Experimental Device Generates Electricity From the Coldness of the Universe (phys.org) 129
An anonymous reader quotes a report from Phys.Org: An international team of scientists has demonstrated for the first time that it is possible to generate a measurable amount of electricity in a diode directly from the coldness of the universe. The infrared semiconductor device faces the sky and uses the temperature difference between Earth and space to produce the electricity. In contrast to leveraging incoming energy as a normal solar cell would, the negative illumination effect allows electrical energy to be harvested as heat leaves a surface. Today's technology, though, does not capture energy over these negative temperature differences as efficiently. By pointing their device toward space, whose temperature approaches mere degrees from absolute zero, the group was able to find a great enough temperature difference to generate power through an early design.
The group found that their negative illumination diode generated about 64 nanowatts per square meter, a tiny amount of electricity, but an important proof of concept, that the authors can improve on by enhancing the quantum optoelectronic properties of the materials they use. Calculations made after the diode created electricity showed that, when atmospheric effects are taken into consideration, the current device can theoretically generate almost 4 watts per square meter, roughly one million times what the group's device generated and enough to help power machinery that is required to run at night. By comparison, today's solar panels generate 100 to 200 watts per square meter. The study has been published in the journal Applied Physics Letters.
The group found that their negative illumination diode generated about 64 nanowatts per square meter, a tiny amount of electricity, but an important proof of concept, that the authors can improve on by enhancing the quantum optoelectronic properties of the materials they use. Calculations made after the diode created electricity showed that, when atmospheric effects are taken into consideration, the current device can theoretically generate almost 4 watts per square meter, roughly one million times what the group's device generated and enough to help power machinery that is required to run at night. By comparison, today's solar panels generate 100 to 200 watts per square meter. The study has been published in the journal Applied Physics Letters.
uhm... (Score:1)
Point one side at space, and the other at our sun?
Re:uhm... (Score:5, Insightful)
It doesn't work like that; there is only one "side" that can be pointed, the other side is physically coupled to a heat source.
The amount of cooling isn't going to exceed what you'd get with a sheet of black paint; Earth is hotter than space, and a few photons will be emitted at night because of the temperature difference. Basically, a tiny tiny amount of infra-red light is created. This is the same as when you get something hot and it glows, aka infra-red cooling.
The clever part is just to force it out through a diode so that they can make that photon push some electrons in a circle as they exit. It's like a cross between a tea pot, a flash light, and a windmill.
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But with all that i don't see a reason, why the heat source couldn't be the focal point of a parabolic mirror pointed at the sun.
OTOH a solar panel would probably be more efficient ... incidentally a solar panel works based on just the p-n transition of a diode, and they also need to get rid of "waste heat".
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That's effectively what solar panels in space do. One side pointed at the sun, the other side pointed away from the sun (in the form of a radiator).
On the surface, if you've got a heat source, convective cooling by the atmosphere or water is much more effective, so there'd be no point. But if your heat source is the ambient heat of the atmosphere you could use radiation to space as your heat sink.
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There's a wall coating that does the same trick (Score:5, Interesting)
Paint a wall, the coating beams heat to outer space and becomes cool. https://science.sciencemag.org... [sciencemag.org]
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Radiometer, Peltier Junction just ot name 2 (Score:1, Insightful)
Stirling engine for another, Really what is new here ? They derived electric power from a temperature difference rejecting heat into a reservoir. Only what every engine ever built has done.
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Dude! 4 watts per square meter, eventually. Think big.
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If you are living in a desert whee it cools rapidly at night, 4W per sqm does not sound bad. ... hm, that basically was it, it would be free energy over night.
The house of my wife in Thailand has estimated 220sqm wall surface plus something like 200 sqm roof. That would be 800W constant energy production over night. Considering that we only have the fridge running, a few LED lights, my Laptop
Depending where you live and what you do, and how energy saving is proceeding, 4W per sqm is not that bad.
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Wrong on all marks ... it is not a heat engine and it is not using a reservoir ...
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You're an idiot, you were born an idiot and you will die an idiot, and it's really not even worth the effort to say this to you.
But it is worth the laugh to see my friend from the country where it never rains, doesn't get dark but everyone is in bed by 8 again.
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You have a bad memory.
It hardly rains between October and Februar.
It is a certain region, and not a country.
And yes, most people living rural go to bed early ... which you clearly can see when you either "know them" or drive with the car through the town and see: no one has TV on or lights on. As most people get up around 5:00 - 6:00 in the morning, I guess they sleep early :P
But as you can not remember simple things like certain periods of a year and certain regions which are not countries ... you seem to
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Truly it's never you.
as a power generation method it's hilarious (Score:2)
you could make more electrical power with a heat engine with cold sink buried a few feet below ground... why do they bother?
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TFS left me thinking "this sounds like the shittiest geothermal power imaginable"
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So you don't see that 'solar power at night' is something of a breakthrough it its own right?
Doesn't mean that there aren't 'better' solutions in some (even most) circumstances, but if we only ever looked at the easiest generator, we'd never have produced solar panels, and might still be wondering how to power satellites...
Rgds
Damon
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... And were hopeless for almost all but the most exotic use cases until very very recently. Now 'suddenly' they are in may places the cheapest source of utility electricity. Which means it's worth continuing to look at the non-obvious ones like in TFA rather than rejecting them off-hand. Which was my point.
Rgds
Damon
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The value of power at night (esp in warm nights when a/c may be needed) is likely to remain relatively high, since it complements normal solar, and solar is getting really really cheap so that excess order of magnitude may well be affordable in the interim, eg as replacement for peaking power in the time just after sunset where there is still peak demand.
Highly/perfectly anti-correlated (renewable) power sources are potentially very valuable for balancing and security of supply.
Rgds
Damon
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esp in warm nights when a/c may be needed
Heat/cold storage is your friend. Freeze water.
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We simply don't have enough space (or appropriate terrain) for the pumped storage we'd need in many places.
For example, we'd have to flood quite a lot of Scotland and the Lake District of the north of England to cover the benchmark 5-cold-dark-windless UK days never mind interseasonal storage. The people in those places would object to the proposed flooding.
Flatter places don't even have those options.
Storage is good, but getting 'enough' is hard.
Being able to generate at time of demand from a combination
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We simply don't have enough space (or appropriate terrain) for the pumped storage we'd need in many places. For example, we'd have to flood quite a lot of Scotland and the Lake District of the north of England to cover the benchmark 5-cold-dark-windless UK days never mind interseasonal storage. The people in those places would object to the proposed flooding.
I'm pretty sure that the north of UK has massive pumped storage potential. A global survey has recently demonstrated that. [anu.edu.au] If you want, you can extract UK data from this list [dropbox.com]
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Simply not the case AFAIK.
We have about 1GW of potential new run-of-river type non-storage hydro. Though as the co-owner of a scheme torpedoed by NIMBYs (and two that happened), I can tell tell you that that is pretty theoretical.
But storage? I know of a few 100MW by power. We'd need ~20GW+ power and that backed up by days to months as above of storage. That's a LOT of water.
As I say, if you're prepared to flood a *lot* of new pretty and partly occupied valleys, lots may be possible theoretically, but t
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The Chief Scientific Advisor of the UK's energy minister disagreed with you, and he might possibly have access to better (and non-public) data.
Rgds
Damon
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OK, I hear you.
But Prof MacKay's views are not very old either, and he will have had access to things that you and I and probably ANU don't about the UK, and the geography hasn't changed much in that time.
Another point (possibly better on another thread of our discussion, but I'm meant to be working!) is that almost Mackay's last email (he died of aggressive cancer fairly recently) was that he was going off wind and sun because they don't help at really key points in winter in the UK, and I suspect that thi
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Again, thank you. I'll take a read,
I'm not hopeful on this front because everyone here in the UK involved in energy I think knows that storage at scale would be a complete game changer, and our grid operator, ministers, their official advisors (CCC), etc, are not talking about it, eg:
https://theenergyst.com/nation... [theenergyst.com]
(More relatively-small rapid-response storage for frequency management and some behind-the-meter distributed storage definitely *is* on the cards.)
Rgds
Damon
Not sure if that's a parody (Score:2)
I'm not sure if that "study" is a parody or a serious attempt to mislead. I wouldn't be at all surprised if the authors point out the dozen different ways that it is bullshit, and ridicule those who published it.
Just a few examples:
Flooding major cities (or any cities) is generally frowned upon.
And yes, cities tend to be built in large valleys.
Actually building reservoirs [Banqiao] uphill from cities [200,000 dead] is a bad idea. I bet you can't guess why that's a bad idea [11 million lost their homes]. Th
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no, it's not a breakthrough at all, because it's a negligible amount of power at night. I just told you how you could get more power at night by order of magnitude (or two or four) or more at much less cost.
You're the one not seeing the big picture, which is that for any practical application this "invention" is a waste of time and money.
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The case right now is not the same case (a) when lots of smart people have been working on the problem for a while and (b) engineers make various implementations work well. If we dismiss it out of hand and stop looking, no it won't get better.
Useful work from cooling to space actually has vast potential (more than even peak demand at limit when I last looked?), even if we don't have the mechanisms yet.
And are you aware that on land solar PV is nearly an order of magnitude more energy dense than wind (W/m^2
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Your talk about wind in the UK only proves how stupid a solution it is for the UK, there are smarter ways to get electricity there.
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I don't think that throwing around the word "stupid" is helpful.
The classic problem that the energy ministry used as a benchmark is when the UK gets five (or more) cold cloudy windless days. It happens. Hydro is at least an order of magnitude too low to take the strain and will be for the foreseeable future, and the storage (eg mainly pumped hydro) we currently have and are likely to get any time soon covers more like 5 hours.
It's complicated, and any anti-correlated renewables would be very valuable then
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"Stupid" is the perfect word, known fact wind power has raised the cost of electricity in the UK. In the face of that hard fact, your "expert analysis" becomes poorly absorbent toilet paper at best, if printed out.
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Not helpful, not true, and not the point either. Lots of 'cheap' coal-fired would kill us.
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You dislike inconvenient facts. wind raised average bill £18 a year in Uk in 2015.
Not helpful...yeah raining on the parade between your ears isn't helpful, hah.
I don't like carbon pollution but the industrial age and use of coal and oil overall has lengthened human life, lowered amount of diseases, raised people out of poverty and driven progress to where we are now. Lots of cheap coal saved most mankind.
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Being rude does not bend facts in your favour, please just stop being unpleasant. It does not add to the debate.
As for costing, and depending on your metric and which subsidies and externalities to each energy industry you include or not, and how much of costs to date you include as a forward payment for tech development to bring future prices down, it is quite clear that even in the UK the effect of wind has already been a downward pressure on costs. And wind is getting rapidly cheaper.
And that's ignorin
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Agreed.
But there's still plenty of things that could be done, eg reverse concentration might work, given the work that has been done with simple thermal cooling based on the same idea. I suspect that appropriate lenses would be fiercely expensive to start with given the cost of those in thermal cameras, but maybe not. But in any case is the m^2 still of ground space. at that point?
And we have accommodated ~12GW of solar PV in the UK with most rooftops still unused, so ultimately space doesn't feel like a
ZPM (Score:3)
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At 64 nanowatts per square meter it might as well be statistical error or the researchers smart phones emitting radio waves getting rectified.
Don't keep your hopes up on this one.
cool, as long as it's not cloudy (Score:2)
When it's cloudy, the sky temperature is that of the clouds, which is what, 18 degrees or so?
So unless you're in the tropics, the cloud temperature is going to be close to or higher than the ground temperature in the middle of the night.
Why is this interesting? (Score:2)
Serious question.
Its published in a major journal, but it just looks like a standard heat engine (something like a thermoelectric generator) that operates between the warm earth and the colder outer space. I feel like I'm missing something.
Its obviously not practical, but that isn't he point - what is it showing that wasn't obvious? (and it would be a lot simpler to use a cryostat for the cold side).
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This is solid state, through a diode.
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It's a physics demonstration. I remember a story about this process on Slashdot years ago, but someone actually went out and built the thing, along with a test rig that was sensitive enough to measure the power produced.
Basic science experiments are often along the lines of "yup, this experiment shows that this thing works the way we thought it would."
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I'm fine with a demonstration but what are they demonstrating? Semiconductors can provide thermoelectric power from a temperature difference, and the sky is much colder than the earth (since its not heated by the sun).
Again, its a serious journal article, so there must be something interesting here - I'm just not seeing it. Not worrired about practicality, but the result seem so obvious that I don't know why they needed an experiment.
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Knowing exactly how much power trickles out of the setup seems like useful information.
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It's not just the temperature difference between the ground and the air above it (for example). They're showing that you can extract energy from the energy gradient between the surface of Earth (at, say, 290 K) and the background temperature of deep space (at close to 0 K) by radiating infrared photons. All of the bits of the environment that are actually in contact with that diode are at the same temperature, and the electricity is generated purely from the temperature gradient produced by radiation into
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but it just looks like a standard heat engine (something like a thermoelectric generator) that operates between the warm earth and the colder outer space. .... standard heat engines are based on ideal gases and follow the 7 laws of thermodynamics ... this is based on quantum effects, like a solar panel. Two different things.
That is not a standard heat engine
A practical use (Score:5, Interesting)
I can actually think of a practical use for this, if it could be made really lightweight.
I work with groups that fly small, long-duration stratospheric balloons with ham radio beacons. The payload weight budget is too small (15 grams) for batteries, and even with them the extremely low temperatures would be a problem. Supercaps work well at low temperatures, but energy densities are too poor to store enough energy for an entire night. So the payload only operates during the daytime from two thin-film solar cells.
I've been wracking my brain trying to think of another source of ambient energy (besides sunlight) that could be harvested. Even a few milliwatts could be useful, accumulated in a supercap until there's enough energy for one GPS fix and radio transmission cycle. Harvesting broadcast radio stations is one idea, but that only works near population centers. I'd thought of some sort of heat engine working between the warm earth below and the cold sky above, but did not know if it was at all practical. Maybe it still isn't, but it's an interesting idea.
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I know nothing about anything relevant, but could a Piezoelectric harvester work up there if you had something dangling down with a tiny sail to provide vibrations?
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Look at thermoelectric devices (basically a heat engine without moving parts). Unfortunately they are not close to ideal Carnot efficiency, but on a night with a clear sky you might get a bit out of it.
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Dyson (Score:2)
This would be the perfect material to use in construction of a Dyson sphere with.
Title is wrong (Score:2)
old novalty? (Score:2)
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generating electricity (that's just a common phrase people use AC) from temperature difference has been known for a very long time - it's called termocouple
Yeah, and it has nothing to do with this.
A termocouple (is it really spelled that way?) is based on having two different metals coupled. One lsoes electrons to the other, due to heat, that is a current, hence you have electric power.
No idea why you mix that up with quantum effects involving radiation of photons.
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Good point: "thermocouple", and regarding to the nature of both phenomena, though in both cases electrons and photons are involved I agree they are different enough not to mix them.
BTW, do you have a good source, which would say more about this quantum optoelectronic effect (some equations), I have not found any more detail explanation of this device after a brief search, however I've found something interesting related to the topic thermionic generator [physicsworld.com].
Peltier element? (Score:2)
The thermoelectric effect has long since been known and it is a bit more efficient that this meaningless stunt. But here is news: It is expensive to manufacture respective elements or they would have replaced solar cells a long, long time ago. Although I now have a compressor-less kitchen fridge based on the reverse of this effect, which is pretty cool. Took merely about 200 years to be solved for this application.
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Fridges based on peltier elements we have since over 100 years.
And as they are very inefficient they only have niche uses. As in hotel rooms.
Coldness of the universe? (Score:2)
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Hillary who? We don't care about her anymore. Our boners are dedicated to Biden 2020.
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