Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

New Thermocell Could Turn 'Waste Heat' Into Electricity

Soulskill posted about a year ago | from the my-laptop-is-now-a-free-energy-device dept.

Power 181

dryriver sends this quote from Phys.org: "Harvesting waste heat from power stations and even vehicle exhaust pipes could soon provide a valuable supply of electricity. A small team of Monash University researchers ... has developed an ionic liquid-based thermocell (abstract). Thermocell technology is based on harnessing the thermal energy from the difference in temperature between two surfaces and converting that energy into electricity. The new thermocell could be used to generate electricity from low grade steam in coal fired power stations at temperatures around 130C. This would be implemented by having the steam pass over the outer surface of the hot electrode to keep it hot while the other electrode is air or water cooled."

cancel ×

181 comments

Sorry! There are no comments related to the filter you selected.

WELCOME 20TH CENTURY !! WELCOME !! (0)

Anonymous Coward | about a year ago | (#44302417)

What went around comes around !!

Re:WELCOME 20TH CENTURY !! WELCOME !! (1)

crutchy (1949900) | about a year ago | (#44302729)

i guess you hold a bunch of patents for this technology already?

welcome to hindsight

Re:WELCOME 20TH CENTURY !! WELCOME !! (1)

ackthpt (218170) | about a year ago | (#44302851)

i guess you hold a bunch of patents for this technology already?

welcome to hindsight

Hindsite?!?

Of course! Patent beans to energy after they've been used for food!

TAANSTAFL! (2)

stevew (4845) | about a year ago | (#44302463)

How do you keep the other side of the item cool? The waste heat goes somewhere?

Re:TAANSTAFL! (1)

Farmer Tim (530755) | about a year ago | (#44302569)

From TFA:

This would be implemented by having the steam pass over the outer surface of the hot electrode to keep it hot while the other electrode is air or water cooled.

Re:TAANSTAFL! (0)

Nutria (679911) | about a year ago | (#44302861)

while the other electrode is air or water cooled.

But energy is needed to circulate the air or water. That requires energy, reducing (eliminating?) the efficiency of the thermocell.

Thus, TANSTAAFL.

Re:TAANSTAFL! (4, Informative)

Antipater (2053064) | about a year ago | (#44302991)

It's being circulated already in the power plant's existing cooling tower.

Re:TAANSTAFL! (0)

Anonymous Coward | about a year ago | (#44303063)

Rivers flow downhill they don't need help, if you are already next to one and use it for cooling purposes then it may not be free but it can be close to that. The issue is whether it is better than the alternatives such as a secondary turbine running of the waste heat, I have seen suggestions for non water/steam based turbines to add to normal power stations at the same stage.

Re:TAANSTAFL! (1)

MightyYar (622222) | about a year ago | (#44303269)

Your objection applies to any heat engine. If the temperature drop is high enough it justifies pumping the water.

Re:TAANSTAFL! (4, Informative)

Farmer Tim (530755) | about a year ago | (#44303317)

Let me introduce you to the convection cooled heatsink [jaycar.com.au] . No moving parts, powered entirely by the dissipated heat itself, it just has to have sufficient surface area for the job (and they scale up more easily than actively cooled systems).

Re:TAANSTAFL! (0)

jklovanc (1603149) | about a year ago | (#44303795)

A thermocell works by having a sharp temperature differential. Passive cooling does not cause a sharp temperate difference. Passive cooling also has a limitation as the surrounding air also becomes hot unless fans are used. Try running your computer without a case fan and see how long your passively cooled motherboard chip lasts.

Re:TAANSTAFL! (0)

adolf (21054) | about a year ago | (#44304119)

Let me introduce you to the convection cooled heatsink. No moving parts, powered entirely by the dissipated heat itself, it just has to have sufficient surface area for the job (and they scale up more easily than actively cooled systems).

It also requires sufficient thermal conductivity, and the presence of air, and freedom of air movement and a means to exchange heated air with lower-temperature air. Oh, and gravity.

Other than that: Yeah, as long as you've got enough surface area, they're really quite simple!

Re:TAANSTAFL! (1)

fustakrakich (1673220) | about a year ago | (#44302571)

Well yeah, you put the boiler on one side and a refrigerator on the other.

I would like to know if this is more efficient than your regular Peltier module..

Re:TAANSTAFL! (1)

ackthpt (218170) | about a year ago | (#44302631)

Well yeah, you put the boiler on one side and a refrigerator on the other.

I would like to know if this is more efficient than your regular Peltier module..

News at 5: Ocean water temperatures suddenly rise while middle America experiences heatwave and use Air Conditioners in record numbers, polar ice caps reduced to a few ice cubes.

Re:TAANSTAFL! (1)

ShanghaiBill (739463) | about a year ago | (#44302815)

I would like to know if this is more efficient than your regular Peltier module..

I think you mean Seebeck [wikipedia.org] . Seebeck is heat->elec, while Peltier is elec->heat. Seebeck generators are silent, compact and reliable, but they are also notoriously inefficient. They are much less efficient than a heat engine using the same temperature differential.

Re:TAANSTAFL! (3, Informative)

fustakrakich (1673220) | about a year ago | (#44302965)

I was under the impression that a Peltier could go both ways, and it uses the Seebeck effect for it

Re:TAANSTAFL! (0)

Anonymous Coward | about a year ago | (#44303273)

peltier can go both ways, you can get small peltier driven fans to put on top of a stove

Re:TAANSTAFL! (1)

camperdave (969942) | about a year ago | (#44303361)

The device is called a Peltier device because it is most used that way. Whatever it is called, it uses the Peltier effect to generate a heat differential from electricity, and The Seebeck effect to generate electricity from a heat differential.

Re:TAANSTAFL! (1)

fustakrakich (1673220) | about a year ago | (#44303655)

It appears the generic name I was looking for is 'Themoelectric effect'.

Re:TAANSTAFL! (1)

Anonymous Coward | about a year ago | (#44303705)

I was under the impression that a Peltier could go both ways

Peltier could go both ways, but he didn't.

Re:TAANSTAFL! (1)

dbIII (701233) | about a year ago | (#44304475)

I was under the impression that a thermocouple could go both ways, and uses the peltier effect when it's run backwards to produce a temperature difference :)

Re:TAANSTAFL! (1)

gl4ss (559668) | about a year ago | (#44302575)

earth cooling.. outside window, have a stream, have winter outside.. whatever.
though at 130c you could run a steam turbine too, no? and afaik that's more efficient than usual tec's(peltiers).

these new tec materials seem to pop up every few years. about 10 years ago there was some talk about something that could be put on the exhaust tubes of the car and have enough juice from that(being 10cm10cm slab) to run the AC in the car. haven't heard since nor seen it.. dunno if that one had some construction impracticalities.

Re:TAANSTAFL! (2)

leonardluen (211265) | about a year ago | (#44302667)

i believe the idea is that the exhaust from a steam turbine is still hot enough to collect additional electricity by using this.

Re:TAANSTAFL! (3, Informative)

Anonymous Coward | about a year ago | (#44303163)

Exhaust from a steam turbines are on the order of 40-50 C. This works because the condenser actually operates in a vacuum (created from the thousand-fold volume decrease from steam to liquid water). And this makes more sense than wasting steam (since you would want to condense it anyways to save water).

Really, there is no magic technology with thermoelectrics. And with any heat engine, what matters is the delta-T and entropy. Unless you waste water, you are bound by the Carnot cycle. And anybody who has worked with steam knows that things like pulling extraction steam or main steam and using it in reheaters, as well as preheating your feedwater will give a shitload more efficiency gains than worrying about fucking with the ends of your LP turbines.

Re:TAANSTAFL! (0)

Anonymous Coward | about a year ago | (#44302599)

It's cooled by water in a cooling tower, or just by external air. If you don't install the thermocell, that's where the heat will end up anyway.

Re:TAANSTAFL! (0)

Anonymous Coward | about a year ago | (#44302611)

The same way engines or thermoelectric generators are kept cool.

Re:TAANSTAFL! (2)

luckytroll (68214) | about a year ago | (#44302697)

I could totally use a version of this - I would wrap it around the exhaust riser on the diesel, and then cool the other side with incoming cooling seawater before it entered the cooling heat exchanger. The difference would be 400C inside vs 22C outside, and might be able to generate some more energy from the waste heat.

I also considered running ammonia through this hot spot and making it an adsorption refrigerator, but that can generate some interesting (chinese) pressures, which can be a hazard.

Of course, normal folks just put an alternator on... but why be normal!

Re:TAANSTAFL! (1)

c-A-d (77980) | about a year ago | (#44303339)

In a car, as long at it is moving, you have a good source of cooler air and even on the hottest of days, you're probably looking at a 70C temperature difference which could still yield some energy, even if its used to reduce the load from the alternator and run the ignition system.

Re:TAANSTAFL! (1)

FatdogHaiku (978357) | about a year ago | (#44303363)

What do you think those snow covered volcanoes are for? Fill up some reservoirs and cut down on the lahars danger all while getting our juice... of course we could end up with some pissed off Yeti...

Re:TAANSTAFL! (0)

Anonymous Coward | about a year ago | (#44303713)

How do you keep the other side of the item cool? The waste heat goes somewhere?

TANSTAFL means There Ain't No Such Thing As a Free Lunch. But this isn't about getting something for free; the heat was created by burning fuel or by friction. This is about recapturing it. That heat was being removed by something anyway. Maybe air flow, maybe cooling water. This would allow some of that heat to be recaptured and turned into electricity. It doesn't invent energy from nothing, it just converts it.

Cost/Benefit Analysis? (0)

Anonymous Coward | about a year ago | (#44302465)

How do they plan on keeping the air or water cool? Sounds like a net energy loss.

Re:Cost/Benefit Analysis? (4, Informative)

icebike (68054) | about a year ago | (#44302881)

Net energy loss is what you already have today.

Drive your car down the road, and your exhaust is always hotter than the ambient.
Run your exhaust thru this device, and you can recapture some of that existing loss to power your car's Air Conditioning.

This isn't the only research looking for such technology:
http://phys.org/news/2011-05-high-performance-bulk-thermoelectrics.html [phys.org]

Re:Cost/Benefit Analysis? (1)

crutchy (1949900) | about a year ago | (#44303049)

Sounds like a net energy loss

this kinda should be obvious, but the technology uses waste heat, which means the energy is normally completely lost anyway. even harnessing a small amount of it is more efficient than just letting it be completely wasted. after all you aren't producing heat specifically for this technology... the heat has already been produced for some other application (such as exhaust heat being generated originally to power the crankshaft of a car engine).

i could definitely see use for this in the power industry, where there is usually huge cooling towers designed to condense steam passing through a turbine circuit by only a few degrees and in the process huge quantities of fresh cooling water gets evaporated into the atmosphere. in an age where both energy and potable water is in demand, any technology that can reduce the quantity of cooling water evaporated in cooling towers whilst simultaneously generating much needed useful energy, has to be a good thing.

my only reservation is where the technology sits in the spectrum of power generated, because if like solar, wind, geothermal etc it requires massive infrastructure investment for a relatively small payoff compared to coal and nuclear base load generators, it will only serve to share the same niche as other renewables. if on the other hand you can generate significant amounts of electricity with reasonable investment it will have a much better chance at widespread adoption.

the usual problem with any renewable energy sources is that whilst the energy may be "free" from the sun or wind or whatever, there is still a cost of development, construction and maintenance for the generators themselves and the infrastructure connecting the generators (such as massive amounts of cabling required for large wind farms). proponents of renewable energy often simply don't realize just how much power comes out of the large fossil fuel base load stations that they hate so much. one lignite power station with four units can generate in excess of 2000 MW. according to wikipedia (http://en.wikipedia.org/wiki/Wind_turbine#Records) the largest wind turbine in current operation is about 7.6 MW, so you would need 264 of these just to replace a single 2000 MW base load coal-fired power station, and that's assuming all wind turbines are generating at their full capacity 24/7, which is never the case. similar for solar, which only works during the day... you would need to cover huge areas of land at great expense to replace a single existing base load station. so whilst these monash researchers may not be doing anything as cool as mr fusion on back to the future, making the most of existing base load infrastructure by increasing its efficiency is helping to work towards a short term solution to a long term problem. its all well and good to say that we will aim to reduce emissions by 2020, but these guys are actually working on it rather than just talking about it.

Re:Cost/Benefit Analysis? (-1, Flamebait)

Waffle Iron (339739) | about a year ago | (#44303159)

How do they plan on keeping the air or water cool? Sounds like a net energy loss.

You know what? You're right!

Heads are going to roll at this university when the funding providers find out that not one of the so-called "academics" in this department had even thought of that problem. It's sad that it took a sharp-eyed AC to point out that all their efforts have been for naught.

Plans announced to install in Washington DC. (5, Funny)

Anonymous Coward | about a year ago | (#44302475)

Greatest source of hot air in the country. Expected to solve the energy crisis.

Re:Plans announced to install in Washington DC. (2)

MightyYar (622222) | about a year ago | (#44303399)

But then the whole town would become USEFUL, and that would create a paradox that would tear space time apart.

Little known fact (2)

fustakrakich (1673220) | about a year ago | (#44302527)

We already suffer a glut of energy [oregonlive.com] , but I suppose this might serve as a nice little accessory for your backyard distillery...

Re:Little known fact (0)

Anonymous Coward | about a year ago | (#44302731)

Little known fact We already suffer a glut of energy

Your says at some times in one power grid, there may be too much energy. That's nothing like what you're trying to pretend.

Re:Little known fact (1)

khallow (566160) | about a year ago | (#44302805)

The US Northwest and its analogue, British Columbia on the Canadian side are large exporters of power to elsewhere in the US. If they're reporting excess power, then that's an indication that a large portion of the US is experiencing that condition over the time period in question.

Re:Little known fact (4, Informative)

ShanghaiBill (739463) | about a year ago | (#44302931)

We already suffer a glut of energy [oregonlive.com]

A temporary and localized surplus is not what "glut" usually refers to. Hydro-power surpluses from spring rain have been around as long hydro-power. That is not proof that we have too much capacity.

Re:Little known fact (2)

fustakrakich (1673220) | about a year ago | (#44303081)

Capacity we have plenty of, just like food and water and everything else. Distribution and who's in control are the outstanding issues that need to be dealt with.

Re:Little known fact (1)

MightyYar (622222) | about a year ago | (#44303445)

Not only that, with energy you need a "glut" all the time so that you can handle unexpected shutdowns, demand spikes - or for hydro - droughts. Just like our food supply, we certainly don't want shortages.

Re:Little known fact (2)

Rob Bos (3399) | about a year ago | (#44302977)

Odd that they wouldn't use the excess electricity to pump water up into a storage reservoir for future generation. That's what BC Hydro does.

Re:Little known fact (1)

fustakrakich (1673220) | about a year ago | (#44303101)

It's all about the commodities market and pricing, very little to do with energy per se.

Re:Little known fact (1)

kaatochacha (651922) | about a year ago | (#44304285)

When I first read this, I thought you said "future generations", and I thought "Will the water really last that long?"

Re:Little known fact (1)

turp182 (1020263) | about a year ago | (#44304049)

That story was for 2012 (posted in April of 2012), there's no mention of 2013 conditions. Just FYI.

I don't know the current conditions (a great pun actually, hydro power).

Next big thing (0)

Anonymous Coward | about a year ago | (#44302533)

The idea to use the Seebek effect and generate power from temperature differentials is centuries old, the only problem is it's very low efficiency in the 10 % range. A gas turbine can achieve 50% efficiency, while a nuclear reactor steam turbine is about 33% efficient, heat to electrical. So an efficient method to directly extract electricity at high efficiency would revolutionize power generation.

Re:Next big thing (1)

camperdave (969942) | about a year ago | (#44303457)

Considering the Seebek effect was only discovered in 1821, the idea is not centuries old.

Hmmmm (2)

rossdee (243626) | about a year ago | (#44302589)

Did Congress repeal the Laws of Thermodynamics?

Re:Hmmmm (4, Funny)

AliasMarlowe (1042386) | about a year ago | (#44302723)

Did Congress repeal the Laws of Thermodynamics?

Yes. And because that makes us all criminals now, it means the NSA snooping is quite legitimate...

Re:Hmmmm (1, Interesting)

Farmer Tim (530755) | about a year ago | (#44302995)

No. If you have a machine that's 50% efficient, where does the other 50% of the energy go? That's right, heat. If you can recover 10% of that heat as electricity, your machine is now 60% efficient. Even if you could recover the theoretical 100% of the waste heat the total energy efficiency is still only 100%, so it doesn't violate the laws of thermodynamics.

Re:Hmmmm (1)

Anonymous Coward | about a year ago | (#44303149)

Even if you could recover the theoretical 100% of the waste heat the total energy efficiency is still only 100%, so it doesn't violate the laws of thermodynamics.

Sure it does. Otherwise you just invented the perpetual motion machine.

Re:Hmmmm (0)

Farmer Tim (530755) | about a year ago | (#44303405)

Hence the word "theoretical". No machine can ever be 100% efficient in practice.

Re:Hmmmm (0)

Anonymous Coward | about a year ago | (#44303569)

Theoretically you can't even get close to 100% efficient use of the waste heat, otherwise you would end up with a perpetual motion machine like the previous post said. If you could beat the Carnot cycle efficiency for a given temperature difference, you could combine your device with a less than ideal heat pump and create a setup that produces useful work without any net movement in heat.

Re:Hmmmm (2)

mattack2 (1165421) | about a year ago | (#44303209)

Wait, if you're recovering 10% of the heat, you're recovering 10% of the 50% 'wasted'. So you're really only 55% efficient in total.

Re:Hmmmm (1)

Farmer Tim (530755) | about a year ago | (#44303385)

You're absolutely correct, thanks for pointing out my error.

Re:Hmmmm (0)

Anonymous Coward | about a year ago | (#44303675)

But how much more heat do you generate by carrying this device around? i.e. the extra weight of the device requires you to spend more energy which generates more heat.

Re:Hmmmm (0)

Anonymous Coward | about a year ago | (#44303755)

try that math again...10% of 50% is only 5% of the total = 55% efficient

Re:Hmmmm (1)

Greyfox (87712) | about a year ago | (#44303471)

Thermodynamics is OK with it as long as you don't get more energy out of it than you put into it. Anywhere you have a thermocline you can derive work from the differential... until the two two sides equalize in temperature. If you pump a lot of energy into one side, it gets hotter and you can get more work out of it. The other side will get hotter as a result. Eventually it will stop working again. You'll also get decreasing amounts of power out of it as the two sides equalize.

If you're considering trying to harvest energy from a car's exhaust heat this way, it would generally be more efficient to just not make all that hot exhaust in the first place by using electric motors instead or something.

Knowing how these things usually go, I'm guessing this technology won't end up being cost effective. That's the impediment for most of these fringe power generation ideas. Yeah, you can get a little work out of it, but the system costs so much to install that you're better off just sticking with what you have.

Re:Hmmmm (1)

davesays (922765) | about a year ago | (#44304169)

No, the executive branch just selectively enforces it....

Nuclear steam (1)

dadelbunts (1727498) | about a year ago | (#44302591)

I would love to see how this would work on a nuclear power plant. Since they seem to put out alot of steam this should provide a sizeable increase in power output. And the best, cleanest source of energy we have, would get even better.

Re:Nuclear steam (0)

Anonymous Coward | about a year ago | (#44302705)

They already use that steam. Often they take it (that steam) and use it to pre-heat the incoming cold water, through heat exchangers. This makes the entire process more efficient. While there could potentially be an increase in power with these new devices, from reading the article there is no way it is economically efficient.

Re:Nuclear steam (0)

Billy the Mountain (225541) | about a year ago | (#44303005)

Eliminating Steam from a Nuclear Reactor is totally feasible. Probably the most economical way to do it is a Brayton Cycle system:
http://en.wikipedia.org/wiki/Brayton_cycle [wikipedia.org]

This has the great advantage of eliminating the high-pressure and associated containment requirements that efficient steam turbines require. Plus it's probably much more efficient than what's being described here.

Re:Nuclear steam (5, Informative)

gewalker (57809) | about a year ago | (#44303309)

For efficient conversion of heat to you MUST have high temps. Modern pressurized water nuclear reactors run at about 150 atmospheres -- corresponding temperature of 315 C / 600 F. There is no way to avoid this with liquid water as the working fluid. Contain 150 atmosphere of pressure at all times dominates the design of the reactor. Some newer designs use different working fluid. E.g. a LFTR reactors (drawing board only) using a Brayton cycle based on helium or nitrogen gas and a 700 C temperature source -- no high pressure used in the the nuclear vessel.

Also look at the design of the power generation cycle in a power plant. There is a relatively small high-temperature turbine that generate 2/3 of the electricity and a much larger secondary turbine that generates 1/3 of the electricity. The lower-temp output of the first turbine is the input for the 2nd turbine.

Re:Nuclear steam (3, Interesting)

nojayuk (567177) | about a year ago | (#44303831)

The most efficient nuclear power stations in operation today are the Advanced Gas-cooled Reactors (AGRs) in the UK. They use CO2 as a coolant circulating through the carbon-moderator core at over 600 deg C with a generating efficiency of about 41% conversion of thermal energy to electricity compared to steam-moderated PWRs at about 34%. The low cost of uranium fuel per kWh generated means the extra efficiency doesn't help that much in terms of price of electricity generated or operating costs.

Whats the efficiency? (0)

Anonymous Coward | about a year ago | (#44302593)

This sort of thing is nothing new. They might have a new way of doing it. Funny how the efficiency is not mentioned.

Re:Whats the efficiency? (0)

Anonymous Coward | about a year ago | (#44302751)

From the Abstract:
"Power densities reached >0.5 W m2 in unoptimized devices, operating with a 130 C hot side. "

So apparently it generates 50 watts per square meter on a temperature drop of about 100 degrees (assuming the cold side is room temperature or about 25-30C).

Re:Whats the efficiency? (1)

cyclopropene (777291) | about a year ago | (#44302963)

From the Abstract:
"Power densities reached >0.5 W m2 in unoptimized devices, operating with a 130 C hot side. "

So apparently it generates 50 watts per square meter on a temperature drop of about 100 degrees (assuming the cold side is room temperature or about 25-30C).

I gather that 50 is indeed >0.5, but I'm not sure how you go from ">0.5 W M^-2" in the abstract to 50 watts per square meter. It's half a watt per square meter, which is pretty poor.

Re:Whats the efficiency? (0)

Anonymous Coward | about a year ago | (#44303053)

He thought it meant 0.5 watts per square meter per degree of temperature difference.

So many problems! (1)

Anonymous Coward | about a year ago | (#44302633)

(With TFA.)

Harvesting waste heat from power stations and even vehicle exhaust pipes could soon provide a valuable supply of electricity.

Value is relative. $1 says the value of the electricity produced doesn't come close to what is needed to produce the widget. I'm guessing here, of course, because TFA doesn't say how much electricity it can produce.

PhD student Theodore Abraham said that by using heat already produced in industrial processes that would otherwise be untapped, the thermocell is an attractive method of relieving some of the present reliance on fossil fuels.

See above, cf. the well-known phrase "pissing in the sea".

"We have found that it can work at elevated temperatures typical of important heat sources, as opposed to water-based systems, which cannot operate at temperatures above 100 degrees Celsius," Professor MacFarlane said.

This was either written by one of that new breed of marketeers that infest educational institutes or the good professor has never heard of superheated steam. Please, God, let it be the first one.

"The major benefit of a thermocell is that it harnesses energy that is already readily out there; you're just harnessing energy that is otherwise lost to surroundings," Mr Abraham said.
Mr Abraham was supervised by Dr Jenny Pringle of Deakin University who said the development was a significant achievement for a PhD student.

Maybe where he works. The last place I worked that had steam plant used the waste heat to... heat the buildings and provide hot water. Still, it is an impressive achievement for a student. It's just a shame that the article was so over-inflated.

tl;dr It's a novel variation on the classic thermoelectric generator, but neither the article nor the abstract say how well it works.

Re:So many problems! (0)

Anonymous Coward | about a year ago | (#44303219)

The abstract says half a watt per square meter of electrode, given 130-degC waste heat.

Re:So many problems! (0)

Anonymous Coward | about a year ago | (#44303427)

Fair enough. Scratch the "I'm guessing" and the tl;dr parts. I stand by the rest.

Re:So many problems! (0)

Anonymous Coward | about a year ago | (#44303745)

This was either written by one of that new breed of marketeers that infest educational institutes or the good professor has never heard of superheated steam. Please, God, let it be the first one.

Or the third option: you've misunderstood what they are referring to. Solutions of electrolytes can be very strong thermoelectric materials and can easily display Seebeck coefficients more than twice advance solid materials. However, those solutions are limited to temperatures of around 100 C for use as a thermoelectric device, way below what is typically needed for reasonable efficiency. Here they are using an ionic liquid [wikipedia.org] which has a much higher boiling point than water or other organic solvents commonly used for electrolyte based thermoelectrics. The 100 C limit is not the limit of the heat source, but of the conversion device when the conversion device is based on water (and there is not much room, in terms of volume or efficiency, for running much higher pressure).

Wrong problem (2, Insightful)

jklovanc (1603149) | about a year ago | (#44302635)

The electricity issue is not a generation issue. We have enough technology to produce more electricity that we need. The problems we have are transmission , storage, and reliability. While we can produce much more energy than we need the challenge is to store it for when we need it, transmit it to where we need it and to be sure that it will not fail. For example, solar farms in the Sahara desert could power all of Europe. The issue is transmitting that power to Northern Europe and storing enough power to last the night. While Some HVDC line are being installed it is not enough to get that power to Germany and north.

Re:Wrong problem (0)

Anonymous Coward | about a year ago | (#44302693)

Um, OK. If you say so.

OR we could increase the efficiency of our current power plants and therefore not have to waste as many resources.

But to each how own, I guess.

Re:Wrong problem (1)

glenebob (414078) | about a year ago | (#44302777)

Yeah sure we can generate plenty of electricity. Just toss up another coal fired plant. Yay.

I'm thinking solar. If this technology, coupled with tracking solar concentrators, can be done more cost and radiation efficiently than current solar technologies, then it may be a huge win.

Re:Wrong problem (1)

museumpeace (735109) | about a year ago | (#44302961)

yep. you're on a better track than the author of TFA who felt a need to mention coal.

Re:Wrong problem (4, Insightful)

jklovanc (1603149) | about a year ago | (#44303325)

Solar does not work well during nigh or storms or at high latitudes. That is what I mean by the storage/transmission issue. Sure the Sahara can generate more solar electricity than we need. Getting to where and when we need it is a different story.

Re:Wrong problem (1)

Anonymous Coward | about a year ago | (#44304367)

Hello, they've already figured out how to run solar power plants at night.

http://en.wikipedia.org/wiki/Andasol_Solar_Power_Station

This was also tested in the USA and it "just works". Everything is off-the-shelf, no new inventions or unobtanium required.

Re:Wrong problem (2)

jklovanc (1603149) | about a year ago | (#44303719)

I'm thinking solar. If this technology, coupled with tracking solar concentrators,

How do you keep the cold side cool? The thermocell works on temperature differential. Keep anything in the sun and it will become evenly hot. I think cooling the back side will take more energy than the cell will produce.

Re:Wrong problem (0)

Anonymous Coward | about a year ago | (#44302847)

You're wrong, the only thing we really have problems with is storage. smaller more localized nuclear power is readily available, it's just the kooks and NIMBY's who prevent it. As soon as the public interest grows a set of balls or pays high enough electric bills, the kooks and NIMBYS will continue to win because they are the vocal minority.

Thermoelectric Power (2, Informative)

Anonymous Coward | about a year ago | (#44302651)

Thermoelectric power has been around for a long time. There is, literally, nothing new about this. The efficiency is still not high enough to make it worthwhile for any sense of scale. They are better off using waste heat the way they currently do, to heat up the incoming cold fluids that get turned to steam through heat exchangers.

On cars, you do not get enough power out of the current materials to make it worthwhile.

Discrepancy between the press release and abstract (1)

DRJlaw (946416) | about a year ago | (#44302687)

The press release: ""The device offers the possibility of a cheap and flexible design suitable for harvesting waste heat in the 100- to 200-degrees Celsius range."

The abstract: "Power densities reached >0.5 W*m-2 in unoptimized devices, operating with a 130 C hot side."

For half a watt per square meter had better be incredibly cheap and flexible considering wind and solar [azimuthproject.org] are about 4 and 10 times more dense, respectively, on a real-world basis. Nevermind that gains in optimization must be offset by losses in building a system which can pass cooling water over a large surface area and delivering the cooling water to it.

Re:Discrepancy between the press release and abstr (1)

khallow (566160) | about a year ago | (#44302909)

I imagine the idea is that you have a profitable process that generates waste heat. If this becomes cheap enough, it'd be a way to make a few more nickles on what you already have.

Peltier effect? (1)

Hadlock (143607) | about a year ago | (#44302709)

How different is this from existing Peltiers? Peltiers were all the rage back in the Celeron 300A days, but the amperage output is minimal at best.

Re:Peltier effect? (2)

SteveAstro (209000) | about a year ago | (#44302789)

Peltiers manage around 5% conversion efficiency.

Bullshit... (0)

Anonymous Coward | about a year ago | (#44302717)

We've had the ability to turn waste heat into electricity for decades. From complex like the stirling engine. To simple like the thermocouple.

We're not going to do it. Why? MONEY!

World is run by cheap greedy fucks. And these solutions all cost money to implement. You know what doesn't cost money (right now)? Dumping the waste heat to the air.

Re:Bullshit... (1)

khallow (566160) | about a year ago | (#44302979)

The key is that they cost money rather than make money to implement. One doesn't have to be a "cheap greedy fuck" in order to want solutions to yield more value than they cost.

Units (0)

Anonymous Coward | about a year ago | (#44302749)

Are the units on that graph right? 15,000 gigawatts sounds high for renewable energy generated in just the northeast...

How About Home Use? (1)

LifesABeach (234436) | about a year ago | (#44302871)

How about placing ionic liquid-based thermocells on a home roof? Then wire the output to the "Electricity Grid?"

I just wish I could write a Grant for this. It sounds like a "cool" project.

Comparison (1)

Anonymous Coward | about a year ago | (#44302901)

This Technology: 0.5W per square meter
Solar Irradiance on Earth: 1361W per square meter [wikipedia.org]

coal? (1)

museumpeace (735109) | about a year ago | (#44302925)

Oh please. With such lop sided support for the notion we might already have enough carbon in the air,why not apply this to low-grade heat differentials in
* oceans
* buildings in sunny places like the parched SW US states
* my freakin' roof [and that is in upstate NY]


but first, please headline the INSTALLED $/Watt. we can take it from there...or not.

or did some coal company pay for this finding?

first 4ost (-1)

Anonymous Coward | about a year ago | (#44303093)

EFNet serversP. [goat.cx]

Will it work as a heat-sink? (1)

medv4380 (1604309) | about a year ago | (#44303477)

If only it could be used to cool off a CPU and generate a bit of excess energy to power misc. devices.

Throwing the NOT flag here.... (3, Interesting)

bobbied (2522392) | about a year ago | (#44303697)

Without going too deep into a lesson on thermodynamics, there is not going to be much chance that this works in a modern power station.

Let me put it this way. Current power stations are already engineered to be as efficient as possible. This generally means they are keeping the phase translations of the working liquid using the minimum temperature differentials possible to avoid entropy loss over the ideal Carnot cycle. Any thermally driven power producing device put in series with the heat exchangers is not likely to capture any more power than will be lost by the increased temperature differential required by the device. If this wasn't true, why don't we just attach a boat load of sterling heat engines (http://en.wikipedia.org/wiki/Stirling_engine) to do the same thing? Reason: It wreaks the efficiency of the power plant by making the temperature differentials higher.. Chances are this new idea has the same problem.

Now, on your car, or other internal combustion engines, there *might* be some application, but I don't think there will be enough power output to make up for the weight increase. There is a HUGE amount of waste heat from your car engine but the question is how efficiently can we capture that and make useful energy out of it? Answer: Not very... Worth looking at because of the amount of heat being just dumped and the high differential temperatures but not likely to be much gain overall.

Mod parent up (4, Informative)

Animats (122034) | about a year ago | (#44304205)

Right. What we have here is another crap materials science article. Somebody did something vaguely interesting at lab scale, and then issued a bullshit press release.

Trying to get the last remnants of recoverable energy out of a heat engine is an old game, going back to the reciprocating engine era. Basic steam engines had one cylinder running off boiler pressure. Double-expansion steam engines had a second cylinder running off the output of the first. The second cylinder is bigger and runs at lower pressure. Triple expansion steam engines had a third, even bigger cylinder. Some quadruple expansion engines were built, but this is a diminishing-returns thing, and triple expansion is about as far as it's worth going economically. Marine engines were often triple-expansion.

Large steam turbines do the same thing, with a succession of rotors of increasing size. Three to twelve stages have been used. Again, this is a diminishing returns thing. At some point the steam condenses to water, which you don't want to happen inside the turbine. Existing turbines get close to that limit. Some turbine plants have a partial vacuum going into the condenser to keep the steam as a gas below 100C. 90C exit temperatures are not uncommon. Almost all of the usable energy has been extracted with an exit temperature like that.

If this new thermoelectric thing is a better way to convert heat to electricity than a steam turbine, it should replace steam turbines, not just be used on the cold end of the system. An efficient solid-state way of converting heat to electrical energy would be valuable. All the existing thermoelectric devices have low efficiency compared to heat engines. Back around 2011, there were several startups [bloomberg.com] getting Federal grants for R&D into "heat harvesting". Commercial products were supposed to appear in 2012. Didn't happen.

Coal, yay! (0)

Anonymous Coward | about a year ago | (#44303789)

So glad scientists are finding ways we can make more effective use of coal. Because, for my money, we can never burn enough coal. Mmm, coal - nothing better!

Hunting / Camping (0)

Anonymous Coward | about a year ago | (#44303809)

Hell, I've been using a thermocell when hunting and camping.

http://www.thermacell.com/mosquito-repellent

It's always been possible (2)

Solandri (704621) | about a year ago | (#44304177)

Extracting usable work energy from waste heat has always been possible [wikipedia.org] . The problem isn't making the heat do work. The problem is doing so cost-effectively. For most applications, these heat capture devices have such low power densities that it's counterproductive to add them (e.g. adding a stirling engine to your ICE car's exhaust system would burn more fuel due to the extra weight than the fuel savings you'd get from putting the heat energy to work). At that point, it's not worth implementing compared to just dumping the heat straight into a heat sink.

The abstract says they're getting power densities of 0.5 Watts/m^2 in an unoptimized device. That's pretty deep in "not worth it" territory. This device would have to have an area of 1,5000 square meters exposed to the car's exhaust gases just to generate 1 extra hp. I suspect the additional back-pressure alone from all that piping (never mind the weight) would cost the engine a lot more than 1 hp of generation capacity.
Load More Comments
Slashdot Login

Need an Account?

Forgot your password?

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>