Solar trackers adjust the reception angles of solar equipment for optimal energy collection. Due to Earth's rotation the sun transits across the terrestrial sky, and Earth's axial tilt causes a variety of sunlight reception angles. To maximize the amount of sunlight a PV panel, reflector, or lens is exposed to, the solar tracker keeps reception surfaces at the optimal angle of incidence. In commercial applications solar trackers are essential to harvest energy efficiently. Many factors should be considered when purchasing solar trackers: power usage, drive type, government rebates, land constraints, latitude, and climate.
Solar trackers are classified by the type and number of axes they offer. Single-axis trackers have one axis upon which the tracker can rotate components, be it vertically or horizontally. All other single-axis trackers are considered tilt trackers and operate about the Y axis. Polar trackers, a type of tile trackers, maintain a tilt angle equal to the latitude of its location. Single-axis trackers are popular for positions which are very high or very low in latitude. Dual-axis trackers can move components around two axes of rotation. Tip-tilt trackers have a vertical orientation determined by the rotating base of the equipment, while a separate mechanism determines the horizontal angle; azimuth-altitude trackers operate conversely. These types of solar trackers ensure a very low angle of incidence in moderate latitudes.
Image credit: Project Free Power