Single big fan vs. two small fans in a laptop cooler pad

Question

Is it true to say that a single fan in the middle of the laptop cooler pad would be sufficient because the fan will "dissipate" the cooling air around?

Or is it true that most of the dissipation would mean that the cooling air is lost and hence a laptop cooler pad with two fans aimed directly at the hot parts of a laptop (instead of having 1 big fan at the center) would be much much more efficient in cooling the laptop?

Solution

No.

Fans don't dissipate air, they move air around in the hope of dissipating heat from nearby hot objects using convection (or, in the case of hot sweaty humans, by also increasing evaporative cooling).

What is important is the temperature of the air relative to the temperature of the hot object, the exposed surface area of the hot object and the rate of flow of air across that surface. None of these can be determined by counting fans or by simply considering their location - since nearby surfaces and ducting affect where the air flows to.

Comments

[CarlF]

It's worth mentioning that I have seen no good evidence that laptop coolers provide any benefit in the first place. It's commonly accepted but that isn't the same as evidence.

[Pacerier]

@CarlF !! that's shocking do you mean you to say my cooler is doing nothing?

[CarlF]

I mean that there is no evidence that it is doing anything, which is not quite the same. I certainly haven't done testing to prove it's useless, I just have no reason to think it's useful. Note that I can't even prove an external fan is cooling the CPU-all we know is that it cools the outer shell. Cooling the bottom of the case may not have a meaningful effect on internal components at all, depending on the design.

[user5249203]

I suspect that many users don't care if the laptop-cooler cools their computer so long as it cools the top of their lap.

[Pacerier]

@RedGrittyBrick well i don't really care if my laptop cools anything at all as long as it makes my laptop last longer!

[fixer1234]

It isn't clear how this answers what was asked in the question.