Saturday, July 25, 2009

Solar Panel Tracking Systems

By Walter Hull

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.

The Sun changes daily, monthly, and seasonally the way it carves its path across the sky. Therefore the angle of beam radiation is constantly changing. The solar panels should be oriented perpendicular to the Sun at all times to best receive this radiation. A solar power tracking systems helps us achieve this.

The amount of energy gained will depend on your location and the type of tracking system used. We looked up the solar energy tables for the state of Washington, and the difference between a fixed solar panel system and one with tracking was ~40% more in the summer months. The spring months showed a 25% increase, and winter about 10%.

The simplest type of tracking is a manually adjustable one axis system. The solar panels are installed in a south facing direction, with a rotating mechanism on their horizontal axis. One can make seasonal adjustments to maintain the best operating angle for that time of year. A simple system such as this can gain 20% better performance when compared to a fixed solar panel installation. The Rotek design we use is an example of one such system.

To further boost performance we can add a control system to our one axis tracking. This is called active solar tracking, where the solar panels automatically rotate throughout the day. These systems provide the largest gains, up to 50% in the summer months. Performance remains good throughout the year as well, so for a little more cost they are worth investigation.

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 systems are commonly used with concentrating solar collector designs. These types of collectors, like a magnifying glass, focus the rays of the Sun. Systems with these installations require the highest possible operating temperatures. Examples include thermal power stations, stirling engines, and pebble bed transfer systems.

When it comes to using solar panels to generate electricity, a two axis system is not the way to go. They will yield a very modest 5% gain over an actively tracking one axis system. For the cost and simplicity, we recommend a manually adjustable or actively tracking one axis system.

The primary applications for solar power are with generating heat and electricity. A solar power tracking system is useful in either case. The more energy we receive, the more heat and electricity we can manufacture. It's that simple.

If you are serious about maximizing your solar power system, then you should be considering a tracking system. One axis systems are available that are effective, inexpensive, and easy to use. Two axis systems are more complex and normally used for high temperature systems. Either which way, a good tracking system will go a long way in getting the most out of your solar panels.

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