SOLAR ENERGY 101: Solar Trackers - Part I

Posted on the 09 November 2012 by Derick Ajumni

The concept of Solar trackers was mentioned briefly when we discussed the types of solar PV - Part II. We said that it involves including a tracking mechanism with the PV installation that enables it to  follow the sun as it moves across the sky. We also noted that this addition makes the system produce more energy and provide the biggest returns in net metering. The advantages of orienting a solar PV installationSouthwards was also discussed, and clearly solar tracking technology builds on this notion - better orientation for optimum performance.

Flat surface depicts panel

Well today we are going to elaborate on this point and dig deeper into the realm of trackers and how they are used in the solar energy industry. A solar tracker is a mechanism that when added to the solar PV installed system constantly verifies and orients the panels towards the sun. The idea behind using trackers is thatsolar panels are static - and the sun isn't at any time in the day - so trackers are used to help optimize the incidence angle at which the sun's rays reach them.
The use of solar trackers is occasional for flat PV systems as long as the engineer gets the orientation right. But on concentrated PV installations mostly for large commercial energy systems, its often paramount to include a tracker as the inclinations of individual panels make it difficult for optimal incidence sincethe sun shifts in the sky. It is often advised that the sun's rays reach the panels at a perpendicular angle or in other words the incidence angle as shown in the diagram above should be reduced as much as possible. 
By trying to avoid too much tech details we can add that the use of a solar tracker increases the system's output by 50 percent in the summer months and by 20 percent in the winter months. Solar trackers are grouped under two basic categories the single axis trackers and the dual axis trackers. The single tracker rotates east to west following the sun's movement, and the dual trackers include vertical and horizontal movements i.e. they can incline or tilt to account for winter and summer sun angles.
We'll continue the discussion in a Part II by discussing the various tracking techs including the pros and cons of adding trackers to an installed system in our next update.