I have some devices that need to know the sun position. It is a subject that comes up from time to time on the forums as well. I found some code that worked very well, but is a monolithic program. So I did a lot of work on it, and packaged it in a library. I have the approval of the original author, who says he is interested about how people are using the program. A special feature, is some math to prevent inaccuracies due to floating point truncation when using the standard formulas verbatim.
Nice work. 
In the same spirit, I wrote a more complex Arduino library for the full Solar System: equatorial coordinates (RA/Dec), horizontal coordinates (Alt/Az), rise, set, distance (in A.U), and apparent diameter (in arcminutes) for Sun, Mercury, Venus, Earth's Moon, Mars, Jupiter, Saturn, Uranus, Neptune.
Thanks for sharing!!!
Hi,
This will be great to have a solar pannel at an optimal position.
Thanks!
Jacques