# Energy transfer in solar panels

1. Sep 1, 2013

### ZanyCat

Compound A has an albedo value (visible spectrum) of 0.08, and an emissivity (infrared) of 0.08.
Compound B has an albedo value of 0.04 and an emissivity of 0.88, in the same spectrums.

We need to explain why A is more effective at transferring energy to the water flowing behind it, when used as a coating on a solar panel.

So far, I've determined that (imagining the incident sunlight is, say, 1000W)...

- B reaches a higher temperature when at thermal equilibirum
- B reflects 40W, absorbs 960W, and thus emits 960W at thermal equilibirum
- A reflects 80W, absorbs 920W, and thus emits 920W at thermal equilbirum

So B is both at a higher temp (and thus has a higher transfer of energy by Newton's law of cooling) and it's also emitting 960W, as opposed to 920W for A.
So everything seems to be pointing to B as a more effective energy transferrer.
Where am I going wrong?

Thanks :)

Last edited: Sep 1, 2013
2. Sep 1, 2013

### ZanyCat

This is falling quickly off the front page so I'm going to be petulent and bump it.
Didn't post any formulas because alfredo/reflectivity and emissivity are pretty much just ratios.