Cooling what would happen if.....

all your case fans were just exhausts? how would this affect cooling?
PV = nRT
if you lower the P(ressure) you would lower the T(emperature), ideally.

 

PV=nRT only works in a closed system, and your PC is not one of them.

-Lemur 6

 

if you can manage to keep the inside of your case below 1atm, you will reduce the temp a lot. at 0.95atm, the temp can go from 88F to 60F if my calculations are correct.

 

Those figures do relate to a close system, and only the air temperatures. By your thinking sucking all the air out of the case would mean you wouldn't need cooling. Best thing to do is get good airflow, intake at the front bottom, exhaust at the top rear.

 

While this can produce a temperature drop, you have to be careful - place vents in front of components you want to cool only - air being sucked in willy nilly will cool nothing before it's expelled, resulting in the air inside the case gettign heated up, and that little bit of warm air that needs to get out becomes a little bit of HOT air soon enough.

 

You'd probably screw up your fans too, they're typically not designed to work under high pressure.

 

It's a thinking error. First, there is no way that a bunch of computer fans will cause any appreciable air pressure drop --the airflow inside will just stall.

Second, even if it were possible to reduce the air pressure, although it may reduce the air temperature inside the case, the components still need to get rid of their excess heat, do they? All you would get is that your components, unable to pass their heat to the surrounding air, would fry.

 

The fans won't suffer from the pressure drop, but heat dissipation most surely will.

 

Basically all that will accomplish is turning every small hole in your case into a vacuum cleaner.

 

I'm with nexxo on this one. If anything, you'd want more air making contact with your heatsinks.

 

The temperature drop occurs during the act of reducing the pressure of the gas inside the PC case. So basically yes you could drop 20 degrees or so by reducing the pressure. But that would only happen once, the low pressure air would just heat up.

 

I try to balance the air flow/pressure in my sytem. I get the fan for the rad where i want it (7V atm) and adjust the back fan to move the same amount of air. Which usually works out to 5V. Theres no point turning this fan up any more cause it just starts sucking air from the various seams and such around the case and this extra air flow benefits nothing and is noisier. I use a lighter to check for the small airflows, its quite sensitive.

 

Absolutely. Balancing the in- and outflow is the key. Anything else just creates more noise and no benefits.

 

Okay, you DON'T want the inside of your case to be under 30in. Mercury vacuum (1 atm). That effectively removes the majority of the cooling medium (air), it's like running a water cooling loop and sucking out all the water so that all your hoses are collapsed. And like I said, your PC is NOT a closed system, PV=nRT does NOT hold true because there is stuff going into and out of the system at all times. For PV=nRT to work you need to put your computer in a insulated bubble, and you can't turn it on since electricity is energy into the system.

Another way to think of it is that heat has two ways of travelling, radiation and conduction. You can only get rid of so much heat through radiation, so the majority of the heat is gotten rid of by conduction. You need a medium to conduct heat to, it just doesn't magically get transported away, and in this case, you need air. If you're in perfect vacuum (no air at all), you have ZERO conduction, and your components fry basically.

Like Biff and Nexxo said, if you want good cooling, go for high flow into and out of the case in a balanced ratio. Just like high flow setups in WC loops (assuming you have a radiator that can dissipate more heat than you can ever put into it, and in air cooling case, since the air volume in the room is so large its like having an infinite radiator) the higher the flow the better your cooling performance will be. But, this comes at the cost of noise.

-Lemur 6