Split Spectrum Benefits

Repnitskiya,

The long, parabolic arrays of mirrors provide a concentrated full spectrum of sunlight. Any material in the path of that light will diminish part of the spectrum of light thus reducing the efficiency of the heating of the metal tube filled with an oil that's encased in specialized glass. The glass is a type that is able to pass more of the light spectrum than any other type of glass.

Removing part of the light energy to be used to energize photovoltaic collectors would diminish the efficiency of both the production of steam and photovoltaic power due to the inefficiency of photovoltaic conversion and the optical filtration effect of the prism material.

Jon

Hi Jon, my name is Andrey. Removing all visible and UV light from heating process will not affect the process much, because only infra red light is producing heat. I am not a specialist on PV panels, but I heard from one that the panel will not produce electricity from whole spectrum of the sun light, and people try to use the most efficient part of it. And it is true that some semiconductor materials will work on higher frequency and will not work on lower, when other will not work on high frequency light but will produce electricity on lower frequency... If we do not separate the spectrum, we might not be able to find such a universal semiconductor which would work on whole spectrum.

Another thing is that on Nevada-1 they "compress" light 70 times! It means that the light is of very high intensity; so, maybe other semiconductor materials will be needed, different from those we use now, but the good news is that the demand for the photo voltaic, the most expensive part, is 70 times smaller. The visible and UV lights will not heat the panel (at list not much) because heat is produced by infra red rays that are concentrated on the pipe. Thank you for your comments!

Hi Andrey,

Nice to see you here.

Your idea has merit.

Each portion of the solar spectrum is associated with a different level of photonic energy. Within the visible portion of the spectrum, for example, red light is at the low-energy end and violet light is at the high-energy end. In the invisible portions of the spectrum, photons in the ultraviolet end of the spectrum have more energy than those in the visible region. Likewise, photons in the infrared region have less energy than the photons in the visible region.

Separation of the light spectrum is a good idea for Photovoltaic production of electricity because Photonic energy is greater above the red end of the spectrum and Photovoltaic materials mostly use photons from that end for conversion of light to electricity. Heating effects from the photonically weaker red end of the spectrum cause a greater need for cooling in the designs for Photovoltaic panels.

However, the process of spectral separation, such as using optical materials like prisms or filters in the path of the light reduces the efficiency in both heating effects for the boiler and especially the photonic effects for Photovoltaic production of electricity. Even plain glass blocks a huge amount of light in the UV end of the spectrum.

But the energy source is free so it may not matter so much in the end result.

That being said, building very large Photovoltaic arrays attached to the mirror system would keep them aligned for maximum exposure to the sun and using less concentration of light would require less need for cooling.

The initial expense may be great but would pay for itself over time.

Jon

You are right,

this approach s much better for photovoltaic electricity.

If the light is split into "colors" then 3 or more different solar cells may be used so that efficiency is optimised. These solar cells have their maximum conversion efficiency in the blue, green, red...

Freiburg, GERMANY, Fraunhofer Institute, is developing this since a long time but no commercial use until today.

RHABE