Yep, a lot of people are confusing the impossible of eg. "We can never go to the moon", which was actually just an exaggerated infeasible - it was possible, but only at great expense - with the literally physically impossible.
The moonshot wasn't about the laws of physics, it was about the laws of economics. A scale-up problem in terms of money. Whereas this charger is about trying to evade some very difficult laws of physics.
Even if you exclude the extreme physical improbability of the device, it still has massive problems in terms of practicality. It would require installing a large number of expensive ultrasound emitters in every coffee shop and fast food joint. Then installing recievers in every phone. And it will still be massively inefficient power-wise. Whereas the alternative is to install comparatively low power, more efficient wireless charging pads in every table.
So even ignoring the physics, this was going to be an incredibly hard sell.
Yup. Some things (not all) are impossible in a literal sense.
Want to extract 2 kW / m^2 from solar radiation somewhere near the Earth? Won't work, the Sun doesn't pump out that kind of power density (the max is 1.whatever kW). Literally impossible.
No you can't, because you're increasing the surface are of the collector so the 1.366kWh / square meter still stands.
From Wikipedia:
Average annual solar radiation arriving at the top of the Earth's atmosphere is roughly 1366 W/m2. The Sun's rays are attenuated as they pass through the Atmosphere, leaving maximum normal surface irradiance at approximately 1000 W /m2 at sea level on a clear day.[1]
Therefore it is impossible to get more than about 1kW / m2 from any solar panel. Until such times as something fairly fundamental changes, like a loss of atmosphere or an increase in energy output from the sun.
Well, you're mostly correct; but not technically correct.
From /just/ a solar panel it isn't possible to achieve higher density, however you can use reflectors in the spectrum that your solar panel operates in to increase the energy available for capture at a focal point.
But there's also TheSpiceIsLife's opening comment which says:
> ...you're increasing the surface are of the collector so the 1.366kWh / square meter still stands.
It feels like your second sentence
> ...[H]owever you can use reflectors in the spectrum that your solar panel operates in to increase the energy available for capture at a focal point.
plays rhetorical games by ignoring the existence of large parts of your solar collector (namely the reflectors) in order to arrive at an inflated energy density figure.
