Recent content by thopsy

The first part of what you said is true. If you had blue light hitting a perfect cell with a blue bandgap, you would get a very high efficiency. However you would never get 100% due to radiative recombination under the conditions of detailed balance. Basically some of the electron-hole pairs...

Unfortunately, a prism generally only works under collimated radiation. Otherwise each color will not be properly separated. Therefore, I recommend you remove the prism. You can buy triple-junction cells (e.g. from Azur Space, or Cyrium) with efficiencies above 40% under concentrated radiation...

The direct normal irradiance (DNI) on a sunny day is around 1000 W/m^2, though values from 600-900 are more common due atmospheric attenuation. Generally a DNI of 1000 W/m^2 is used as a standard value and is termed "1 sun". The total irradiance can only be intercepted for a 2-axis tracking...

Atmospheric attenuation!

Can it be made work at lower intensities? The maximum possible concentration ratio for sunlight is < 50 000 times (for a cell immersed in a medium of refractive index = 1). For a direct normal irradiance of 1000 W/m^2, this gives a maximum solar flux on the cell of 50 million W/m^2. According to...

Thanks for the sketch. It's quite difficult to calculate the heat transfer for a complex geometry like this, but you can do a simplified calculation. In general smooth flow has worse heat transfer. The rough profile caused from the drill holes will help to create turbulence which increases the...

Eeek, people are going to be upset. I forgot that Tidal energy comes from gravitational forces, not from the sun. Sorry. But anyway the Tidal resource is rather limited.

Oops, I didn't realize that, sorry. Actually, solar is the only ongoing source of energy on the Earth, (I guess you could count Nuclear potential as non-solar), so the question of cost is rather moot once we run out of fossil fuels.

Jeez, I hope not. My knowledge ends here. :(

Here's something quick and dirty, and also very useful. It will give you the wavelength corresponding to the maximum blackbody spectral emissive power for a given temperature, i.e. which portion of the EM spectrum emits the most energy at a given temperature. It's called Wien's displacements...

Thermal radiation is a VERY important topic in Mechanical Engineering. I have taken an entire course on thermal radiation heat transfer and it was probably the most interesting course I have ever taken. This topic is of special importance to the field of solar energy, which is, in my opinion...

One more thing...the change in the speed of light is due to a change in the "phase velocity", i.e. the speed of the propagating wavefront, and not the velocity of the photons.

@Drakkith...neither. Photons like Dyson all the way.

Let's be clear on something...electromagnetic radiation, i.e. electromagnetic waves, is composed of photons (no mass), not electrons (which have mass).

A perfect vacuum is a finite area with zero mass (no atoms, or other massive particles, protons, neutrons, electrons, positrons, etc...). Electromagnetic radiation is composed of photons, which, to my understanding, have zero mass. Therefore, you certainly can have electromagnetic radiation...