Laptop Fans

[Blaise170]

I've never quite grasped the reason why laptop fans are on the BOTTOM of the computer??? I know laptops are meant to be small, but what does putting fans on the bottom accomplish? I'd rather have the slightly uncomfortable feeling of having the fans below the keyboard or something. But with the fans on the bottom my whole computer tends to become really hot, especially when I'm playing games.

[Evans]

I'll go on a stretch and assume that if that's where they always are, it means there's a conceptual reason behind it. One would be that they have to be as close to the CPU as possible because there's no place for heatsinks.

[polobunny]

Because the CPU is in the back of the laptop (close to the hinge normally) and a fan sucks and shoots air (that's the idea no?) it's quite hard to do something else than what is already done. Normally sucks cool air from under the laptop and shoots it 1) Out of the back 2) Out of the side.

[Banned]

I have multiple fans in my laptop, I get air shooting out of the back and the bottom of it, hot air when I'm really working it.

[Mistral]

Available surface area to maximize air flow. The largest exposed areas of the laptop are the flat surfaces of the keyboard, display, top, and bottom. Of these, the keyboard and display are rather occupied, and the top is disjoint from the actual guts of the machine. I can just imagine trying to wire the keyboard around a spinning fan, since you can hardly channel air through the wide hunk of silicon that is the motherboard, and the keys would play havoc with airflow. The bottom's the only place left. Why you'd want a large area to draw air in stems from flow conservation, which basically means that air entering across a wide cross-sectional area will accelerate as the cross-sectional area decreases. Basically, you don't need as powerful a fan at the base to get a fast airspeed across the internal structure and out the small side vents.

Hey, those college studies are actually pretty useful. I didn't even need to BS all that much. Maybe I could throw a rho or v or something in there...