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Tracking systems are designed to orient your solar panels toward the Sun. They will add an extra level of performance to your solar power system, for a little bit of expense and complexity.

Tracking systems are needed because of the complex path of the Sun. It traces an arc every single day, with a peak elevation that differs through the seasons. The more our solar panels are pointed directly at the Sun, the greater the beam radiation they will receive. This is the basic principle of a solar power tracking system.

When analyzing solar energy data, one can quickly see the advantage of a tracking system. We studied the State of Montana and found that summer time increases of 50% can be obtained. Spring and Fall months showed strong gains possible at 25% to 30%. Winter months showed an improvement of approximately 15%. The exact value of these numbers will depend on the type of system used and the installed location.

One of the first tracking units one might consider is a manually adjustable one axis system. With a simple adjustment, the solar panels can be rotated on their horizontal axis to any angle. Each season will have an optimal tilt angle for maximizing the Sun. By adjusting our solar panels to that angle, we experienced summertime gains of 25% compared to a fixed solar panel installation. In the winter months this improvement was ~15%.

Automatic (active) one axis tracking systems are also available. They are self-adjusting units that rotate daily with the arc of the Sun. Performance gains are 40% or more in the summer months, which commands serious consideration. There is the added complexity of the electronic and mechanical control mechanisms, but this cost can be offset by their superior performance.

Two axis tracking systems are the most complex and most accurate installations available. With these systems, your solar panels have additional flexibility on their vertical axis (East to West). These systems are the most exact when it comes to following the Sun.

Two axis tracking is often used with concentrating solar collection systems. Solar concentration is necessary when higher operating temperatures are desired. Thermal steam generators, pebble bed transfer systems, and modern Stirling engines are two such examples. If the concentrating collectors are not perfectly oriented with respect to the Sun, then their performance will greatly suffer. Concentrating solar collection designs, then, benefit most from the two axis systems.

Two axis tracking is not ideal with photovoltaic solar panels. In reviewing the energy tables, a two axis tracker will gain only 5% more energy over the one axis system. The greatest gains are realized, then, with the one axis system. For the cost, complexity, and convenience most users are better off with a one axis system.

There are two general functions in mind when designing for solar energy. These functions are solar power electricity, and thermal storage or heating. No matter what the design purpose is, a good tracking system is an easy way to boost performance from your solar power system.

Solar power tracking systems are useful for anybody who wants to enhance their system performance. There is a tradeoff, however, with the additional cost and installation. For those who like simplicity but want a little extra performance, then a manual one axis system is a good way to go. For those looking for maximum energy production, then active tracking systems should be explored.

Walter Hull is a mechanical engineer with expertise in solar energy power systems. For a short time you can get his free checklist to solar energy from your own backyard.