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Professor Mercouri Kanatzidis holds up his device that can harvest 14 percent of waste heat as usable electricity.  (Source: Northwestern University)
New lead-based compound could see a variety of scenarios -- including helping power the machines in the absence of sunlight

A new material from researchers at Northwestern University could offer a way to capture and recycle waste heat better than ever before [press release].  The material can convert a record 14 percent of the waste heat passing through it to usable electric energy.

When manmade devices perform work, be it a computer or a car, they produce heat.  That heat is ultimately lost, reducing the energy efficiency of our devices.  Some have cleverly exploited this fact, using waste heat to offer desirable comfort heating.  But ultimately, the only good solution is to try to somehow recapture that heat in a usable form.  To do that, the right material was necessary.

Semiconductors have long been considered a promising candidate, as they can produce electricity when heated.  Lead telluride (composed of lead and tellurium ions on a lattice) was considered one of the most promising candidates, as it was relatively efficient in accomplishing the heat to electricity transformation.  

But attempts to improve that efficiency via various techniques, such as nano-inclusions resulted in an undesirable side effect -- increased scattering of electrons, reducing overall conductivity.  Obviously, if you're converting heat to electricity, you have to funnel it out of the device, so this was unacceptable.

The NU team, lead by Chemistry professor Mercouri Kanatzidis discovered that by using a special type of nano-inclusion, the scattering could actually be reduced.  The trick was to use special crystals of rock salt (SrTe).  Professor Kanatzidis sums up, "It has been known for 100 years that semiconductors have this property that can harness electricity. To make this an efficient process, all you need is the right material, and we have found a recipe or system to make this material."

Materials Science professor Vinayak Dravid also assisted in the study.  He describes the results, stating, "We can put this material inside of an inexpensive device with a few electrical wires and attach it to something like a light bulb. The device can make the light bulb more efficient by taking the heat it generates and converting part of the heat, 10 to 15 percent, into a more useful energy like electricity."

The study on the promising material earned a place [abstract] in the prestigious peer-reviewed journal Nature Chemistry.

So the material seems great, but what about its commercialization prospects?

Well, lead telluride is relatively rare , but occurs naturally in mountain deposits as the mineral Altaite.  Significant deposits have been found in the Altai mountains of northeast Asia;  Zyrianovsk, Kazakhstan; the Ritchie Creek Deposit in Price County, Wisconsin; the Koch-Bulak gold deposit in Kazakhstan; Moctezuma, Mexico; and Coquimbo, Chile.

Given that air or liquid bearing waste heat can be channeled through a relatively small area, a little telluride (say in a heatpipe on a computer component) could go a long ways, recycling almost a sixth of the wasted energy.

Strontium is very abundant, so coming up with sufficient quantities of the nano-inclusion material shouldn't be as big an issue.

Aside from making existing devices more efficient, the material could be used to make new low voltage electronic devices, powered by waste heat from the human body.



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By CZroe on 1/19/2011 9:19:07 PM , Rating: 0
Green Peace either thinks that kids like the PCBs in their video game consoles or they think that we throw away perfectly good video game systems with lead solder that seeps out and poisons the water table. Their pressure has lead to all major corporations supporting the RoHS (lead-free) initiative. As we've seen with the extremely high XBOX 360 and PS3 failures directly attributed to this (the brittle lead-free solder on the BGA packages form poor joints and break from the normal heat cycle flexing), they have only cause MORE electronic waste. Way to go, Green Peace!

I can see this being really useful but because it has a lead-based component, expect them to throw a hissy-fit when any manufacturer tries to use it.




By eegake on 1/19/2011 9:25:47 PM , Rating: 2
Of course some ninny would go tangential on the sight of the word "lead", looks likes it's you.


By CZroe on 1/20/2011 5:42:56 AM , Rating: 2
In case you didn't notice, I was heading off any complaints about using lead. As long as we aren't consuming it and it isn't seeping into the water table, it's fine. Slapping warning labels on anything containing it and pressuring manufacturers to pledge to RoHS is going too far.


By CZroe on 1/20/2011 5:45:52 AM , Rating: 2
FWIW, "like" in my OP was supposed to be "lick." My point was that kids don't lick the printed circuit boards in their home video electronics so the direct threat is irrelevant.


By FaaR on 1/19/2011 9:42:26 PM , Rating: 1
Yeah, lead is great, just ask the ancient romans. If it was good enough for them as a liner for their water mains, I say it's good enough for us too!

Fuck those greenpeace hippy treehugger bastards, who needs nature anyway amIright or amIright! I'm going to go idle my car right now for an hour just to piss off some peacenik pinko environmentalists.


By NT78stonewobble on 1/20/2011 2:56:08 AM , Rating: 2
Hehe I can't remember where I read it but some researchers believe that the average american IQ was lowered by 5-10 points due to leaded gasoline? ...

I kinda believe the word "pinko" proves that theory.

*lol*

;)


By CZroe on 1/20/2011 5:43:56 AM , Rating: 2
And what does this have to do with it being safe to use in electronics but fought tooth-and-nail by Green Peace anyway?


By FaaR on 1/20/2011 9:11:32 PM , Rating: 2
It's called "sarcasm". You have heard about that, right? :P


By Shadowmaster625 on 1/20/2011 8:46:55 AM , Rating: 2
For the money we spent implementing RoHS, we could have implemented an electronics recycling infrastructure similar to what many states have for bottle returns. Even just 50 cents a pound would be enough to keep most circuit boards out of the landfill. Even without an organized system in place, people who sat on tons of old circuit boards for 20 years are making a lot of money now.


By MikieTImT on 1/20/2011 2:45:26 PM , Rating: 2
You might check into your local metal recycling business. The one I take empty cans, scrap aluminum, and copper to also recycles desktop computer parts. I can get $1 a pound for motherboards and power supplies, both of which have a fair amount of copper in them. Anyone who throws computer parts in the garbage is already throwing money away.


By FITCamaro on 1/20/2011 10:59:21 AM , Rating: 2
The second I saw that it was lead based I thought the same exact thing. You even mention the word lead today and you're an evil corporation trying to kill people.


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