Good use of some simple principles here. I assume there will be a trickle fan or similar to top-up the cooling but even so it helps break to loop with more power used to cool down then more power needed to cool the PSU then...
Mobo maker MSI has come up with a novel way of keeping processors cool and conserving energy at the same time: the CPU to drive its own fan. It's actually a new implementation of an old discovery. MSI's Air Power Cooler uses the energy inherent in the expansion of air as it warms up to drive a fan. MSI's Stirling Engine …
.. the only snag with this type of Stirling Cycle engine is that it is not self starting. You have to spin the shaft for the thing to work. Given that it's buried in the innards of the machine, this does'nt seem altogether practical. They're not particularly quiet, either, given the number of linkages and reciprocating masses. But points for a nice try.
Really, this translates 70% of the heat power into mechanical energy in the fan? There must be a mistake. This is a heat engine, and heat engines are never 70% efficient. Large electric generation systems --- some of the most efficient heat engines out there --- are only maybe 40-60% efficient MAX.
I would believe that this Stirling engine is 7% efficient.
With the way this is setup it will either blow hot air towards the ddr dims adding heat or suck the warm air back over it's own heat sink.
most north bridge coolers vent at 90 degrees to the board to allow the case fans to expel the heat.
Story says cpu fan when intell socket can be seen on photo?.
If it does work on the cpu how will the system start as most boards sense the cpu fan at startup . you could plug in a case fan into the connection but how will that save power?.
bit dangerous if case heat builds up.... say in july, in a non aircon'd room..
the best stirling engines are only less than 40% efficient (these are the free piston electro generators from sun power aka NASA @ Glen) the mechanical versions like this are very poor say 15% energy conversion. perhaps just a big alu fin might work better. will be interesting to see the stats..
Now what if they used a high efficiency free piston style electo generator and used it to power a case fan to produce through flow .. that would be really cool...
Having (at one point) built a Stirling engine, I think this is a pretty useless gadget. Cool, but still useless. I suspect it's just another passive heatpipe cooler with extra gadgetry to make it appeal to people that enjoy looking inside their PC.
On the 70% discussion - I would guess that the marketting muppets got the technical documentation, decided 7% was a typo and wrote up 70% without consulting the engineers.
@Joe K earlier
There's something called Negative Feedback, standard to almost all typical control systems. Assuming an increasing in put causes an increasing output, and a decreasing input a decreasing output, then connecting a portion of output to input means you can stabilise the output. In summary, perturb the input and the system will stabiise itself.
Then again, you might be a professor of control systems and were trying to make a joke, which I missed........
And more importantly, i'm joe K with a lowercase 'j', didn't know there was another joe K on here, what are the odds....
This post has been deleted by its author
"It's not totally efficient, which is why it won't run in perpetuity,"
Given a big enough thermal gradient between the item being cooled (the chip) and the surrounding medium (air), a Stirling engine should run indefinitely.
This thing won't stop due to *inefficiency*, it will stop once the CPU has cooled sufficiently.
Theoretically, if the chip is perpetually on, the engine will run in perpetuity, even though it is not a perpetual motion device.
Y'all might want to check out the following book:
It talks about a company called SunPower, which developed, among other things, a Stirling CPU cooler. Since Stirlings are also used to produce liquid helium, I think we can safely say they get REAL cold. The one they developed allowed the CPU to be overclocked 50-100%.
No, that's NOT a typo.
Is anyone else as fed up as me with the constant typos on thereg? Near enough all software including browsers have built in spell checking software now.
Also a habit seems to be repeating things, e.g "then when you when you add the chip it.." (not from an actual article but you get the idea).
I'm with you. When I commented on it in another article a while ago, another commenter stated that getting the "information" was more important that the ability to successfully read said information. Repeated words/phrases make it very difficult and confusing to parse the sentences. That, together with the misspellings and other grammar problems (actual problems, not US/UK differences) make it painful to read many of the articles now.
It occurs to me that 70% is entirely possible. Please read the whole post before arguing with it.
The CPU puts out (for example) 100W. I know modern chips aren't doing this, but just for the sake of easy maths lets assume that they are.
70% means that only 30% would be left to accumulate, i.e. like having a 30w heater rather than a 100w heater.
The Stirling Engine is 7% efficient. This means that if it takes in 10W there's only 0.7W left at the output to use, rather than it takes 7% of the available power and converts it 100% efficiently to mechanical motion as some people seem to be suggesting. Every single watt of power being used to turn the fan means that the Stirling engine was sucking up 14 or so watts of heat from the heatsink. And a small 12Vdc fan can take a few watts of power to drive. Say 5watts of power is used to rotate the fan and push all that air- that's 70W of heat being sucked off the processor by the stirling engine (and dissipated by its body)
So it's sucking up quite a bit of power on its own to turn the fan.
The fan is blowing over a dual-heatpipe fed radiator. This will suck away even more heat than the stirling engine, what with having cold(er) air blown over it and all.
So yes, 70% seems to me to be entirely possible _for the whole system_. Though a 70% stirling engine is clearly wrong.
Paris because (insert obligatory "that's hot" reference)
A Stirling Engine is just a particular type of heat engine.
Heat engines have a maximum theoretical efficency of 1-(T_c/T_h),
Where T_c is the "cold" temperature, and T_h is the "hot" temperature.
Given, say, temperatures of 20 and 60 degrees celsius, you'd get a maximum efficency value of about 12%.
The 70% figure is presumably 70% of 12% (~ 8.5%).
Good thinking. Its basically self regulating once its calibrated. Its just a matter of how long the piston seals last.
Otherwise its a niftly idea. Once the underlying chip gets to a certain temp it starts driving the fan until they reach an equilibrium. Should help keep the temp consistent (which is good).
Where else can you continually reinvent things and be acclaimed for it.
How about a bimetallic generator, which emits current as it heats up and use the current to drive a small fan. I actually think fans are rather passé and that a punkah could waft air over the chip, so cooling it and automatically switching off when it has cooled sufficiently to generate enough current to run it.
Heath Robinson lives on in all of us!
Stirling engine performance is based on the temperature coefficient, in this case, chip set surface temp. vs. ambient case temp. If the case is properly ventilated, and assuming the room is reasonably cool, then this thing should operate fairly efficiently.
What happens in situations where the case is poorly ventilated, or the room begins to get warm... Seems to me that the chip set surface temp will have to rise (and continue to operate at a higher temp.) to make this work in a warmer environment.
Factor in the piston seals and the complex mechanical nature of converting reciprocating motion into rotary motion in a generally dusty/dirty environment...
I'll stick with my 12VDC fans with RPM monitoring for all my PC cooling needs.
I think the point about efficiency has been lots here (and 70% is beserk figure - you'd need a huge temperature difference to make that possible). However, it doesn't need to be that efficient - just sufficient power has to be generated to turn the fan. If there's 100W of thermal energy available and 7% of that could be turned into mechanical energy then that's 7W to turn the fan.
A CPU cooling fan I have is rated at 3W (although I have a chassis fan rated at just 2W). I suspect that the actual consumption is quite a bit lower - especially on temperature controlled cooling fans. So the energy saving isn't earth shattering, even if power supply overheads are taken into account. Just whether the energy savings will compensate for the extra used in manufacturing such a complex device is debatable (also it's quite liable to have a shorter lif if it is more complex).
As for the overclockers, there's bad news here (not that they tend to care one iota about power consumption save their ability to extravagantly cool it). Successful overclocking depends on cooling the processor to much lower temperatures than is required for normal running. As the thermodynamic efficiency of this device is inherently related to the difference between the heatsink and the ambient air in the case then this efficiency goes down (albeit that total heat energy available increases). To give an idea, to get 7% theoretical thermodynamic efficiency the chip thermal pad temperature would have to be 20 degrees above the ambient temperature in the case at anything like room temperature. So if it's 30 degrees air temperature in the case you need that to be at least 50 degrees. If they get anywhere remotely close to the theoretical figure for a carnot cycle I'd be amazed. The carnot cycle calculations make no allowances for things like mechanical losses. It would not surprise me if you need thermal pad temperatures closed to 60 or 70 degrees to hit an overall 7% thermodynamic efficiency.
It would be a nice little irony if the chassis cooling had to be boosted to make this little thing work. In all, I suspect this is an insignificant development and a much more elegant method of fanless cooling could be designed.
What would be really cool is that it would keep going for a while after the computer is turned off... Which would bring the temp of the chip down quicker than an idle heatsink.
Of course the whole thing is pretty stupid. As has been said heaps, if the air temp inside gets too high, it won't work very well. At least electric fans move the air around in the case, so they get pretty much the best air they can. This would not move air if it got warm around it while not moving.
I am sure it will work but it looks like my friend Heath Robinson has been at work.
There are a few issues:
Noise, reciprocating even Sterling engines make noise.
Heat, the engine needs heat transfer to make it work. If you take away the heat with a heat pipe what heat is left to operate the engine? This application is the equivalent of running up a very soft sand dune.
I thought Sterling engines needed a kick start to get them turning.
As I keep saying to my collegues, "Just because you can do it does not mean you should".
We, the undersigned, am having serious objections to your most learned assertion that punkahs can be adding to Mobos. It is becoming bad enough for us to be working in very, very cramped conditions and, now, you be having us work inside a PC case ??
We will be having a pukka strike !!
PUKKA PUNKAH WALLAHS UNION
All this to save a couple of watts?
I think I'll stick with the electrically driven version - at least then the mobo can monitor (as well as control) the fan speed; better that my PC goes beep instead of bang!
Why not pass the heat through a peltier effect pump? Some of that juice could be fed back to the supply so the PC takes less power - the Seebeck Effect (that's good for more than a couple of watts anyway).
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