My correspondent elaborates on high tech materials:
I was thinking more along these lines: http://news.mit.edu/2016/hot-new-solar-cell-0523
Ah! Interesting!
The basic principle is simple: Instead of dissipating unusable solar energy as heat in the solar cell, all of the energy and heat is first absorbed by an intermediate component, to temperatures that would allow that component to emit thermal radiation. By tuning the materials and configuration of these added layers, it’s possible to emit that radiation in the form of just the right wavelengths of light for the solar cell to capture. This improves the efficiency and reduces the heat generated in the solar cell.
I forget the name of the principle, but I ran across it in The Climate Fix, I think. Basically, the reason CO2 is a hot house gas is this: Sun light (radiation) at the most energetic frequencies reaching the earth is not absorbed by CO2, but it is absorbed by the Earth. By some well-understood principle, which of course I’ve forgotten, all objects emit the energy they absorb, but at a different wavelength. So when the Earth emits the energy it’s absorbed from the Sun, the emission is at a different wavelength – one (more likely a small range) to which the CO2 is not transparent! Thus, by increasing the percentage of CO2 in the atmosphere, we increase the energy retained by the atmosphere – and, thus, we become hotter.
This sounds like the same principle – converting the energy from difficult to harvest wavelengths to easier to harvest wavelengths. I like it. I wonder if any energy is lost in the conversion…
