The solar panels for maximum efficiency must always be oriented with the correct angle to the sun, but the movement of the earth makes this angle has to vary constantly, to correct this created the solar tracker.
SOLAR TRACKER: WHAT THEY ARE AND HOW TO CHOOSE THEM
Next we will talk about solar trackers, what they are, how they work and how to choose them
What is a solar tracker?
The solar tracker is a very particular type of photovoltaic system that allows it to capture the sun’s rays thanks to its regular movement that rotates continuously, moving in the direction of the sunrise and the path of the sun. This solar tracker kit is based on photovoltaic panels that are not fixed. Solar panels are placed on an axis that can be operated, causing them to move to follow the direction of the sun’s rays.
So it is a very useful system, because it is more capable of capturing the sun’s energy to transform it into electrical current to be used in our home. From this aspect we can already see how it is especially useful. But let’s find out more about its features and also see how much it costs , depending on the model that best suits our needs.
Solar trackers are used to increase the energy production of solar panels and solar receivers. The solar tracker is a device that follows the movement of the sun as it rotates from east to west every day.
Solar trackers are used to maintain solar / solar collectors. panels facing directly toward the sun as it moves across the sky each day.
The use of solar trackers increases the amount of solar energy that the solar energy collector receives and improves the energy production of the heat / electricity that is generated.
Solar trackers can increase solar panel production by 20-30% which improves the economics of solar panel project.
WHAT TYPES OF SOLAR TRACKERS ARE THERE?
There are two types of solar trackers , uniaxial and biaxial, which are classified according to:
- the number of axles;
- the methodology of mechanical orientation;
- electronic control.
Single axis solar trackers have a high performance in generating electricity compared to a traditional fixed photovoltaic system, estimated at 15-30%; they track solar radiation rotating around an axis and according to their own orientation they are classified into:
- The tilt trackers , also called pecks (of solar radiation), rotate around the east-west axis, or the angle of inclination, which should not be set during daylight hours, nor during the seasons, but rather follow the height of the sun . in the sky. This movement is done manually twice a year;
- Roll trackers follow the sun along its trajectory in the vault of the sky through servo mechanisms, but only in the central hours of the day. To avoid shady areas, this type of trackers reverses the movement of the structure at sunrise and sunset;
- the azimuth trackers rotate around a vertical axis placed perpendicular to the ground, while the solar panels are installed in a coplanar structure that tracks solar radiation, but without varying the inclination;
- Followers of the polar axis , as the word itself indicates, track solar radiation, rotating around an axis parallel to the north-south axis of rotation of the earth.
Solar tracker on one axis
Biaxial photovoltaic trackers guarantee an increase in electricity production by up to 40% and, compared to the monoaxial type, they have two axes of rotation, perpendicular to each other, which move in relation to the movement of the sun over the celestial dome, a through a computerized control. Depending on the different orientation, biaxial solar trackers are classified into:
- Azimuth-elevation trackers track the movement of the sun in real time through a solar sensor system that captures radiation. A structure with an axis parallel to the ground and the other capable of moving (the altazimuth mount) allows increasing the efficiency of electricity production, even avoiding shadow areas, given the fully automated system;
- The tilt-roll trackers have the primary axis parallel to the ground, while the other perpendicular to the second axis and multiple groups of solar panels can be installed, also taking advantage of the backtracking technique, which avoids shadow areas, moving the axes in hours of operation. Sunrise and sunset.
What are active and passive solar trackers?
A solar tracker is active or passive depending on the movement mechanism used to orient itself towards the sun.
Active solar trackers are equipped with an electric motor with gear reduction devices that allow a slight movement of the photovoltaic panel, not continuously, but only when necessary, since they consume electricity.
Based on electronic motion control, active trackers are divided into:
- analog trackers , in which the movement is generated by sensors that identify the best position for absorbing solar radiation. In this typology it is not necessary to estimate the alignment of the entire structure;
- digital trackers , in which the movement is generated by a microprocessor that, through the data stored on the solar positioning, manages to orient the panels at the most advantageous point. In this typology it is necessary to estimate the alignment of the entire structure, but it guarantees a higher performance even on days with low solar radiation.
Passive trackers do not need electricity to orient themselves towards solar radiation, but instead move through autonomous physical phenomena, such as the thermal expansion of a compressed fluid gas heated by the sun that, by producing hydraulic pressure, moves the structure that supports the solar radiation. solar modules.
How to choose solar trackers
Today there is much more awareness than in the past of how important it is to resort to the use of clean energy sources, so as not to pollute the environment and at the same time have the opportunity to save . That is why the solar tracker is really convenient , for all those who choose to take advantage of the energy provided by the sun’s rays.
Depending on individual needs, different types of trackers can be more or less convenient and advantageous. For example, uniaxials are ideal for saving on production and installation costs, azimuth uniaxials are especially suitable for high latitudes. Two-axis trackers have higher costs, but they are exactly what we do if we want to build a small residential system.
If we go for polar axis devices, we will have the most productive types available, but we must be careful not to expose them too much to the sun, because they could risk instability. Azimuth trackers need large spaces to be installed to avoid shady areas. Incline trackers, on the other hand, can be defined as the cheapest types on the market.
How does a solar tracker work?
A solar tracker directs solar panels or modules towards the sun. These devices change their orientation throughout the day to follow the path of the sun and maximize energy capture.
In photovoltaic systems, solar trackers help to minimize the angle of incidence (the angle that a beam of light makes with a line perpendicular to the surface) between the incoming light and the panel, thereby increasing the amount of energy produced by the installation.
Concentrated solar photovoltaic and concentrated solar thermal have optics that accept sunlight directly, so the solar trackers must be at the correct angle to collect energy. All concentrated solar systems have followers because the systems do not produce power unless they are properly directed towards the sun.
The single axis solar tracker rotates on one axis moving back and forth in only one direction. The different types of single axis trackers include horizontal, vertical, inclined and polar aligned, which rotate as the names imply.
How to install a solar tracker or tracker
The solar trackers dual axis continuously look at the sun that can move in two different directions. Types include tip-tilt and azimuth-altitude.
Dual-axis tracking is generally used to orient a mirror and redirect sunlight along a fixed axis toward a stationary receiver. Because these trackers follow the sun vertically and horizontally, they help obtain maximum solar power generation.
There are also several methods of driving solar trackers. Passive trackers move from a fluid of compressed gas propelled to one side or the other.
Motors and gear trains direct active solar trackers by means of a controller that responds to the direction of the sun. Finally, a time tracker counters the rotation of the Earth by spinning in the opposite direction.
The selection of a solar tracker depends on the size of the system, electricity rates, land limitations, government incentives, latitude, and weather.
Large-scale and large-scale projects typically use horizontal single-axis solar trackers, while dual-axis trackers are primarily used in smaller residential applications and locations with high government power rates. Vertical axis trackers are suitable for high latitudes due to their fixed or adjustable angles.
Using solar trackers can increase electricity production by around a third, with some claiming as much as 40% in some regions, compared to modules at a fixed angle.
In any solar application, conversion efficiency improves when modules are continuously adjusted to the optimum angle as the sun passes through the sky.
Since improved efficiency means better performance, the use of trackers can make a big difference to a large plant’s revenue. This is why utility-scale solar installations are increasingly mounted on tracking systems.
However, there are some downsides to solar trackers. Adding a solar tracking system means adding more equipment, moving parts, and gears, which will require regular maintenance and repair or replacement of broken parts.
Also, if the solar tracking system breaks down when the solar panels are at an extreme angle, the loss of production until the system is operational again can be substantial. A solar tracker is also more prone to storm damage than actual panels.
There may also be a problem with warranties. A fixed solar system that will last 30 years usually comes with a 25-year power performance guarantee. But a solar tracked system only comes with a 5-10 year warranty.
What type of solar tracker is more economical?
- Single-axis solar trackers are ideal to benefit from low production and installation costs, especially in the type of roll and, therefore, they are recommended in areas where energy is most needed, such as in large photovoltaic parks. Particular importance in this typology assumes the setback , an innovative method that allows to reduce shading, optimizing the space for installation;
- the followers of uniaxial azimuths are suitable for high latitudes, where the sun never reaches heights high in the sky dome of the sky;
- biaxial trackers , on the other hand, due to higher costs, are recommended in small residential systems;
- The polar axis trackers are considered the most efficient and productive, but they have a defect in the profile: too exposed to the wind, causing instability;
- azimuth trackers are effective in producing energy, almost as much as the solar axis type, but require large installation spaces to avoid shady areas that significantly reduce electricity production;
- Tilt trackers are the cheapest on the market: the advantage lies in the lack of mechanical movements