Physics 10273 - Solar Energy Lab

These are the paths of the Sun across the sky as seen from Fort Worth (latitude of 33 degrees North). Each dot represents the Sun at a given hour, so the dots are an hour apart in time. The pink gridlines parallel to the horizon are marked at altitudes of 10, 30, 50 and 70 degrees. Solar cells work best when the Sun is at least 30 degrees above the horizon, assuming the sky is clear and the PV cell is pointing towards the Sun. For about how many hours of the day at each time of year is the Sun more than 30 degrees above the horizon?

These are the paths of the Sun across the sky as seen from Honolulu, Hawaii (latitude of 21 degrees North). Note how much longer the Sun is at a favorable altitude during the day.