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'Thermoelectrics' Could One Day Power Cars

Soulskill posted about 7 months ago | from the hot-wheels dept.

Power 174

sciencehabit writes: "Fossil fuels power modern society by generating heat, but much of that heat is wasted. Researchers have tried to reclaim some of it with semiconductor devices called thermoelectrics, which convert the heat into power. But they remain too inefficient and expensive to be useful beyond a handful of niche applications. Now, scientists in Illinois report that they have used a cheap, well-known material to create the most heat-hungry thermoelectric so far (abstract). In the process, the researchers say, they learned valuable lessons that could push the materials to the efficiencies needed for widespread applications. If that happens, thermoelectrics could one day power cars and scavenge energy from myriad engines, boilers, and electrical plants."

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power cars? technically no (5, Insightful)

noh8rz10 (2716597) | about 7 months ago | (#46772833)

technically, you would still need an energy source (gasoline, natural gas, batteries) to power the cars. thermo electrics could make it more efficient by recycling waste heat. but the thermoelectrics themselves would not power the cars.

Re:power cars? technically no (1)

i kan reed (749298) | about 7 months ago | (#46772947)

Fuel provides energy. Power comes from the conversion rate of the engine. You "power" things with an engine, but the net energy comes from fuel. Some engines can handle multiple fuel types, e.g.

Re:power cars? technically no (2)

ShanghaiBill (739463) | about 7 months ago | (#46773051)

thermo electrics could make it more efficient by recycling waste heat. but the thermoelectrics themselves would not power the cars.

If they are sufficiently efficient, they could power a car directly. An internal combustion engine is typically only about 15-20% efficient, so the bar is not too high. Using thermoelectrics directly could have several advantages: being solid state, they would be reliable and require little or no maintenance; and since the fuel is just used to create heat, it could use cheaper grades of fuel.

Re:power cars? technically no (1)

noh8rz10 (2716597) | about 7 months ago | (#46773123)

ok but then the car is still powered by fuel. in your scenario you would still need an external combustion engine to produce heat.

Re:power cars? technically no (1)

stewsters (1406737) | about 7 months ago | (#46773157)

Or a RTG [wikipedia.org]

Re:power cars? technically no (1)

Guspaz (556486) | about 7 months ago | (#46773931)

It's not as silly as you might think. I believe you get roughly 500W of heat per kilo of plutonium-238. A Tesla Model S driving at normal speeds consumes something like 15KW. If you could get 50% efficiency for your thermoelectrics, you could build an RTG-powered model S with 60 kilos of plutonium. You'd need capacitors for surge demand, obviously.

Of course, this would be completely insane, but I don't see why it's not theoretically possible, since the battery pack on the car that you'd be replacing already weighs something like 600 kilos.

Then again, with sufficiently efficient thermoelectrics, you might see the military using RTGs.

Re:power cars? technically no (2)

ShanghaiBill (739463) | about 7 months ago | (#46774541)

There are several problems with your scenario:
1. Current TEs are no where close to 50% efficient. More like about 5%.
2. Pu238 is available in very limited quantities from reactor fuel reprocessing
3. You can't "turn-off" an RTG. They have to run continuously.

Re:power cars? technically no (3, Insightful)

Guspaz (556486) | about 7 months ago | (#46775235)

1. I realize that they're currently at 5%, the whole point of my scenario was examining what sort of changes a large increase in efficiency would produce... that's the whole point of the article, after all. Efficiency would need to be somewhere around 50% to justify replacing ICEs with thermoelectric engines. Is that possible? I've got no idea, TFA gives zero layman-friendly information about what sort of efficiency improvements are foreseen.

2. Supply isn't as big a problem as the incredible safety issues. I acknowledge in my post that the idea is totally insane, which is why I doubt that, even with a big improvement in efficiency, you'd probably never see RTGs used outside of military applications.

3. That's not necessarily a problem. They conveniently provide power that can be used for active cooling. Cooling them in a vacuum is an issue (hence the giant heat dissipation fins), cooling them in an atmosphere isn't as much of an issue.

I suspect that sufficiently efficient thermoelectrics might find their way into military UAVs, which could remain airborn for extended periods of time, for example. Or as an alternative to shipping diesel to remote outposts (although they're currently looking into robotic trucks to solve that problem).

Re:power cars? technically no (1)

tragedy (27079) | about 7 months ago | (#46776675)

2. Supply isn't as big a problem as the incredible safety issues. I acknowledge in my post that the idea is totally insane, which is why I doubt that, even with a big improvement in efficiency, you'd probably never see RTGs used outside of military applications.

The safety issues aren't really that bad. You could put 60 kilos inside a casing that would easily block the radiation down to negligible levels and would be effectively indestructable in the worst conceivable accident. Worries about "dirty bombs" are ridiculous considering the large array of easily available substances that would be much more dangerous (not very) in such a bomb. As for a nuclear weapon, I'm not exactly sure how fissionable it is, but I do know that you would need a massively powerful nuclear weapon in the first place in order to actually induce fission in it, so it's not dangerous in that respect either.

So, right now, the supply probably is the biggest problem. At the rate the US is currently producing it, it would take 40 years to get enough for one car. Not that the rate of production couldn't be ramped up considerably, but it would still be so expensive it would only be useful for powering things in space or at the bottom of the ocean, or deep under the earth, etc. Places where power is otherwise impossible or incredibly expensive to obtain.

Re:power cars? technically no (2)

tragedy (27079) | about 7 months ago | (#46776637)

1. Current TEs are no where close to 50% efficient. More like about 5%.

The article was about new, higher-efficiency materials. Still not high enough, and not near 50% efficiency, but certainly getting up there. Good enough so that, if you could get hold of the material, you could at least use it to charge your electric cars batteries currently, even if you couldn't power the car directly. Of course, at present, you'd be better off with a Stirling engine.

3. You can't "turn-off" an RTG. They have to run continuously.

Presumably, you could plug them into the power grid in most places you park them

Re:power cars? technically no (0)

Anonymous Coward | about 7 months ago | (#46773163)

ok but then the car is still solar powered. in your scenario you would still need an external sun to grow the plants that fed the dinosaurs that died and turned into oil that was refined into gasoline.

Re:power cars? technically no (1)

noh8rz10 (2716597) | about 7 months ago | (#46773229)

point granted, the "powered by" slope is a slippery one. but saying the car is powered by thermoelectrics is like saying it's powered by suspensions.

Re:power cars? technically no (1)

ShieldW0lf (601553) | about 7 months ago | (#46774921)

point granted, the "powered by" slope is a slippery one. but saying the car is powered by thermoelectrics is like saying it's powered by suspensions.

If it was pointed out to you that thermoelectrics operate anywhere there is a heat differential, and that you could technically "fuel" your car by pouring liquid nitrogen into the tank and have the thermoelectrics exploit the heat differential between the liquid nitrogen and the ambient temperature to generate work over time, aka power, would that be enough for you to concede that thermoelectrics are indeed what is generating the power?

Re:power cars? technically no (1)

gman003 (1693318) | about 7 months ago | (#46773425)

It is completely valid to say "a car is powered by an engine". The engine is powered by fuel, but the car's power comes from the engine. Replacing the reciprocating engine with a thermoelectric engine allows for the headline to, in fact, be an accurate statement.

Re:power cars? technically no (1)

noh8rz10 (2716597) | about 7 months ago | (#46773489)

if you have a "thermoelectric engine" then what is producing the heat to power the thermoelectrics?

Re:power cars? technically no (1)

ShanghaiBill (739463) | about 7 months ago | (#46773657)

if you have a "thermoelectric engine" then what is producing the heat to power the thermoelectrics?

A flame.

Re:power cars? technically no (1)

noh8rz10 (2716597) | about 7 months ago | (#46774443)

what are you burning to produce a flame?

Re:power cars? technically no (1)

sexconker (1179573) | about 7 months ago | (#46774977)

Fuel. You've been bitching about the use of the word "power" when you're the one who's using it wrong. The word you want is fuel.

Thermoelectrics generate power in the presence of heat.
Internal combustion engines deliver power when shit explodes inside them.

Gasoline is a fuel, not a power source.

Re:power cars? technically no (1)

ShieldW0lf (601553) | about 7 months ago | (#46775135)

Fuel. You've been bitching about the use of the word "power" when you're the one who's using it wrong. The word you want is fuel.

Thermoelectrics generate power in the presence of heat.
Internal combustion engines deliver power when shit explodes inside them.

Gasoline is a fuel, not a power source.

If you built a car engine that delivered power by causing fuel to explode, you'd change the world. Car engines work through deflagration, not detonation. Detonation releases way, way more power. It's hoped that it will be the replacement for scramjet engines... envision a jet being driven by a series of explosions. No one has admitted to successfully making one, though. I've spent years doodling different ideas about how you might make one if we had the materials necessary, but it's like building a space elevator... fun to think about, but you'd need materials far stronger than anything we have available.

Car engines run on boring old combustion. The difference in scale between combustion and detonation is not dissimilar to the difference between a compost heap and a bonfire.

Re:power cars? technically no (2)

tragedy (27079) | about 7 months ago | (#46776765)

A detonation doesn't neccessarily release more power than a deflagration. That's apples to oranges. It's more a matter of intensity. For example, ANFO detonates, and has a specific energy of something like 3.7 MJ/kg whereas a gasoline/oxygen mixture in an engine typically deflagrates (although it can also detonate under the right conditions, which isn't good for the engine, as you point out) and has a specific energey of something like 9.7 MJ/kg (counting the gasoline plus the oxygen needed for combustion). Clearly averaged over time you can get more power out of an equivalent mass of gasoline/oxygen than from ANFO. Although, if you slice time thinly enough you can say that you get more instantaneous power out of the ANFO because you can get all of the power out of it faster than you can from deflagrating the gasoline/oxygen mixture.

Re:power cars? technically no (3, Interesting)

Em Adespoton (792954) | about 7 months ago | (#46773983)

The power plant -- just like in Diesel Electric trains; you have the electric engines that power the train and the power plant that powers the engines. Diesel fuel powers the power plant, and it in turn was powered by solar energy. The sun is powered by hydrogen fusion reactions; the hydrogen fuel was provided by gravitational attraction, which was powered by time and space.

I'll leave it up to the reader to determine who/what powered time and space.

Re:power cars? technically no (1)

Newander (255463) | about 7 months ago | (#46773573)

If the car is electric it could be powered by waste heat from industrial processes and primary power generation.

Re:power cars? technically no (4, Informative)

ShanghaiBill (739463) | about 7 months ago | (#46773639)

If the car is electric it could be powered by waste heat from industrial processes and primary power generation.

TEs are bound by the same Carnot efficiency limitations as any other heat engine. If you use low grade "waste heat" then you are going to get very little power.

Re:power cars? technically no (1)

sgt scrub (869860) | about 7 months ago | (#46776649)

Is an exothermic reactor considered internal combustion?

Re:power cars? technically no (1)

jellomizer (103300) | about 7 months ago | (#46773301)

So say we can double that. That makes the fuel 40% efficient as we use some of the heat towards efficiency. That will double the gas mileage. However if you need a smaller engine, then it will be producing less heat. That is good if it is 1 for 1. However if their needs to be a particular heat starting limit then it may cause an issue. Unless you go with a bigger car.

The idea as the engine gets more efficient people buy bigger cars, is economically sound and proven. A large truck today can do about the same as a station wagon 30 years ago. But what happened is more people started buying trucks.

Prius does better (0)

Anonymous Coward | about 7 months ago | (#46773957)

The toyota prius engine is about ~38 percent efficient. The prius also has some prius specific stuff to get its mpg higher, but hybrid synergy drive can be applied to a variety of vehicles. oh yes, internal combustion engines are quite cheap... i imagine thermoelectrics are useful in deep probe probes.

Re:power cars? technically no (1)

Anonymous Coward | about 7 months ago | (#46774193)

If I might nitpick, the ICE's 15-20% efficiency figure is the gas tank-to-wheels efficiency which includes substantial losses in the transmission and differentials. The ICE itself might be 30+% efficient. In diesel-electric applications, where the ICE is optimized to run at a single speed, efficiency can be even higher. Diesel-electric plus batteries for peaking (Even a Lincoln Navigator uses less than 20hp except when accelerating) with an all-electric drivetrain seems like an excellent immediate-term way to reduce fuel consumption; I wish it was more widely available.

As far as using cheaper fuel, the whole reason we use more expensive grades now is to reduce pollution. Remember back in the early 2000s when gas was reaching obscene new heights like $2.50 a gallon (*snert*), but diesel was like $1.50, then all of a sudden the price of diesel was >= gas? That's the price of desulfuring the diesel, because sulfur oxides are bad to breathe and are the main contributor to acid rain (sulfur trioxide + water = instant sulfuric acid).

Re:power cars? technically no (3, Insightful)

fuzzyfuzzyfungus (1223518) | about 7 months ago | (#46773179)

My (admittedly pretty hazy at this point) memory of heat engines is that their theoretical peak efficiency depends on the thermal delta they manage to achieve. Exactly the same resource that thermoelectric materials scavenge (albeit at miserable efficiency) into electricity.

Anybody who actually has some grasp of the matter want to chime in on where and why you would use thermoelectrics (and how efficient they would have to be) rather than simple insulation or one of the various waste-heat-recovery systems that transfer some amount of the heat remaing in outgoing exhaust gases into incoming working fluids?

Is the thermoelectric advantage purely that, assuming material reliability is OK, they are a 100% solid state, trivial to scale from 'handle with tweezers and magnification' to 'pretty large', and their output is easy to transfer and useful for all kinds of things after just a little DC-DC cleanup, or are there actually situations where they might be absolutely more efficient than insulation and heat recovery, rather than just easier to tack in almost anywhere in a design that you have a few extra cubic centimeters and expect a temperature difference?

Re:power cars? technically no (0)

Anonymous Coward | about 7 months ago | (#46773307)

The lack of efficiency is precisely why NASA is looking into replacing thermoelectric generators with linear Stirling engines.

Re:power cars? technically no (1)

Dare nMc (468959) | about 7 months ago | (#46776563)

> insulation or one of the various waste-heat-recovery systems that transfer some amount of the heat remaing in outgoing exhaust gases into incoming working fluids?

Several reasons this isn't done in the engine intake. The main power conversion in a ICE is through the thermal expansion of the gasses trapped in the cylinder, so heating it before the intake valve is closed only reduces the density of the air taken into the cylinder (PV=nRT so at the same Pressure and volume, the higher the temperature, the fewer molecules, less O2 available to burn.) Once the air is trapped in the cylinder all heat added will then be converted, so a cold intake, then a hot block helps contribute to efficiency. But then metals have limitations on the allowable temperatures (for at least the last 40 years Ceramic engines have been on the verge of a breakthrough making higher temp more efficient engines a reality, maybe next year.) Also combustion properties of carbon fuels create emissions problems when combustion occurs at too high of temperatures.
Power stations will harness the waste heat from Ng Generators, and pump that into a sterling engine, then take that waste heat into another conversion, then take that waste heat as warm water for buildings, etc. But that takes too much space, weight, and cost (I assume) to be put into a mobile vehicle (other than used as a heater in the winter.) Although I would hope Cruise ships, etc would utilize this waste heat as well.

Re:power cars? technically no (0)

Anonymous Coward | about 7 months ago | (#46773353)

Thanks for telling us what the synopsis provided by Slashdot just told us.

Re:power cars? technically no (1)

LifesABeach (234436) | about 7 months ago | (#46773589)

Maybe Solar Heat?

Re:power cars? technically no (1)

viperidaenz (2515578) | about 7 months ago | (#46773859)

If the thermoelectrics are significantly more efficient that than internal combustion engine, removing it completely would save a lot of weight and may result in a more efficient system.

Re:power cars? technically no (0)

Anonymous Coward | about 7 months ago | (#46774691)

Ecat

Hotter Earth (4, Funny)

neonv (803374) | about 7 months ago | (#46772837)

We better speed up this global warming thing so we can power our thermo cars!

Re:Hotter Earth (4, Informative)

ShanghaiBill (739463) | about 7 months ago | (#46772923)

We better speed up this global warming thing so we can power our thermo cars!

That doesn't work. TEs aren't powered by heat, but by heat gradients. So if everything is uniformly heated by the same amount, there is no benefit.

Re:Hotter Earth (1)

MozeeToby (1163751) | about 7 months ago | (#46773063)

So... sink a steel pipe half a mile into the ground, it isn't that hard to create a heat gradient. That's of course, if it's possible to hit anywhere near decent efficiencies with standard materials, which is something I'll have to see in production before I fully believe.

Re:Hotter Earth (2)

ShanghaiBill (739463) | about 7 months ago | (#46774319)

So... sink a steel pipe half a mile into the ground, it isn't that hard to create a heat gradient.

That would give you enough of a gradient to generate a micro-watt from a ton of TEs. In a perfect ideal TE, the efficiency is (1 - Th/Tc) where Th= Hot side in Kelvins, Tc = Cold side in Kelvins. Existing TEs are no where close to ideal, and the earth's heat gradient is about 0.025K/meter. A negligible amount of heat would flow through the TE, and far less than 1% of that would be converted to electricity.

Re:Hotter Earth (1)

ceoyoyo (59147) | about 7 months ago | (#46774801)

Why yes, I have been to Iceland.

Re:Hotter Earth (0)

Anonymous Coward | about 7 months ago | (#46773143)

Global warming + AC = free energy*

Re:Hotter Earth (1)

fuzzyfuzzyfungus (1223518) | about 7 months ago | (#46773249)

Well, you could build a thermoelectric shell around the entire earth... Of course, if you can do that, 'stop global warming' is probably something you did in high school as a busy-work lab project at your school for particularly gifted hypersentient disembodied intelligences.

Who shot Mr Burns? (1)

Thud457 (234763) | about 7 months ago | (#46773691)

you guys just really don't get it, do you?

Global warming is a non-issue. Elon Musk is going to put up a orbital sunshade and hold the world ransom to turn the lights back on.
And there's NOTHING you can do to stop him.

Re:Hotter Earth (0)

Anonymous Coward | about 7 months ago | (#46774591)

I hope you are not talking about the kind of cars in Fallout 3.

Re:Hotter Earth (1)

Immerman (2627577) | about 7 months ago | (#46775111)

Good luck with that. Human energy production is directly a miniscule factor in global warming - it's the CO2 byproducts that's the problem. In the 90+ years it takes for a unit of CO2 to be removed from the atmosphere it will capture roughly 1,000,000x as much solar thermal energy as was produced by the burning of fuel that created it. If we generated 1000x as much heat directly, but without producing the CO2, then global warming would be a non-issue.

New in the US, not elsewhere (3, Informative)

Anonymous Coward | about 7 months ago | (#46772901)

Several vehicle manufacturers have been experimenting with supplemental power generation systems [wikipedia.org] in their cars. BMW for instance has a steam turbine. [wikipedia.org] Honda's doing thermal recovery more efficient than regenerative braking.

Ah, the clickbait (2, Informative)

Anonymous Coward | about 7 months ago | (#46772953)

Now, scientists in Illinois report that they have used a cheap, well-known material to create the most heat-hungry thermoelectric so far

Because it's soooooo hard to actually state what the well-known material is

Ultralow thermal conductivity and high thermoelectric figure of merit in SnSe crystals

Oh, I guess it's not hard at all. A salt made of Selenium and Tin.

Re:Ah, the clickbait (5, Funny)

rogoshen1 (2922505) | about 7 months ago | (#46773127)

"Illinois scientist uses this one weird trick to generate free electricity from waste heat; oil companies hate him"

That's about what that sentence sounded like to me =/

Re:Ah, the clickbait (2)

K. S. Kyosuke (729550) | about 7 months ago | (#46773359)

A salt made of Selenium and Tin.

Apparently, the author is a lunatic from some tinpot university.

Re:Ah, the clickbait (0)

Anonymous Coward | about 7 months ago | (#46774021)

A "salt"? High school chemistry a bit far in the past, eh?

Re:Ah, the clickbait (1)

ceoyoyo (59147) | about 7 months ago | (#46774825)

It is hard when your job as a "submitter" consists of copying and pasting the first paragraph of the article. At least they usually remember to put quotes around it.

not before i get my flying car! (1)

turkeydance (1266624) | about 7 months ago | (#46772959)

...from my cold, dead hands...

This is amazing (0)

Anonymous Coward | about 7 months ago | (#46773031)

We just discovered on slashdot the other day that transistors, and therefore ICs, are actually thermoelectric devices that use heat to modulate conductivity. Will this mean we will see solid-state cars in the future?

Oh boy is this for the wrong crowd? (1)

50000BTU_barbecue (588132) | about 7 months ago | (#46773049)

You expect slashdotters to generate heat... on a mattress?

Re:Oh boy is this for the wrong crowd? (1)

PIBM (588930) | about 7 months ago | (#46773321)

I guess they could use your BBQ, in some ways ?

Re:Oh boy is this for the wrong crowd? (0)

Anonymous Coward | about 7 months ago | (#46773389)

No I do not, because it is more efficient to do it while standing.

Re:Oh boy is this for the wrong crowd? (1)

Immerman (2627577) | about 7 months ago | (#46775489)

Oddly enough that is exactly the position portrayed in the article - on a mattress. Without spilling your wine. Which is also on the mattress.

Not so fast, Thermodynamic laws are pesky things (4, Informative)

bobbied (2522392) | about 7 months ago | (#46773295)

I debunked this LAST time it was posted..

Look, these things are NOT going to get you thermodynamic efficiency gains on anything of value. Any system which is designed to be efficient now, will not benefit from this kind of heat to electricity device. Thermodynamic rules demand a maximum efficiency that is as good as you can do. Most industrial scale energy production is pretty darned good compared to the maximum possible. So you are NOT going to be able to just hook up these things and get electrical energy for *free* (even without the device costs). Any energy you manage to get, will be lost someplace else because you put these devices in the heat flow. Don't even bother trying this, it simply won't work. Don't let them fool you with all this "waste heat" garbage, at least until you understand the Thermodynamic laws that govern all this and can explain what a heat engine is.

As I concluded before, in situations where you have less than ideal conditions, like in cars with internal combustion engines, you MIGHT get a little bit of energy, but I ask you is it going to be worth it? Are you sure you are going get enough gain to make it worth the weight, cost and complexity? Where I'm not so sure that answer is a good one, I'm willing to entertain that it *might* be possible for internal combustion engines. Go ahead and work on that idea, but I'm fairly sure it's not going to work very well.

I'd also suggest that there are more efficient heat engines you might consider. These heat flow direct to electricity devices are horribly inefficient compared to the ideal.

Re:Not so fast, Thermodynamic laws are pesky thing (1)

sconeu (64226) | about 7 months ago | (#46773395)

Lisa, in this house, we obey the LAWS OF THERMODYNAMICS!!!!

Re:Not so fast, Thermodynamic laws are pesky thing (1)

bobbied (2522392) | about 7 months ago | (#46774235)

Lisa, in this house, we obey the LAWS OF THERMODYNAMICS!!!!

LOL Why yes, yes we do. Like it or not.

Re:Not so fast, Thermodynamic laws are pesky thing (0)

Anonymous Coward | about 7 months ago | (#46773559)

Nuclear power plants are very efficient, yet they still use cooling towers and still run millions of gallons of heated water through cooling ponds. This technology is about capturing waste heat, which is the product of a process which has already obeyed all the rules of thermodynamics.

Re:Not so fast, Thermodynamic laws are pesky thing (0)

Anonymous Coward | about 7 months ago | (#46774093)

Yeah, but extracting the heat from that warm water is not going to really get you any current worth measuring. What makes this work is a high delta-T between the two sides of the thermoelectric. A few degrees is as good as worthless.

Re:Not so fast, Thermodynamic laws are pesky thing (1)

bobbied (2522392) | about 7 months ago | (#46775517)

Nuclear power plants are very efficient, yet they still use cooling towers and still run millions of gallons of heated water through cooling ponds. This technology is about capturing waste heat, which is the product of a process which has already obeyed all the rules of thermodynamics.

Here we go "waste heat". Please learn a bit more about thermodynamics and heat engines. Power is generated from the TRANSFER of heat. Power plants are huge heat engines, that produce electrical power by taking heat from a high temperature source, transferring that heat to a low temperature sink. There is very little WASTE in a power plant (nuclear or otherwise). Yes you have to dump heat to generate power, but it is not like you are just wasting power when you dump heat. This "waste heat" is not a free resource you can exploit to get more power from the plant.

Adding any other devices in the path of the heat flow will only impede the heat flow and drive down efficiency. I contend that the loss of efficiency will be more than the power you can generate using devices that directly convert heat transfer to electrical power. These devices are not nearly as efficient as what we have already in a modern power plant, thus there is zero chance they will be better.

Re:Not so fast, Thermodynamic laws are pesky thing (1)

rasmusbr (2186518) | about 7 months ago | (#46773717)

The one application that I've heard about that sounds semi-plausible is sandwiching something like this between a solar cell and a liquid cooler. The difference in temperature between the PV cell and the cooler might be enough to yield meaningful amounts power and the waste heat that the cooling system captures could be used for heating.

Re:Not so fast, Thermodynamic laws are pesky thing (1)

bobbied (2522392) | about 7 months ago | (#46775567)

I'm not sure how the cooling works for PV cells. But, if they are actively cooling the liquid there is little to be gained from this arrangement and it is likely going to lead to hotter cell temperatures and cooler liquid temperatures.

So it *might* work, but only if the temperature differential they can stand is high enough and they are not expending energy to cool the liquid through some heat engine.... (I.e. if they use something like a swamp cooler or something.)

Re:Not so fast, Thermodynamic laws are pesky thing (0)

Anonymous Coward | about 7 months ago | (#46773845)

Many systems currently designed to be as efficient as possible are still short of the maximum efficiency allowed under thermodynamics. How to best improve that efficiency, whether refinements of the original technology or using a mixture of techniques can be quite subtle and depend heavily on what situation and purpose, which is a long way from something being a matter of being debunked.

Re:Not so fast, Thermodynamic laws are pesky thing (1)

bobbied (2522392) | about 7 months ago | (#46775609)

Until these devices they describe approach the current efficiency of a power plant, there is zero chance they will be helpful on an industrial scale. Modern power plants are usually within a few percentage points of ideal so these devices are going to have to come way up the efficiency scale, and they are horrible now. Given how they work at the subatomic level (holes, electrons etc) I seriously doubt we are in any danger of reaching this level.

Re:Not so fast, Thermodynamic laws are pesky thing (0)

Anonymous Coward | about 7 months ago | (#46773875)

Before you make a bigger ass of yourself, please look up what "waste heat" actually is and familiarize yourself with the "Thermo" in thermodynamics.

Engines run HOT. Every bit of heat that travels into the metal and outside the engine is lost energy. Capturing bits of that lost energy and putting it to good use is the concept here. This is waste heat, so it is free, just as eating food out of the garbage bin is "free food" -- someone else paid for it, but they threw it out so it is "free" for you. It's not disobeying thermodynamics any more than burning a gallon of gasoline to make a car move 30 miles is disobeying the laws of thermodynamics.

For other automotive-related things that defy your idiotic concept of physics, please see turbochargers and hybrid cars.

Re:Not so fast, Thermodynamic laws are pesky thing (0)

Anonymous Coward | about 7 months ago | (#46775461)

The waste heat is rarely free in modern engines, at least in any practical quantities. By adding devices to recover a small amount of power, you necessarily increase the temperature the engine block runs at which may cause efficiency problems elsewhere, whether from causing changes in the thermodynamics of the main operation of the engine, or necessitating changes in design to handle the higher temperatures. Turbocharges are not the greatest example, because they have the analogous problem of creating back pressure that makes the engine run less efficiently, but over comes this by using more fuel. It is a net gain in power, but not in efficiency.

Re:Not so fast, Thermodynamic laws are pesky thing (2)

bobbied (2522392) | about 7 months ago | (#46775663)

Before you make a bigger ass of yourself, please look up what "waste heat" actually is and familiarize yourself with the "Thermo" in thermodynamics.

Engines run HOT. Every bit of heat that travels into the metal and outside the engine is lost energy. Capturing bits of that lost energy and putting it to good use is the concept here. This is waste heat, so it is free, just as eating food out of the garbage bin is "free food" -- someone else paid for it, but they threw it out so it is "free" for you. It's not disobeying thermodynamics any more than burning a gallon of gasoline to make a car move 30 miles is disobeying the laws of thermodynamics.

For other automotive-related things that defy your idiotic concept of physics, please see turbochargers and hybrid cars.

If you read my post.... (and apparently you didn't) ... I specifically stipulate that automotive applications *might* be successful and worth of investigation. The reason I say this is because of the huge amounts of heat transferred out the tail pipe and radiator in a modern internal combustion engine at sometimes very high temperature differentials leaves something to recover. This is totally unlike a modern power plant, where heat transfer has been carefully engineered to be as efficient as possible, thus leaving little room for thermodynamic improvement. However, my doubts about automotive application are over costs, weight and complexity not about the Thermodynamics of the application.

Re:Not so fast, Thermodynamic laws are pesky thing (1)

DerekLyons (302214) | about 7 months ago | (#46774759)

Any energy you manage to get, will be lost someplace else because you put these devices in the heat flow.

You sir, are ignorant as fuck. It's a sad comment on the state of affairs that a clueless bullshit comment like your could be moderated informative.

We've been extracting energy from waste heat, without incurring extra losses, for over a century now - it's been a standard practice in steam [wikipedia.org] engineering [wikipedia.org] since the 1800's. In the same way, if you put these devices in an IC engine's exhaust you can recover energy that would otherwise simply be vented into the atmosphere without incurring any losses "someplace else".
 

Don't let them fool you with all this "waste heat" garbage, at least until you understand the Thermodynamic laws that govern all this and can explain what a heat engine is.

Before cautioning others to educate themselves, first pull your head out of your own ass and educate yourself.

Re:Not so fast, Thermodynamic laws are pesky thing (2)

bobbied (2522392) | about 7 months ago | (#46775067)

Any energy you manage to get, will be lost someplace else because you put these devices in the heat flow.

You sir, are ignorant . It's a sad comment on the state of affairs that a clueless bullshit comment like your could be moderated informative.

We've been extracting energy from waste heat, without incurring extra losses, for over a century now - i

Calm down and think about what I said. Your average power plant is pretty darn good efficiency wise (which is what I said if you don't mind reading), which is exactly what you are saying too. Yea, we've come a long way from just dumping waste steam, we have optimized things very well actually. I'm saying that there is very little room for improvement left at this point and there is NO FREE LUNCH here. These devices that convert heat flow directly to electric power are NOT going to increase the efficiency of industrial scale power plants. These devices are simply NOT EFFICIENT enough and will disrupt the current efficiency we've already designed in, they will only disrupt the heat flow, raise entropy and result in less power output for the same input. They don't help.

Don't let them fool you with all this "waste heat" garbage, at least until you understand the Thermodynamic laws that govern all this and can explain what a heat engine is.

Before cautioning others to educate themselves, first pull your head out of your own ass and educate yourself.

What on earth did I say that was incorrect? I admit to having struggled with thermodynamics class, but I believe I captured the essence of heat engines and efficiency. So you want to step down off the pedestal and discuss exactly what you think I have wrong in my understanding of thermodynamics? Or are you going to stay up there and keep yelling about how stupid everybody else is?

Re:Not so fast, Thermodynamic laws are pesky thing (1)

cusco (717999) | about 7 months ago | (#46774829)

There's a lot of energy available from an IC engine. If you doubt me let your car run for anything more than two minutes and then touch the exhaust manifold. Bumped one with my arm when I was in high school and it took twelve years for the scar to fade.

Re:Not so fast, Thermodynamic laws are pesky thing (1)

bobbied (2522392) | about 7 months ago | (#46775115)

There's a lot of energy available from an IC engine. If you doubt me let your car run for anything more than two minutes and then touch the exhaust manifold. Bumped one with my arm when I was in high school and it took twelve years for the scar to fade.

Which is why I stipulate that these heat to electricity devices MIGHT be of value for internal combustion engines. The heat dumped by them is significant and the temperature differential quite high. There is at least opportunity to get something that would normally just get dumped. I just openly wonder if for a car or truck it will be worth the cost, weight and complexity it will add. I strongly suspect that it's not worth it, but I'm not totally sure.

Re:Not so fast, Thermodynamic laws are pesky thing (1)

cusco (717999) | about 7 months ago | (#46776155)

Then I misunderstood your previous post, which I took to mean that there wasn't enough to bother with. It would be interesting to me to see an estimate of how much it would cost to make an exhaust manifold of thermocouple material, and what the estimated output would be. With hybrid vehicles like the Prius, which just uses the IC engine to charge the batteries that actually propel it, it might well be worth it.

Re:Not so fast, Thermodynamic laws are pesky thing (2)

Immerman (2627577) | about 7 months ago | (#46775615)

The maximum limit on an an arbitrary heat-conversion system is that doesn't break accepted theory is the Carnot-cycle heat engine, where eff 1 - T_cold / T_hot (as measured from absolute 0). But it's a rare real-world engine that gets anywhere near the Carnot efficiency limit - a car engine might run at 1100K for an ideal efficiency of around 73%, but the reality in most cars is closer to 25%. Being solid-state a thermoelectric device could potentially operate at very near the ideal (no mechanical losses), roughly tripling the efficiency. Assuming 90% efficient electric wheel motors the total system efficiency could be nearly as high.

Re:Not so fast, Thermodynamic laws are pesky thing (2)

bobbied (2522392) | about 7 months ago | (#46775733)

The maximum limit on an an arbitrary heat-conversion system is that doesn't break accepted theory is the Carnot-cycle heat engine, where eff 1 - T_cold / T_hot (as measured from absolute 0). But it's a rare real-world engine that gets anywhere near the Carnot efficiency limit - a car engine might run at 1100K for an ideal efficiency of around 73%, but the reality in most cars is closer to 25%. Being solid-state a thermoelectric device could potentially operate at very near the ideal (no mechanical losses), roughly tripling the efficiency. Assuming 90% efficient electric wheel motors the total system efficiency could be nearly as high.

Don't be fooled that "hey they are solid state and convert directly to electricity". Deep down, it's still a physical process that produces electricity, even if the moving parts are not something you can see. In actual practice, what happens with these things produces horrible efficiency.

These electronic devices are semiconductor junctions that you get heat to flow through in hopes the electrons will bounce their way across the junction into the cooler side and get stuck... They are not efficient from a thermodynamic perspective, and unless my physical understanding of how they work is totally wrong, they are never going to approach the efficiency of even an internal combustion engine, from a thermodynamic perspective anyway.

why cars as the first application (1)

u19925 (613350) | about 7 months ago | (#46773351)

the first application of such devices would be more like a solar cell, power plant, backup generator etc. Putting a new device in car can take decades, but putting in these can be done much more quickly as the number of approvals needed is far few. Whenever, someone uses "car" where it is not justified, I know the innovation is most likely worthless showoff or it is decades away from practical use. Yes, one day all cars will run on fusion power. Thanks.

Re:why cars as the first application (0)

Anonymous Coward | about 7 months ago | (#46776427)

This is slashdot. We like cars. Maybe this will make them fly.
Nobody likes solar panels. Are you trolling? Yes that's it, you're trolling.
When you troll, usually it's in a boat. But for a full blown, drive by shooting you need a car. And a gun. But let's not get those folks involved.
If people start arguing about guns, i'll never get my flying car.

better peltiere devices (0)

Anonymous Coward | about 7 months ago | (#46773413)

I think this would be more likely to be quickly seen in Peltier devices... CPU heatsinks, car airconditioners.
Seeing as bismuth telluride has a ZT of 1.4, that's a 185% improvement of over common implementations today.

Hybrid Engine That Doesn't Power The Car? (0)

Anonymous Coward | about 7 months ago | (#46773455)

From TFA:

If anyone succeeds in producing a high-ZT material, Heremans says, it could lead to new, cheaper hybrid car engines in which the internal combustion engine doesn’t power the car, but rather generates heat that thermoelectric devices convert into electricity to power an electric motor.

This doesn't make sense to me. If the ICE isn't going to power the car, why not skip the engine and just burn the fuel to create heat, then thermoelectrics to turn heat into electricity?

Nasa RTGs would get the first benefit (0)

Anonymous Coward | about 7 months ago | (#46773497)

Any small improvement in efficiency would be best used in current RTG applications where the thermo couples are only about 30%. A 1KW heat source would produce an extra Watt for every percentage point increase.

Considering Republicans have already... (-1)

Anonymous Coward | about 7 months ago | (#46773521)

outlawed this and said they're going to put people that work with them in prison, why are we even talking about this? They are not going to allow this to happen. It goes against their anti-environment party position.

Eh. (1)

Ober66 (3618987) | about 7 months ago | (#46773675)

A high FoM on this compound but take that with salt. Thermoelectrics still have a long way to go and there are plenty of groups, called ZT hunters, looking for something that could be useful. The best TE, including the reported values here, are still not what we would consider efficient. Also, there are many ways to....'influence' the ZT for best results. Good for them; it's always nice to nab a Nature paper, but dont expect to see this impact any commerce. Unless you have a lot of TE micro-fridges in your car.

Cheap Solar Power (1)

nwaack (3482871) | about 7 months ago | (#46773707)

Why not use this in place of expensive solar panels? Sun + focusing device + black metal + thermoelectric = cheap electricity.

Because like standard panels (0)

raymorris (2726007) | about 7 months ago | (#46773949)

> Sun + focusing device + black metal + thermoelectric = cheap electricity.

With a four foot diameter focusing lens, you could almost power an iPod.
With a lens a mile across, you could power a house. Of course the lens would cost $XX million. Rather than "cheap electricity", this would be "outrageously expensive electricity".

> Why not use this in place of expensive solar panels?

Indeed, why not. The idea has a lot in common with typical c-Si solar panels: extremely expensive, and provides power for several hours per day, but only on sunny days. I bet you can get the government to give you half a billion dollars to start thinking about maybe someday producing them.

Re:Because like standard panels (0)

Anonymous Coward | about 7 months ago | (#46774307)

Luddite. Hard drives got better, therefore everything else will too. Especially when you put them in space. Then they really get better.

Piezoelectric cars? (0)

Anonymous Coward | about 7 months ago | (#46773779)

Given the bouncing fat asses in modern cars, perhaps their kinetic energy could be converted into electricity by piezoelectric components.

I for one welcome our Steam Overlords (1)

WillAffleckUW (858324) | about 7 months ago | (#46773825)

Oh, wait, isn't the energy density and storage ratio far lower than compressed air?

E = (T2-T1) / T1 (3, Informative)

Animats (122034) | about 7 months ago | (#46773857)

E = (T2-T1) / T1

Everyone with an engineering degree knows this. Trying to extract much energy from low-grade heat at the output end of an engine is inefficient. This was figured out a long time ago. Here it is in The Manual of the Steam Engine [google.com] . It's possible to increase steam engine efficiency by compounding, where the exhaust from each cylinder feeds a larger, lower pressure cylinder. This is cost-effective up to about 3 cylinders ("triple expansion"). Engines up to quintuple-expansion have been built, but the additional power from the last two cylinders in the chain isn't worth the trouble.

Re:E = (T2-T1) / T1 (0)

Anonymous Coward | about 7 months ago | (#46774167)

I don't disagree with your larger point, but technically speaking, getting anything out of waste cannot be called "inefficient". In this case, it simply does not add much to the total efficiency of the system.

Re:E = (T2-T1) / T1 (1)

Herder Of Code (2989779) | about 7 months ago | (#46774305)

Well, steam engines were *mostly* immobile and powering crap like pumps or press so yes it would not be less efficient. However in the case of a steam carriage, sorry I mean a car, the additional weight might actually make it *less* efficient.

Re:E = (T2-T1) / T1 (0)

Anonymous Coward | about 7 months ago | (#46775283)

You realize nuclear, coal, and natural gas fired powered plants are "steam engines" right?

Re:E = (T2-T1) / T1 (2)

joe_frisch (1366229) | about 7 months ago | (#46774349)

In mobile systems (cars, planes, etc), the extra hardware to extract energy from the waste heat adds weight and can reduce the overall efficiency of the vehicle. In fixed power-plant type applications they already extract energy down to pretty low discharge temperatures.

This idea has been around for a LONG time - I remember in the early 70s reading an article in popular science on a system to extract waste heat from car engines. It "worked" but the added weight and expense made it not worth the effort.

An interesting tidbit is that modern aircraft jet engines are LESS efficient than piston aircraft engines in terms of mechanical energy delivered for the fuel used. Almost all modern transport aircraft use jets because the power to weight is so much higher than for piston engines that the overall efficiency of the aircraft is better than with piston engines.

Could I use these to cool my data center? (1)

mmell (832646) | about 7 months ago | (#46774311)

Replace current refrigeration/cooling technology (essentially heat pumping or heat moving) with this - I get paid to provide cooling or refrigeration, not in cash but in Watts. Put in calories (which I wanted to get rid of anyhow), pull out watts.

And - no, I don't want to hear about perpetual motion. The only perpetual motion machine in the Universe is the Universe, and the jury's still out on that one.

Sounds fishy (1)

exploder (196936) | about 7 months ago | (#46774467)

they have used a cheap, well-known material to create the most heat-hungry thermoelectric so far

Did they do it with one weird trick discovered by a mom?

And they will fly too! (0)

Anonymous Coward | about 7 months ago | (#46774519)

I'm sure we will get this technology in cars right after we all get flying cars.

percentages (0)

Anonymous Coward | about 7 months ago | (#46775129)

Anyone have some percentages as to how much of the chemical energy of fuel gets turned into sweet, sweet electrical energy? If its anywhere near a ICE, we got a winner.

More distractions... (0)

Anonymous Coward | about 7 months ago | (#46776351)

We have cars that run on compressed air. If we REALLY wanted to end our dependence on fossil fuels, we'd have done so by now.

All this is, is another bullshit attempt to get us to believe we are actually looking for fuel alternatives. Meanwhile, the oil companies continue to shove their corporate cock up our ass and then laugh about it while vacationing with their families in the Bahamas.

Fuck this worthless research and fuck anyone who disagrees.

Mod me a toll, i don't even care. Truth is truth, regardless of ignorance.

there is no such thing as wasted heat (0)

Anonymous Coward | about 7 months ago | (#46776367)

The universe is dark and cold on average.
On average, I am a poor, Chinese female.
I am counting on you overclockers, you're our only hope.

Screw cars... cool/power my server room (0)

Anonymous Coward | about 7 months ago | (#46776553)

Anything that can take heat and turn it back into electricity for the machine room sounds good to me.

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