Stirling Engine Motherboard Fans Powered by Waste Chip Heat
Motherboard manufacturer MSI is toying around with new "powerless" cooling fans in their labs that harvest heat from processors with tiny Stirling Engines. Brilliant!
MSI employs Stirling Engine Theory [TweakTown.com]
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Doesn't this present some sort of Grandfather Paradox, to which I am probably over-thinking? If the fan runs on the processor's heat, but the fan's main purpose is to stop the processor from getting hot, if it cools the processor where will the fan get energy to run, and so on and so on?
You are over thinking it. This is just converting some of the heat to a differnt form of energy. Imagine a current heatsink has to get rid of X heat. Right now, all that X heat has to be moved from being thermal energy in the heatsink to being thermal energy in the air.
Now imagine this. The heatsink converts half of X into kinetic energy, first in the fan and then in the air, leaving only half of X that needs to be transfered to the air as heat.
Kurtmac, the fan and heatsink probably don't remove heat fast enough for that to happen. But if it did, and the fan stopped, it wouldn't be a problem - since the fan would restart as soon as the heat built up again. Think of it as a temperature controlled fan: the more heat is applied to the system, the faster it likely spins.
That's all conjecture, though.
The more dangerous scenario is: what if the other components in the computer heated the air up to the same temperature as the heatsink? Wouldn't there be no heat exchange to move the fan, thus causing it to stop? Well, then I guess the heatsink would get hotter and it would then start again but at a reduced efficiency/effectiveness.
So I think you need to make sure the case itself is well ventilated, too!
But on the plus side, the fan will draw cooler air through the heatsink attached to the cooler side of the Stirling engine. And the case'd need to be ventilated _anyhow_, whether it's self-powered or no- a heatsink doesn't do much good unless there is a temperature differential.
dculberson@#3:
+1, although I'll bet the maximum acceptable surface temperature for the CPU is so much lower than expected air temperatures that you'd have ton of other problems first if the air in your PC got that hot.
It looks like a toilet.
Go Stirling Cycle!! Woot!
Always like to see waste energy recovered. Good show!
Codeloss, it sure does! It must be the toilet for those little drinking bird kinetic toys.
( http://en.wikipedia.org/wiki/Drinking_bird )