4.

a) Solar constant is 1367 W/m², and the average at the top of the atmosphere is 342 W/m² and about half of this is absorbed at the surface. How much solar radiation on average is absorbed at the surface during daytime?

b) Assuming the atmosphere absorbs 16%, how much is incident at the surface for an overhead sun?

c) Using the same conditions and the answer of b), how much per unit area would be absorbed in a roof per unit roof area, if the roof is tilted 60º to horizontal?

d) same as b), but the sun is 30º from the horizon

e) use Eq. (2.15) to determine the solar zenith at noon at 30ºN

f) repeat c) for 10 am, and at the equator

g) An architect wants to put an overhang on a house at 30º N that will shade the top 2 m of the wall from the spring to the fall solstice. What would be the minimum extent of this overhang to meet this objective?

h) do problem 2.7 of the book

i) do problem 2.8 of the book.