Where to put the cabinet fan?

[Homietheclown]

I'm just needing a 2nd (and 3rd,4th, etc) opinion here.

I have two 80mm fans to put in the cab but I am not sure which location is best. I have two locations A or B to install the fan at.

Which location would be more optimal and why. Thanks!

[johnrt]

Hot air rises so the intake fan should be placed as low as possible, and your outtake fan at the top. But your intake fan is too high in my opinion. You will only get an effective cooling on the marquee.

Edit: I think you need to move your intake fan to a lower point in your cab. If you install it that way I think the fans (no matter how you mount them) will prevent hot air from exiting the cab.

[bfauska]

I think an exhaust fan at location B blowing out and some filtered intake slots or holes low in the cabinet somewhere. Location A could be a problem because things get set on the flat top of cabinets sometimes and if the fan is behind a flat opening then the things could block the hole and if the fan is behind a lumpy opening (like a grill) then something like a drink set up there could easily tip over.
Another option for cooling could be a filtered intake fan placed low in the cabinet and then a simple exhaust port near the top. The advantage of a filtered intake fan and passive exhaust is that you build positive pressure in the cabinet and all the air leaks act as exhaust ports as well rather than sucking in dust. And passive exhaust up high means you're less likely to overheat your fan.

[JDFan]

I'd agree with both -- you want the cool air pulled in low and toward the front and pulled over the components and up and out so intakes down low and exhaust up high (plus as bf mentioned location A may cause other problems if something is spilled on the top or might let light leak out from the marquee if using a lighted marquee so location B is better of the 2.

[Homietheclown]

I guess I should have fully explained myself. Sorry about that.

I have a speaker cloth covered opening at the bottom of the arcade. So basically it's a vent. It's about 8" x 28". It's at the base of the cabinet in the back. No fans. That's where the air will come in. I was just  talking about the exhaust part of the ventilation.

The picture that I have with "A" & "B" are for two possible locations of my two exhaust fans. I'm wanting to put then on panel B instead of A because I want them as far away as possible for the noise aspect.

[brihyn]

My first cab initially had what you're explaining...intake port low, exhaust fan up high. I'm not running a fast pc by any means, and using an LCD, so limited heat there. That said, I found the inside of the cabinet to still be way too warm. Swapped them around, intake fan low, exhaust port around your B area, and things run much better.
Incidentally, I use HVAC intake vents, painted black for my exhaust port...find a smaller one and it doesn't look too bad.

[Generic Eric]

My first cab initially had what you're explaining...intake port low, exhaust fan up high. I'm not running a fast pc by any means, and using an LCD, so limited heat there. That said, I found the inside of the cabinet to still be way too warm. Swapped them around, intake fan low, exhaust port around your B area, and things run much better.
Incidentally, I use HVAC intake vents, painted black for my exhaust port...find a smaller one and it doesn't look too bad.

Do you have a link to your project? Or a posted picture?

[Homietheclown]

My first cab initially had what you're explaining...intake port low, exhaust fan up high. I'm not running a fast pc by any means, and using an LCD, so limited heat there. That said, I found the inside of the cabinet to still be way too warm. Swapped them around, intake fan low, exhaust port around your B area, and things run much better.
Incidentally, I use HVAC intake vents, painted black for my exhaust port...find a smaller one and it doesn't look too bad.

It's funny that this works for you. It definitely goes against the laws of thermodynamics heh.

Do you have a link to your project? Or a posted picture?

No not yet. I'm waiting till I finish it before I post. I see so many threads of 'cades that are started but not finished. Life gets in the way sometimes. So i'll wait until I'm done. Plus... I am a little nervous about showing my work. I'm not sure if it will look good compared to what I see here.

[bfauska]

My first cab initially had what you're explaining...intake port low, exhaust fan up high. I'm not running a fast pc by any means, and using an LCD, so limited heat there. That said, I found the inside of the cabinet to still be way too warm. Swapped them around, intake fan low, exhaust port around your B area, and things run much better.
Incidentally, I use HVAC intake vents, painted black for my exhaust port...find a smaller one and it doesn't look too bad.

It's funny that this works for you. It definitely goes against the laws of thermodynamics heh.

That's what I thought when I first read it too, but the only part that got reversed was where he put the fan, it's still intake low and exhaust high. I think this may be an example of positive pressure in the cabinet working better because the intake fan forces cool air in low, if you use an exhaust fan on top it may just be exhausting air that leaks around the marquee or something so the hot air from the rest of the cabinet may not even be moving.

[brihyn]

That's exactly what was happening. Enough cool air was entering from high-up (cracks around the door, monitor, marquee, etc) that there wasn't much getting in around the pc. I'm just running an old OptiPlex 280, so definitely not generating a lot of heat, but it was enough to actually shut down the pc once or twice. Reversed fan and intake vent around and the thing stays nice and cool inside of the cabinet.
And I can point the fan directly at the pc to make sure the initial air is flowing right to the pc...makes a huge difference.

[Homietheclown]

That's exactly what was happening. Enough cool air was entering from high-up (cracks around the door, monitor, marquee, etc) that there wasn't much getting in around the pc. I'm just running an old OptiPlex 280, so definitely not generating a lot of heat, but it was enough to actually shut down the pc once or twice. Reversed fan and intake vent around and the thing stays nice and cool inside of the cabinet.
And I can point the fan directly at the pc to make sure the initial air is flowing right to the pc...makes a huge difference.

I C.

I think I might have to copy this idea. Either that or make sure I seal the the cab up nicely so there are no leaks.

[edekoning]

The picture looks like a full size LCD cab, so why do you need cabinet fans (=active cooling)? What heat source are you worried about? Why not just add some ventilation to the bottom (in) and top (out), and let the hot air rise naturally out of the cab? That's what I did on my Cab, and that's what I am doing on my bartop.

[Generic Eric]

If passive cooling is not effective, consider setting up some thermometers or using a digital thermometers to learn where the hotspots are. 

[EvilNuff]

The purpose of the fan in a pc case is to increase airflow.  So the answer to your question is, it depends on the rest of the contents of your cab.  You should place fans in a manner to maximize the airflow over the pc components to aid in the air cooling of them.