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Have you ever noticed the movement of the sunflower along with the sun from east to west? This is to ensure that it captures maximum sunlight. Solar trackers implement the same technique in solar panels to maximise electricity production.
A solar tracking system moves the panels to ensure that it changes directions as per the sun’s position. The article discusses more on solar trackers and their advantages.
What are solar trackers?
A solar tracker is a device which helps to maximise the production of electric power by moving the solar panels towards the sun’s direction.
This is done by optimising the angle at which the panels receive solar power. This system is commonly used for large-scale solar power plants such as free-standing and ground-mounted solar installations.
What do solar trackers do?
Solar trackers orient the panels towards the sun to maximise the rays falling on them. Thus, solar trackers actively track the sun’s movement and appropriately guide the panels to maximise power production.
The angle at which the sunlight falls on the panels is known as the angle of incidence. This determines how effectively the panel can convert solar radiation into electric power. The lesser the incidence angle, the greater the energy produced and vice-versa.
Solar trackers ensure that the angle of incidence is low in order to maximise energy production.
Types of solar trackers
Solar trackers are primarily classified based on the mode of their motion. These trackers can be moved in two different axes. They are:
- Vertical axis
- Horizontal axis
The idea is to tilt the entire system in a way that it receives the maximum sunlight.
Single axis tracking system
This happens when the solar panels are adjusted by rotating around one axis. On the other hand, dual-axis tracking is when the panels are adjusted by turning in two axes.
Here are some of the applications of the single axis tracking system.
As the name suggests, the single-axis tracking system moves only in one direction. They are capable of boosting electricity production by about 30%. Single-axis tracking systems follow the movement of the sun from east to west. The trackers are designed to maximise exposure to solar radiation.
As one proceeds towards the north, single axis trackers may not be much of use. This is because the solar angle varies significantly between winter and summer in the northern hemisphere.
Let us look at some of the different versions of single-axis solar trackers.
Horizontal Single-Axis Solar Tracker (HSAT)
Compared to other single-axis solar trackers, this is the most cost-effective. This tracker rotates from east to west following the sun’s movement from dawn to dusk.
Horizontal tracking geometry helps to minimise the requirement of material structure and keeps the module close to the foundation.
Horizontal Tilted Single-Axis Solar Tracker (HTSAT)
Unlike the HSAT, HTSATs are more complex and expensive. In addition, the requirement for a concrete foundation further adds up the cost.
HTSAT looks similar to HSAT. However, the device is installed with a certain tilt. These are tilted upward and focused towards the south. HTSAT rotates the panels from east to west to track the sun’s movement.
One drawback of HTSAT is that as it is not scalable, the mechanical components cannot be shared between the units, flaring up the cost per array.
Vertical Single-Axis Solar Tracker (VSAT)
These are often installed at high altitudes in mountainous locations. They actively track the sun and move from east to west throughout the day.
VSATs are usually placed in the northern latitudes, for example, between 40° and 55°.
Here the vertical field layouts need to accommodate the vertical tracker’s taller profile to avoid the energy loss problem due to self-shading.
As these are not parallel to the ground, it is easier for the trackers to retain a consistent angle with the sun even when the sun is lower.
Vertical-Tilted Single-Axis Solar Tracker (VTSAT)
In design, it is similar to that of HTSAT. The only difference is that it rotates on a vertical axis, and the tilt is parallel to a horizontal position. However, due to the high structural requirement, more steel and concrete is required.
These are subjected to increased wind loading due to the tilted angle. Unlike horizontal trackers, the power harvested is high for these.
Other Types of Solar Trackers
These trackers use a compressed gas fluid with a low boiling point. As a result, the gas fluid moves from one side to another in case of an imbalance. The movement of fluid creates a rotation action which moves the tracker from one side to the other.
These are commonly used for ordinary PV panels and not for concentrating PV collectors, as the movement is not precise.
Unlike passive trackers, these devices use gear and motors to direct the tracker to the desired position. As the movement of the motor burns some energy, it is used only when required.
Pros and cons of solar trackers
Let us look at some of the advantages and disadvantages of solar trackers.
- Solar trackers help to generate more electric power due to increased exposure to sunlight. This can range from 10-30% depending on the area and geography of the installation.
- Maintenance costs of solar tracking systems are relatively low due to technological advancements. These tracking systems are relatively maintenance-free in the long term due to reliability and advancements in tracking systems.
- Solar trackers produce more power in the same amount of space than fixed-fit systems, helping optimise land usage.
- In some states, power authorities pay a higher rate for the power generated during peak times. So greater the energy generated during this time, the greater the income generated. Using tracking systems helps to maximise the electric power generated during this period.
- Trackers have very complex systems. It requires additional trenching and more site preparation.
- As complex technology and moving parts are required in solar trackers, these are more expensive than their stationary counterparts.
- Solar tracker requires warm weather for its best performance as its operations are typically obstructed by snow. However, fixed tracking systems perform well in the harshest environments as they can easily accommodate weather disturbances.
- Fixed tracking systems can accommodate 20% slopes in the East/West direction, while tracking solar systems offer only 10% slope accommodation in the North/South direction.
- As the tracking systems are more complex and have a chance of breaking down, they are considered risky investments by financiers.
Solar trackers FAQs
How much difference do solar trackers make?
Solar trackers become highly useful if you have a limited installation area and a large-scale commercial installation. This is mainly because exposure to solar rays can be increased by as much as 10 to 30%. In the same space needed for a fixed tilt system, solar trackers produce more electricity, helping optimise land usage.
What is the most efficient solar tracker?
In general, a dual-axis solar tracking system is considered the most efficient solar tracking system. However, this depends on several factors, such as:
- Type of solar tracker.
- Location of the tracker.
- Overall size of the solar panel system.
Are solar trackers expensive?
Buying a tracking system will incur more costs for your solar installation. This could approximately be around 40-100% additional cost.
The cost will depend on the following:
- Complexity and scale of installation &
- Type of tracker you purchase
Having solar trackers fitted to panels comes with immense benefits. Solar trackers help to ensure that the maximum amount of sunlight is converted into electric power, thus, improving efficiency and maximising profit.
Nowadays, solar trackers are fitted in most commercial solar power generation facilities. However, the household solar installation might take some time to shift to trackers.