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Dept. of EEE i CMRIT, BANGALORE
PROJECT REPORT on
Artificial Sunflower (A survey on commercial solar trackers & preliminary implementation steps for
an indigenous model)
BACHELORS OF ENGINEERING
in
ELECTRICAL AND ELECTRONICS ENGINEERING
Visveswaraya Technological University
Submitted by
ISHAN GAUTAM (1CR12EE043)
DEEP SIDDHARTH (1CR12EE029)
DIBYASHA MAHAPATRA (1CR12EE033)
GURUPRIYA RAJENDRAN M V (1CR12EE042)
DILIP B S (1CR12EE034)
Under the guidance of
Dr. Chaitanya Lekshmi Indira Department of Chemistry
Dept. of EEE ii CMRIT, BANGALORE
Department of Electrical Engineering
C.M.R Institute of Technology
BANGALORE-560037
CERTIFICATE
Certified that the project work entitled “ARTIFICIAL SUNFLOWER” is
an original work carried out by Ishan Gautam, Deep Siddharth, Dibyasha
Mahapatra, Gurupriya Rajendran M V and Dilip B S in partial fulfillment
of 6th semester Bachelor of Engineering in Electrical and Electronics
Engineering of CMR Institute of Technology, under the Visvesvaraya
Technological University, Belgaum under the guidance of Dr. Chaitanya
Lekshmi Indira during the year 2014-2015. The Project report has been
approved as it satisfies the academic requirements in respect of project
work prescribed for the Bachelor of Engineering degree.
Signature of Guide Signature of HOD
Dept. of EEE iii CMRIT, BANGALORE
Contents
Chapter 1. Introduction....…………………………………..1
1.1. Objectives....……………………………………………1
1.2. Achievements and Boundaries ………………………...2
Chapter 2. Background ……………………………………..3
2.1. Sources of energy ……………………………………...3
2.2. Global warming and climate change …………………..3
2.3. Solar energy ....…………………………………………4
2.4. Efficiency ………………………………………………5
Chapter 3. Efficiency of PV panel ………………………….7
3.1. Parameters affecting performance ……………………..7
3.2. Methods to increase efficiency ………………………...9
Chapter 4. Solar tracker …………………………………...12
4.1. Hardware ……………………………………………...12
4.2. Software and programming …………………………...15
Chapter 5. Outcomes and achievements ………………......21
5.1. Implementation in large scale …………………………22
5.2. Conclusion …………………………………………….25
Chapter 6. References ………………………………………26
Dept. of EEE 1 CMRIT, BANGALORE
1. Introduction
Solar energy is the cleanest and most abundant source of energy available. It can be
harnessed like any other type of energy and used to create electricity. As of now
many vehicles, instruments and machines harness solar energy to function. One of
the efficient and most commonly used methods to harness solar energy is by using
solar panels made up of photovoltaic cells (semiconductor in nature). Si based
photovoltaic cells are the most widely used type and largely put into commercial
usages.
Generally we assess the performance of any system by its efficiency, higher the
efficiency better the system works. When it comes to conversion of solar energy into
other useful forms of energy, efficiency is still not largely a plus point. The typical
solar panel setups installed so far can achieve up to 15% efficiency which is very
less. There are, however methods of increasing the efficiency of solar panel system.
This project concentrates on one such method involving an apparatus called ‘Solar
tracker’. A solar tracker is a device which holds the solar panel, orienting it towards
the sun as the sun moves throughout the day, all through the year. Solar tracker
increases the efficiency of the solar panels by enabling them to face directly the sun
throughout the daylight time period and thus can generate maximum electricity. Use
of solar trackers increases the amount of sunlight received by the solar panel during
the day.
By surveying existing techniques and using a suitable one, we target to build a dual-
axis solar tracker with minimum cost that orients any payload towards the sun
throughout the day and year. As the features of this solar tracker are very similar to
that of a sunflower which faces the sun throughout the day, we have titled the project
as artificial sunflower.
1.1 Project Objectives
To summarize, the project objectives are:
Literature survey of current and existing technologies involving solar energy
and solar trackers and materials for antireflection coating on solar panels.
To collect necessary data needed to evaluate the efficiency graph of solar
panels with and without solar tracker.
Designing and building a dual axis solar tracker using Arduino open source
hardware technology. Reduce the expenses by using power saving methods
and increased accuracy.
Dept. of EEE 2 CMRIT, BANGALORE
1.2 Achievements and Boundaries
The main objective of the project ‘Artificial sunflower’ is to successfully build a
dual axis solar tracker with less expenses and power saving methods. This
was achieved by using a 8-bit microcontroller ATmega328 which has power
saving mode that hibernates the entire tracker when not needed, i.e. during
night time and even during rain or other weather conditions.
At the time of the conception of the project, the aim was to record data of
solar panel exposed to sunlight throughout the day with the help of the solar
tracker we built. This way we would have the comparison between the
efficiency achieved by stationary solar panels and the solar panels using solar
trackers. This however could not be completed to limited time available.
Dept. of EEE 3 CMRIT, BANGALORE
2 Background
In the present world of increasing population the demands for settlements and other
facilities increase exponentially. To meet these demands, energy requirements also
increase. The increase in energy production has its own side effects /drawbacks.
2.1 Sources of energy Two broadly classified sources of energy are renewable energy sources and non-
renewable energy sources. Renewable energy is generally defined as energy that
comes from resources which are naturally replenished on a human timescale such
as sunlight, wind, rain, tides, waves, and geothermal heat. Non-renewable energies
are those that do not self-sustain naturally. Examples of non-renewable energies are
coal, oil and natural gas.
2.2 Global warming and Climate change
Unlike renewable energy sources like wind, water and sun--most of which are
converted to power cleanly--the conversion of fossil fuels to usable energy can result
in harmful emissions and its collection can disrupt local wildlife.
The processing of fossil fuels emits harmful greenhouse gases into the air. These
gases, primarily carbon dioxide, damage the ozone layer which protects us from the
sun's radiation. The air pollution also negatively affects our respiratory health
Acid rain is created by the emission of sulfur and other chemicals into the
atmosphere, often from the conversion of fossil fuels into electricity. It is corrosive to
machinery and can disrupt local ecosystems. Harmful ash is stored in solid waste
containment areas which are prone to rupturing and causing havoc in the
surrounding areas. Totally we can term these chain of events as global warming.
Global Warming is the increase of Earth's average surface temperature due to effect
of greenhouse gases, such as carbon dioxide emissions from burning fossil fuels or
from deforestation, which trap heat that would otherwise escape from Earth. This is a
type of greenhouse effect. The most significant greenhouse gas is actually water
vapor, not something produced directly by humankind in significant amounts.
Dept. of EEE 4 CMRIT, BANGALORE
Greenhouse gas emissions recorded at international energy agency over years
However, even slight increases in atmospheric levels of carbon dioxide (CO2) can
cause a substantial increase in temperature.
The figure above shows a statistics graph of increase in the emission of carbon
dioxide (CO2) recorded over a span of 20 years from 1990 to 2010, recent increase
in automobiles and increased energy demands, the rate at which fossil fuels are
processed is high. This in turn increases the carbon dioxide (CO2) emissions.
Most of the generators are run by a steam turbine. Those steam turbines are
indirectly increasing the amount of water vapor, added to that are the emission of
greenhouse gases by fossil fuel.
2.3 Solar energy
The most abundant renewable source of energy that we have available is solar
energy. We receive solar energy in form of heat and light from sun, the star of our
solar system. Solar energy can be converted to useful form of energy using solar
panels. Solar panels are made up of photovoltaic cells which are semi-conductive in
nature.
Dept. of EEE 5 CMRIT, BANGALORE
Photovoltaics (PVs) are arrays of cells containing a solar photovoltaic material that
converts solar radiation into direct current electricity. Solar cells produce direct
current (DC) electricity from sunlight, which can be used to power bulb/equipment or
to recharge a battery, however, for grid connected power generation; an inverter is
required to convert the DC to alternating current (AC).
A number of solar cells electrically connected to each other and mounted in a
support structure or frame is called a photovoltaic module. Multiple modules can be
wired together to form an array. In general, the larger the area of a module or array,
the more electricity that will be produced.
The most common PV devices use a single junction, or interface, to create an electric field within a semiconductor such as a PV cell. In a single-junction PV cell, only photons whose energy is equal to or greater than the band gap of the cell material can free an electron for an electric circuit. In other words, the photovoltaic response of single-junction cells is limited to the portion of the sun's spectrum whose energy is above the band gap of the absorbing material, and lower-energy photons are not used. One way to get around this limitation is to use two (or more) different cells, with more than one band gap and more than one junction, to generate a voltage. These are referred to as "multijunction" cells (also called "cascade" or "tandem" cells). Multijunction devices can achieve a higher total conversion efficiency because they can convert more of the energy spectrum of light to electricity.
2.4 Efficiency
Efficiency of any system is the ratio of the obtained output to the rated input. In case
of solar panel, the energy conversion efficiency of a solar cell is the percentage of
the solar energy that is converted into useful form of energy (electrical energy). One
of the basic formula to calculate the energy conversion efficiency is
where,
Pm represents maximum power output of solar cell in watts
G represents the input light in W/m^2
Ac represents the surface area of the solar cell in m^2.
Dept. of EEE 6 CMRIT, BANGALORE
Most solar panels are around 11-15% efficient. The efficiency rating measures what
percentage of sunlight hitting a panel gets turned into electricity that you can use.
The higher the efficiency, the less surface area you’ll need in your solar panels.
We can see that the efficiency of conventional solar panels is very less. A survey
was conducted which shows us that the solar panels do not meet the expected
requirements when it comes to efficient conversion,
The above graph is a comparison between flat plate solar panel and evacuated tube
solar panel against the reference of annual demand of energy. We can see that both
type of solar panels do not meet the annual demand required. The conversion
efficiency is less due to this. The efficiency of a solar panel is affected by many
factors which are discussed in next chapter.
Dept. of EEE 7 CMRIT, BANGALORE
3 Efficiency of a photovoltaic cell
As discussed in the previous chapter, even though theoretically the expected
efficiency is around 90%, the actual efficiency is around 15%. The Fraunhofer
Institute for Solar Energy Systems ISE, Soitec, CEA-Leti and the Helmholtz Center
Berlin jointly hold the record for achieving highest solar energy conversion efficiency
of about 44.7%.
Various types of solar panels give different range of efficiency as shown,
Hence we can see that the average efficiency lies under 15%, this is due to the
various factors affecting the performance of the solar panel.
3.1 Parameters affecting performance of PV cells
Considering the size and efficiency some other factors affect the performance i.e.
how the solar panel generates. Some of them are given below,
Effects of temperature: The output of a solar cell, and therefore a solar panel, is
affected by its temperature. The photons when they hit the solar panel hey bump into
an electron and give it the energy they were carrying. When this happens the
electron goes from a low-energy state to a high-energy one. The solar cell is then
Dept. of EEE 8 CMRIT, BANGALORE
designed to extract this electron in the high energy state and run it through an
electrical circuit to use up this extra energy that the electron has. Sometimes though
this high-energy electron will bump into other atoms in the solar cell before it
manages to get out, and the electron loses this extra energy which turns into heat
rather than electricity. As a result the power output will be reduced by between
0.25% (amorphous cells) and 0.5% (most crystalline cells) for each degree C of
temperature rise.
Panel temperatures in the summer in warm climates can easily reach 50 degree C
resulting in a 12% reduction in output compared to the rated output at 25 degree C.
This reduction if efficiency maybe important if there is a high demand for electricity in
summer.
Panel Orientation and pitch: Photovoltaic panels collect solar radiation directly from
the sun, from the sky, and from sunlight reflected off the ground or area surrounding
the PV panel. Orienting the PV panel in a direction and tilt to maximize its exposure
to direct sunlight will optimize the collection efficiency. The panel will collect solar
radiation most efficiently when the sun's rays are perpendicular to the panel's
surface. The angle of the sun varies throughout the year as shown in the figure
below. Therefore, the optimal tilt angle for a PV panel in the winter will differ from the
optimal tilt angle for the summer. This angle will also vary by latitude.
Range of midday sun angles at 12.97° south latitude(Bangalore)
The main step in determining optimal PV panel orientation and tilt angle is to review
the site where the PV lighting system will be installed. Trees, large buildings, or other
structures or obstructions surrounding the site might cast shadows onto a tilted PV
panel at various times of day or during winter months when the sun is at a low angle
in the sky. Therefore, it may be best to orient the PV panels horizontally to face the
sky directly. This may allow the panels to collect the maximum amount of solar
radiation with the least obstruction.
Dept. of EEE 9 CMRIT, BANGALORE
Shade: Shade can be the enemy of solar power. The way solar is designed even a
little shade on one panel can shut down solar production on all the other panels.
Solar cells are connected in series, and will operate at the current level of the
weakest cell, if one solar cell is shaded it will adversely influence the output of all
other cells. When deciding on a location for your solar panels do a shading analysis,
make sure no shadows will fall on the solar panel array during peak sunlight hours.
This may mean trimming a few trees.
Front surface soiling: Solar cells cannot absorb light as effectively when the surface
of the solar panels are covered with dirt or pigeon droppings, which doesn’t get
washed by the rain. Making frequent physical inspections and spraying water on the
modules can help reduce the problem.
3.2 Methods of increasing efficiency
There are various methods of increasing the efficiency of solar panel. Among those
in this project we choose to concentrate on these two methods,
a) By using anti-reflective coating
b) By using solar tracker
Anti-reflective coating
Selection of the Anti- reflective coating:
For a solar panel to be used efficiently, the maximum sunlight falling on it should be
absorbed into it. A regular solar panel is made up of silicon material. So usually the
sunlight rays travel from the air to the panel made up of silicon. But when using air
there is some amount of the light which gets reflected. So we can use an anti-
reflective coating made of glass which reduces the amount of light reflected back.
The following calculations show how the reflection is reduced theoretically,
We know that the refractive indices of air (n0) =1, glass (n1) =1.5 and that of silicon
(n2) = 3.44.
And we use the wavelength (λ) as 0.6µm since that’s the range of sunlight which is
more abundant
i) When the solar panel is used without anti – reflective coating:
Dept. of EEE 10 CMRIT, BANGALORE
Let us represent the refractive index of the anti-reflecting material as nf.
Consider the surrounding medium to be just air since we are not using an anti-
reflective coating
We can calculate the value of nf =√n𝟎 ∗ n1
Therefore by calculations, nf =1.8547
The thickness (d) of the anti-reflective can be determined as
d= λ/(4* nf)
By calculations, d=0.08 μm.
The amount to light which is reflected is given by the following formula,
Reflected Light(R) =r1^2+r2^2+2*r1*r2*cos2θ
1+r1^2*r2^2+2*r1*r2*cos2θ
Where r1= (n0- nf)/(n0+ nf)
r2= (nf – n1)/ (nf + n1)
θ= (2*π*nf*d)/λ
Therefore by calculations for this case,
r1=-0.3
r2=0.3
θ=1.57
R=0.000326
ii) When using an anti-reflective coating:
So we have glass as anti-reflective material
Same formulas are used, the values are as follows:
nf=2.27
d=0.066μm
r1=-0.204
r2=0.205
θ=1.57
R=0.00013
Dept. of EEE 11 CMRIT, BANGALORE
Therefore by the calculations it’s clear that the amount of light reflected is reduced
with glass as an anti-reflecting material. As the amount of reflected light reduces, the
amount of light absorbed by the solar panel increases. Hence more amount of
sunlight is getting converted using the same solar panel of same surface area. The
maximum power output is increased significantly by introducing anti-reflective
coating.
Even though as shown by our calculations, on addition of glass over the silicon
based solar cell, the amount of there is still some amount of energy that is being lost
which in turn directly effects the efficiency of the solar cell. In order to improve the
efficiency of the solar panel, by decreasing the energy lost, we have to put an anti-
reflective coating over the glass.
Anti-reflective coating is an optical thin film material. Some of the materials that
proved to be useful to this respect are silicon dioxide, indium-tin oxide and titanium
dioxide. Each of these have a refractive index of around 1.05, which is lower than
glass and can cause a possible total internal reflection which could improve the
efficiency further.
It is been shown that silicon dioxide and titanium dioxide coating on the glass of the
solar panel increases the cell efficiency by 3-4 %. Sono Tek corporations have
already started using an ultrasonic spray system designed to provide these coating
on the panels. So by using an anti-reflective coating, we can increase the efficiency
of the solar panel.
Dept. of EEE 12 CMRIT, BANGALORE
4 Solar tracker
The main objective of this project artificial sunflower is to design and build a solar
tracker which automatically orients itself towards the sun such that the payload it lifts
get as much as sunlight as possible throughout the day and year. We are using
existing technology and electronic components to build a circuit which makes the sun
tracking possible. Our solar tracker is made of light sensors which is connected to
programmable servo motors. These servo take the action as instructed and rotate
the panel 180º to adjust towards sunlight.
4.1 Hardware
The solar tracker is built using,
An 8-bit microcontroller ATmega328
4 light dependant resistors
2 servo motors-9v dc
An open source electronic platform-in this case Arduino.
Passive electronic components such as resistors, potentiometers etc.
The diagram below shows the block diagram of the tracker
Dept. of EEE 13 CMRIT, BANGALORE
The main circuit is the control circuit block which contains electrical circuit consisting
of passive resistive elements, the light dependant resistors are the input devices
which take in the sunlight to determine the position and orientation of the entire
tracker. In our project the LDRs are interfaced with the Arduino board through the
analog pins present on the Arduino used. We obtain the analog input from the LDRs
through the board and find the most suitable position for the solar panel such that the
maximum amount of light falls on the panel. In accordance to the values from the
LDRs, the rotation of the motors are controlled.
The following figure shows that the light dependant resistors are connected,
Four LDRs are placed on either sides of two sheets intertwined, this allows us to
detect the position of the sun by following points.
The LDR which receives maximum light closes the path for current. The program is
written such that the motors turn the entire such that, all the LDR receive maximum
light as possible.
Dept. of EEE 14 CMRIT, BANGALORE
A servo motor gives precise control of rotation, acceleration and even the velocity.
Since the solar tracker has to be employed throughout the day and the sun moves
over the horizon over span of 10~12 hours based in weather, we need precise
movement of the solar panels to get maximum sunlight. Hence servo motors are
preferred over any other motors. Also servo motors require very less power which
can be obtained by small batteries.
The motors we use in this project are micro servo which operate at 9v. It operates on
Direct current and hence easy to maintain and costs less too. The motors receive the
signal from LDRs via a microcontroller.
Micro controller is a small computer on a single integrated circuit containing a
processor core, memory and programmable input/output peripherals.
In our project we have to control the rotation of the two motor with respect to the
illumination of LDRs.
If we try to use any hardware means to make this system work, the system might
become bulky and design also becomes complicated. So we need a system which
reduces the size as well as improve the efficiency of the system.
This can be easily achieved by using a micro controller. A micro controller can be
used for interfacing the LDRs and the motors on one single board. Here we interface
the LDRs to the analog pins of the microcontroller and the motors to digital pins.
So here we can consider LDRs interfaced as the input peripheral and motors
interfaced as output peripherals.
We can use simple C++ coding to control the motors through the micro controller.
We have used an Arduino board which is a micro controller board. It is a small circuit
that contains whole computer on small chip. The main advantages of using these
boards are they are flexible, it’s great for developing interactive objects, software and
hardware.
It is optimal for our project because our project also uses interactive systems (i.e.
LDRs and motors).
Dept. of EEE 15 CMRIT, BANGALORE
4.2 Software and programming
The software used to dump the program into microcontroller is an open source
software called Arduino IDE. Using this software we can program the microcontroller
to run the motors. We can see from the figure the pin diagram of Arduino with an 8-
bit microcontroller ATmega328.
Dept. of EEE 16 CMRIT, BANGALORE
Coding for the rotation of the panels:
#include <Servo.h> // include Servo library
Servo horizontal; // horizontal servo
int servoh = 60; // stand horizontal servo
Servo vertical; // vertical servo
int servov = 60; // stand vertical servo
// LDR pin connections
// name = analogpin;
int ldrlt = 0; //LDR top left
int ldrrt = 2; //LDR top rigt
int ldrld = 1; //LDR down left
int ldrrd = 3; //ldr down rigt
void setup()
{
Serial.begin(4800);
// servo connections
// name.attacht(pin);
horizontal.attach(9);
vertical.attach(10);
}
void loop()
{
int lt = analogRead(ldrlt); // top left
int rt = analogRead(ldrrt); // top right
int ld = analogRead(ldrld); // down left
int rd = analogRead(ldrrd); // down rigt
int dtime = 51.2;//analogRead(4)/20; // read potentiometers
int tol = 256;//analogRead(5)/4;
int avt = (lt + rt) / 2; // average value top
Dept. of EEE 17 CMRIT, BANGALORE
int avd = (ld + rd) / 2; // average value down
int avl = (lt + ld) / 2; // average value left
int avr = (rt + rd) / 2; // average value right
int dvert = avt - avd; // check the diffirence of up and down
int dhoriz = avl - avr;// check the diffirence og left and rigt
if (-1*tol > dvert || dvert > tol) // check if the diffirence is in the tolerance else
change vertical angle
{
if (avt > avd)
{
servov = ++servov;
if (servov > 180)
{
servov = 180;
}
}
else if (avt < avd)
{
servov= --servov;
if (servov < 0)
{
servov = 0;
}
}
vertical.write(servov);
}
if (-1*tol > dhoriz || dhoriz > tol) // check if the diffirence is in the tolerance else
change horizontal angle
{
if (avl > avr)
{
Dept. of EEE 18 CMRIT, BANGALORE
servoh = --servoh;
if (servoh < 0)
{
servoh = 0;
}
}
else if (avl < avr)
{
servoh = ++servoh;
if (servoh > 180)
{
servoh = 180;
}
}
else if (avl == avr)
{ // nothing
}
horizontal.write(servoh);
}
delay(dtime);
}
The above written is the code used for the controlling and optimization of the solar
panel efficiency.
We can better understand the program with the help of a circuit diagram. The circuit
diagram shows us how the pins of Arduino are connected to LDRs and also the main
control circuit.
Dept. of EEE 19 CMRIT, BANGALORE
Circuit schematic diagram
The LDRs are interfaced using the analog pins 0, 1, 2 and 3 and the motors are
interfaced using the digital pins 9 and 10. The values each LDR is read by the
function analogRead().
The analog values read using this function is proportional to the amount of
illumination of the LDRs. We calculate the average values between two of the LDRs
and it is repeated for every combination of the LDRs. The Difference between the top
and down LDRs and left and right LDRs are calculated and compared to a tolerance
value (Here the tolerance value=256).
Dept. of EEE 20 CMRIT, BANGALORE
Depending the conditions checked with the tolerance requirements, signal is sent
through the digital pins and the vertical and horizontal motors are controlled and
brought to a position such that the LDRs are equally illuminated.
The rotation of the motors are controlled by the angles send to it through the digital
pins using the write () function.
The analog pins continuously monitor the light falling on the LDRs and according to
the calculation the motors are rotated which causes the Solar panel to receive
maximum amount of sunlight for the power generation.
Dept. of EEE 21 CMRIT, BANGALORE
5 Outcomes
Solar energy is the future, harnessing solar energy has been the aim of most of the
countries. Unlike other sources of energy, solar doesn’t need investment. The sun is
not going to run out of light and heat for few billion years. So harnessing solar energy
efficiently should be one of the major achievement of our country.
India as of now runs mostly on fossil fuels. Studies show us that up to 90% of the
energy generated in India are fossil fuels and other fuels which emit greenhouse
gases. Installing solar power plants with tracking system not only decreases the
need for fossil fuels it also keeps the environment clean with less global warming to
worry about.
Dept. of EEE 22 CMRIT, BANGALORE
5.1 Implementation in large scale
A dual axis solar tracker as explained in this project report is a prototype model. In
large scale very limited number of dual axis tracking system exist worldwide. Some
of the examples of solar power plant with tracking are
An ongoing pole mounted dual axis tracker project in Sizziwangqi
One of the largest dual axis solar trackers in New Mexico
Dept. of EEE 23 CMRIT, BANGALORE
Using solar tracking devices increases the efficiency of solar power plant setup
significantly. But the area required increases which again increase investment. Since
these investments are one time only it is better to have a tracking system in many
solar power generation stations.
We can see that the efficiency of solar panels with tracking system increases as it
increases the total sun hours. Sun hour is the amount of maximum duration of the
sunshine given by the sun. A dual axis solar tracker automatically adjusts towards
the thus throughout the day like a sunflower, thus increasing the sun hours. The
statistics show that the amount of energy converted with the help of solar tracker is
more than the fixed solar panels.
[Survey] - ISSN: 2319-5967 - International Journal of Engineering Science and
Innovative Technology (IJESIT)
A research study conducted has obtained the following data which conveys and
agrees with the theoretical concept of increase in the efficiency when a solar panel is
mounted on a solar tracker,
(a) Tabular column with recorded data of a fixed mount and solar panel mounted
on a dual axis solar tracker
Dept. of EEE 24 CMRIT, BANGALORE
(b) Output vs time curve indicates that the power obtained for the same amount
of time is more in case of the solar panel mounted on a solar tracker(dual
axis)
Comparison between fixed solar panel and solar panel with dual axis tracker system
Dept. of EEE 25 CMRIT, BANGALORE
5.2 Conclusion
It can be seen that adding anti-reflective coating to the solar panel significantly
reduces the amount of light reflected back. This in turn increases the amount of
sunlight in taken. More amount of sunlight is getting converted with the same area of
solar panel. Thus without increasing the size of the solar panel we are increasing the
efficiency of the same solar panel.
We have designed and built a dual axis solar tracker with a microcontroller
monitoring the entire circuit. This could be achieved by interfacing servo motors in
two axis to the main control circuit. Hence this allows the servo motors to rotate
precisely towards the sun. Rotary motion in two axis is difficult but can be achieved
with a little skill. The height of the solar tracker can be designed based on the
demands.
Even though the initial cost of the solar tracker is high, the increase in efficiency pays
off for this factor. Adding a solar tracker significantly increase the efficiency of the
solar power plant system as well as any household systems. Ultimately solar energy
utilization must be done effectively.
While solar energy has many advantages there are a few disadvantages. The initial
cost of installation can be steep, but when one takes overall savings into mind it can
be seen as a wise investment. When the weather or air pollution is bad it may be
harder to harvest the sun’s power. This disadvantage can be combated by using an
energy storage system that saves up power for use in the nocturnal hours and dark
days. With a little consideration most of the obstacles that may be presented by solar
energy can be overcome. Technology improves every day and with the cost of non-
renewable energy on the rise it’s easy to see why our global community needs to
focus on the future.
Dept. of EEE 26 CMRIT, BANGALORE
6 References
[1] Wikipedia; https://en.wikipedia.org/wiki
[2] PV Education; http://www.pveducation.org
[3] Instructables; www.instructables.com
[4] Energy Informative; http://energyinformative.org
[5] Million Solar Roofs; http://www.millionsolarroofs.com
[6] DF robot; http://www.dfrobot.com
[7] Electrical4U; http://www.electrical4u.com
[8] International Energy Agency; http://www.iea.org
[9] International Journal of Engineering Science and Innovative Technology
[10] Sono Tek http://www.sono-tek.com