How Does Solar Tracker Work?

A good way to maximize the output of a solar PV system is to mount it on a solar tracker. Solar trackers can significantly increase the power output of a photovoltaic system, allowing you to earn more from the feed-in tariff. However, as discussed in this article, the economics of solar trackers are more suitable for large installations, and in fact rely more on the level of on-grid tariff assistance provided by geographic location.

What is a solar tracker?

A solar tracker is a device that tracks the sun through the sky during the day, exposing your photovoltaic cells to more sunlight and generating more electricity. This is because PV cells work best when facing the sun directly. As the Earth's tilt relative to the Sun changes, the angle of the Sun in the sky changes throughout the year. In the summer, the sun is high in the sky and longer in the sky as it passes longer arc lengths. In winter, the sun is lower in the sky, and when it passes through a shorter arc, the time around it is shorter.
The farther away from the equator, the more obvious this effect. In Tasmania, summer is long and winter is short. In Darwin, the variation is much less.

How does solar tracker work?

A solar tracker is a mechanical device that works by tracking the path of the sun during the day. There are two different types of mechanisms that are the most commonly used "active trackers and passive trackers." The active tracker points to the sun through circuitry in the form of a photosensor. The motor and gear train are then used to direct the tracker to the direction of the sun in accordance with the instructions of the photosensor. The active tracker contains electronic components and therefore uses a small amount of power. Passive trackers use a hydraulic mechanism that responds to solar heat. The low boiling compressed gas fluid is driven to the side or the other side by the heat of the sun, creating a gas pressure that moves along the mechanism. Passive trackers typically do not consume any power. In general, activity trackers are more accurate than passive trackers and therefore facilitate applications requiring precise precision, such as in the case of concentrating solar collectors. For solar photovoltaic applications, the accuracy of the passive tracker is more than enough.

What happens when the sun is covered by clouds?

On cloudy days, solar cells still produce energy, although their performance is significantly reduced. In this case, the solar tracker will be optimally oriented to pick up the most reflective ambient light by based on the same principle. Once the sun begins to shine again, it will reposition itself to face it.
What types of solar trackers are there?
There are two main types of solar trackers, single and dual axis.

Single axis

The single-axis solar tracker tracks the sun from sunrise to sunset as it moves from east to west in the sky. They are called single-axis trackers because the mechanism only rotates in a plane around a single axis. The axis can be oriented such that the cells stand with a tilt (called a polar axis) or a flat lay (called a horizontal axis). The horizontal axis is more suitable for small latitudes (tropical areas and areas close to the equator, ie northern Australia), while the polar axis is more suitable for larger latitudes (far from the equator, south of Australia).
The advantage of single-axis trackers is that they are less complex and therefore less expensive. As you can see from the image below, the single-axis tracker captures many of the benefits of solar tracking. In the vicinity of the equator, the arc of the sun through the sky changes less during the day and the season, and the single-axis tracker is particularly effective.
The single-axis horizontal tracker is also structurally more robust and stable, so it is less likely to be damaged during a storm. In addition to the normal single-axis option, a new type of solar photovoltaic technology called tubular solar energy has been developed in which the cells themselves are cylindrical in shape and the cells capture the maximum amount of light as the sun passes through the daily cycle.

Dual axis

The dual axis or dual axis tracker completely follows the sun. The two rotating axes allow the tracker to always position the solar cell directly perpendicular to the sun's rays. Because they are able to adjust the height of the sun and the east-west rotating dual axis tracker to fully adapt to the season and adjust to face the sun because it is at the low end of the horizon at sunrise and sunset, and high noon in the sky.

The dual axis tracker captures the full range of the sun, but they are a bit more complicated and therefore more expensive. The dual axis tracker produces greater differences in larger latitudes (more southerly in Australia) where there is a significant seasonal variation in the height and curvature of the sun.