Murata Helping Turn Laptop Heat into Power
by Jaymi Heimbuch, Central Coast, California on 10. 9.08
Photo of burned laptop via Stewart, Murata prototype photo via PC Advisor
Have you ever been working away on your laptop and realize that the sucker is putting out some serious heat – enough for it to be not so cozy sitting on your lap? Well, that waste heat could be put to good use, and Murata Manufacturing is on to something with a new prototype demonstrated at CEATEC that could just solve those heat – and battery power – woes.
Murata demoed a thermoelectric device that could turn waste heat into electricity, which could be used for laptops and similar products. The prototype could generate 38 milliwats of energy per square centimeter at 360 Celsius. Here’s how:
The thermoelectric device generates electricity when two ceramic semiconductors are subjected to different temperatures. When the semiconductors are connected, the temperature gradient produces a slight electric current.
Very cool (har har) stuff. It isn’t going to be ready for consumers right away. In fact, Murata thinks it’ll take about 10 years before it is advanced enough to be marketable. Big bummer. Perhaps the push for efficiency and alternative energy sources for our gadgets can give the tech a needed nudge.
Via PC Advisor
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This would be beautiful. As much as my MBP heats up my lap at times I'd love to see that go to use. Put a USB connection on that bad boy and instead of running a cooling pad, the heat could be charging my ipod.
just a thermopile no? Nothing ground breaking here, and if it could have been done usefully in the past, it would have. It's just not a good way to generate electictiy...
I agree, it certainly is NOT an efficient way to generate electricity.
But over time it's likely that the circuits and batteries will produce less heat and the thermopyle will become more efficient. And putting smart minds in the laptop business to work on the idea could lead to spin-off applications that would improve efficiencies of other waste-heat generating devices.
So I think this is good news.
The efficiency of such a device is poor. I believe that they are around 5%. If it takes 360 C to make only 38 milliwatts per then it is not worth the expense to put it into a laptop since that is 1/78th of the amount of power needed to power my laptop, which has average power usage for mid-end laptops. You are only going to approach those temperatures directly over top of the main processor chip and possibly the main graphics chip.
Lets not forget that in order for thermoelectrics to work they have to have high electrical conductivity and LOW thermal conductivity.In other words, to work, this thing has to insulate the heatsource: your laptop. Not a good idea by any stretch.
Jack, you got the point right. But 38 milliwatts in not 1/78th the power of a typical laptop. That ratio would imply that a typical laptop is only 4 watts. It's more like 1/780th of the power. Much less.
I have to agree with Foraker. This is good news. Over time doesn't it seem likely that they can improve the efficiency of it?
Also, they said "38 milliwats of energy per square centimeter at 360 Celsius". How many square centimeters could they put in?
Since when is 360 C " laptop heat" ???
There is no such thing as laptop component that generates 360 C.
( except maybe an exploding battery ).
A CPU can heat up about 95 C maximum.
Beyond that, it will either burn or shutdown automatically to avoid burning.
And at that temperature, the heat recovery system will have much lower efficiency than at 360 C.
So you won't even get those 38 mW .
"But over time it's likely that the circuits and batteries will produce less heat and the thermopyle will become more efficient"
Not so. The less heat you produce, the smaller your temperature gradient, and the less power you can generate. In other words, this energy-recovery scheme would be less effective in a more efficient laptop. Not that 38 mW/cm2 would be enough to really affect my laptop's operation much, anyway.
It'd be much easier, and more effective, to use more efficient power supplies, better batteries, and lower-powered processors and other parts in our laptops. Save the high powered stuff for a desktop, where you can really make use of the graphics capabilities with a real monitor, and where you can fit appropriately sized and placed fans in the case for good airflow and cooling.
Having worked extensively with thermo-electric generators in the past I can tell you something does not add up in this story. The TEC shown in the picture looks to be around the same size of the unit I'm working with 4x4cm. At 360º C it should be generating more like 3-3.5W. However at that temp it's lifetime will be extremely short (around 6 months). Beside the low efficiency of these TEC's there is another problem... They contain Tellurium, a hazardous substance, that needs to be properly collected and recycled. Not something you would want to end up in a landfill.