Physicists Build Circuit That Generates Clean, Limitless Power from Graphene(news.uark.edu)
news.uark.edu
Physicists Build Circuit That Generates Clean, Limitless Power from Graphene
https://news.uark.edu/articles/54830/physicists-build-circuit-that-generates-clean-limitless-power-from-graphene
89 comments
> If this is representative of press releases from universities
If you want reporting that accurately represent science, in my experience, the university press releases are even worse than the worst mainstream shit-tier media.
If you want reporting that accurately represent science, in my experience, the university press releases are even worse than the worst mainstream shit-tier media.
It's super sad. My boss was once at the center of one of these big press release splashes at the university I worked. She said it was almost more of a burden than a boon, because the attention it attracted was almost all of the wrong kind. And among the right kind of people, she had to spend time and effort excusing the embarassing and ridiculous press release.
I wonder if universities understand that they're sometimes harming their own people with these things.
I wonder if universities understand that they're sometimes harming their own people with these things.
The incentives for the PR team is to make news. They don’t have to spend a ton of time cleaning up the mess of misleading press releases.
At some point it tarnish the reputation of the university. If your university get famous for sending ridiculous press releases, I hope that eventually the journalist will notice and just forward them to The Onion.
MIT has a reputation for super sketchy press releases, but their research reputation is fine still. Even with the whole epstein scandal. I wonder how much it takes to actually tarnish their reputation.
There's no shortage of reasons to criticize at MIT but I'm not sure Epstein is one of them.
AFAICT the administration did not turn a blind eye to Epstein, and in fact barred him. And the scandal is that Joi knew that he was persona non grata and therefore took steps to hide Epstein's funding. That is unquestionably terrible but in my mind doesn't tar the Institute.
I'm certainly not defending (or criticizing) MIT as an institute (there are bigger problems than the dreadful press releases from the publicity office). But if my understanding is correct, Epstein, while lurid, might not be a useful line of attack.
AFAICT the administration did not turn a blind eye to Epstein, and in fact barred him. And the scandal is that Joi knew that he was persona non grata and therefore took steps to hide Epstein's funding. That is unquestionably terrible but in my mind doesn't tar the Institute.
I'm certainly not defending (or criticizing) MIT as an institute (there are bigger problems than the dreadful press releases from the publicity office). But if my understanding is correct, Epstein, while lurid, might not be a useful line of attack.
An institution is its people. If institutional policies aren't followed, the reputation suffers.
Well sure, but the point is the institution put a stop mechanism in place, when it was found out that someone had worked around it then a group of them were canned too. The media lab is a tiny part of the smallest school in a very large institution and the sums were correspondingly trivial compared to the institute's annual budget. (even all of education is a small fraction of that budget).
It's as if Google's parking valets were found to be running a car theft ring (made up example): unless Google seemed to think it below their notice, I would have a hard time considering that should be grounds for condemning Google.
I'm not defending MIT (or conflating car theft with sexual abuse) I'm merely saying that if you want to attack MIT consider something more substantive like its slow progress in recruiting and retaining female scientists; it's intimate ties with the government and military (despite various fig leaves assembled over the decades), or its treatment of undergraduates which at best is neglect. Don't waste your efforts on a small, if noisy, lab that has produced negligible research of consequence.
It's as if Google's parking valets were found to be running a car theft ring (made up example): unless Google seemed to think it below their notice, I would have a hard time considering that should be grounds for condemning Google.
I'm not defending MIT (or conflating car theft with sexual abuse) I'm merely saying that if you want to attack MIT consider something more substantive like its slow progress in recruiting and retaining female scientists; it's intimate ties with the government and military (despite various fig leaves assembled over the decades), or its treatment of undergraduates which at best is neglect. Don't waste your efforts on a small, if noisy, lab that has produced negligible research of consequence.
Also MIT != MIT Media Lab. (Although in terms of reputation the two are usually conflated.)
That point is too far in the future for anyone currently in power to care. If that point is ever reached it would require larger numbers of the population to be scientifically literate. I don't see that happening, everything is clickbaity now.
Yup, there are no consequences for these people so why should they change? No skin in the game I tell ya.
It's kind of funny that the person writing the press release thought it was their job to just spice up the headline a little bit by claiming they'd discovered a source of unlimited clean energy.
I am guessing the clickbait title is to make the article widely shared and attract funding.
Probably have to read the journal paper to get accurate details.
Probably have to read the journal paper to get accurate details.
In all honesty funding is given by institutions and people who evaluate the goal they spend there money on. So this sort of attention gathering, should be pre-filtered out by all serious sources of funding.
So what remains is a prestige, attention metric of the university.
So what remains is a prestige, attention metric of the university.
Money is money, whether it comes from a prestigious science institute or an old guy who inherited it and wants it spent on cool stuff.
The abstract of the paper Fluctuation-induced current from freestanding graphene [1]:
> At room temperature, micron-sized sheets of freestanding graphene are in constant motion, even in the presence of an applied bias voltage. We quantify the out-of-plane movement by collecting the displacement current using a nearby small-area metal electrode and present an Ito-Langevin model for the motion coupled to a circuit containing diodes. Numerical simulations show that the system reaches thermal equilibrium and the average rates of heat and work provided by stochastic thermodynamics tend quickly to zero. However, there is power dissipated by the load resistor, and its time average is exactly equal to the power supplied by the thermal bath. The exact power formula is similar to Nyquist's noise power formula, except that the rate of change of diode resistance significantly boosts the output power, and the movement of the graphene shifts the power spectrum to lower frequencies. We have calculated the equilibrium average of the power by asymptotic and numerical methods. Excellent agreement is found between experiment and theory.
[1] https://journals.aps.org/pre/abstract/10.1103/PhysRevE.102.0...
> At room temperature, micron-sized sheets of freestanding graphene are in constant motion, even in the presence of an applied bias voltage. We quantify the out-of-plane movement by collecting the displacement current using a nearby small-area metal electrode and present an Ito-Langevin model for the motion coupled to a circuit containing diodes. Numerical simulations show that the system reaches thermal equilibrium and the average rates of heat and work provided by stochastic thermodynamics tend quickly to zero. However, there is power dissipated by the load resistor, and its time average is exactly equal to the power supplied by the thermal bath. The exact power formula is similar to Nyquist's noise power formula, except that the rate of change of diode resistance significantly boosts the output power, and the movement of the graphene shifts the power spectrum to lower frequencies. We have calculated the equilibrium average of the power by asymptotic and numerical methods. Excellent agreement is found between experiment and theory.
[1] https://journals.aps.org/pre/abstract/10.1103/PhysRevE.102.0...
"However, there is power dissipated by the load resistor, and its time average is exactly equal to the power supplied by the thermal bath."
As the "thermal bath" is supplying power, this seems consistent with it being a Carnot-equivalent heat engine.
There is certainly nothing in physics that prevents the extraction of energy from an environment in which the temperature fluctuates - devices that do so to keep mechanical clocks running indefinitely have been around for some time.
http://atmosadam.com/howitworks.html
As the "thermal bath" is supplying power, this seems consistent with it being a Carnot-equivalent heat engine.
There is certainly nothing in physics that prevents the extraction of energy from an environment in which the temperature fluctuates - devices that do so to keep mechanical clocks running indefinitely have been around for some time.
http://atmosadam.com/howitworks.html
The clock in your link uses the temperature fluctuations, for example if it hot during the day and cool during the night. So you can have a flux of heat from the hot part to the cold part, and extract a small part as useful energy.
If we take the press release at face value, in this device there is no difference of temperature. So if the Second Law of Thermodynamics is correct it is not possible to extract some useful energy to do something interesting, like turning on the lamp in the animation.
If we take the press release at face value, in this device there is no difference of temperature. So if the Second Law of Thermodynamics is correct it is not possible to extract some useful energy to do something interesting, like turning on the lamp in the animation.
I am not inclined to take the press release at face value, as its author is apparently unaware of just how radical its claims are, if taken at face value, which in turn suggests that the author is out of his depth.
The above quote is from the abstract, and just before it, we see the much more reasonable "numerical simulations show that the system reaches thermal equilibrium and the average rates of heat and work provided by stochastic thermodynamics tend quickly to zero."
The above quote is from the abstract, and just before it, we see the much more reasonable "numerical simulations show that the system reaches thermal equilibrium and the average rates of heat and work provided by stochastic thermodynamics tend quickly to zero."
>> numerical simulations show that the system reaches thermal equilibrium and the average rates of heat and work provided by stochastic thermodynamics tend quickly to zero.
It make sense, but the problem is more subtle. It's better compare the clock with a brick.
In the example of the clock there is a temperature difference that can be used to extract "useful" energy. You can use it to move the clock, or make a sound or light or something.
(I'm saying "useful" as in the a quote of the main author of the paper "What we did was reroute the current in the circuit and transform it into something useful.” .)
If you put a brick in a oven and keep it at the same temperature for some time, until the temperature, humidity and other properties have stabilized, you reach thermal equilibrium. It doesn't mean that the heat energy in the brick is perfectly constant, it exchanges heat with the oven. The heat energy has small random variations.
But unlike in the clock scenario, you can't use this additional accumulated energy for something "useful". To check if it is in a high or a low, you need a variant od the Maxwell's Demon. You can measure the energy exchange and analyze the theoretical and experimental properties anyway.
(Also, if you put the clock in the oven at a constant temperature for a long enough time, it will stop working.)
Stealing the name from a sibling thread, to make the grapheme device produce "useful" energy, you probably need a Maxwell's Diode.
It make sense, but the problem is more subtle. It's better compare the clock with a brick.
In the example of the clock there is a temperature difference that can be used to extract "useful" energy. You can use it to move the clock, or make a sound or light or something.
(I'm saying "useful" as in the a quote of the main author of the paper "What we did was reroute the current in the circuit and transform it into something useful.” .)
If you put a brick in a oven and keep it at the same temperature for some time, until the temperature, humidity and other properties have stabilized, you reach thermal equilibrium. It doesn't mean that the heat energy in the brick is perfectly constant, it exchanges heat with the oven. The heat energy has small random variations.
But unlike in the clock scenario, you can't use this additional accumulated energy for something "useful". To check if it is in a high or a low, you need a variant od the Maxwell's Demon. You can measure the energy exchange and analyze the theoretical and experimental properties anyway.
(Also, if you put the clock in the oven at a constant temperature for a long enough time, it will stop working.)
Stealing the name from a sibling thread, to make the grapheme device produce "useful" energy, you probably need a Maxwell's Diode.
> ...the problem is more subtle.
What is 'the problem' that you are apparently trying to address here? Everyone in the discussion is well aware that the 2nd. law of thermodynamics prevents the continuous extraction of work from ambient heat without there being a temperature difference. Are you saying that the paper is claiming that this has been done? If not that, are you claiming that the device, as described in the paper, is incapable of generating power from fluctuations in the ambient temperature? Have you identified some other problem in the paper? Alternatively - I don't think you are saying this, but I will put it in for completeness - could it be that you are saying that the paper shows that this team really has invented a Maxwell's diode, capable of continuously extracting work from the ambient heat of a closed system in thermal equilibrium?
If you are still only taking issue with the press release, you are just nerdsplaining to a bunch of people who already get it, thank you very much.
What is 'the problem' that you are apparently trying to address here? Everyone in the discussion is well aware that the 2nd. law of thermodynamics prevents the continuous extraction of work from ambient heat without there being a temperature difference. Are you saying that the paper is claiming that this has been done? If not that, are you claiming that the device, as described in the paper, is incapable of generating power from fluctuations in the ambient temperature? Have you identified some other problem in the paper? Alternatively - I don't think you are saying this, but I will put it in for completeness - could it be that you are saying that the paper shows that this team really has invented a Maxwell's diode, capable of continuously extracting work from the ambient heat of a closed system in thermal equilibrium?
If you are still only taking issue with the press release, you are just nerdsplaining to a bunch of people who already get it, thank you very much.
> Everyone in the discussion is well aware that the 2nd. law
Probably not, but it is good to know that you are.
The paper is not about a device that harvest energy from the thermal variations of the environment. There is no mention of macroscopic thermal variations in the press release or in the abstract of the paper. Also, the graphene is inside a ultra high vacuum chamber, that is a weird place to put a device that that depends on the macroscopic thermal variations of the environment.
From the abstract:
> However, there is power dissipated by the load resistor, and its time average is exactly equal to the power supplied by the thermal bath.
My interpretation is that the resistor is dissipating some power (from the graphics ~1pW), but it is also absorbing the same amount of power due to the 2nd law. It is not a Carnot engine that produces work from heat.
Probably not, but it is good to know that you are.
The paper is not about a device that harvest energy from the thermal variations of the environment. There is no mention of macroscopic thermal variations in the press release or in the abstract of the paper. Also, the graphene is inside a ultra high vacuum chamber, that is a weird place to put a device that that depends on the macroscopic thermal variations of the environment.
From the abstract:
> However, there is power dissipated by the load resistor, and its time average is exactly equal to the power supplied by the thermal bath.
My interpretation is that the resistor is dissipating some power (from the graphics ~1pW), but it is also absorbing the same amount of power due to the 2nd law. It is not a Carnot engine that produces work from heat.
I am not sure what your claim is in that last paragraph. If it takes heat energy from the thermal bath and produces electrical energy (which is then dissipated in a load resistor), in what way is it not a Carnot engine?
Are you taking the quoted passage as implying it is performing 100% conversion? This would indeed be a problem, as there is no heat sink at 0K here. That quote, however, is ambiguous, as it says power supplied by the heat bath and not lost from it, and may merely be a statement that it obeys the conservation of energy (i.e. the point being made here may be that the power being supplied to the load comes from the heat bath, as opposed to coming from another possible source, such as the bias voltage supply.)
I really should buy and read the paper, but I am not that motivated yet.
Are you taking the quoted passage as implying it is performing 100% conversion? This would indeed be a problem, as there is no heat sink at 0K here. That quote, however, is ambiguous, as it says power supplied by the heat bath and not lost from it, and may merely be a statement that it obeys the conservation of energy (i.e. the point being made here may be that the power being supplied to the load comes from the heat bath, as opposed to coming from another possible source, such as the bias voltage supply.)
I really should buy and read the paper, but I am not that motivated yet.
It is not producing a macroscopic current, it is producing something like Johnson noise https://en.wikipedia.org/wiki/Johnson%E2%80%93Nyquist_noise (The interesting part seams to be that it has another frequency distribution, but I don't understand the details.)
A real engine transform heat into electric energy that can be used to dissipate heat inside a container at any temperature. In particular at a higher temperature that the graphene and the support and the circuit. In the PR they claim that it produce "something useful" that I interpret as "work" or "electrical energy", but in that case it breaks the Second Law even if in their setup the resistor is at the same temperature.
After reading the paragraph again, I'm not sure if your interpretation is right and they are claiming that the device is transferring energy from the graphene to the resistor, but that breaks the second law, in spite in the PR they claim it doesn't.
I think they never claim a 100% conversion anyway. They just don't have a temperature difference to operate the engine.
A real engine transform heat into electric energy that can be used to dissipate heat inside a container at any temperature. In particular at a higher temperature that the graphene and the support and the circuit. In the PR they claim that it produce "something useful" that I interpret as "work" or "electrical energy", but in that case it breaks the Second Law even if in their setup the resistor is at the same temperature.
After reading the paragraph again, I'm not sure if your interpretation is right and they are claiming that the device is transferring energy from the graphene to the resistor, but that breaks the second law, in spite in the PR they claim it doesn't.
I think they never claim a 100% conversion anyway. They just don't have a temperature difference to operate the engine.
Have you actually read the paper? So far, you have only supported your claims with references to the press release and the abstract. As it stands, you are alleging they have made a pretty serious blunder, which should not be made without reference to the paper itself.
It is difficult to tell at this level if they're claiming to have built Maxwell's Daemon out of graphene - or at least an approximation thereof.
imagine a very thin and very short wire - just for one electron to move a bit left and a bit right. The surrounding environment - in particular Brownian motion molecules, especially the ones with large dipole moment, and the background EM radiation - will cause the electron to move left-right. Thus we have electric current generation. Now diode-terminate the wire to allow aggregating of many of such wires without mutual cancellation of the current generated by those wires. Well, meet the Maxwell's Daemon remote cousin - Maxwell's Diode.
Basically, there are always local micro gradients even though the macro integration of those gradients gives 0. It may as well happen that graphene being few atoms thick and thus dipping into the local scale properties may bridge and aggregate without [total] mutual cancellation those properties into the macro scale (graphehe sheet vibrations may happen be [one of] such a filter, kind of piezoelectric effect). There is no violation of the 2nd law as extracted work/energy wouldn't be larger than the entropy increase resulting from the smoothing of the micro gradients (bringing the Universe's heat death closer).
Or even imagine a pond with no visible movement of water and place over it a myriad of very very small water mill wheels - they will be rotating chaotically back and forward due to small perturbances in the water (and the smaller a giving wheel the larger share of local gradient it will be extracting as the smaller share of it will be mutually cancelling with the neighboring gradients under the wheel). That chaotic rotation of that myriad of wheels can be aggregated into usable work/energy.
Basically, there are always local micro gradients even though the macro integration of those gradients gives 0. It may as well happen that graphene being few atoms thick and thus dipping into the local scale properties may bridge and aggregate without [total] mutual cancellation those properties into the macro scale (graphehe sheet vibrations may happen be [one of] such a filter, kind of piezoelectric effect). There is no violation of the 2nd law as extracted work/energy wouldn't be larger than the entropy increase resulting from the smoothing of the micro gradients (bringing the Universe's heat death closer).
Or even imagine a pond with no visible movement of water and place over it a myriad of very very small water mill wheels - they will be rotating chaotically back and forward due to small perturbances in the water (and the smaller a giving wheel the larger share of local gradient it will be extracting as the smaller share of it will be mutually cancelling with the neighboring gradients under the wheel). That chaotic rotation of that myriad of wheels can be aggregated into usable work/energy.
There is no such thing as temperature at the scale they are taking about. There is only Brownian motion with a random distribution of impact speeds from surrounding molecules. At any given time the graphene might be experiencing more or less force over its area than the thermal average.
Another way of thinking about it is that random noise although uniform at large scale, is intrinsically noisy when you zoom in.
Another way of thinking about it is that random noise although uniform at large scale, is intrinsically noisy when you zoom in.
The temperature can be defined even for very small systems using Statistical Mechanics, and also the distribution of speeds and energy in the Brownian motion of the surrounding molecules and movement of the membrane (and phonons?) depend on the temperature.
This is true. It also has nothing to do with the point I was making.
I'm not sure was is your point. I'll try with another answer.
I don't remember something like the clock at the molecular level, but I think it is "theoretically possible" (or to be more accurate, "not theoretically impossible").
[Weird example warning]
In the mitochondria the ATP synthase https://en.wikipedia.org/wiki/ATP_synthase use the H+ difference of the inner and outer part to produce ATP. The main problem is how to create this difference without sugar or pyruvate, using only a change of temperature.
Perhaps it is possible to put a weak acid outside of a mitochondria, and select the weak acid that changes the dissociation constant a lot with the temperature.
So when temperature is high it is mostly dissociated and the acidity is high and the mitochondria produces ATP. But after some time there is no difference in the concentration of H+ inside and outside of the mitochondria and the process stop.
Then reduce the temperature so the acidity outside is low, and the H+ inside the mitochondria can escape by other pores. (Perhaps we need to make some additional pores for this? The pores must be small and not very polar.) After some time, the concentration of H+ inside the mitochondria is low again. And we can repeat the cycle.
[/Weird example warning]
This will be painfully slow and painfully inefficient. My biochemistry level is too low to be sure this is possible, but at lest I think it is not theoretically impossible.
It is a small system, so I think it is a relevant comparison in spite it is very different of a graphene membrane in a vacuum chamber.
I don't remember something like the clock at the molecular level, but I think it is "theoretically possible" (or to be more accurate, "not theoretically impossible").
[Weird example warning]
In the mitochondria the ATP synthase https://en.wikipedia.org/wiki/ATP_synthase use the H+ difference of the inner and outer part to produce ATP. The main problem is how to create this difference without sugar or pyruvate, using only a change of temperature.
Perhaps it is possible to put a weak acid outside of a mitochondria, and select the weak acid that changes the dissociation constant a lot with the temperature.
So when temperature is high it is mostly dissociated and the acidity is high and the mitochondria produces ATP. But after some time there is no difference in the concentration of H+ inside and outside of the mitochondria and the process stop.
Then reduce the temperature so the acidity outside is low, and the H+ inside the mitochondria can escape by other pores. (Perhaps we need to make some additional pores for this? The pores must be small and not very polar.) After some time, the concentration of H+ inside the mitochondria is low again. And we can repeat the cycle.
[/Weird example warning]
This will be painfully slow and painfully inefficient. My biochemistry level is too low to be sure this is possible, but at lest I think it is not theoretically impossible.
It is a small system, so I think it is a relevant comparison in spite it is very different of a graphene membrane in a vacuum chamber.
It’s more like “limitless power from heat transferred into graphene from an external power source”. So it’s a special type of a thermo electric generator basically.
Only in the load resistor. Electron flux in the graphene membrane appears to be solely due to geometry. This curvature does not necessarily need to be buckled via heat energy. It could be mechanical or electrical, if I understand things correctly...
More detail in this video clip with UArk's Paul Thibado:
https://www.youtube.com/watch?v=wrleMqm3HiU
I think what this research opens up is the possibility of "optimal" harvesting. There is some resonant frequency, some circuit configuration yet to be discovered that is perhaps self-sustaining. They've chosen "stochastic thermodynamical" circuits because its low hanging fruit. But it seems really exciting to me. Almost like a third class of energy production after solar and hydrogen (where 99% of research funds are allocated). Ocean wave energy harvesting perhaps?
In any case, congrats to the researchers on their painstaking hard work ;)
Fluctuation-induced current from freestanding graphene: toward nanoscale energy harvesting
https://arxiv.org/abs/2002.09947
More detail in this video clip with UArk's Paul Thibado:
https://www.youtube.com/watch?v=wrleMqm3HiU
I think what this research opens up is the possibility of "optimal" harvesting. There is some resonant frequency, some circuit configuration yet to be discovered that is perhaps self-sustaining. They've chosen "stochastic thermodynamical" circuits because its low hanging fruit. But it seems really exciting to me. Almost like a third class of energy production after solar and hydrogen (where 99% of research funds are allocated). Ocean wave energy harvesting perhaps?
In any case, congrats to the researchers on their painstaking hard work ;)
Fluctuation-induced current from freestanding graphene: toward nanoscale energy harvesting
https://arxiv.org/abs/2002.09947
Yea that video is helpful and it looks like mechanical energy or thermal could be used to deform the graphene film to do some work on that film which them stores it. So it seems like what’s happening is that thermal energy is being used to put energy into the free standing graphene lattice. Then as it extends in length due to the film heating, it stores energy almost like inflating a balloon, then it touches one of the electrodes nearby and the electrons in this unique material transfer charge to the other electrode and causes the film to contract so a portion of the charge was transferred away, and it contracts then can repeat the process. So it’s a small motor that harvests either mechanical or thermal energy. But given the tiny size, it would seem like thermal might be the dominant thing since the membrane would probably need some sort of mass to benefit from random movements. Or the graphene would need to be extremely flexible. But not totally sure..
This does sound promising. Is it possible to run this process in reverse a la a heat pump to create an AC with no moving parts? Or is this purely a one way process?
I'd say Joule heating is the reverse of this process:
https://en.wikipedia.org/wiki/Joule_heating#Microscopic_desc...
Peltier coolers are probably in line with what you're suggesting, but they're not super efficient.
I was hoping for an alternative to those. They are neat but with such low efficiency they aren’t super useful.
I'm completely out of my area of expertise here (I can mostly follow the press release but I can't understand that much of the actual paper outside of the introduction), but your comment about resonant frequencies reminded me of of some recent research on layering graphene at a "magic angle" to produce special fractal moire patterns that have special physical properties. I wonder if that work can be combined with the work here. To a non expert like myself, it seems like there is a lot of really exciting research in this area at the moment.
Could they add this to waste heat pipes in power plants to extract more energy?
Thank you; awful title.
Ignoring the horrible horrible horrible title ...
This can only work if there is a temperature difference between the grapheme membrane and the load resistor (the lamp in the animations). Other wise, it breaks the Second Law of Thermodynamics.
The problem is not that it breaks some remark from Feynman, the problem is that if there is no temperature difference, it breaks the Second Law of Thermodynamics and in particular an example in an explanation of Feynman.
This can only work if there is a temperature difference between the grapheme membrane and the load resistor (the lamp in the animations). Other wise, it breaks the Second Law of Thermodynamics.
The problem is not that it breaks some remark from Feynman, the problem is that if there is no temperature difference, it breaks the Second Law of Thermodynamics and in particular an example in an explanation of Feynman.
At least it doesn't break conservation of energy. The second law of thermodynamics is already kind of suspect in that random fluctuations break it all the time on a microscopic level. It's closer to a statistical observation.
Turning heat into usable energy without temperature differential is still an extraordinary claim that demands extraordinary evidence, but I wouldn't dismiss it out of hand
Turning heat into usable energy without temperature differential is still an extraordinary claim that demands extraordinary evidence, but I wouldn't dismiss it out of hand
The second law requires to take the average over a sufficiently long amount of time though.
Doesn’t the article explicitly say that is not the case?
> Though the thermal environment is performing work on the load resistor, the graphene and circuit are at the same temperature and heat does not flow between the two.
I’m not a physicist or even an educated layman, can you explain your comment more?
> Though the thermal environment is performing work on the load resistor, the graphene and circuit are at the same temperature and heat does not flow between the two.
I’m not a physicist or even an educated layman, can you explain your comment more?
I read that part a few times, but it makes no sence.
I prefer another quote
> What we did was reroute the current in the circuit and transform it into something useful.
Let's suppose that they get some "useful" energy to turn on the lamp like in the animation or power a small device.
Let's suppose that you use it to power a laser and send a beam that heat some object far away. As a side effect, you are extracting energy from the device with the graphene in the lab so it will get cooler.
So the net effect is that the device in the lab gets cooler and the object far away get hotter. So you have a flux of heat. But if the other object is hotter, you have a lux of heat from in the wrong direction, that is impossible according to the Second Law.
There are a million ways to rewrite this https://en.wikipedia.org/wiki/Second_law_of_thermodynamics in more abstract or more concrete ways. With some oversimplifications, another is that you need at least two heat baths and the efficiency of the device to transform heat from the "hot" bath to of "useful" energy can be calculate using the temperatures of the baths. When the difference of temperature is zero, the efficiency is zero and the device can produce no "useful" energy. Or in other words, with only one heath bath, you can produce no "useful" energy.
I prefer another quote
> What we did was reroute the current in the circuit and transform it into something useful.
Let's suppose that they get some "useful" energy to turn on the lamp like in the animation or power a small device.
Let's suppose that you use it to power a laser and send a beam that heat some object far away. As a side effect, you are extracting energy from the device with the graphene in the lab so it will get cooler.
So the net effect is that the device in the lab gets cooler and the object far away get hotter. So you have a flux of heat. But if the other object is hotter, you have a lux of heat from in the wrong direction, that is impossible according to the Second Law.
There are a million ways to rewrite this https://en.wikipedia.org/wiki/Second_law_of_thermodynamics in more abstract or more concrete ways. With some oversimplifications, another is that you need at least two heat baths and the efficiency of the device to transform heat from the "hot" bath to of "useful" energy can be calculate using the temperatures of the baths. When the difference of temperature is zero, the efficiency is zero and the device can produce no "useful" energy. Or in other words, with only one heath bath, you can produce no "useful" energy.
>So the net effect is that the device in the lab gets cooler and the object far away get hotter. So you have a flux of heat. But if the other object is hotter, you have a lux of heat from in the wrong direction, that is impossible according to the Second Law
I don't think your hypothesis would necessarily break the Second Law. Wouldn't the hotter distant object result in making Brownian motion around it? The same Brownian motion which would eventually end up as energy input at the graphene membrane - provided a thermodynamically closed system?
As so I'm not convinced this study breaks the Second Law, nor do I see how it produces useful work. To me it only seems so, because the system isn't being modeled as a closed system...
EDIT: Actually, I'm pretty sure the following statement is completely false:
>the graphene and circuit are at the same temperature and heat does not flow between the two.
I'd suspect heat does flow between the two, it's just outside their modeling of the system.
I don't think your hypothesis would necessarily break the Second Law. Wouldn't the hotter distant object result in making Brownian motion around it? The same Brownian motion which would eventually end up as energy input at the graphene membrane - provided a thermodynamically closed system?
As so I'm not convinced this study breaks the Second Law, nor do I see how it produces useful work. To me it only seems so, because the system isn't being modeled as a closed system...
EDIT: Actually, I'm pretty sure the following statement is completely false:
>the graphene and circuit are at the same temperature and heat does not flow between the two.
I'd suspect heat does flow between the two, it's just outside their modeling of the system.
So, spooky thermocouples at a distance? This paper is one that really needs further attempts at replication.
Naive question, wouldn't this (converting Brownian motion into electricity) violate the 2nd law of thermodynamics?
(edit, this is explicitly addressed further in the article: That's an important distinction, said Thibado, because a temperature difference between the graphene and circuit, in a circuit producing power, would contradict the second law of thermodynamics. "This means that the second law of thermodynamics is not violated, nor is there any need to argue that 'Maxwell's Demon' is separating hot and cold electrons," Thibado said.)
(edit, this is explicitly addressed further in the article: That's an important distinction, said Thibado, because a temperature difference between the graphene and circuit, in a circuit producing power, would contradict the second law of thermodynamics. "This means that the second law of thermodynamics is not violated, nor is there any need to argue that 'Maxwell's Demon' is separating hot and cold electrons," Thibado said.)
This sounds like a mangled explanation. It seems to me, somewhat naively, that the resonator must be held at a higher temperature than the rest of the circuit to produce work on the load.
I think some minuscule amount of energy is taken from the thermal bath (the environment is considered a thermal bath - you can take heat from it and it's so big its temperature won't budge), converted into electricity and then back to heat in the load resistor. They all remain in the same temperature if I'm not gravely mistaken.
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> The idea of harvesting energy from graphene is controversial because it refutes physicist Richard Feynman’s well-known assertion that the thermal motion of atoms, known as Brownian motion, cannot do work. Thibado’s team found that at room temperature the thermal motion of graphene does in fact induce an alternating current (AC) in a circuit, an achievement thought to be impossible.
So it sounds like, if this really works, it may have some impact on our general understanding of thermodynamics or the properties of Brownian motion?
So it sounds like, if this really works, it may have some impact on our general understanding of thermodynamics or the properties of Brownian motion?
If it works as described in the press release, this is a direct trip to Stockholm to pick the Nobel Prize. I can't read the research paper now.
My guess is that there is a temperature difference between the grapheme and the resistor. In that case it's a normal experiment, perhaps with some tweak, but not a groundbreaking experiment. The power generated by the device is tiny (not "unlimited"), and there are a lot of similar devices.
Sometimes the experiment is interesting in some niche (this experiment is related to tunnel microscopy) but this is totally overhyped.
My guess is that there is a temperature difference between the grapheme and the resistor. In that case it's a normal experiment, perhaps with some tweak, but not a groundbreaking experiment. The power generated by the device is tiny (not "unlimited"), and there are a lot of similar devices.
Sometimes the experiment is interesting in some niche (this experiment is related to tunnel microscopy) but this is totally overhyped.
If it works as described in the press release, this is a direct trip to Stockholm to pick the Nobel Prize.
There are too many PR announcements like that in the nanotechnology and battery areas. It's either Nobel Prize material or nothing, and you can't tell from the article.
No power numbers. Are they talking about generating a picowatt or something like that?
Somebody like EVworld should publish "1, 5 and 10 years ago today in energy announcements".
There are too many PR announcements like that in the nanotechnology and battery areas. It's either Nobel Prize material or nothing, and you can't tell from the article.
No power numbers. Are they talking about generating a picowatt or something like that?
Somebody like EVworld should publish "1, 5 and 10 years ago today in energy announcements".
Most press release about batteries claim a x2 improvement in 5 years or something like that. If they were true perhaps you can get a Nobel, but you must wait in the queue for a few years. If you break the Second Law you can skip the queue and even the voting.
> No power numbers. Are they talking about generating a picowatt or something like that?
The figures in the research article claims ~1pW. I still can't get the research paper, but reading the information that is available, and some enlightening discussions in HN I guess they measured a ~1pW exchange of heat in the other side of the device (the "lamp" in the animation). But it is ~1pW in one direction and exactly the same amount in the other direction. There is no net energy flux or "useful" energy.
This may be an useful experimental result in the research branch they are working, but not "Limitless Power".
> No power numbers. Are they talking about generating a picowatt or something like that?
The figures in the research article claims ~1pW. I still can't get the research paper, but reading the information that is available, and some enlightening discussions in HN I guess they measured a ~1pW exchange of heat in the other side of the device (the "lamp" in the animation). But it is ~1pW in one direction and exactly the same amount in the other direction. There is no net energy flux or "useful" energy.
This may be an useful experimental result in the research branch they are working, but not "Limitless Power".
Without getting all quantum about it, it seems to work by configuring the graphene as one electrode (or both) of a capacitor. As the graphene flaps in the breeze (actually Brownian motion, I assume), the changing geometry will change the capacitance. If there is a charge on the cap, then the voltage would flap too, inversely (Q = CV). A changing voltage would tend to push about a current (i.e. charge motion). If their diodes somehow have a negligible forward voltage drop, then brief moments of higher voltage on the flappy cap would push increments of charge onto the storage cap (the one to the right of the diodes) until the storage cap voltage rose to equal the peak flappy voltage (minus the diode voltage drop). When the storage capacitance is greater than the flappy graphene capacitance, the stored energy will be greater than the tiny increments (energy = 1/2 CV^2). Then every so often the storage cap could be switched to drive some load.
So why would there be a charge in the flappy capacitor? Well, a bias voltage is applied by this battery in the circuit. Ahem, before invoking any principles of thermodynamics, I'd like to see some detailed measurements, or even careful theory, of the current out of the battery and back into the battery, particularly w.r.t. the instantaneous voltages (P = VI), to prove that the time-average power delivered by the battery is precisely zero, or at least far lower than that putatively transferred to the load (light bulb in the animation). Otherwise it's behold, we found a high-resistance path for our battery to run a light bulb.
There is some precedent for semiconductor thermal magic in the Peltier junction. It makes one end colder and the other end hotter by applying electric watts to it, with no moving parts aside from the electrons and holes recombining, or something. But nobody sees thermodynamics being violated or extended there.
But here the magic is to take away thermal energy from one place, the flappy graphene (thereby cooling it) and moving the energy to the light bulb (thereby heating it). It seems you could then use any old heat engine to extract work by letting the heat flow from the resulting hotter place back to the colder place, getting "limitless power" for free from your perpetual motion machine. Conceivably it's a sort of heat pump that gets some multiplier above the battery power. But I think the burden of proof is on the Arkansas folks to explain how this can be. If I had more energy (no pun intended, really) right now I'd try to find the paper that the press release is based on, to see if there's a little more truth there.
Meanwhile, I doubt it.
So why would there be a charge in the flappy capacitor? Well, a bias voltage is applied by this battery in the circuit. Ahem, before invoking any principles of thermodynamics, I'd like to see some detailed measurements, or even careful theory, of the current out of the battery and back into the battery, particularly w.r.t. the instantaneous voltages (P = VI), to prove that the time-average power delivered by the battery is precisely zero, or at least far lower than that putatively transferred to the load (light bulb in the animation). Otherwise it's behold, we found a high-resistance path for our battery to run a light bulb.
There is some precedent for semiconductor thermal magic in the Peltier junction. It makes one end colder and the other end hotter by applying electric watts to it, with no moving parts aside from the electrons and holes recombining, or something. But nobody sees thermodynamics being violated or extended there.
But here the magic is to take away thermal energy from one place, the flappy graphene (thereby cooling it) and moving the energy to the light bulb (thereby heating it). It seems you could then use any old heat engine to extract work by letting the heat flow from the resulting hotter place back to the colder place, getting "limitless power" for free from your perpetual motion machine. Conceivably it's a sort of heat pump that gets some multiplier above the battery power. But I think the burden of proof is on the Arkansas folks to explain how this can be. If I had more energy (no pun intended, really) right now I'd try to find the paper that the press release is based on, to see if there's a little more truth there.
Meanwhile, I doubt it.
> Otherwise it's behold, we found a high-resistance path for our battery to run a light bulb.
It's like a nano Rube Goldberg!
Paper is here btw: https://arxiv.org/abs/2002.09947
It's like a nano Rube Goldberg!
Paper is here btw: https://arxiv.org/abs/2002.09947
> In the 1950s, physicist Léon Brillouin published a landmark paper refuting the idea that adding a single diode, a one-way electrical gate, to a circuit is the solution to harvesting energy from Brownian motion. Knowing this, Thibado’s group built their circuit with two diodes for converting AC into a direct current (DC).
So, they built a full-wave rectifier (albeit with only 2 instead of, say, 4 diodes)? Pretty neat to see electrical engineering fundamentals at work.
(also, for any who wanted specifics: article is at https://journals.aps.org/pre/abstract/10.1103/PhysRevE.102.0... ; abstract contains a couple of circuit diagrams)
edit: updated link, thanks for pointing that out
So, they built a full-wave rectifier (albeit with only 2 instead of, say, 4 diodes)? Pretty neat to see electrical engineering fundamentals at work.
(also, for any who wanted specifics: article is at https://journals.aps.org/pre/abstract/10.1103/PhysRevE.102.0... ; abstract contains a couple of circuit diagrams)
edit: updated link, thanks for pointing that out
Remove the semicolon at the end of the above link to get to the actual journal paper; paper is behind the APS paywall.
Working link for the lazy:
https://journals.aps.org/pre/abstract/10.1103/PhysRevE.102.0...
Working link for the lazy:
https://journals.aps.org/pre/abstract/10.1103/PhysRevE.102.0...
So apparently this is the “small device eliminates need for AC” that I see advertised everywhere! </s>
But in all seriousness, it seems this converts ambient heat (not a heat differential) directly into electricity. Therefore it must necessarily cool its surroundings by the equivalent energy extracted?
So it’s a kind of air conditioner which doesn’t use electricity to move heat but rather converts heat directly to electricity? I thought we “knew” this was impossible...
But in all seriousness, it seems this converts ambient heat (not a heat differential) directly into electricity. Therefore it must necessarily cool its surroundings by the equivalent energy extracted?
So it’s a kind of air conditioner which doesn’t use electricity to move heat but rather converts heat directly to electricity? I thought we “knew” this was impossible...
> “People may think that current flowing in a resistor causes it to heat up, but the Brownian current does not. In fact, if no current was flowing, the resistor would cool down,” Thibado explained. “What we did was reroute the current in the circuit and transform it into something useful.”
Based on this I understood that it'd indeed cool down and create a heat gradient if it wasn't doing any work, but the difference it'd create is instead used to induce a current, which means it probably wouldn't cool down as long as that potential is used in this way instead (?)
Based on this I understood that it'd indeed cool down and create a heat gradient if it wasn't doing any work, but the difference it'd create is instead used to induce a current, which means it probably wouldn't cool down as long as that potential is used in this way instead (?)
If it works, it'd be a great cooler for electronics that could put back into the circuit some of the electricity that had been turned into heat. CPU and GPU coolers could become built into the structure of the ICs themselves.
If the title of this post were true, the paper would have been published in nature instead.
While I share your disappointment in the quality of the press release, Nature is by no means the bar for measuring significance. I've been both accepted and rejected by Nature, I've seen colleagues accepted and rejected by Nature, and I've found results published outside of Nature, Cell, Science more reproducible!
I fully agree. But I still think if you could show violation of 2nd maw of thermodynamics and potentially solving all of human energy needs, I believe you would submit it to nature (or science). At least as signaling for getting funding for your trillion dollar startup commercializing the result.
What does 'limitless' mean, physically?
If I'm understanding the article correctly, a very tiny piece of graphene can pick up a very tiny amount of energy from the random jiggles at the atomic scale.
Presumably, those jiggles are always going to be there, unless somehow earth becomes a cold, dead place.
So imagine the solar panel on your calculator didn't need light, just a temperature above absolute zero.
Presumably, those jiggles are always going to be there, unless somehow earth becomes a cold, dead place.
So imagine the solar panel on your calculator didn't need light, just a temperature above absolute zero.
This is exactly what the press release say, but this is impossible due the the Second Law of Thermodynamics. So (select at least one)
1) The press release is wrong
2) The research article is wrong
3) The Second Law of thermodynamics is wrong.
[As a fast explanation, if the grapheme membrane and the lamp in the animation are at the same temperature, then the electrons in the lamp will get an equivalent amount of random jiggles and will counter the effect described in the article. (There may be also a similar problem with the diodes, capacitor, etc.)]
1) The press release is wrong
2) The research article is wrong
3) The Second Law of thermodynamics is wrong.
[As a fast explanation, if the grapheme membrane and the lamp in the animation are at the same temperature, then the electrons in the lamp will get an equivalent amount of random jiggles and will counter the effect described in the article. (There may be also a similar problem with the diodes, capacitor, etc.)]
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I think it's going to be able to essentially deliver a very small current virtually indefinitely.
That's how I understand it as well. It harvest the brownian motion of atoms in graphene.
I definitely don't know enough about this subject to judge the plausibility of the claim but "graphene" and "limitless power" in the same headline does trigger a few red flags.
I definitely don't know enough about this subject to judge the plausibility of the claim but "graphene" and "limitless power" in the same headline does trigger a few red flags.
I can't find the actual electrical power generated by the prototype circuit in the press releases, but it sounds like in the mA power range? It is "limitless" as long as the graphene mechanically survives (wonder how long that buckling will take to compromise the graphene) and there is some kind of minimum temperature maintained for the given required amount of electrical power output desired. Definitely not "free energy", but always good to reach further down into the physical realm in Feynman's "Plenty of Room at the Bottom" sense.
I'm rooting around for alternative sources of the paper without success, but for those who have read it, what kind of graphene did they use (monolayer, CVD, GO, rGO, etc.)? I suspect that will somewhat throttle the manufacturing supply chain.
Batteries are the least interesting application to me. This brings "sensor dust" out of solid fantasy into the realm of possibility in the far future; at first it will be "sensor clods", but let it follow the same evolutionary Shockley-to-ARM development path, and let's see where it goes. Permanently implanted medical chips to measure the blood, nervous and other internal medicine metrics we want to get our hands on might be more miniaturized; need to figure out how to extract out the incredibly weak signal.
I'm rooting around for alternative sources of the paper without success, but for those who have read it, what kind of graphene did they use (monolayer, CVD, GO, rGO, etc.)? I suspect that will somewhat throttle the manufacturing supply chain.
Batteries are the least interesting application to me. This brings "sensor dust" out of solid fantasy into the realm of possibility in the far future; at first it will be "sensor clods", but let it follow the same evolutionary Shockley-to-ARM development path, and let's see where it goes. Permanently implanted medical chips to measure the blood, nervous and other internal medicine metrics we want to get our hands on might be more miniaturized; need to figure out how to extract out the incredibly weak signal.
You’ll still need a source of heat. This is a power converter not a source of free energy.
But that means the graphene sheet need to be hotter than the surroundings? Or is this just converting heat from the air and infrared radiation into electric energy?
So essentially its converting energy from the sun, via latent heat in the atmosphere into energy
Could also use geothermal heat I guess
Could also use geothermal heat I guess
'bullshit'
Is this based on the physics of the Seebeck effect to generate a voltage from a temperature difference? https://en.wikipedia.org/wiki/Thermoelectric_effect#Seebeck_...
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So how much energy would you harvest by using these en masse to reduce the temperature of the earth by around 2.5 degrees centigrade? (I appreciate this is highly unlikely to be possible).
So it converts heat into work without a temperature gradient? That is the real revolution. I wonder if this could scale into a cooling solution for chips.
Isn't it some kind of antenna?
I might be completely wrong here, but I don't see that much of a difference, antennas are also "harvesting" power in some ways.
I might be completely wrong here, but I don't see that much of a difference, antennas are also "harvesting" power in some ways.
Can this be scaled up to provide power that isn't just a gimmick in the grand scheme of things?
this is the doi of the paper: https://doi.org/10.1103/PhysRevE.102.042101
I read the words "limitless power" and assumed it is crap. In case it it not, please reply to this comment, and I will give the article a read. There is no reason for you to do this, but thanks in advance, kind strangers.
The article is indeed garbage.
It smells like there's actually some interesting research being done here using graphene to extract energy from the ambient environment (possibly harvesting the work done as the graphene expands during hearing?) but the press release was written by someone who does not understand the subject at all.
It smells like there's actually some interesting research being done here using graphene to extract energy from the ambient environment (possibly harvesting the work done as the graphene expands during hearing?) but the press release was written by someone who does not understand the subject at all.
Sounds like nonsense to me but the article is so badly written that it's hard to tell. In fact it is hard to be sure whether they have actually created a prototype or merely simulated it.