CAUTION People often forget to
make seasonal adjustments. Ideal
angles (from horizontal) are:
Summer optimum = latitude –15°
Winter optimum = latitude +15°
CAUTION: 0-25° latitudes: Apply a
minimum tilt angle of 10°, or dust
and debris will accumulate.
Setting the Solar Array 3.5 Tilt Angle
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:
Year-round compromise1. (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.
Seasonal adjustment2. 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.
Seasonal use only3. If the pump is to be used no
more than half of the year, set the array to the appro-
priate 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).
Solar Array Tilt Angles by LatitudeTable 1:
Location
(example)
Latitude Summer Tilt Winter Tilt Year-round
Compromise Tilt
Southern Canada 50° 35° 65° 50°
Upper Third USA 45° 30° 60° 45°
Middle Third USA 40° 25° 55° 40°
Lower Third USA 35° 20° 50° 35°
Central Mexico 20° 5° 35° 20°
To Next Page
Loading...
Need help?
General
