amount of radiation received dependng on angle

[jc.int]

hello,

I'd like to know how does the solar radiation received on a flat surface vary if we change the angle of it.

To simplify, if I've got a board of 1*1meters (at 0º -parallel to the ground-) and it is receiving 1Kw/h, the sun being at 90º, how will it received if I turn it 10º?

 

Thank you

Jaime

[John Cuthber]

You move it so the sun hits it at 80 degrees rather than 90.

Sin(80º) is 0.9848

It will receive roughly 985W.

 

There is another factor- more of the light will be reflected from the steeply sloping surface so the efficiency drops more rapidly than the simple geometry would suggest.

That factor depends on the material from which the cell is made etc- it's rather difficult to calculate. If I were you, I would ask the manufacturer how the angle affects the energy output.

[jc.int]

Thank you for your reply,

can you explain me why do you use the sine of the angle?

 

Jaime

Edited January 8, 2012 by jc.int

[swansont]

Thank you for your reply,

can you explain me why do you use the sine of the angle?

 

Jaime

 

It's the projection of the area onto the perpendicular surface. Draw the triangle and you can see it's the sine.

[jc.int]

In this case, wouldn'y it be the cosine? If you look at this graph, where [bC] is the board, it seems that the projection of the area onto the perpendicular surface is the cosine,isn't it?

Edited January 9, 2012 by jc.int

[swansont]

I can't view the image, but it would probably be the other angle, since sin(80) = cos(10). John used the large angle, and I'm guessing you are looking at the small angle.

[jc.int]

ok, I've understood the answer.

Thank you very much for your help,

Jaime