Lexicon: Single & Dual Axis Solar Trackers
photo: Concentrix Solar
Nevermind Single or Dual Axis varieties, what are solar trackers?
In the broadest sense solar trackers move the solar panel so that it is position as close to optimum as possible in relation to the angle of the sun, across seasons and time of day. Compared to just laying a panel flat, correct positioning can boost the panels output by up to 15%, but by using a motorized tracker gains due to efficiency of between 27-40% can be achieved.
Currently, there exist two types: Single Axis and Dual Axis. Single axis trackers move on one axis over the course of the day, following the sun; doing so can boost output by about one-third. Dual axis trackers on the other hand move both east and west but also vertically; this can increase output by 35-40% as compared to a flat panel.
Single-axis tracking is one of the most straightforward ways to improve the potential performance and economics of a commercial solar installation. By using relatively simple equipment, considerably more performance can be expected. Tracking system manufacturer RayTracker, for example, says its systems have been proven to improve energy yield over fixed angle modules by up to 23% and over flat modules by 38%.
Manufacturers of the simpler, single-axis devices have claimed that the additional net energy yield delivered by a dual-axis system over a single-axis system is frequently lost as a result of additional installation, permitting and on-going maintenance costs. And, such systems are at greater risk of failure, having more moving parts than a single-axis tracker. Furthermore, single-axis trackers tend to have a lower profile, sometimes half the height of dual-axis trackers, and are therefore more likely to receive planning permits.