SOLAR PUMPING Guidelines - Electrical design and installation of solar pumps
3. OPTIONAL COMPONENTS 8
SOLAR TRACKING SYSTEMS (MANUAL OR AUTOMATIC) Photovoltaic solar panels perform best when the collecting surface is oriented perpendicularly to the sun’s rays. If panels are
fixed, with the ideal orientation and the ideal tilt angle, then the panels will only catch the sunlight perpendicularly for a very
short time: between 12Noon and 2PM, in spring (March) and autumn (September).
Outside this window (time of the day and year), the sun’s rays will not be perpendicular to the panel’s surface, and solar
panels will produce less than their potential output. To maximize the panel’s performance, it is possible to install panel
supports with the ability to change their orientation and / or their tilt depending on the season and time of day. This can be
done manually or automatically.
Fully automated systems (see picture beside) are commonly called solar tracking systems in
all countries (including French speaking). They are not recommended for rural and remote site
installations because the risk of failure and limited repair options can have an important impact.
On the other hand, we should not ignore the possible gains that can be made by installing a
simple system, i.e. by changing the orientation and / or the tilt of the panels manually.
Manual modification systems of the horizontal axis according to the season (figure 12) generally
increases the yield by + 15% per year compared to a fixed support. Manual modification with
vertical or inclined axis (figure 13) allows for a 25% gain in efficiency compared to fixed supports.
These last systems have a great potential but require having an operator permanently on-site to
modify panels orientation according to the time of day.
FIGURE 12: HORIZONTAL AXIS MODIFICATION - MAIN SYSTEMS (following the season)
Central axis
Locking/Moving system at the
rotation axis
Central axis
Locking system backside of
the panel
Tilt modification by
changing legs length
FIGURE 13: VERTICAL AXIS MODIFICATION – MAIN SYSTEMS (following hours)
Tilted axis for important latitudes
(> 40°)
Vertical central axis – self standing
(small group of panels)
Offset axis with support on circular
concrete strip
Rear view of “solar tracking system” Full automatic system (dual-axis).
