Summary: Solar trackers enable to keep the solar panels normal to the incident sunlight, and hence enhance electricity generation significantly
Did you know that by changing the angle of solar panels frequently, you could generate much more electricity from the same panels? Trackers help you do these frequent changes.
Solar panels generate the most electricity if they are placed perpendicular to the sun rays.
Solar trackers assist solar panels in keeping an orientation to enable them receive maximum sunlight.
However, the sun moves from the east to west during the day. Over a year, it also moves some distance from north to south (all right, to clarify – the sun does not move, but it is the earth that moves; however, for the solar panels, like it is for us simple folks, it is as if the sun is moving!).
If the solar panels are fixed, they cannot have sunlight striking them perpendicular all the time of the day. Solar trackers assist the solar panels in keeping an orientation that enables them to be perpendicular to sunlight.
Types of trackers
The two main types of trackers used in solar farms are single-axis and dual axis trackers.
Single axis trackers - From any fixed location, the sun travels close to 180 degrees from between day and night. A solar panel in a fixed orientation between the dawn and sunset could see a significant motion of the sun to either side (about 80 degrees each side), and thus, could miss out on significant amounts of energy, if it were not aligned suitably. Rotating the panels to the east and west can optimize such alignment over the day. A tracker rotating in the east-west direction for alignment over a day is known as a single-axis tracker.
Dual axis trackers - While the single axis trackers are used to track the sun as it moves from east to west, dual axis trackers track elevation to follow the height of the sun on the horizon.
As you can easily guess, dual axis trackers result in even higher output from the same panels than single axis trackers. However, they also cost more.
Questions from the curious cat
Should I use single axis or dual axis tracking for my solar power plant?
This depends on the region. For some regions, dual axis trackers do not significantly increase the output, over and above what single axis trackers can. Thus, for these regions, single axis trackers will be the recommended option.
How much do trackers cost?
There are different vendors and tracking systems in the market. Single axis tracking systems could increase your upfront cost by about 10% while dual axis tracking systems could increase it by 15-20%. Thus, if you upfront cost to put up a 1 MW solar PV power plant is $2 million, having trackers could increase this cost to about $2.25-2.5 million.
What are the cost-benefit benchmarks for trackers?
Single axis trackers could increase output from the same panels by about 15-17%, while they increase the upfront cost by about 10%.
Dual axis trackers have the potential to increase overall output by 25-30%, while they increase the upfront cost by about 15-20%.
How do trackers really work?
There are two main types of trackers – Active and Passive – and each works differently to achieve the same result.
Passive trackers – these depend on solar heat to move the tracker. Depending on the heat created by the sun, which in turn depends on the sun’s position, a low boiling point compressed fluid is driven to one side or the other to move the tracker.
Active trackers – which are more commonly used in large installations – use a sensor based controller that monitors the position of the sun’s movement. This controller, using a motor, in turn moves the trackers to the right position.
As they contain moving parts, will they require significant maintenance?
Where there are moving parts, especially motors, you can be sure that some maintenance will be required. But these are mostly minor activities, mainly periodic inspection and lubrication.
Are there manual solar trackers?
In some countries, especially the developing and underdeveloped countries, drives and motors have been replaced by manual operators who regularly adjust the trackers. Owing to the dependence on manual labour and the consequent challenges, We do not expect this to be a sustainable solution, except in select cases.
What are the main components of trackers?
The main components are as follows:
- Tracker Mount
- Sensors and Sensor Controllers
- Motor and Motor Controller
- Tracker Solving Algorithm
Some nice videos for you
A simple illustration of the working of a solar tracker
DIY solar tracker video illustration
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