Why Not Use Air For Cooling ?

paulselhi

paulselhi

paulselhi

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Joined
3 Sep 2009
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125
I know this is a dumb question and there is obviously a reason why multi millions are spent on heat sinks but please help me along

The CPU heats up and passes that heat to the base of a cooler which transfers the heat via pipes ( losing heat on the way) to fins which loose their heat by having air blown across them

So in effect the CPU is loosing heat to air which is blown away, but why do we need the heat sink ? If the idea is to get the heat into the air and blow it away as fast as possible why not just have high powered fans blowing across the CPU perhaps with some sort of venting to funnel the air away ?

Is it that the base of a heatsink heats up faster than air thus is better at removing heat than air ? Could chiiled air not do as good a job ?

EDIt you may as well delete this crap post as it is obviously to do with conductivity rates..sorry !!
 
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because there isn't as much material for excess energy to go to or surface area for it to be taken from

more surface area of material which conducts heat better than air = heat can get away from the CPU quicker

it's why water cooling is better than air cooling, water can absorb(probably not the right word) energy 8x better than air
 
HSF's make mounting easier for the vast majority and just using directed air would be quite hard i would imagine you would need one hell of a fan to do it even if it was possible and the other advantage with the tall tower HSF's is that should the fan die they can keep most cpu's passively cooled long enough for you to realise fan has gone. If you were just using one fan and it went damage might happen quite quickly. I am no where near as good on the technical stuff as some on here and i may well be wrong in what i have said above which others will correct as they come into the thread :).
 
paulselhi said:
Is it that the base of a heatsink heats up faster than air thus is better at removing heat than air ?
Click to expand...

Yes, basically...

A heatsink allows a larger surface area for the cooling air to make contact with, and therefore allows cooling at a lower air flow rate. If there was no heat sink, air would need to be blow onto the CPU very, very fast to be able to cool it quick enough, and most people (I know I would!) would not be happy with the noise that would be generated to propel that amount of air onto such a small area. If you think of radiators in a house, they are used rather than just a water pipe going through the room as they allow a larger amount of heat to be transfered into the air under the same condition.

Hope that helps, and isn't too confusing ;)
 
Pretty much what has been said above. If you want to read up more then thermodynamics is a nice subject to learn. Temperature loss is down to the the surface area and the temperature difference between the two mediums. (Volume does have an effect to but for CPU's they are small so ignoring it for now) CPU coolers are designed to draw heat away from the actual CPU, now this in itself will cool the CPU slightly but they greatly increases surface area, which means generally less airflow is needed to maintain the same temperature.
 
The time when mid to high end CPUs could be cooled by a blowing fan at any speed has long since passed. These CPUs now produce so much heat that they would melt themselves very quickly if not cooled properly, or if they didn't have internal safety cut off thingies.

Not even a Delta fan would stop the CPU from frying.
 
Nice way to remember it: Metal conducts heat faster than air. All those fins increases surface area, meaning more air can carry the heat away from the heatsink.
If you want to blow something directly at the CPU, you'll need some liquid nitrogen ;)
 
lol science fail.

A heat sink gives a much bigger surface area, meaning that the heat is transferred away from the CPU faster.
 
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