The graphene isn't pulled taut like a sheet pulled flat, but slightly loose, like a sheet slightly drooping, and the graphene naturally buckles and deforms.
Imagine air molecules colliding with the sheet causing buckles to form, invert, or flatten out, with the deformation popping up nearby.
Each time it buckles, a tiny current is generated. If it buckles in one direction, current goes one way, if it buckles in the other direction, current goes the other way.
Because of quantum effects - brownian motion - no collisions have to occur, the heat going into the graphene sheet itself is enough to chaotically produce buckling, with a direct transformation of mechanical energy deformation to electricity.
Heat storage is really easy. It'll be interesting to see how efficiency scales, in practice. If it exceeds modern thermoelectric performance, it's got a future, but this might get really high efficiency. The limit is the effective surface area of the graphene.
Because it's solid state, it makes low temperature / shallow geothermal much more feasible.
No gradient needed is the revolutionary phenomena here. It's a solid state quantum motion based electricity generator. The higher the temperature, the more rapid the brownian motion, the more power is produced.
What I don't understand is what would happen if you put a bunch of these inside a highly insulated really hot cavity. The paper suggests that it doesn't cool down while generating current, but that it cools while no current is being drawn. Is that just a "wtf, nature?!" thing or is something being missed?
I really think you are misreading the paper. They are specifically calling out that they aren't claiming to be Maxwell's demon and they the system quickly reaches equilibrium and the power drops to zero.
Nope, the quantum dynamics of individual atoms of carbon cause the buckling, no gradient needed. It doesn't make macro sense. I'm leaving the door all the way open for some alternative explanation, but so far the science seems solid. It needs to be replicated and scaled up.
The weird bit is the cooling while not passing current. Does the system as a whole have a tendency to cool, and why does removing energy as electricity not cool it down? Is the quantum buckling effectively separated from the heat of the system? Particles are weird.
I guess I'm confused about the source of the buckling, then. Is it directly caused by air molecules colliding with the graphene?
If that's the case, then by definition, as current is produced, energy is taken from the collisions mechanically, and temperature would decrease. Thibado says that when current is not flowing the resistor cools down, and implies that when current is flowing, it doesn't heat up.
>>“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.”
If current is produced and the system isn't extracting heat (cooling) then the energy has to come from somewhere, right? That's why I was assuming they were talking about the Brownian motion of the graphene itself. If it's just the graphene, the system would work in a vacuum. If it's air molecules then Thibado has to be wrong, or the quote was sloppy or out of context.
The buckling is caused by hits of the air molecules, sound waves transmitted by the support, photons that hit the surface (probably very small at room temperature), and any other stuff ...
The idea is that the resistor acts as a small generator that produces a current that is electric notice. This transform some mechanical energy into electricity, and in a magical universe it would cool down the resistor.
The problem is that the rest of the circuit is also producing electric noise. So the small current of the noise of the rest of the circuit goes to the resistor and is dissipated as heat and warms the resistor.
If you live in a magical word, you can magically turn off the noise of the rest of the circuit, but in the real word that is impossible and both effect cancel and the resistor keeps it's temperature.
This is pretty standard theory, but perhaps it's not the best way to explain it.
My guess is that the important result of the research paper is that the spectrum of the noise of the part of the circuit with the graphene is different of the spectrum of the noise of the resistor. It's interesting, but it does not break the current laws of Physics.
>>> What we did was reroute the current in the circuit and transform it into something useful
That's a direct jump into the "totally wrong or Nobel price" category. That's a claim that breaks the Second Law, so they are totally wrong or they get a Nobel price, there is no middle ground. (Sometimes the Nobel committee takes a few year to assign the price, but a result like this would cause immediately a huge discussion in the Physic community, like the discovery of the Higgs boson or LIGO.)
Imagine air molecules colliding with the sheet causing buckles to form, invert, or flatten out, with the deformation popping up nearby.
Each time it buckles, a tiny current is generated. If it buckles in one direction, current goes one way, if it buckles in the other direction, current goes the other way.
Because of quantum effects - brownian motion - no collisions have to occur, the heat going into the graphene sheet itself is enough to chaotically produce buckling, with a direct transformation of mechanical energy deformation to electricity.
Heat storage is really easy. It'll be interesting to see how efficiency scales, in practice. If it exceeds modern thermoelectric performance, it's got a future, but this might get really high efficiency. The limit is the effective surface area of the graphene.
Because it's solid state, it makes low temperature / shallow geothermal much more feasible.
No gradient needed is the revolutionary phenomena here. It's a solid state quantum motion based electricity generator. The higher the temperature, the more rapid the brownian motion, the more power is produced.
What I don't understand is what would happen if you put a bunch of these inside a highly insulated really hot cavity. The paper suggests that it doesn't cool down while generating current, but that it cools while no current is being drawn. Is that just a "wtf, nature?!" thing or is something being missed?
I can't wait for this to be replicated.