Solar cells and Carnot Engine

1. Jan 27, 2014

jontyjashan

I have undertaken a course on Semiconductors. My professor told us that a sun-solar cell system can be taken as a Carnot Engine. He assumed that the surface temperature of sun is 6000k and that of solar cell is 300k.And then he found out the efficiency by (1-T1/T2), which came out close to be around 100 percent. How far this analogy is true? And on the first note, why is this analogy made? Can I get some serious calculations?

2. Jan 27, 2014

Baluncore

I think it is a major distraction.
The wavelength of the light from the sun is narrow band because it passes through the atmosphere.
The efficiency of a solar cell involves it's band gap energy matching the energy of the available wavelength photons.

3. Jan 27, 2014

Staff: Mentor

Agreed. Seems a very odd/pointless calculation. Clearly, right now solar cells are limited by other issues that keep them well below Carnot efficiency.

4. Jan 27, 2014

sophiecentaur

Hmmm. Sounds to me like someone trying to be too damned smart by saying something just to confuse the students. There may be some validity there but he certainly isn't help anyone's understanding of anything.

5. Jan 27, 2014

jontyjashan

He also said that if we take into account black body radiations , then we can make calculations very close to the actual efficiency(around 16-32 percent).

6. Jan 27, 2014

Staff: Mentor

That part is true and much better than using Carnot.

7. Jan 27, 2014

jontyjashan

OK. Can I get a link or the actual calculations themselves?

8. Jan 27, 2014

nsaspook

http://org.ntnu.no/solarcells/pages/Chap.2.php [Broken]

Last edited by a moderator: May 6, 2017