Is a Sun-Solar Cell System Truly Equivalent to a Carnot Engine?

[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?

 

[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.

 

[russ_watters]

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

 

[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.

 

[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).

 

[russ_watters]

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).

That part is true and much better than using Carnot.

 

[jontyjashan]

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

 

[nsaspook]

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