piece of transparent plastic tube, bent into a U shape with some water in the bottom of the U.
Put one end against a hole in the case and make sure the water in that arm of the U is lower than in the open end of the U.
Food dye may help too.
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PostPosted: Mon Aug 12, 2013 3:05 am    Post subject: Reply with quote

while true wrote:
I can not seem to get cable extension nor 12cm filters!!!

You can always splice the wire to extend, just make sure you re-insulate what you expose (electrical tape, wire nut, heat shrink tubing, etc). As far as filters go, there's always the old school makeshift ways before they sold us the shiny toys: 1mm thick active carbon filter sheeting for AC units can work well in a pinch and is cheap, in fact depending on the density used it can work better than the commercial plastic grids. Thin pantyhose stretched and cut to size will work too if you're desperate or just want to amuse friends and family. :lol: I've seen people make them from used dryer sheet material also. Whatever you use, make sure you can easily breathe through it so you don't starve the fan intake. The only challenge involved is frame mounting the material (so the fan doesn't munch on the filter). Wood popsicle sticks and glue are a cheap way to pull that off.

Quote:
and this bottom clearance, I take that everything should be away from case at least 4-5 inches (10-12 cm)?

An inch is ok from bottom if there's a fan involved and no carpeting such as a hard floor/desk surface. A half inch is minimal under the same conditions, but a number of cases give only that much clearance with a power supply fan pulling in from the bottom. This on a carpeted surface is bad news. When it's passive intake from bottom (no immediate fan or PS fan is on other side of case exhausting out back) the half inch clearance is fine. Your ears will help you know if you're restricting clearance on an intake fan too much.

Quote:
I hope that during next week I will find at least filters, since those cable extensions are a bit hard to came by...

Both can be fairly easy to resolve in a do it yourself manner, it just depends on how much (temporary) looks vs performance matter to you. In the past I've tended to get bare wire end or solder only contacts only on fans to run a clean run of quality wire rather than the super tiny and aluminium in short lengths they usually sell today's fans with. 22-24 AWG wire is good enough to handle low amp (<1A) 12V DC fans. If they seem to run noticeably slower and/or the wire feels warm, then you need a lower gauge (thicker).

Good luck!
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PostPosted: Fri Aug 16, 2013 10:27 pm    Post subject: Reply with quote

aah, friday night...


Ola NeddySeagoon,
Khuh, I have strict policy that no drink, not even bottled one, is allowed on my table.
I have made a shelf, just behind my sit for my precious coffee.
So I read your post shivering... clumsy as I am I already saw disaster.

But you did make me think about how I could check the pressure,
or air flow, and I did blow my cigar smoke into fans, khaha,
nothing to be seen so do not do that, khaha.

I have specifications of fans I bought, but I could not get for cased one.
From bios I can see their speed, by rpm I have cca 1000-1500 rotations more intake.

Navar, man, I cherish this post, you shared a lot of experience for each of my concerns, thank you!

So here is what I, after two days(!) came up with:
For intake I managed to put one (original one) fan at front panel, without extending the cord.
http://shrani.si/f/1Y/mQ/3SGOMNNG/dscn2307.jpg
Filters I got require to be placed on the outside of the case, which took almost all bottom intake space,
so I moved that bottom fan to side of the case for additional intake.
The thing was, that blades were hitting the side of the case,
so I ended up placing it on the outside side of the case.
http://shrani.si/f/f/4l/28p6byLH/dscn2308.jpg
(yes, that is tape, and please do not ask)

For outtake I put at back side one fan.


I must say, this assembling was no easy nor plesent task for me.
What I thought that would be a matter of installing fans in several minutes,
every re-arranging took hours, problems with hardware are just poping up,
from short cables to indentation of the case, freaking motherboard is always in the way,
huh, I hope I did my rig!

The main thing is that temperature readings did drop for 5 degrease Celsius approximately.


now on to next step, to see if we can manipulate those fans,
I know there are posts about that so let me do my reading and I'll pop up new post then.

For now thank you
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PostPosted: Wed Aug 28, 2013 1:49 am    Post subject: Reply with quote

while true wrote:

I saw a picture that I can mount two fans one after the other[...]

Sorry, I had missed this question before.

I don't use fans close together in series (stacked--one pushing directly into the intake of another). Too many variables work against much gain (if any) in airflow out. What you'll get instead is a lot more noise (via increased immediate turbulence and vibration).

Fans in parallel work fine (if your case allows such), although you generally can't expect to double the airflow.

http://www.ebmpapst-ad.com/media/content/technical_articles/TA_Using-fans-in-series-and-parallel.pdf gives a good technical discussion.

5 C case ambient drop is decent and you definitely made some progress. Not sure what you were measuring prior or what your ambient temp outside the case was.
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