MSI Develops a Heat-Driven Cooler

V!NCENT tips us to a write-up about an addition to MSI's Ecolution motherboard which harvests heat from the chipset to power a fan. The device is based on a Stirling engine. The heat from the chipset expands a trapped gas, which pushes against a piston to generate power. The article contains a YouTube video of how the device works. According to MSI, the device has 70% efficiency.

Headline misleading

[Anonymous Coward]

It's a fucking fan, not a cooler. In this house we obey the laws of thermodynamics.

Re:Please define efficiency for me

[dreamchaser]

Efficiency is just a matter of how much of the input energy is turned into some kind of practical work, in this case spinning a fan. That being said I'd be surprised if they were as high as 70%. Sounds like eco-friendly (note the name of the motherboard) marketing to me. Still, a neat idea.

Why?

[Vellmont]

A fan can't draw much more than a few watts. What's the point? It seems like a complicated array of technology just to save a few watts of power. You'd be better off buying a more efficient power supply if you wanted to be "green".

Re:Why?

[VGPowerlord]

A fan can't draw much more than a few watts. What's the point? It seems like a complicated array of technology just to save a few watts of power. You'd be better off buying a more efficient power supply if you wanted to be "green".

That makes the assumption that you can't do both. Why wouldn't you be able to do both?

Re:Please define efficiency for me

[BoChen456]

I suspect 70% efficiency means they can reach 70% of the theoretical limit maximum at these temperatures. The theoretical limit for heat reservoirs of 55C and 25C is about 10% http://en.wikipedia.org/wiki/Carnot_heat_engine#Carnot.27s_theorem [wikipedia.org].

So really this fan can convert up to 7% of the waste heat. This doesn't sound very impressive, but as long as it provides a little bit of convection it'll be better than passive cooling.

But the winner is...

[whit3]

The moving part is cute, of course, and gives a bit of visual
tension to the apparatus you see through your peekaboo case.

Still, it's a bit of a clunker compared to the old-tech way of
making a no-moving-parts air pump powered by waste
heat. I refer, of course, to the 'chimney'.

Re:Headline misleading

[slackergod]

In a physics sense, no, that's not a cooler.

Typical "air conditioner" situation: you want to make the inside of a room cooler than the outside temperature.
Since the room starts out similar in temp to the outside, you have to spend energy pushing heat "uphill" to
an increasingly warmer outside. Making heat flow against the direction it would normally flow,
that's a cooler in the thermodynamic sense.

In the CPU situation, you want to make the inside of the cpu EQUAL to the outside temperature.
Since the running CPU starts out way warmer than the outside temp, the heat will flow naturally on it's
own "downhill" to the outside. Any sort of cooling system merely hastens the flow.

In this situation, any device like a fan, etc is merely a more efficient radiator...
as the temp of cpu gets closer to the outside, this device loses efficiency... and in no case
could it get the cpu any _colder_ than the outside.

Being able to do that is what makes something a "cooler" in the physics sense.

Re:Why?

[Jeff DeMaagd]

That mechanism looks like a lot of complexity and cost to save what probably amounts to a single watt. How much more energy would it take to make that over a one watt fan? Not only that, a large passive heat sink would probably do even better, nothing to break and it would just use existing air flow. I've yet to own a computer that has or needs a fan just for the chipset, not necessarily through trying, it's not really that necessary to have.

Re:Why?

[moderatorrater]

That makes the assumption that you can't do both. Why wouldn't you be able to do both?

You can do both, but his point is that if you're looking at the efficiency of your dollar, you'd be better buying something else that'll save you more power than this fan will. Buy a better power supply, new monitor, more power efficient CPU, better light bulbs, etc. For the amount of energy saved, it's likely that there's quite a long list of things that could save more energy for your dollar, and since you (presumably) have a finite amount of money, it'd be better to buy one of those things than this fan.

Re:Why?

[mickwd]

"What's the point?"

Maybe just because it's cool - in more ways than one.

Re:Headline misleading

[node 3]

In a physics sense

I'll have to stop you right there.

The rest of what you say is mostly true[*], but just because a term has a specific meaning in a specific context does not mean it's wrong when it has a different meaning in a different context. In both cases, the chip is cooled, making them a cooler, i.e., something that cools.

[*] I say "mostly true" because even in an air conditioner, the heat is "flowing downhill", as it were. The difference is that is the "bottom of the hill" is being manipulated through changes in pressure (or more generally, through work)--essentially by also raising the "top of the hill". In both cases, the net temperature is being raised (in compliance with the laws of thermodynamics).

Additionally, I wonder if you are confusing the terms "cooler" and "heat pump". Is a "cooler" something distinct from a "heat pump" in a "physics or thermodynamics" sense? I'm thinking the former is merely an informal term for the latter.

Re:Good thing it is 70% efficient

[PMBjornerud]

If you want to remove that waste heat before it burns the chip to a cinder, then yes, you probably want some degree of efficiency.

Re:Why?

[TheThiefMaster]

Or you could set the temp shutoff.

Just saying.

Re:Why?

[Anonymous Coward]

Not to mention that, by definition, the conversion of some of the heat into mechanical energy sucks up some of the heat.

Really? It would seem to me any "sucked up heat" would be returned in friction. Or is energy lost in this system?