Reverse Cooling? Blowing from front & Sucking from back?

3

3DChipset

Gawd
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Sep 3, 2007
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Has anyone tried to reverse the way air comes in through the case? For instance instead of the fan above the PS/2 & USB ports blowing out, has anyone have it blown in and the front fans blowing out instead of bringing in fresh air?

Or cases specifically not really designed that way? Just wondering what the temperatures would be between the two?
 
hot air is less dense than cold air, add the effect of the gravity to it and you will get hot air rising above cold air.

so we use this principle here, the idea is that the air intake is at the bottom part of the case (cool air) and the exhaust (warm air) at the top of the case
 
The Lian Li A05 is designed with reverse cooling. It seems to work ok. I never noticed anything too out of the ordinary in terms of temps, although it definitely needed a blowhole or some other exhaust in the top of the case.
 
leSLIe said:
hot air is less dense than cold air, add the effect of the gravity to it and you will get hot air rising above cold air.

so we use this principle here, the idea is that the air intake is at the bottom part of the case (cool air) and the exhaust (warm air) at the top of the case
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Never really looked at it from that perspective. Makes 100% sense. Probably why you always see the cold air intakes in front of cases on the bottom and blow holes on the top. Thanks for the reality check. :)
 
depends on where your vid card blow out if it does, as hot air does rise your PSU if at the top heat will go up, but most back fans are between the vid card and psu, so you would be sucking some air back in.

also if you have your case in a enclosed area you would likely suck the hot air back in.
 
3DChipset said:
Never really looked at it from that perspective. Makes 100% sense. Probably why you always see the cold air intakes in front of cases on the bottom and blow holes on the top. Thanks for the reality check. :)
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yeah but we're talking deltas of less than a single degree.

The air inside a case is so turbulent you cant talk about standing pressures.
 
in reality it all depends on where your psu is.. if its on the bottom then doing the reverse(intake back/exhaust front) wont work because the hot air from the psu exhaust gets sucked back in through the back fans.. but if the psu is on top then it shouldnt really make all that much of a difference if its reversed or not..

though in my case with my antec 300 i have the rear fan as an intake, top as exhaust, front 2 fans intake, side fan intake, and the front 5.25" panels all removed.. but thats due to the pos cpu HSF i have and the fact that i have to keep cool air moving over my PWM/mosfets or they will overheat.. plus i also have my 8800GT w/ duorb exhausting straight into the case..
 
I tried this a few years ago to no avail. Pretty much had the same temps sucking in from the front and blowing out the back.

I've found better results doing a blowhole out the top and fan sucking from the bottom. That's one of the reasons I bought the 690 for my latest build.
 
The fact is that the natural convection of hot air upwards is easily overcome by any sort of forced airflow, so it doesn't really matter that much which direction the air is flowing when it comes to cases with only front and rear fan mounts. However, when you start to add in side panel fans and top fans, depending on their positioning it can be beneficial to have air flowing in a particular direction. Pretty much all modern cases are designed to have a front to back airflow direction, and if you reverse that, you'll probably see an increase in CPU and GPU temperatures, though perhaps not a big one.
 
deff said:
I've found better results doing a blowhole out the top and fan sucking from the bottom. That's one of the reasons I bought the 690 for my latest build.
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Ditto to this. If you have a case with no exhaust fan on the top of the case, and you add a nice 120mm exhaust fan, you can dramatically reduce the in-case temps as the heat tends to build up failry quickly in the top of the case.
 
If your case is upside down, it might be better. Remember, heat rises, and the effectiveness depends on the design of the case.

(on a side note, did anyone else come up with.. different.. interpretations as to the thread title? :p)
 
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