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Boring but really good basic knowledge about fan !

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bing

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Jul 13, 2006
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Although I'm not a fluid dynamic expert, find these quotes very interesting and useful.


PS : If the text looks a bit fuzzy, just click the bar above each pic to get the original size with better view.


The basic of fan in parallel or series that we all know, but this one is really good with the chart and an explanation.

Series and Parallel Operation.png



The "Laws", though simple, believe they will be handy someday.

Speed and Density Changes.png


These above and other useful knowledge came from -> Establishing Cooling Requirements: Air Flow vs Pressure (Comair Rotron Application Note)


Its oldie but still goodies, imo the link worth a place in your bookmark. ;)


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I'm sort of shocked that no one responded to this, way back when. Invaluable.
 
I'm sort of shocked that no one responded to this, way back when. Invaluable.

would really love to see the results of 140mm fan in series for your drive bay setup, if you have some spare time of course :thup:

I'm really curious if the method could substitutes the top intake for better front to back airflow
 
I can't put fans in series. I have only four 5.25-inch slots in total. the bottom is used by a DVD. That's a full-length device. Just above that I have an IO plate. It takes up the front third of the slot, but its cables exit about halfway back. No room for more than one fan.

myrig20121231.jpg


I cover up both the DVD and the IO when I'm not using them.
 
lately, I've been wondering;

does this count as a series fan setup (edit: I've said it's parallel before, which is wrong)
1.png

and compared to this setup:
2.png

which one would be better in order to flowing air?
we commonly see the 2nd image on the bottom intake of most case
 
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You want the fans setup like in image #1

You can also go with image #2, but it's advised to add a 3rd fan ontop as in image #1 so you have airflow thru the case.
 
Counts as Series. as FAN inside the chassis is getting no 'new air', but rather, recycling whatever intake from the previous fan. Though since your chassis is sporous, it will be able to draft a little in additional due to pressure gradient difference, but mathematically the model is closer to series than parallel.

that being said, both setup from #1 and #2 is also dependent on where are your choke points, example being, if your heatsink's fan is already pointing upwards, then an extra fan up adds not as much value. While if there's nothing to obstruct the lower fan's flow and if your chassis has enough bottom room (not too close to the ground) the bottom fan can in fact introduce additional fan into the chassis, thus making it closer to a Parallel set up. :)

I wrote a lot about fans previously, that post in my sig. :)
 
You want the fans setup like in image #1

You can also go with image #2, but it's advised to add a 3rd fan ontop as in image #1 so you have airflow thru the case.

wow...
that's super fast, many thanks :thup:

I'm currently having the 2nd image setup on my bottom front.
my hdds are really cool, but I'm slightly irritated by the noise.

guess I'll have a nice weekend project soon :D
 
You're most welcome! Well you can always use a fan controller to control the speed, thus reducing noise ;)

Depending on how many fans you have, you can get a controller for up to 6 fans. Of course the fan must have a 3pin (not 4pin molex) to be able to use the fan controller.

Take a look around here to give you a general idea.
 
@inVain
I think:
*Image #1 has top fan pulling air from space side fan is pushing into = series
*Image #2 has both fans pushing air into same space = fusterclucked parallel :D

@bluezero5
Nice job! There are too few people who understand airflow and fans.
 
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Or you could build a case with side, top, front and bottom intakes, all filtered. Cut out your grill, remove all unused rear slot covers and perhaps remove the sheet metal between the slots. Then you can have reduced-dust intake, quietly, that exhausts on its own, noiselessly. Like this:

myrig20111203003.png


True, this is optimized for quiet. The top intake, for example, is a PWM fan that shares a PWM splitter with the two cpu heatsink fans. When cpu load goes up, the three fans sweetly spin up. Otherwise they shut up (i.e. -- spin too quietly to hear).
 
Nice job ehume. :thup:

I need to get a good nibbler so I can do more, well, nibbling. Haven't been able to find a good resonable priced one here in UK.
 
You guys are really bunch of thread necros !!!!! :chair: ... j/k :D

Appreciate the bump & glad you find it useful.

Just realized after looking at the date I posted, time really flies and we're all getting older, hopefully wiser too. :cheers:
 
@inVain
I think:
*Image #1 has top fan pulling air from space side fan is pushing into = series
*Image #2 has both fans pushing air into same space = fusterclucked parallel :D

LOL
guess my current setup is a super fusterclucked parallel :D
so here's my curretnt setup:
(the bottom arrow should all be colored with blue, sorry for the mistake)

12.png

I did this setup mainly because one of my HDD runs really hot, not to mention that the NB was quite a stove to touch.
But now, since I disconnected my side panel (recently added a small fan to the NB) I'm quite disappointed by my CPU temps.
It's not that bad, but compared with my side fan on, it's awful.


I'm thinking to convert it into something like this:

11.png

I'll be running four identical fans on the top half of the case (front to back).
The fans will be hooked up to a single channel of the fan controller; thanks for the link, Nebulous. It really fabulous :thup:
The idea was to gain the highest static pressure possible with the slowest possible RPM.
Something like Ehume showed on his pic, but without the top intake installed.
It just a matter of time until I cut my rear grills, but I'm out of cutting wheel ATM.

I'm on my halfway done with the cable management.
So I really need help to hear most of your opinions before I cut my zip ties and re-comb the wire :D

@ehume,
you really should post your 5.25 bay drive mount on this forum.
It really full of inspirations :thup:



Just realized after looking at the date I posted, time really flies and we're all getting older, hopefully wiser too. :cheers:

what time?
I sill think that 90' was ten years ago :chair:
 
@inVain
I was looking at airflow as shown by arrow with front in top out or front in bottom in. Not a complete case layout. Front in top up is good. Front in and bottom trying to push it all up instead of fan on top pulling = FC ;)

I like your first layout / setup.

Second one too but I don't think you need 4x fans in a row. Think one in front, one on cooler, one at rear.. maybe.
Have you considered using a duct from front to cooler and/or from cooler to back vent?
2x intake and 1x exhaust may move air out back vent just fine.
 
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