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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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Use it on vehicles
By DerekZ06 on 1/19/2011 10:15:20 PM , Rating: 1
This could really help make combustion engine vehicles efficient. A combustion engine typically only makes 20-30% of the energy from the gasoline into mechanical energy and the rest is lost with heat. IF they used this, not taking into account the heat lost out the exhaust, between the radiator and the coolant they could prolly drastically increase the efficiency. And what if they layered these devices? They could perhaps get even more than 14%. I would think 2 of them layered together should achieve 26%.




RE: Use it on vehicles
By ddopson on 1/20/2011 12:13:21 AM , Rating: 5
heh, sadly engineering isn't that simple.

One challenge with recovering heat from an auto is that the heat is so diffuse. The engine has a lot of odd shaped parts and a huge ammount of surface area. Imagine trying to cover the entire surface of an engine with this stuff. Also, a car engine produces lots of heat and needs to stay reasonably cool to not break down. For this reason, we tend to actually expend energy pumping air and water and oil around to ensure the heat escapes quickly enough.

I highly suspect that this device was measured under some sort of ideal circumstance. 14% of the energy flowing across a large tempature gradient and as only measure over the surface area of the device (ie, ignoring heat lost to the non-harvested surface area of the heat source. Capturing heat from real world sources is much more difficult.

No doubt there will be useful applications, but this material is not going to be a panacea that returns 14% of the energy lost across a very complex system.


RE: Use it on vehicles
By semiconshawn on 1/20/11, Rating: 0
RE: Use it on vehicles
By gvaley on 1/20/2011 2:28:51 AM , Rating: 1
No, you are thinking in the right direction. This is exactly where past efforts have been directed at. Exhaust is the hottest part of the car and the surface area is relatively small. And it does not need cooling so stacking two or three layers of the energy recovery material would seem possible.


RE: Use it on vehicles
By Fritzr on 1/20/2011 10:41:28 AM , Rating: 1
A secondary radiator would be another good application. Run the hot water through the power unit to extract power from the water jacket, then into the normal radiator to provide the water cooling the engine needs.

The engineering problem is finding a place to put this extra radiator.


RE: Use it on vehicles
By Souka on 1/20/2011 11:32:07 AM , Rating: 2
In front of the engine, next to the radi... oh nevermind, there's already a radiator there!

I like the idea of a radiator in terms of delivering a very controlled temperature, but unless you go really high-pressure I suspect there is a correlation between temperature and energy produced (higher temp = more electricty).

Exaust manifold or nearby will probably be best location.


RE: Use it on vehicles
By lagomorpha on 1/20/2011 1:33:10 PM , Rating: 2
Lead compounds aren't exactly known for their high melting temperatures. And do you have any idea how hot exhaust manifolds get? I don't, my infrared thermometer wouldn't read that high.


RE: Use it on vehicles
By Bubbacub on 1/20/2011 3:47:22 AM , Rating: 2
i think bmw have started doing this to the exhaust system as part of their 'efficient dynamics'.


RE: Use it on vehicles
By superPC on 1/20/2011 5:58:16 AM , Rating: 2
you're right. BMW will use this tech in their car by 2013 ( http://en.wikipedia.org/wiki/Automotive_thermoelec... ). ddopson is also right. there's only a limited places in cars that this tech can be applied to. since car produce a lot of heat but for longevity the engine itself has to be cool so it needs to remove all heat from it. this material is a thermal isolator so it would prevent heat from escaping thereby the engine would overheat and stall if someone cover an engine with this material. if thermoelectric generator do someday become efficient enough (40% or more) than there may be a reason to make a system that transfer as much heat out of the engine and move it to the thermoelectric generator to produce electricity. it must be difficult to keep a balance of sufficient thermal movement and extracting energy so this thermoelectric generator can generate enough energy while the engine can stay cool.


RE: Use it on vehicles
By FITCamaro on 1/20/2011 10:53:22 AM , Rating: 2
The best place for this would be on the exhaust system.

You want the exhaust to stay hot so it moves through the system. So any insulating effect the material has on the exhaust is a non-issue.

You're definitely not going to coat the engine with the stuff though. But what you might be able to do with it on the exhaust system is decrease the load on the motor that the alternator has. If heat can create electricity, then you could channel it back to the battery to keep the engine charged and then the alternator is not needed as much.


RE: Use it on vehicles
By FITCamaro on 1/20/2011 10:56:27 AM , Rating: 2
Sorry the battery charged.

Now for hybrids or electric cars, if this could be put into brake rotors, then the heat from braking could produce electricity to charge the battery.


RE: Use it on vehicles
By mmcdonalataocdotgov on 1/20/2011 11:55:43 AM , Rating: 2
I like that idea, but why stop there? Clutch-drive all the services that run off engine rotation so they can be disengaged. Run them instead with auxiliary electric motors powered by batteries (that are charged by exhaust heat), but only clutch them back to the engine when there is not enough juice to run the electric motors. That would reduce all the service load on the engine when it was up to temp.


RE: Use it on vehicles
By bobsmith1492 on 1/20/2011 12:11:46 PM , Rating: 2
This is happening more and more often:

- Electric power steering
- Electric coolant pump
- Electric radiator fan

We've been developing one of these here at my work, and it does have a clutch to engage the engine belt when the load is greater than the motor can produce.

Perhaps electric brakes may happen soon...


RE: Use it on vehicles
By Qapa on 1/20/2011 6:22:44 AM , Rating: 2
How about putting this in the rooftop, so that in the summer we get energy, would that work?

If so, that would probably be great to electric cars, charging at no cost and/or using this energy to cool down the batteries so that they do not heat so much in order to keep them at the best temperature possible so that they last longer.

And what about using this instead of PV pannels at home? Would this be cheap enough to provide some energy and have a decent ROI?


RE: Use it on vehicles
By FITCamaro on 1/20/2011 10:54:22 AM , Rating: 2
For cars its a toss up to which provides more electricity and weighs less between this and solar panels.


RE: Use it on vehicles
By mmcdonalataocdotgov on 1/20/2011 11:58:02 AM , Rating: 2
Or, you could put a layer of these UNDER the solar panels. Solar panels would get charge from the sunlight, and the heat from that substrate would charge these. I am not sure what the output would be sufficient for.


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.


cpu
By chang3d on 1/19/2011 8:15:02 PM , Rating: 2
my cpu from a couple of years ago could provide power to its cpu fan! too bad that my new cpu runs cool and is capable of passive cooling.

my servers, on the other hand, could use this!




RE: cpu
By Stoanhart on 1/19/2011 8:26:19 PM , Rating: 3
The neat thing is that the fans would automatically speed up as load increases.


RE: cpu
By RamarC on 1/19/2011 8:48:15 PM , Rating: 2
my 3.2ghz p4 turned my PC into a space heater! in the winter months, i didn't even need to turn on the heat when i worked from home (florida) but during the summer, omg was that room hot!


RE: cpu
By superPC on 1/19/2011 9:18:42 PM , Rating: 2
CPU? hell this can help in everything. solar panels (the back of it get quite hot. slap a few of this material and we get 14% of that heat for electricity. since solar panel only has about 20-30% efficiency the additional energy from this material can help boost it. how about insulator? your boiler and pipe can be lined up with this thing and generate electricity from the escaped heat. put it in a hybrid car engine and heat from the ICE can help recharge the battery and the electric motor can be use more often.


RE: cpu
By FaaR on 1/19/2011 9:35:35 PM , Rating: 3
Most likely this process requires a significant temperature differential to generate electricity - IE, you couldn't just stick it to a hot surface and expect to get free electrical current. So you probably don't want to line your hot water pipes with this stuff, as that would lead to heat leakage and a loss of energy (the compound is only 14% efficient, remember?)

It'd be better used where you WANT to get rid of the heat, like in series with a heat exchanger for example, but not neccessarily on hot ICs, as introducing an extra layer of unknown thickness across the IC would reduce the cooling capability of the chip. This stuff doesn't neccessarily transfer heat all that well, so it wouldn't make sense to cook our CPUs just to produce a few watts of electricity.


RE: cpu
By superPC on 1/19/2011 11:07:48 PM , Rating: 3
thermoelectric effect is described in here: http://en.wikipedia.org/wiki/Thermoelectric_effect as you can see it all depend on S = delta T / delta V. since all thermoelectric generator before this has an efficiency of less than 10% ( http://en.wikipedia.org/wiki/Thermoelectric_genera... ) that means a low S value. this though must have a higher S value so it can achieve a higher efficiency. therefore it needs less temperature difference (delta T) to generate the same amount of power. even with less than 10% efficiency they manage to generate 255 watt from an ICE engine ( http://en.wikipedia.org/wiki/Automotive_thermoelec... ). so maybe lining pipes (since this thing is such a good heat isolator) and boiler heatsinks with this thing is not such a bad idea after all.


RE: cpu
By FITCamaro on 1/20/2011 10:57:53 AM , Rating: 2
Solar panels have at BEST 20-30%. Most of the panels you get at home are a lot less than that.


Passive airconditioner in the summer?
By wordsworm on 1/19/2011 8:58:15 PM , Rating: 2
Would it not be possible to use this kind of material as an air conditioner that actually *produces* electricity?




RE: Passive airconditioner in the summer?
By ddopson on 1/20/2011 12:03:24 AM , Rating: 2
No. The device produces electricity when heat naturally flows "downhill" from a more hot side (burner of some sort) to the less hot side (surrounding environment).

The problem with air-conditioning in the summer is that you want to do the reverse, convince heat to flow from the less hot side (your room) to the more hot side (outdoors). That fundamentally takes energy.

I have a friend who was looking into a startup that wanted to take devices like this that generate ~11 watts, bundle them with a cellphone charger and an LED based lamp and sell them in various parts of Africa for $100 - $200. For people with unreliable access to electricity, having a mechanism to read by at night can be a big leg up economically.


By ddopson on 1/20/2011 12:05:58 AM , Rating: 2
In case it isn't clear, the use case for the 11-watt device is to slap it on the side of a wood-burning stove. Such stoves are much more common than many of us city-people realize. My girlfriend's parents in New Zealand have one. They are in the country and don't have access to piped natural gas. On the other hand, they have lots and lots of free trees.


RE: Passive airconditioner in the summer?
By wordsworm on 1/20/2011 1:15:47 AM , Rating: 2
I am an admirer of the Roman method of air conditioning that I read about a number of years ago. They had a pipe leading from underground to the building, and another one that led from the ceiling to the outside. The outside part, through the ceiling to the roof, would be painted black to increase the temperature at the top, which would cause the air to exit faster, and the air cooled through the subterranean pipe to flow into the building.

In any case, it would seem to me that something that makes electricity from heat must be cooling whatever it is that's giving it the source of heat. That is to say, it must remove energy from the air to generate the electricity.

It would seem to me that there ought to be some way to use a gadget like this, if it can extract energy from, say, a room whose temperature is above 25 degrees, then that would effectively be an air conditioner. I'm not sure how exactly the invention works, but you said that there needs to be a downward effect in order for this to work. A pipe leading from the ceiling to the floor would possibly take the warmest air from the room, extract the energy, and make the cooler air heavier, thus completing the air conditioning cycle.

It just seems to me to be possible, and that an AC that can add electricity rather than subtract it would be rather... cool.


RE: Passive airconditioner in the summer?
By Prosthetic Head on 1/20/2011 5:08:25 AM , Rating: 2
Sorry, electricity generating air con is NOT possible with this or anything else. These things use a heat flow from a hot location to a colder one to generate electricity. Heat will not flow from a cold location to a hot one and heat on its own is no good for generating electricity or for that matter any form of useful work.

For more info read the wikipedia pages "Thermoelectric effect" and "Thermodynamics"


RE: Passive airconditioner in the summer?
By erple2 on 1/20/2011 10:11:35 AM , Rating: 2
That's not technically true. It's possible to generate a very small amount of electricity from this. Most AC units that I've seen have a simple "loop" in them - use some sort of gas (Freon, usually), expand it (which is very endothermic - simple expansion) to draw heat out of the surrounding area, then pump that into a compressor to re-compress the gas (which is where all of the electricity comes from - that process is pretty difficult to do). The side effect of that is that the compressed Freon is now very hot, and has to be cooled effectively, so you can again, expand it thus cooling off the surrounding area etc.

The cooling of the compressed Freon is what your outside unit is essentially for. The hot Freon gas (that's already been compressed) can be used to generate the power.

The problem, of course, is that perpetual motion machines are impossible. So the amount of electricity you can get out of the system is a small fraction of the amount of electricity required to power the A/C unit (well, according to above, about 14% in ideal circumstances). So you could theoretically have an A/C unit that uses about 14% less electricity (recirculating the electricity back into the A/C unit) than your current unit. But that's as good as your going to get.


RE: Passive airconditioner in the summer?
By Netjak on 1/20/2011 12:53:05 PM , Rating: 2
quote:
The problem, of course, is that perpetual motion machines are impossible. So the amount of electricity you can get out of the system is a small fraction of the amount of electricity required to power the A/C unit (well, according to above, about 14% in ideal circumstances). So you could theoretically have an A/C unit that uses about 14% less electricity (recirculating the electricity back into the A/C unit) than your current unit. But that's as good as your going to get


Wrong. AC doesnt produce heat or coldness. Heat is just transfered from one side to another by the AC unit and amount transfered is 3-4 times bigger than electricity used to run compressor and all other components inside. So, with your numbers, this device can provide 50% of electricity neded and theoretically one cun run AC free. But, ones need some source of heat on the inside, ie Sun, so this is not perpetum mobile.


By Chernobyl68 on 1/21/2011 12:21:49 PM , Rating: 2
An Air Conditioner is a type of heat pump. It transfers heat energy from inside your house to outside your house. Heet Energy will only flow naturally according to Entropy, that is, towards a lower state, which we measure as temperature. "Hot" or "Cold" is simply a sensation based on a temperature differential. In order to transfer heat out of the house, it uses a compressor, and in doing so increases the temperature of the gas used (via the ideal gas law, PV=nRT) which is pumped through the coils on the radiator outside the home (or on the back of the fridge, for that matter) and then uses either ambient or forced air flow over these coils to transer heat to the surrounding air. These coils are where the electrical generating substance could be placed.


Compare to normal TEC's?
By joe4324 on 1/20/2011 12:16:02 AM , Rating: 2
So I have used TEC's (Peltiers, Thermocouples?) for years. And they are hell-a in-effective as power producers but they do work. Those cute wood-stove TEC fans push a lot of air if the fire is hot enough. (http://www.amazon.com/Ecofan%C2%99-Heat-powered-Wo...

I might be pulling this number out of my rear but I feel as if normal TEC's at peak Delta are 5-7% efficient? If that is true more than double would be fantastic! But if its rare-earth metals then.... well... poop...

I've wanted to build all matter of devices to make power with TEC's but I could never get the math to work in my favor vs just buying a solar panel or whatever else I want to make power just not enough efficiency...




RE: Compare to normal TEC's?
By joe4324 on 1/20/2011 12:34:46 AM , Rating: 2
On a second note, If I could spend 200-300$ plus some DIY fabrication and experimenting and figure out how to pull a few amps of continuous 12v+ DC power so long as the wood stove was loosing heat out of the flue well then I would be on board to give it a shot!

Just for fun! Lets assume that:

My wood stove looses 40% of the BTU's of the wood out the flue (I'm sure mine is worse than this actually!)

So, 40% waste heat. At 7,000 BTU's per pound of seasoned firewood (this is a low'ish number) I'm loosing 2800 BTU's out the roof.

So, if I could somehow harness 50% of that energy to run through this new device (say a section of Aluminum flue pipe with a plate built in to bolt this TEC to it then heatsink it etc) That gives me 1400 BTU's per lb of wood.

1400x.14% = 196 BTU's, eh, thats not much... a little more conversions...

196 BTU = 0.0574419298 kilowatt hours, or 57 Watts.

Hey thats not so bad actually!

I burned 65Lbs of wood three nights ago when it was -16F.

65x67 = 3.7 Kwh power production for the day?

That sounds too good to be true...

Lets cut it in half just to assume everything works half as good as this stupidly ideal senario...

65lbs of wood burned @ 40% heat loss = 3.7KwH x.50% = 1.85KwH.

That still sounds too good to be true... Even if I got half that again it would be worth investigating. I will burn 6000-8000lbs of wood this winter (and this is a very small amount compared to most!)

dreams of KwH....


RE: Compare to normal TEC's?
By superPC on 1/20/2011 6:05:29 AM , Rating: 2
57 watts? 3.7 kWh a day? that's bad. 57 watts is not even enough to light my entire house. not enough for most laptop (maybe enough for netbook). 3.7 kWh would cost only around 37 cent a day. a month it cost 11.10 $.


RE: Compare to normal TEC's?
By joe4324 on 1/20/2011 5:09:36 PM , Rating: 2
It really is subjective, I live on less than 3.7Kwh for a whole day right now. I am averaging betwee 1.5-2.5 KwH per day for my home. Its off-grid and right now while I am at work my inverter is turned off so I'm using zero energy. I also turn it off when I am sleeping, so my home only 'consumes' energy from around 6pm to 2-3am everyday. This will change with the addition of a few more people. But its totally doable. And this includes me playing Bad Company 2 on my desktop for a few hours every now and then!

It realy is subjective :) I could live the rest of my life on a trickle of 57Wh indefinately :) Provided I could bank it up.


RE: Compare to normal TEC's?
By superPC on 1/20/2011 6:12:47 AM , Rating: 2
sorry, i missed that part where you said the calculation is for per pound of wood. 3.7 kWh per day per pound of wood is great. if you burn 8000 pounds of wood each winter that that would generate nearly 30000 kWh. that would save you 3000 $ for the whole winter electric bill! awesome. that makes me want to use this thermoelectric generator all around my house.


RE: Compare to normal TEC's?
By Strunf on 1/20/2011 7:54:33 AM , Rating: 2
The problem is that this 14% are connected to the delta in the temperature, if you put your TEG inside your flue at some point your delta will be close to 0 and then your production would be none. If you put your TEG on the flue part that is on the roof then the energy you could harness there is much lower.

What I see and seems much more effective (in terms of energy) is to put pipes filled with water around your flue and connect them to a central heating, then you just have to make this water circulate and you heat your all house with it.


This Just In...
By mmatis on 1/19/2011 10:16:15 PM , Rating: 1
Al Gore has just found some spotted owls in Price County, Wisconsin. Rumors that he and his minions personally relocated them there have been branded as "right wing lies spread by Sarah Palin and Rush Limbaugh", and ABCNNBCBS as well as their dead-tree fellow travelers are making "target" posters of Palin and Limbaugh for distribution to school children nation wide.




RE: This Just In...
By wordsworm on 1/20/2011 6:45:53 AM , Rating: 2
Cool... can I get the one with Sarah Palin? Whatever you want to say about her politics, she's the only running mate in history that would have done OK in a Playboy rag. I think everyone knows why John McCain chose her for that race.


RE: This Just In...
By nstott on 1/20/2011 12:28:36 PM , Rating: 2
Of course we know why. Logic dictates that John McCain chose Sarah Palin because you're a misogynist. :P


RE: This Just In...
By wordsworm on 1/20/2011 9:16:02 PM , Rating: 2
No, I'm not a misogynist. I'm married. I'm a masochist.


why not
By Bubbacub on 1/20/2011 3:52:08 AM , Rating: 2
say that someone has made a slightly more efficient thermocouple and cut half the bumpf in the article.

on another note im sure nasa/esa would be interested in this. if it works then it could improve the efficiency/life span of deep space probes.




RE: why not
By CZroe on 1/20/2011 5:49:06 AM , Rating: 2
What technique do the radioisotope thermoelectric generators (RTGs) in the Voyager probes use for generating electricity and how efficient is it compared to this?


RE: why not
By Bubbacub on 1/20/2011 10:34:16 AM , Rating: 2
they use thermocouples strapped alongside some plutonium dioxide (other elements can be used). i don't know the exact efficiency (its probably classified like most nuclear related secrets) but its going to be of the order of 3-7%.


By Smartless on 1/19/2011 8:02:34 PM , Rating: 2
Hopefully this leads to breakthroughs using something a little more common like gold or something lol. But seriously, if they could find an efficient way to convert thermal energy that doesn't require a boiler and turbine, that would be a huge benefit. Especially when the robots start putting us in a matrix.




many possible applications
By chromal on 1/19/2011 8:49:04 PM , Rating: 2
I wonder if this could be practical on a vehicle for some useful purpose, and what it would weigh. A typical vehicle's engine output is rated around or above 100kw output in mechanical energy and heat, so even just 10% of the heat might go a long way. The seemingly obvious way to do that would be to integrate it somehow into the catalytic converter, one of the hotter points in the exhaust system. Maybe a boon to hybrid vehicles? Also mentioned as a way to help photovoltaic cells operate with greater efficiency, better using solar infrared photons.

Another seemingly obvious application would be in RTG 'batteries' such as those on some robotic space vehicles, e.g.: Voyager I/II, or the 2006-launched en route to Pluto, E.T.A. July 2015.

Nice overview at wikipedia: http://en.wikipedia.org/wiki/Thermoelectric_genera...
Discussion within the article mentions 7.2% efficient was available prior.




So tell me again
By createcoms on 1/20/2011 1:57:12 AM , Rating: 2
Why are we doing the research that allows the machines to enslave us all in the matrix

All so we can see Neo go bullet-time in our neighbourhoods?




PV pannels replacement?
By Qapa on 1/20/2011 6:26:55 AM , Rating: 2
Could this replace PhotoVoltaic panels to produce electricity at home?

Yes, low efficiency, but if it works and is cheap enough, it may be an interesting idea.




Some Notes
By nstott on 1/20/2011 12:21:56 PM , Rating: 2
* The lead and tellurium are 'in' the crystalline lattice, not 'on' the crystalline lattice. Even so, the wording is awkward. Semiconductor-grade lead telluride is crystalline. I'm not sure how much more you need to say unless you're writing a textbook.

* SrTe is NOT a special form of rock salt. Rock salt is rock salt, also known as halite, which is a crystalline form of sodium chloride (NaCl). The strontium telluride nanocrystals that they are growing have a "rock salt" crystal structure, which is to say that the periodic placement of Sr and Te relative to each other is the same as the Na and Cl ions in rock salt (the interionic/interatomic distances are different, though). Crystal structure plays an important role on material properties. For example, the most abundant crystalline form of nickel is face-centered cubic (FCC), which is magnetic, but the hexagonal close-packed (HCP) form of nickel is nonmagnetic with respect to its bulk properties.

* The abundance of natural lead telluride deposits are not so important to commercialization. The amounts of lead and tellurium in any form are what are important. The semiconductor-grade PbTe crystalline films are grown by MBE from separate Pb and Te precursors. That isn't to say it's impossible to take natural lead telluride crystals and cleave them properly.




solar THERMAL panels?
By Chernobyl68 on 1/20/2011 12:38:30 PM , Rating: 2
how about making a solar panel out of this material?




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