Solar tracker, what is it?

Introduction

Solar panels, parabolic troughs, Fresnel reflectors, lenses, or heliostat mirrors are typical examples of loads. Solar trackers enable your solar panels to move like a sunflower to track the Sun’s course across the sky. This allows your solar panels to generate a more significant amount of solar electricity. However, the cost of installing a solar tracking system might be relatively high.

What is Solar Tracker?

A Sun tracker is a mechanism that tilts an item towards the Sun. Positioning photovoltaic (PV) panels, also known as solar panels, so they remain perpendicular to the Sun’s rays is one of the most common applications for solar trackers. Another common application is positioning space telescopes to determine the direction in which the Sun is pointing. PV solar trackers adjust the orientation of a solar panel so that it always faces the Sun regardless of where it is in the sky. By maintaining a panel orientation perpendicular to the Sun, more light will be absorbed by the solar panel, while the amount of reflected light will be reduced. This energy has the potential to be transformed into usable electricity. Solar trackers are often installed in conjunction with ground-mounted solar systems; however, rooftop-mounted trackers have just recently been available on the market. In most cases, the solar tracking equipment will be attached to the panels’ racking. From that vantage point, the solar panels can follow the Sun’s path as it travels across the sky.

Basic concept

The “direct beam” carries approximately 90 percent of the solar energy, and the “diffuse sunlight” carries the remaining 10 percent; the “diffuse portion” is the blue sky on a clear day, and it is a more significant proportion of the total on cloudy days. Sunlight comprises the “direct beam” and the “diffuse sunlight.” Because the direct beam contains the vast majority of the Sun’s energy, optimal collection involves keeping the Sun given the panels for the most extended amount of time feasible. On the other hand, when there is a lot of cloud cover, the ratio of direct light to diffuse light may drop as low as 60:40 or even lower.

Tracker type selection

The installation size, power prices, government incentives, land limits, geographical latitude, and regional climate all have a role in the choice of tracker type. Other considerations also come into play.

Large distributed and utility-size projects are often the best for installing horizontal single-axis trackers. When applied to large-scale implementations, combining increased energy efficiency, decreased product cost, and simplified installation complexity results in convincing economics. In addition, the robust performance in the afternoon is significant for extensive grid-connected solar systems since this ensures that output will coincide with the period of highest demand. Additionally, during the spring and summer months, when the Sun is at its highest point in the sky, horizontal single-axis trackers contribute a significant amount of additional production. High dependability is achieved as a consequence of the inherent toughness of their supporting structure as well as the inherent straightforwardness of the mechanism. This helps to keep the costs of maintenance to a minimum. As a result of the panels’ horizontal orientation, they may be arranged in a condensed fashion on the axle tube without running the risk of shading themselves. They can also be easily removed for cleaning.

A vertical axis tracker has panels that are either vertical or at an elevation angle that is either fixed, adjustable, or tracked. This kind of tracker pivots around a vertical axle. Such trackers are excellent for high latitudes, where the apparent solar path is not very high but where there are long days in the summer due to the Sun moving around a lengthy arc. These trackers may have angles that are either permanently set or seasonally adjustable.

Dual-axis trackers are generally used in residential applications that are smaller in scale and in places with highly high government feed-in rates.

Manual solar trackers

For solar panels to be aligned with the Sun using a manual tracker, the panels need to be manually adjusted at various daily intervals. Because of the need to have someone continually watch the Sun and change the location of the solar panel system, this is not always a feasible option.

Active vs. passive solar trackers

In addition to the distinction between sun trackers with a single axis and those with multiple axes, there is also the distinction between active and passive solar trackers. The most important thing to remember is that active solar trackers utilize a motor to move, whereas passive solar Sun trackers use the Sun to move; as a result, active solar trackers are far more sophisticated in their construction and performance. There is still another alternative available, which is the use of manual solar trackers. Because of this, you can make manual adjustments to your panels during the day to follow the Sun’s path. This kind of tracker may be helpful since it has lower related maintenance costs than active or passive trackers. Still, it is not particularly practical because it requires someone to shift the panels routinely. Active or passive trackers have no such need.

Passive solar trackers

As exposed to solar light, the liquid in passive trackers has a low boiling point. Thus, it evaporates when the device is heated up. Because of the evaporation of the liquid, the tilt system will become unbalanced. Because of this imbalance, the panels have begun to lean towards the direction from which the Sun’s rays are. The Sun is also tracked by passive solar trackers, although no additional energy source is involved. They get their movement by heating gas with the Sun’s heat, which then propels them. A mechanized action of the solar panels is brought about when that gas expands and puts pressure on them. The discussions will return to their original position after the Sun has completed its orbit and the gas has returned to its average temperature. This explanation does not do justice to the true complexity of the science underpinning passive solar trackers but will simplify things for the time being. Because of their lesser precision, passive trackers are primarily helpful for pretty straightforward PV systems. In addition, passive solar trackers are not as effective in colder temperatures since the liquid often contained inside the tracker takes longer to reach the desired temperature.

Active solar trackers

Active trackers can shift positions using either motors or hydraulic cylinders. Active trackers are solar systems that use engines to go photovoltaic panels so that they face the Sun. Although this is more convenient than manual trackers, the moving elements inside the motors are prone to failure and might cause the device to malfunction. This may result in increased expenses for system maintenance throughout the system’s lifespan.

Single-axis solar tracking system

Solar tracking systems that move along a single axis to monitor the Sun are called single-axis systems (vertical or horizontal). In most cases, the inclination angle is modified manually at certain times during the year, while the movement in the east-west direction is accomplished automatically. However, single-axis systems have poorer yields in terms of efficiency, although they are more cost-effective than two-axis systems. Single-axis solar tracking systems may move either vertically or horizontally along their axis, depending on the position of the Sun in the sky and the conditions of the environment.

Vertical Single-Axis Solar Tracker (VSAT)

During the day, vertical single-axis solar trackers, also known as VSATs, spin in the opposite direction of the Sun, from east to west. These systems are often built in regions located at a high altitude or in hilly terrain. Because the profile of VSATs is not parallel to the ground, it is simpler for trackers to maintain a constant angle of solar incidence when the Sun is lower in the sky. This is because the profile of VSATs is not parallel to the ground. This is especially useful in northern latitudes, such as between 40 and 55 degrees. In contrast to planar horizontal arrays, however, vertical field design has to consider the vertical tracker’s higher profile and spread out the units to prevent self-shading and energy losses. Consequently, vertical single-axis trackers tend to provide a power density that is significantly lower per acre.

Vertical-Tilted Single-Axis Solar Tracker (VTSAT)

Horizontal, single tracking is most analogous to this particular kind of tracker. The sole distinction is that the tilt rotates on a horizontal axis rather than a vertical one and is parallel to a horizontal position. When compared to flat trackers, these trackers can boost energy harvesting. On the other hand, Tilted single-axis trackers are susceptible to higher wind loading compared to horizontal devices as a direct result of the ideal tilt angle.

Dual axis solar tracker

This device follows the Sun as it travels east to west and north to south. It can do both functions simultaneously. It is more typical for residential and small commercial solar projects with limited space to use two-axis trackers. This allows the projects to generate sufficient power to satisfy their energy requirements despite the restricted area.

Horizontal Single-Axis Solar Tracker (HSAT)

During the day, a horizontal solar tracker with a single axis revolves counterclockwise around a fixed axis perpendicular to the earth’s surface. In many different applications, this tracker geometry is regarded to be the most cost-effective tracker geometry available. Horizontal trackers with a single axis can trace the path taken by the Sun as it travels across the sky from dawn to evening. When compared to alternative tracking geometries, an HSAT structure has the potential to be supported at a more significant number of places along the rotating axis. As a result, its construction calls for less complexity and fewer materials. Because it keeps the modules at a relatively low profile to the foundation, the horizontal tracking geometry is the geometry that is recommended because it cuts down on the amount of structural material that is required. In addition, the system’s rotation around its center of gravity does not need any particular connection.

Horizontal Tilted Single-Axis Solar Tracker (HTSAT)

A solar tracker with a single axis, such as this one, is comparable to the HSAT. Having said so, the gadget is fitted at an angle of a specified degree. Tracking systems with tilted axes often require a solid base since they are significantly more complicated than horizontal trackers with a single axis. The panels of HTSATs are rotated from east to west during the day to follow the path of the Sun as it travels across the sky. That is angled upward and pointed toward the southern or northern hemispheres. Because HTSATs are more challenging to administer, their costs might be higher. In most cases, HTSATs cannot be scaled, which implies that the mechanical components are not shared across several units. Because of this, it is possible that the cost of each panel will not decrease as the array size increases.

Feasibility of Solar Trackers

Solar trackers boost the efficiency of solar panels; however, installing a solar tracker requires a significant financial commitment due to its high upfront cost. In addition, the cost of putting in place a solar tracker must account for the cost of labor and the required area. In addition, since the price of solar panels is lower than it has ever been, it would be more cost-effective to install more solar panels than it would be to build a tracking system. Because of this, the issue is whether installing a solar tracker is truly possible in the long term. The answer is straightforward: it depends on how efficiently things are done. For example, a standard size 60-cell (1 m x 1.65 m) polycrystalline panel with 18-20 percent efficiency and typically with a power rating of 300-330 Watts is less efficient than one that is monocrystalline and can produce up to 37 oW/440 W. This is because monocrystalline panels have a higher crystallinity, which results in a higher power rating. As a result, we can assert that the expense of using the tracker will be the same for both panels of the same size. However, despite this, the creation of energy will be different. In addition, when we claim that a solar tracker can boost energy output by thirty percent, we are referring to an increase in power production that will be far more in high-efficiency cell panels. In light of this, installing a solar tracker for highly efficient solar panels is possible and highly recommended.

The efficiency of Solar panels

In environmental terms, improved efficiency often indicates that a solar panel would pay back the embedded energy in a shorter time. Embedded energy is needed to extract the raw materials and build the solar panel. However, due to improvements in panel efficiency that went beyond 206, the payback period has decreased to less than two years in many different locales. Efficiency is a valuable indicator of performance for solar panels, particularly considering that many high-efficiency boards employ better quality N-type silicon cells with an enhanced temperature coefficient and reduced power degradation over time. Even after 25 years of usage, certain manufacturers, like LG, Panasonic, and Sun Power, stand by their products with guarantees that guarantee a maintained power output of at least 90 percent. One form of high-energy solar panel, known as bifacial solar panels, typically has power output ratings of more than 500 watts. They perfectly match solar trackers, which considerably boost the system’s efficiency.

Advantages of Single-Axis Solar Tracking System

Single-axis trackers feature one degree of flexibility that acts as an axis of rotation and are often oriented along a North-South direction. This kind of tracker is also known as a single-degree tracker. The following is a list of significant benefits offered by single-axis trackers:

•  The reliability of single-axis trackers is higher.
•  Dual-axis trackers often have a shorter life than single-axis trackers.
• Single-axis trackers are more cost-effective than dual-axis trackers because their mechanisms are less complex, and they need fewer resources to run.
• Single-axis trackers are a good choice for businesses that operate in often overcast places or have a limited budget.
• Compared to fixed solar panel tracking, the efficiency of single-axis trackers is about 32.17 percent higher.
• These trackers can maintain a constant power output throughout the day as they move with the Sun from east to west.
• Compared to a stationary station with the same installed capacity, the trackers produce 15–16 percent more yearly electricity than the fixed station.
• The maximum density of photovoltaic panel deployment per square foot is achieved using single-axis trackers.
• The payback time for the investment in the solar project is significantly reduced, and there has been a substantial boost in earnings.

Cons of solar trackers

Having a solar tracking system does come with a few drawbacks, though, including the following:

• Solar tracking systems come at a higher price than fixed solar panel systems. This is due to the extra effort required and the additional components needed to have a site ready for trackers.
• Solar trackers often need more regular maintenance than solar panels mounted in a fixed position (which require almost no maintenance to begin with)
• Because trackers are often too big and heavy to be utilized on roofs, you will need to install a system attached to the ground instead.

Installation and upkeep expenses for tracking systems are often more significant than those for other systems. Because it is a more sophisticated technology and has moving elements, purchasing a solar tracker will initially set you back more money than buying a solar panel system that is fixed in place. This results in the second component of rising costs for solar tracking systems, which is maintenance. A more complicated system requires more care, which might result in increased expenses over time. In most cases, the expenditure is not worthwhile for home installations. However, the enhanced efficiency that comes with a solar tracker may be well worth the expense for commercial buildings. This is especially true for enterprises with limited roof areas but a higher power output.

Another drawback of a solar tracker is that it is often far too hefty to be used in rooftop installation projects. You will need to prepare to install a ground-mounted array if you want a solar panel system that includes tracking capabilities.

Are solar trackers worth the additional investment?

Even though solar trackers have a higher capacity to generate power, making the extra financial expenditure is not worthwhile. Because solar panels are now more affordable than ever, it would be less expensive to install more solar panels than to construct a tracking system.

Take, for instance, the case where you erected 15 solar panels on the ground, each of which had a power rating of 300 watts. This system would have a total price tag of $14,625.

Let’s imagine you were interested in incorporating a sun tracker with a single axis into this system. That would add an extra $500 to the price of each solar panel. Simply purchasing the tracking equipment will set you back $7,500. You will incur an additional cost of $15,000 to install tracking equipment with a double axis.

Conclusion

Large commercial projects, generally above 1 megawatt in size, are another everyday use for solar tracking systems (MW). When it comes to solar arrays on a commercial scale, the long-term advantage of increasing output over time is sufficient to make the original investment, as well as the costs for maintenance, worthwhile. In addition, solar trackers are an option for large-scale commercial solar installations since these projects are often ground-mounted. Solar tracking is the process of determining the position of the Sun to the item being aligned using sophisticated sensors. These instruments typically include computers, which can process complex algorithms that allow the system to track the Sun, as well as sensors, which either provide information to a computer about the location of the Sun or, when attached to a solar panel with a simple circuit board, can track the Sun without the need for a computer. Computers are also used in some of these instruments.