Question

The concept of a projected area is important so that designer can calculate the effective area (in^2) of a surface exposed to solar rays which will in turn be multiplied by the slolar irradiation to determine the energy striking the surface at any given instant time. A projected area exists when the solar ray and a surface are not at rght angles to each other. The projected area can be found by multiplying the surfce area by the cosine of the angle between the normal and solar ray . Use sketch and geometry /trignometry to show and prove the relationship.

At noon on the winter and summer solstice, calcuate the power output of a photovoltaic system with 12% efficiency. The stationary solar cell panel is positioned at an angle 30.6 degrees above the horizon. Also the solar system is 12 square meters in size and it is mounted so that the equinox the sun's ray are normal to the surface. Recall that at noon on the winter and the summer solstice, solar rays are 36 degrees and 83 degrees above the horizon respectively. show all work inlcluding detailed sketches and explanations

Answer 1

The solar irradiation to determine the energy striking the surface at any given instant time theta rightarrow between of normal radius Projected area = AB (area 1as to rays) } Let width lex Actual area = AC n = (normal to AC as shown) = (AC) ^x projected area, AP = (AB) x = (AC cos degree) x = (AC) x cos theta AP = A cos theta