cheap, high performance, thermo electric material discoverd

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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mvanwink5
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Re: cheap, high performance, thermo electric material discov

Postby mvanwink5 » Thu May 01, 2014 10:34 pm

Just capitalize the words it don't Lik.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

ohiovr
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Re: cheap, high performance, thermo electric material discov

Postby ohiovr » Fri May 02, 2014 1:29 am

Tom Ligon wrote:Since a grapheme is the smallest unit of a written language, and graphene is supposed to be an element in an especially efficient thermoelectric generator, maybe the board engine is trying to tell us to build TEGs and power them using the heat from all the talk in Washington?

Do phonemes produce phonons?

What do institutions created by Hamilton have to do with Hamiltonians?

This is all very curious.


Phonemes can produce phonons like in the case of a speaker/resonator.

The hot air from washington is still not warm enough for an efficient engine if you go by the Carnot limit. But they don't play by the laws...

ohiovr
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Re: cheap, high performance, thermo electric material discov

Postby ohiovr » Thu May 15, 2014 8:46 pm

I wrote an email to one of the lead researchers on this case. Thankfully he bothered to respond. Basically they have only half of this figured out, they have the n material but they lack a suitable p material. He believes that to commercialize this would require a million dollar investment in research. Sorry fellas....

Skipjack
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Re: cheap, high performance, thermo electric material discov

Postby Skipjack » Fri May 16, 2014 3:17 am

Oh, that sucks :(

ohiovr
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Re: cheap, high performance, thermo electric material discov

Postby ohiovr » Fri May 16, 2014 3:58 am

Skipjack wrote:Oh, that sucks :(


I have a better idea though

Tom Ligon
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Re: cheap, high performance, thermo electric material discoverd

Postby Tom Ligon » Thu Jun 09, 2016 1:34 am

I'm bumping this topic because I've been wondering if there has been any progress on graphene TEGs since this exchange two years ago.

A quick search turned up a couple of papers in 2015 discussing Seebeck Coefficients and lots of layers of graphene, but the abstracts did not seem to indicate that they were to the point of working TEGs yet.

Has anyone here been following this?

While on a consulting visit a month ago (on a totally unrelated tech), I got into a discussion with a technical lead at the company, who has been interested in TEGs as well, and knew about these higher-efficiency devices. At some point I hope to be able to talk with him again in more depth.

What reminded me was a comment by a fellow who I know personally as favoring photovoltaic-thermal (solar cells backed by heat collectors) with a fellow who has been pushing a national campaign to develop solar power satellites. Since the prospect of 60% efficient TEGs would drastically change thinking of both approaches, I started thinking about graphene TEGs again.

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Re: cheap, high performance, thermo electric material discoverd

Postby Tom Ligon » Thu Jun 09, 2016 1:53 am

Sniffing around a little I found an outfit with more recent announcements, evidently interested in selling working lead telluride TEGs. As of this posting they are showing news posts into Nov 2015. This particular news page was hit when I looked for home applications, and they've got stuff in there on wood stoves, for example. Intriguing ... I'm not interested in fabricating my own thermopiles from lead telluride. However, I'm also not likely to buy a 40 mm square PbTe module for $700 that's rated at 3 watts output and is still in beta testing. These guys charge $40 for a BiTe module I can get for a tenth of that.

http://thermoelectric-generator.com/whats-news/

Now, if we could get somebody selling TEGs made with pencil dust ....

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Re: cheap, high performance, thermo electric material discoverd

Postby ohiovr » Thu Jun 09, 2016 2:38 am

Thanks for the update. 13 watts for $375 is kinda high but might have some interesting niche applications. Since they don't just outright say how efficient it is I'll have to crack open a spreadsheet :mrgreen:

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Re: cheap, high performance, thermo electric material discoverd

Postby ohiovr » Thu Jun 09, 2016 2:47 am

Oh I see they got a bunch os stuff here.. One of these things is 7% efficient.. not too shabby

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Re: cheap, high performance, thermo electric material discoverd

Postby Tom Ligon » Thu Jun 09, 2016 3:00 am

Their data seem a bit patchy. Somewhere in that mess they mention hitting 12% on their Pb-x TEGs, but I think that was pushed into the dotted line parts of their graph where life expectancy is shorter (I think they mean the device, but with lead at 600C, maybe they mean the user).

A life expectancy graph on the Pb-x TEGs was set at xxx, which one must suspect means they don't know yet and need to run the handful they have made a while longer.

They're interesting, but at that price I'd buy BiTe chips in bulk at $3 and plaster them all over the wood stove, back of PV panels, or any suitable waste heat source. The Pb-x chemistry gets interesting for small devices like using waste heat to power the chip in my head that they want to install to make me vote for the leading Presidential candidates. Regarding whom, all I can say is the new show suggesting ants have eaten the brains of everyone in Washington is looking more and more credible.

So I want something so I can hide up at the cabin in the mountains for the next four years.

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Re: cheap, high performance, thermo electric material discoverd

Postby D Tibbets » Fri Jun 10, 2016 3:25 am

I don't know if this is redundant or useful but the advancement of harvesting heat energy continues...

http://phys.org/news/2016-06-electricit ... sions.html

I am a fusion fan boy, but as I have mentioned in the past, as photovoltaics and thermal conversion of Solar output improves, any fusion output other than the proven and readily available fusion output from the Sun may lose the game . Man made fusion reactors of what ever type, if they work ,may be economic failures compared to solar power, and geothermal power, etc. Power storage (eg:batteries) is also a key component in the equation.

Dan Tibbets
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ohiovr
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Re: cheap, high performance, thermo electric material discoverd

Postby ohiovr » Fri Jun 10, 2016 10:33 am

Tom Ligon wrote:
So I want something so I can hide up at the cabin in the mountains for the next four years.


Yeah I know what you mean... :cry:

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Re: cheap, high performance, thermo electric material discoverd

Postby Tom Ligon » Fri Jun 10, 2016 1:35 pm

D Tibbets wrote:I don't know if this is redundant or useful but the advancement of harvesting heat energy continues...

http://phys.org/news/2016-06-electricit ... sions.html

Dan Tibbets


I think that article is plenty relevant.

By the argument in the article, 2D is better than 3D, which should automatically make one wonder about 1D. The original concept of a thermopile was a string of thermocouples, electrically in series but thermally in parallel, and each leg a wire (approximating 1 dimension) with heat flow producing a thermal gradient along it, which in turn produces electron flow.

The low efficiency of TEGs to date is due in part to their thermal conductivity. Playing with a Bi-Te Peltier module last night, I put current thru it to produce the heating/cooling effect ... gets hot on one side incredibly fast. Then I turned it off and it is remarkable how fast the temperature gradient vanished. They constantly fight heat leakage across the material, and they do the same when used as TEGs. Thus, much of current research is in attempting to come up with less thermally conductive materials, which can still conduct electricity efficiently. We're still tending to use bulk thermoelectric materials, but with a lot of effort spent making them in many thin layers.

But I suspect we'd get the best effect by designing long molecules that are very poor thermal conductors, and can only transmit heat efficiently by moving electrons. This would require some very clever molecular engineering, comparable to the electron transport tricks of some biological molecules (think in terms of chlorophyll).

Even Dr. Bussard thought geothermal, under the right conditions, was always going to be a good idea, even compared to fusion. If you could do it with no moving parts and with less waste heat (for instance, 60% efficient TEGs instead of the Carnot cycle), even more better. And we'll always need something like solar for remote applications. But photovoltaic approaches tend to use a small fraction of the solar spectrum. Solar thermal/TEG, with sufficiently efficient TEGs, ought to use the entire spectrum.

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Re: cheap, high performance, thermo electric material discoverd

Postby JoeP » Fri Jun 10, 2016 6:43 pm

Solar thermal/TEG, with sufficiently efficient TEGs, ought to use the entire spectrum.

Maybe such a device would push solar into a mainstream energy technology.

D Tibbets
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Re: cheap, high performance, thermo electric material discoverd

Postby D Tibbets » Sat Jun 11, 2016 5:34 am

Solar photovotaics have historically been narrow bandpass- using only a relatively narrow wavelength range compared to the total solar radiation. But wider bandpass materials and multiple staged bandpass materials are being pursued.

While not a power harvester per say, I was intrigued by a proposed method to improve incandesent lights to LED efficiencies or better. Normal incandesent lights produce a lot of infared light that does not contribute to the visible light desired. A group have combined pass and blocking filters though. The infrared is blocked (trapped inside the bulb) while the desired white light is transmitted. The bulb heats up- producing more white light due to black body radiation, till most of the energy leaves the bulb as useful white light.

http://news.mit.edu/2016/nanophotonic-i ... bulbs-0111

Dan Tibbets
To error is human... and I'm very human.


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