13
Solar Array Tilt
Angles by
Latitude
0-25° latitudes: Apply a minimum tilt angle of
10°, or dust and debris will accumulate.
4.5
Setting the Solar Array Tilt Angle
CAUTION People often forget to make
seasonal adjustments.
Ideal angles (from horizontal) are:
Summer optimum =
latitude - 15°
Winter optimum =
la 15°
Maximum performance is obtained from a
solar pump when its photovoltaic array is tilted
(elevated) to face the sun. The solar array
racks that are supplied with
the Pump
Systems
are adjustable to the desired tilt
angle. It is the responsibility of the installer to
perform this adjustment.
Some
systems
include a solar tracker, and
others with a fixed (non-tracking) rack. Both
types of array have a manual tilt-angle
adjustment. (The tracker follows the daily
path of the sun, but not the seasonal tilt
variation.)
The optimum tilt angle is determined by the
location (latitude). It also varies with the time
of the year. This data is presented in the table
below.
Should the tilt angle be adjusted periodically
through the year? This depends on the
seasonal water-use pattern, and also on
human factors. There are three options to
chose from.
Select one of these options for seasonal
management:
1. Year-round compromise
(no seasonal
adjustment) Set the angle equal to the latitude
of the location and “forget it”. This is practical
because people often forget to adjust the
array. The performance displayed in the
System Sizing Table
is based on this fixed
compromise setting of the tilt-angle.
2. Seasonally adjusted
It is sufficient to
perform the adjustment only twice per year, at
the spring and autumn equinoxes, to the
summer and winter angles indicated below.
For central USA, this will increase the daily
water production by about 8% in summer, 5%
in winter compared to option 1.
3. Seasonal use only
If the pump is to be
used no more than half of the year, set the
array to the appropriate seasonal angle
shown below, and “forget it”.
If you use the pump all year but do not want
seasonal adjustment to be required, set the
angle to
year-round compromise
(equal to
latitude).
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