Is he trying to violate the laws of thermodynamics?
The front has to let sunlight in, but then keep photons from
escaping. ..... This takes photons from a broad area and
funnels them into the PV chip. The other end of the U acts
like a reflective cap, making it very hard for a photon to
escape from the chip without being reflected back into it.
So basically a funnel with a wide part and a narrow part? And since it's narrow it's less likely for a photon to enter?
That actually doesn't work - the intensity at the narrow end is higher, and the total number of photons going in each direction is exactly the same.
One way mirrors do not, and can not, exist.
(One thing that does work is having slanted walls and lots of reflections giving many opportunities for the photon to be absorbed. But if it doesn't it will inevitably escape again.)
Somebody has already explained it in the comments in the article:
"The light coming in the from sun is pretty directional, and a parabolic setup will focus it down to a handy point. The photons being emitted by the the chip are more diffuse and so most will be reflected back down to be re-captured."
Comments
Is he trying to violate the laws of thermodynamics?
So basically a funnel with a wide part and a narrow part? And since it's narrow it's less likely for a photon to enter?That actually doesn't work - the intensity at the narrow end is higher, and the total number of photons going in each direction is exactly the same.
One way mirrors do not, and can not, exist.
(One thing that does work is having slanted walls and lots of reflections giving many opportunities for the photon to be absorbed. But if it doesn't it will inevitably escape again.)
Somebody has already explained it in the comments in the article:
"The light coming in the from sun is pretty directional, and a parabolic setup will focus it down to a handy point. The photons being emitted by the the chip are more diffuse and so most will be reflected back down to be re-captured."