Dual Axis Solar Panel Tracker Using Arduino
The global increase in energy demand and exponential exhaustion of fossil recourses has leaded to the innovation of new systems to produce electricity. Photovoltaic solar energy is one of the highest applications in housings, due to its simplicity and easy implementation. In this project, a prototype of photovoltaic solar tracker using an Arduino microcontroller was developed. Feedback control system that makes the PV (photovoltaic) panel track the sun path with two axes using two servo motors was established through an electronic circuit based on LDRs (Light Dependent Resistor) used for sensing the maximum incident intensity of the sun radiations. The servo motors (one for the vertical axis and the second for the horizontal axis) controlled by an Arduino MEGA controller, will rotate to scan the position of the sun, according to the inputs received from the LDR sensors.
Background
Nowadays, all energy sources (like fossil fuel, natural gas, coal, etc...) contributes to the usage and development of industrial society. The generation of electric power using renewable energy sources begins to take a big role in fulfilling the demand for electric energy. Expectations say that fossil fuel resources will be exhausted within a hundred years. Renewable energy is generated from nature. Wind, water, sunlight are sources of energy that are renewed.
Solar energy is the most efficient and effective to produce electricity. Moreover, the solar technology is the fastest growing type of renewable energy technology, because the sun radiations are always costless, clean, accessible and safe. Solar radiation is the quantity of energy dropped by the sun on a solar PV panel during a specific time, and called: "Solar Irradiation".
Problem Statement
The quantity of carbonic energy is decreasing in a very dangerous way, so it must be another way to produce electricity. Here comes the importance of renewable energies, especially the solar energy, and the need to use solar panels. But fixed solar panels does not allow us to benefit from all the solar energy all day, so here we have developed a prototype of a tracking solar panel that follows the path of the sun all day, so we can benefit as much as possible from the solar energy.
Literature Review
History of Solar Panels
In 1839, Alexandre Edmond Becquerel discovered the photovoltaic phenomenon which means how electricity can be generated from sunlight. He said that "shining light on an electrode submerged in a conductive solution would create an electric current".
After 100 years later, in 1941, Russel Ohl invented the solar cell, after the invention of the transistor in a short time.
Advantages and Disadvantages of Solar Trackers
Like any system, solar trackers have advantages and disadvantages. The most important are mentioned in the following two sections.
Advantages
- Trackers produce more electricity than fixed solar panels due to increased direct exposure to sunlight.
- Trackers maximize the energy gains during peak time periods: during these times of the day, trackers purchase the power generated at a higher rate. So it is beneficial to generate a greater amount of electricity.
- Advancements in technology and reliability in electronics and mechanics have reduced long-term maintenance concerns for tracking systems.
Disadvantages
- Solar trackers are more expensive than fixed systems, due to the moving equipments.
- Trackers are more complex than fixed systems.
- Solar trackers are designed for warm climates (little to no snow).
- Fixed systems accommodates harsher environmental conditions more easily than tracking systems.
In this section, we will talk about similar systems to ours, regardless of their difference in efficiency.
Fixed Angle Solar Panel
This section covers solar panels fixed at a specific angle. This type of PV panels is frequently used in houses as solar heaters for water. They are rarely used to produce electricity for houses because the small space and the large number of PV panels needed to feed the house with electricity. Fixed solar panels does not benefit from the maximum amount of light because of the fixed angle, so at many moments, there is a loss in the energy. Knowing that PV panels contains a glass layer, a part of the incident light will be reflected if their directions (PV Panel and incident light) are not perpendicular to each other. Here comes the importance of moving PV panels.
Single Axis Solar Panel Tracker
Single axis trackers have one degree of freedom that act as the axis of rotation. With advanced tracking algorithms, it is possible to align the panel in any cardinal direction. Common implementations of single axis trackers include horizontal single axis trackers (HSAT), vertical single axis trackers (VSAT), tilted single axis trackers (TSAT) and polar aligned single axis trackers (PSAT). So, the solution is in a tracker that follows the sun path in two directions.
Servo MotorLight Dependent Resistor
A photoresistor (or Light Dependent Resistor "LDR", or photo-conductive cell) is a light-controlled variable resistor used widely as a sensor in circuits where it is necessary to detect the presence or the level of light. The resistance of the LDR decreases with increasing incident light intensity. An LDR is made of a semiconductor of high resistance. In the dark, an LDR can have a high resistance as many MΩ, while in the light, it can have a few hundred ohms resistance. If the incident light on an LDR is bigger than a certain frequency, photons absorbed by the semiconductor give bound electrons an enough energy to jump into the conduction band. Free electrons (and their hole partners) that result, conduct electricity, thereby lowering resistance.
3D Printer
3D printing is a manufacturing process that creates a physical object from a digital design. There are different 3D printing technologies and material we can print with, but all are based on the same principle: a digital model is turned into a solid three-dimensional physical object by adding material layer by layer. In this system, we made 4 objects for the body of the tracker.
Arduino IDE
The Arduino Integrated Development Environment - or Arduino Software (IDE) - is a software that contains a text editor to write codes, a text console, a message area, a toolbar with buttons for common functions and a series of menus. It connects to the Arduino hardware to upload programs and communicate with them. This software can load several libraries of many hardware components, these libraries can be downloaded from the software itself, and for a certain component, the code must include its corresponding library so the Arduino hardware can communicate with it.
In our system of the solar tracker, we started our code with " #include <Servo.h>; " so the Arduino can control the servos.
Proteus 7 ISIS Professional
Proteus 7 Professional is a software developed by Labcenter Electronics. It is used for microprocessor simulation, schematic capture, and printed circuit board (PCB) design. It has links to other softwares (i.e. Arduino IDE, MPLab X...) by uploading their codes to a microcontroller picked from Proteus library.
In this system, a .hex file of the Arduino code is uploaded to the Arduino MEGA 2560 picked from Proteus devices library. This virtual implementation is very important step so we can observe results before starting in building the hardware.
Results
At the end of the project, a small-scale and functional dual axis solar tracker has been completely designed and implemented. Under the functionality test, the device was able to detect and follow the movement of an observable light source. This applied for indoor light (cell phone flashlight) and outdoor light (sunlight). The solar tracker made use of the servo motors properly, which enabled a wide range of rotation for the PV panel as expected.
Conclusion
The goal of the project was to design and implement a small scale prototype of dual axis solar tracker with basic tracking functions. Designing and implementing processes have been accordingly completed for the work of the project. The final result was a complete design of such a system, with functionality that met the design requirements.
While the project has succeeded in creating a device with basic required features, there are still considerable drawbacks and limitations with the performance of the device. It is possible to overcome these limitations and to improve the performance of the device in future development.
The project was a successful effort in fulfilling the purpose when I started it, that is to research and catch up with current technologies in this field of energy exploitation. It is a useful reference for those who needs to develop similar systems.
Future Work
With the available time and resources, the objective of the project was met. The project is able to be implemented on a much larger scale. For future projects, one may consider the use of more efficient sensors which are cost effective and consume little power, because LDRs that we have used in the project does not meet the optimum accuracy due to the manufacturing. This would further enhance efficiency while reducing costs. If there is the possibility of further reducing the cost of the project, it would help a great deal. This is because whether or not such projects are embraced is dependent on how cheap they can be.
