Comment by schiffern
>But so do solar panels. A PV system turns a moving particle (a photon) into an energy gradient, a voltage.
Solar panels only work because there's a temperature difference between the panel and the optical surface of the Sun.Solar panels are not an example of a Carnot violation. As far as we know, no such examples exist.
https://en.wikipedia.org/wiki/Solar_cell_efficiency#Thermody...
> Solar panels only work because there's a temperature difference between the panel and the optical surface of the Sun.
I believe this isn't quite true (even though it's often repeated).
Consider that you could have an LED, at the same temperature as the PV cell, emitting light onto the PC cell, and so the PV cell would "generate" power without a temperature differential.
The Carnot cycle applies (in its initial form, at least), ONLY to generating power from temperature differentials, but PV uses the photoelectric effect, not temperature differentials.
This is not my area of expertise, but I think you can generalize the Carnot efficiency to talk about low-entropy energy sources instead of temperature differentials, but it's not quite as simple as associating a light wavelength with a temperature, because that doesn't work for radiation from something that's not a black body (like a laser or an LED).