A solar tracker is a generic term used to describe devices that orient solar panel toward the sun. In flat-panel photovoltaic applications trackers are used to minimize the angle of incidence between the incoming light and a photovoltaic panel. This increases the amount of energy produced from a fixed amount of installed power generating capacity of a photovoltaic panel.
This proposal presents a Solar Tracking System with Servo Motor. The system consists of solar panel and the motion follow the direction of a sun by controlled by Lab view programming software. The purpose of this Solar Tracking System is to maximize the power generation from the photovoltaic panel. The hardware designs are of solar panel, motor controller circuit to control the servo and circuit converter comprised the voltage output from the solar panel is stabilized by circuit converter before to be used by application. Benefit of Solar power is pollution-free during use. Production end-wastes and emissions are manageable using existing pollution controls. PV installations can operate for many years with little maintenance or intervention after their initial set-up, so after the initial capital cost of building any solar power plant, operating costs are extremely low compared to existing power technologies.
Table of Contents
CONTENTS PAGE
ABSTRACT ………………………………………………………………. 1
INTRODUCTION ………………………………………………………... 3
PROBLEM STATEMENT ………………………………………………... 4
LITERATURE REVIEW ………………………………………………...... 5
METHODOLOGY ………………………………………………………... 7
OBJECTIVES …………………………………………………………….. 10
BENEFITS/ CONTRIBUTIONS ………………………………………..... 11
WORK PLAN …………………………………………………………..... 12
BUDGET ………………………………………………………………….. 14
CONCLUSION ……………………………………………………...….... 15
REFERENCES ……………………………………………………………. 16
Introduction
The main problem that the world facing now is the fossil energy exhausted. This is because the demand for electrical energy nowadays is very high due to the increasingly rapid development. So the non renewable energy like fuel and coal will run out if this energy continuous using by users. Because of these matters, the world wide scientist now is busy searching for renewable energy like solar, hydro and wind. This energy are the best solution for the problem that world facing nowadays.
Solar energy is the energy that is obtained from the sun. This energy helps and supports all life and Earth. Heat and light from the sun, along with solar based resources such as wind and wave power, hydroelectricity and biomass, account for most the available flow of renewable energy. Solar power is becoming popular, as a friendly environment renewable energy sources that produces no pollution, requires minimal maintenance and free energy from the sun. Solar energy has a wide variety of technologies and is flexible for different application. One types of solar energy is solar photovoltaic power. For example are the residential, commercial, industrial, agricultural, and transportation sectors.
Photovoltaic’s (PV) is a method that to generate electrical power by converting solar radiation or solar energy into direct current electricity using semiconductors that exhibit the photovoltaic effect. Photovoltaic power generation employs solar panels comprising a number of cells containing a photovoltaic material. Materials that are used for photovoltaic’s include monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium solenoid/sulfide.
These solar photovoltaic systems are friendly to environment and can also be used to improve power quality and increase the reliability of the electric power system.
Problem Statement
There are many problems that occur in the previous type of solar tracking system. The problem here is the solar panel that is use only in fixed installation. Because of this problem, the power that can be generated is low. The other problem is the price for the solar tracking system is very expensive for the family that use more power than usual because its need to install more than one solar panel to produce enough power. So this project is to fix the problem that occurs. This solar tracking system can detect a 180 degree of rotation. So the solar panel that can be generating here is very high compare to when the solar panel can only stay in one direction.
The other problem is related with the solar energy. The fixed solar panels do not aim directly to the sun due to the constant motion of earth. As the result the power produce by this device is not the maximum it should produce. The better solution for this system to get the maximum output power is solar tracking system. This is the main reason the project solar tracker is made. The solar tracker will follow the sunlight to get more output power. Indirectly it will reduce the cost of buying more solar panels. These systems also reduce the time for users to change the position of solar panel to face the sun.
Literature Review
Peter Gevorkian in his book “Alternative Energy Systems in Building Design, 2009” have written about solar tracking systems. In his book stated that tracking systems are support platforms that orient solar PV module assemblies by keeping track of the sun‟s movement from dawn to dusk, thus maximizing solar energy power-generation efficiency. He also wrote the type of solar tracker. Trackers are classified as passive or active and maybe constructed to track in single or dual axis. Single axis trackers usually have a single axis tilt movement, whereas dual axis system trackers also move in regular intervals, adjusting for an angular position. In general, single axis tracker, compared with fixed stationary tilted PV support systems, increase solar power capture by about 20-25 percent. Dual axis trackers, on the other hand can increase solar power production by 30-40 percent. The book stated not much information about solar trackers. It only stated about it in general, it is enough if it just for information but it is not enough knowledge to do project about solar trackers. The languages that have been used in this book are a bit more complicated for ordinary people that have no engineering education background.
Since the sun moves across the sky throughout the day, in order to receive the best angle of exposure to sunlight for collection energy. A tracking mechanism is often incorporated into the solar arrays to keep the array pointed towards the sun. A solar tracker is a device onto which solar panels are fitted which tracks the motion of the sun across the sky ensuring that the maximum amount of sunlight strikes the panels throughout the day [1]. When compare to the price of the PV solar panels, the cost of a solar tracker is relatively low. Most photovoltaic (PV) solar panels are fitted in a fixed location- for example on the sloping roof of a house, or on framework fixed to the ground [1]. Since the sun moves across the sky though the day, this is far from an ideal solution.
A Solar Tracker is basically a device onto which solar panels are fitted which tracks the motion of the sun across the sky ensuring that the maximum amount of sunlight strikes the panels throughout the day. After finding the sunlight, the tracker will try to navigate through the path ensuring the best sunlight is detected. In methods of tracker mount there are two kind of it, first is single axis solar tracker and other one is double axis solar tracker. Single axis solar trackers can either have a horizontal or a vertical axle. The horizontal type is used in tropical regions where the sun gets very high at noon, but the days are short. The vertical type is used in high latitudes where the sun does not get very high, but summer days can be very long. The single axis tracking system is the simplest solution and the most common one used.
Double axis solar trackers have both a horizontal and a vertical axle and so can track the Sun's apparent motion exactly anywhere in the World. This type of system is used to control astronomical telescopes, and so there is plenty of software available to automatically predict and track the motion of the sun across the sky. By tracking the sun, the efficiency of the solar panels can be increased by 30-40%.The dual axis tracking system is also used for concentrating a solar reflector toward the concentrator on heliostat systems.
For method in drive there are three methods, that is active tracker, passive tracker and chronological tracker. Active Trackers use motors and gear trains to direct the tracker as commanded by a controller responding to the solar direction. Light-sensing trackers typically have two photosensors, such as photodiodes, configured differentially so that they output a null when receiving the same light flux. Mechanically, they should be omnidirectional (i.e. flat) and are aimed 90 degrees apart. This will cause the steepest part of their cosine transfer functions to balance at the steepest part, which translates into maximum sensitivity.
Next is Passive Trackers use a low boiling point compressed gas fluid that is driven to one side or the other (by solar heat creating gas pressure) to cause the tracker to move in response to an imbalance. The last one is Chronological Tracker counteracts the earth's rotation by turning at an equal rate as the earth, but in the opposite direction. Actually the rates aren't quite equal, because as the earth goes around the sun, the position of the sun changes with respect to the earth by 360° every year or 365.24 days.
So to get more efficiency of absorb the energy, active tracker is most suitable to be using in worldwide. But this type of tracker is use microcontroller as a controller where it easy to get faulty either in data collecting and present the data to motor. By using Lab View, it more accurate because is interface with the user by using the computer as a medium. Computer is more suitable to collect the data and present it.
Methodology
A scaled-down model of a prototype will be designed and built to test the workability of the tracking system. From the sensor, it collect the input signal and send it to the data acquisition / interface card linked to a notebook running a LABVIEW. Via the DAQ it sends a data to the center of the drive is a servomotor. This will be controlled The designed algorithm will power the motor drive after processing the feedback signals from the sensor array. The LabVIEW program will also include monitoring and display of light intensity output from the LDR.
Block diagram
Block diagram for solar tracker using servo motor
Light Dependent Resistor
Light Dependent Resistor (LDR) is made of a high-resistance semiconductor. It can also be referred to as a photoconductor. If light falling on the device is of the high enough frequency, photons absorbed by the semiconductor give bound electrons enough energy to jump into the conduction band. The resulting free electron (and its hole partner) conduct electricity, thereby lowering resistance. Hence, Light Dependent Resistors (LDR) is very useful in light sensor circuits. LDR is very high-resistance, sometimes as high as 1000 000Ω, when they are illuminated with light resistance drops dramatically.
LabVIEW
The software is used to control and display the output. This will be connected with the DAQ card to transfer the data to the Lab View. The software is used to show data from the solar panel and to switch on the solar circuit. It also uses to control the motor movement.
The Data Acquisition/Interface Card
The main aim of the Data Acquisition/Interface Card is to provide testing functionality of the mains parts of the Solar Tracker. It should provide available ports for the sensors input, motor controlling output bits and also other interfaces to be controlled as simply as possible and in the shortest time. It must be within specifications and should be small enough to accommodate all the required components and not draw too much power. Popular choices for Data Acquisition/Interface Card are PCI-7334 and EMANT300.
Servo Motors
Servos contain a small DC motor, a gearbox and some control circuitry, and feed on 5 volts at about 100mA maximum, and about 10-20mA when idle. They have a three-wire connector, one common wire (0 volt, usually black), one +5v wire (usually red), and one signal wire. In normal use they are controlled by pulses of about 1 to 2 milli-seconds at a repetition rate of about 50 per second. A short pulse makes the servo drive to one end of the travel, a long pulse makes it drive to the other end, and a medium one puts it somewhere proportionally between. Some servos have gear components that allow them to rotate continuously. This method needs the servo to have a feedback potentiometer used by internal circuits to measure the position of the output shaft. If this is disconnected and the wires taken to an external pre-set potentiometer, the servo will drive continuously in one direction if fed with short pulses and vice-versa. If there are no pulses, the servo stops. It is uses to drive the Solar Tracker Eastward and Westward. The pulses are at normal TTL levels. The speed though, is not greatly affected by the pulse repetition rate, as long as it is above about 30 per second. These pulses can easily be provided by an output port of just about any computer, for instance the data or control lines of a printer port or a serial port, or a simple addressed latch added to the memory circuits. A possible configuration is the tricycle described above, with one driving and steering-wheel at the front and two idler wheels at the rear. Using a Radio Controlled (RC) servo for steering is a good method, because the position of the steering mechanism is determined by the length of the servo drive pulse, which can be generated by a software countdown loop or a hard-ware counter. If an RC servo is used as a drive motor, wheel motion sensors are needed on at least one wheel as in any DC motor.
Solar panel
Solar panel is the main point of the project. It involves solar panel to get the voltage output. This is renewable energy that needs to convert into voltage. This solar need more study and do the experimental to know the range of the output value. This solar panel will be controlled by software to switch on the circuit that will be converted the output and stabilize the voltage that be used in the project.
Objectives
This research study intends to plug the research gap and will demonstrate the development of the techniques to get maximum solar energy parameter by:
i. To develop a tracking system that constantly tracking the sun during daytime.
ii. To develop a tracking system that maximize the solar panel power generation.
iii. To develop a tracking system based on LDR and LabVIEW.
iv. To develop a tracking system that control and monitor the movement of solar panel based on the intensity of light
Benefits/ Contributions
Based on the objectives above, this research study will propose methods to estimate solar tracking systems reliability parameters and applies them to maximize the power generation. The main reason to use a solar tracker is to reduce the cost of the energy, a tracker produces more power over a longer time than a stationary array with the same number of modules. The main original contributions of this research study can be stated briefly as follows:
1. The presence of this device is extremely important because the sun’s position varies from time to time. And the position of the sun will often vary with the season and the elevation and dependent as well on the time of the day. And this is where the solar tracker comes in the picture. This solar powered equipment will make the solar panel work better and with efficiency since this will be pointed directly to the sun with the help of the tracker.
2. It can be used most effectively in areas with low horizons and locations that are shade free from dawn to dusk each day. Throughout the year the tracking array will be able to utilize the wide open access to gain every available electron from the sun. This way, energy production is at an optimum and energy output is increased year round.
The existence of solar tracker is very useful in situation when the demand of electricity is higher. As to increase the electricity, the solar tracker plays the role in producing more electricity. The solar tracker tracks the sun and concentrates the maximum sunlight to the photovoltaic module to generate electricity. As the solar tracker is used, the electricity can be generating more than the usual amount electricity generate in year if used only solar panels. It can cover the electricity demand so that the users can live better without electricity being cut off and it can cover critical situation when there are technical problem with main electric generator. Overall, the solar tracker is useful and has to be commercialized more for the better future.
Work Plan
The time frame allocated for this research study is 10 months. It will start in January 2012 and is projected to be completed in October 2012. The Gantt chart for the project and its milestone are shown as in Table 1.
Practically, reliability is often more difficult to specify than many major performance characteristics and is certainly more difficult than most to measure. The accurate assessment of the reliability of a product in use is often difficult because of the long period needed or the large number of samples required in order to gain statistical confidence in the assessment. In reliability estimation, the failure rate models are approximations to reality. The failure rate models are normally based on the best field data that could be obtained for a wide variety of parts and systems. This data is then analysed, with many simplifying assumptions applied, to create usable models. Thus, one should not treat a reliability estimation numbers for the system as an absolute prediction of field failure rate. Generally, it has been agreed that these estimations can be very useful when used for relative comparison, such as comparing design alternatives, or comparing products.
Prototype of this solar tracking device configurations for data centre application will be build to enables the community to visualise the impact and application of the proposed methods in determining the best solutions in solar tracking design with respect to reliability and cost. This prototype will be presented in the FYP Presentation Day.
Budget
Hardware
No | Component | Quantity | Cost(RM) |
1 | Solar panel | 1 | 150.00 |
2 | Servo motor | 1 | 189.00 |
Total | 339.00 | ||
Software
No | Component | Quantity | Cost(RM) |
1 | DAQ card | 1 | - |
2 | Lab View software | 1 | - |
Total | - | ||
Motor controller circuit
No | Component | Quantity | Cost(RM) |
1 | Voltage regulator (LM805) | 1 | 1.50 |
2 | Resistor | 12 | 1.20 |
3 | Motor Drive (L298) | 1 | 5.00 |
Total | 7.70 | ||
Total all costing is RM346.70. All the costing and budget above are the estimation only and all the item and components are not finalize at all because there is only estimation and maybe involve with other component and other circuit or any upgrading to the project.
Conclusion
In summary for this research study, this project consists of taking a standard hardware and solar panel that use in this project. This allows the user to get the maximum solar energy. Therefore this project met it goal, it is to developing a system which leveraged the functionality of many different subsystems, spanning the areas of software, electrical, and mechanical engineering into a coherent and useful system.
The project which also involve designing and development of Solar Tracking system has totally exposed to a better way of software and hardware architecture that blend together for interfacing purposes. In implementing the project, it requires the application of graphical software LabVIew to display and acknowledge the data obtained from the hardware. The software development may express the right pin to produce the output in the manner of proper instructions by using software Labview to interface the DAQ Card with the project hardware. From this interface, user is allowed to control the motor motion that can be retrieved from the output of the hardware circuit. This interfacing also uses a click button method as an interaction for the users.
References
Website
(1) “Concept: What is Solar Panel?”
http://www.knowledgerush.com/kr/encyclopedia/Solar_panels/
(2) “1st Solar Panel”
http://inventors.about.com/od/sstartinventions/a/solar_cell.htm
(3) “Solar plant to be set up by 2010 in Singapore”
http://www.wildsingapore.com/news/20070910/071027-1.htm#st
(4) “Solar Tracker Mount Types”
http://en.wikipedia.org/wiki/Solar_tracker
(5) “Solar Tracker Drive Types”
http://en.wikipedia.org/wiki/Solar_tracker
(6) “A General overview of Light Dependent Resistor”
http://www.knowledgerush.com/kr/encyclopedia/Light-dependent_resistor/
(7) “A General overview of Photodiode”
http://www.knowledgerush.com/kr/encyclopedia/Photodiode/
Books
1. Eric Anderson, Chris Dohan, Aaron Sikora. (2003) Solar Panel Peak Power Tracking System, Worcester Polytechnic Institute.
2. Richard Stephenson. (2007) Fundamental Properties of Solar Cell and Paste for Silicon Solar Cell. United State of America.
3. G.F. Frankin, J.D. Powell, and A. Emami-Naeini. Feedback Control of Dynamic System, Addison-Wesly Publishing Company, 1995.
