Airflow in a (PC)-Case

[lukimausi]

Good day to you all,

I have to develop a PC Case, and I am trying to get my head around the question whether it would be a good idea NOT to flush mount the intake fan in the bottom to improve airflow/decrease necessary fan RPM.

Since i have trouble describing what the problem, i made a quick Sketch-Up mock up:
Right side would be the traditional way
Left side the "free hanging" variant.

The fans on top are for exhaust.

If my amateurish question is inappropiate here, just ignore me. Otherwise i would be happy to profit from your expertise.

Regards Lukas

 

[rb1957]

I think the key thing is not to have the case sit on a desk-top (stiffling the lower fan intake).

I'd put 4 feet on the case (like your white blocks) to ensure airflow into the lower fan. Then you'd probably get more airflow with the fan outside the case (and give you more space inside the case to use).

another day in paradise, or is paradise one day closer ?

 

[lukimausi]

Thank you for your quick reply, the case will in any "case" stand on feets/wheels. if i understand you correctly you suggest to lower the bottom fan by about 2 cm, like that:

but which of these to options is smarter. I am wondering if there is any "free" airflow to be gained with the one on the right.

 

[Sparweb]

One fan alone will be effective at cooling the interior of the case. Adding the second fan will not do 2x cooling. The second fan will be marginally effective.
In this case, it doesn't really matter which fan you designate as the "primary" fan. I'd suggest that the top fan blow "in" so that cleaning can be easy and obvious.
In my (limited) experience, electronic enclosures are designed to protect the components, with whatever concessions necessary to allow the cooling air to flow.
Make sure there's a free path to allow the air to flow all the way through.

STF

 

[lukimausi]

@SarWeb, I dont think, that that blowing air downwards is efficent, since the fan would work against convection.

It seems I am having problems to get my question across; the cube on the right is closed of and has a flush mounted bottom fan. The cube on the right has an open bottom with a "free hanging" bottom fan.

.


What i am trying to understand is: Is there any general benefit (more airflow) with one of these to variants?

 

[IRstuff]

Your Left cube should be better. The right one will have issues with getting air flow inside the box to flow correctly. In the left box, the air that's sucked in must go to the hole on the top, while in the right box, you're likely to get air to flow back out through the bottom, which is not what you want.

TTFN
I can do absolutely anything. I'm an expert!
faq731-376 forum1529

 

[lukimausi]

okay, so no fancy dyson effect. Thank you very much.

 

[rb1957]

do you mean the right has no base enclosing the box ... bad idea !

another day in paradise, or is paradise one day closer ?