#Solar mooc problem set 1 alternate exercise 1 solution.
1. Answer to Alternate Exercise
#1 from Problem #1
SolPowerPeople, Inc.
Austin, TX
March 5, 2012
2. Question
You are designing a ground mount PV array at 30°N
Latitude with multiple rows that faces true south. The tilt
of the modules are 20°. The width of the modules are 39
inches and they will be installed in landscape layout.
What is the closest distance the rows of the modules can
be and not cause any shade during the hours of 8AM and
4PM solar time?
3. 1st Step Determine Height of
back of module
39”
?
20°
4. 1st Step Determine Height of
back of module
We have the
angle theta, and
we have the
39” hypotenuse, and
? we need to know
the opposite, so
we should use
20° the sine
function…
10. Now solve for shadow length
We know the opposite, and we have the angle, and we
want to solve for the adjacent, so we use the tan function
39”
13.34”
20° 12°
?”
14. Now solve for distance
between rows
So now we know the angle, and the
hypotenuse, and we need to solve for the
adjacent. We must use cosine function. ?” 66.76” (from prev slide)
55°
15. Now solve for distance
between rows
adjacent
cos(q )° =
hypotenuse
adjacent
cos(55)° =
66.76"
?” 66.76” (from prev slide)
adjacent
0.5735 = 55°
66.76"
adjacent = 66.76"´ 0.5735
adjacent = 38.28"
ANSWER: ~38.28” (depending on how much rounding you did)