Universal solar tracker final report

Universal Solar Tracker
Vassos Tapakoudes
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Supervisor Dr Sanja Dogramadzi
Module UFMEAY-30-3
Undergraduate Final Year Project
Academic Year 2012-2013
11 April 2013

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Universal Solar Tracker Vassos Tapakoudes
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Summary
A detailed analysis has been accomplished in order to investigate the applied science of
Solar Energy systems equipped by a Solar Tracker. A solar energy tracking system was
mechanically designed in SolidWorks and a prototype was manufactured using mainly
existing components. A simple Arduino micro-controller board was designed which
functions with the physical model in order to create a dynamic solar tracking system.
Dynamic solar tracking systems is a proposed approach in order to increase the overall
energy received by a solar panel. Testing the physical model determined the feasibility of
operating a solar energy system with the aid of a solar tracker. Testing results made clear
to the audience that tracking systems are essential for photovoltaic solar energy systems
when an increase in the overall power of the system is required. Eventually the retail price
and the selling price of the Solar tracking system together with a 100W Solar panel is
calculated to be £440.91 and £551.14 respectively, which are significantly low compared
to other solar trackers available in the industrial market.

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Acknowledgements
I would like to express my deep gratitude to Dr Sanja Dogramazi and Dr Ramin Amali, my
supervisor and my module leader respectively, for their guidance, patient, encouragement,
critiques and everlasting help on this thesis. I would also like to thank and show my deep
appreciation to Nahuel Lavino, a graduate student of University of the West of England,
who spent much of his time in order to make clear to me some electronics principles while
helping me to take the real time testings.
Last but not least, I would like to thank “Harwal Group of Companies” and their
technicians who allowed me to work in their workshop and provided me with useful
manufacturing tips and advices in order to manufacture the Solar Tracker Prototype.
Finally I would like to thank my parents who provided me with courage and moral support
throughout my degree and especially during my final year project.

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Table of Content
Introduction ..........................................................................................................................5

Motivation of the Thesis ..................................................................................................5

Justification of the Thesis................................................................................................5

Aims and objectives .........................................................................................................7

Applied Science on Solar Energy (tracking) Systems .........................................................8

Solar cells ..........................................................................................................................8

Solar tracking theory.....................................................................................................10

Literature Review................................................................................................................11

Solar energy system timeline.........................................................................................11

Prior Art on Solar Tracking Systems...........................................................................12

Tracking Techniques ...............................................................................................................................13

Tracking system.......................................................................................................................................15

Solar sensors ............................................................................................................................................16

Solar Tracking Motion.............................................................................................................................18

Paraphernalia.................................................................................................................19

Application of Solar Energy Systems...........................................................................20

Solar Tracking System Methodology and Design .............................................................23

Methodology ...................................................................................................................23

Concept & idea / Output Requirements...................................................................................................24

Alternative designs and Design Selection ....................................................................25

Computer- Aided and Physical Design ..............................................................................28

Computer-Aided Design................................................................................................28

Implementation and Manufacturing Process..............................................................31

Electronic Design ...........................................................................................................50

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Micro-controller Board............................................................................................................................50

Motor-driver Board..................................................................................................................................51

LDR (Light Dependant Resistors)...........................................................................................................51

Remarkable Outputs and Experimental Results ...............................................................54

Cost Analysis ..................................................................................................................54

Do-It-Yourself Product..................................................................................................57

Real time-Testing of the Universal Solar Tracker......................................................58

Method and Calibration of testing ...........................................................................................................58

Fix position solar system Scenario ..........................................................................................................60

Universal Solar Tracker Scenario ................................................................................62

Power produced: Fix position Vs. Universal Solar Tracker......................................63

Future Modifications and Conclusion...............................................................................64

Extension kit Scenario ...................................................................................................64

Conclusion ......................................................................................................................66

Reflective Statement ......................................................................................................67

Appendices ..........................................................................................................................69

References...........................................................................................................................70

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Introduction
Motivation of the Thesis
Greenhouse effect has given rise to global warming due to the excess amount of CO2 in
the atmosphere resulting in unpredicted climate changes worldwide; an integral concern
for the world. John Mankins (2010), a 25-year NASA Veteran and head of the IAA study,
said “There is a consensus among scientists that greenhouse gas emissions pose a great
risk of irreversible global climate change. Hence, during the course of the century, it
seems critical that the mix of energy sources must shift away from fossil fuel, even as the
overall demand for energy soars.” Thus it’s significant that humanity and scientist
concentrate on reducing this phenomenon via alternative ways of producing energy rather
than fossil fuels; environmentally friendly and mainly obtained from natural sources such
as wind, sun and water. “You’d be hard pressed to find another industry with 26% job
growth rate for 2011” said by Rhone Resch (2011) president of the Solar Energy
Industries Association. In addition to that, Navigant Consulting states that by 2025, more
than 25% of nation’s energy must origin from solar energy. Both statements referred to a
considerably new way of energy production which seeks into the nearest future to capture
a big share in the world of energy and manufacturing, called Solar Energy.
Justification of the Thesis
Photovoltaic system, also known as solar energy system is considered to be one of the
leading and widespread alternative way of energy production worldwide. The term
photovoltaic is a combination of two words: the “φως” (phos), which means light, and
“volt”. In simple words, photovoltaic can be defined as “electrical energy provided from
light”. Solar energy systems use the radiation emitted from the sun and convert it directly
into electricity, using solar cells that exploit the properties of semiconductor materials such
as silicon.
Solar energy coming from the sun is unlimited and free of cost. In addition, silicon (raw
material) is the most abundance element on earth. It is an environmentally friendly

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technology as no pollutants are caused by power generation. Furthermore, solar energy
systems can be connected to electricity grids in order to sell the generated electricity and
provide an economical benefit to the investor. Due to the various benefits solar energy
systems offer to the world, the range of application around this technology has rapidly
increased; thus consumer’s demand appears to be at a higher level too. According to
Navigant Consulting, in 2013 global PV market will jump to 2.5 times more than 2008. By
2025 more than 25% of nation’s energy must come from solar energy. Thus, it is
significant that this alternative way of energy production can guarantee to be long lasting
and competitive in the market.
Improvements need to take place for the creation of more reliable and efficient solar
energy systems. Mainly, designers concentrate on the intensity source of radiation and
ways of storing the productive energy. The proposed and most effective way of improving
the efficiency of the system is by setting the system to continuous and direct exposure to
the intensity source of radiation; thus, collecting more energy over time.
There are two methods for increasing the mean intensity of solar radiation received by a
solar. The first method is by focusing the incident ray onto a rigid array, this will force the
incident-ray’s path to reach normal to the array surface. The second method is the use of
solar tracking system, which operates by tracking the radiation of the sun. Solar tracking
systems are divided into two categories; dynamic tracking and fix control algorithm
tracking.

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Aims and objectives
The main aim of this thesis is to create an engineering design prototype and demonstrate
the benefits of a solar tracking system. Testing in real life the prototype will prove that a
solar tracker can increase the efficiency of the system. Initial objective of the thesis was
the design of a single axis solar tracking system operated by a dynamic tracking system.
However the limitations a single axis system has on the aspect of geographical position of
the system, changed the system’s configurations to a dual-mode axis; aim for a worldwide
market; thus, Universal Solar Tracker. Eventually testing the product in real life together
with a cost analysis will exhibit the feasibility of the investment for both a manufacturer’s
and an investor’s point of view. In addition it validates the benefits aided by a solar
tracker. Potential improvements and modifications of the prototype will conclude this
thesis.

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Applied Science on Solar Energy (tracking)
Systems
Solar cells
Sunlight is integrated from photons, small particles of energy. Nuclear fusion reactions
that take place on the surface of the sun supply earth with energy. In fact, energy received
from the sun per minute is greater than the energy used by the world per year. Energy
primarily arrives to earth in the form of electromagnetic radiation, where electrons are
released from their atoms. Solar cell is a semiconductor device structured with p-n junction
diodes. P-n junction diodes are capable of generating a single direction current flow in the
presence of sunlight. A solar element is made of silicon and is usually square in shape,
with dimensions 120-160mm. There are two types of silicon available for the manufacture
of a solar cell: the amorphous and crystalline silicon. The latter one is divided into mono-
crystalline and poly-crystalline.
Poly-crystalline Mono-crystalline Amorphous Thin Film
efficiency Good (12-15%) Good (13-17%) Low (6-8%)
Cost scale 2 3 1
Watts per m^2 120-150 135-170 60-80
Outstanding
operating conditions
Hotter conditions Cooler conditions Hotter conditions
(less expensive in cooler
conditions)
Life span 25-30 years 25-30 years 3-6 months
Table 1-Types of Solar Panels
When the procedure described above takes place, direct current flows through and a charge
controller is maintaining the current flow accordingly in order for the sufficient amount of
current to arrive to the power supply. Energy is then stored in the power supply for later

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use. When energy is required from an appliance, DC power flows from the power supply
to the inverter, where DC power is eventually converted to AC voltage.
Figure 1-Solar Energy System [Available from: http://www.nuffieldfoundation.org/practical-physics/motion-sun]
In order for photovoltaic technology to be competitive in the market, improvements are
necessary. There are three proposals for improving the system: solar cell efficiency,
intensity source of radiation and ways of storing energy. Photovoltaic user’s proposed and
meanwhile simpler way to improve efficiency is by tracking the position of the sun Figure
2- The motion of the sun [Available from: http://www.nuffieldfoundation.org/practical-physics/motion-sun]thus
increasing the intensity source of radiation.

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Figure 2- The motion of the sun [Available from: http://www.nuffieldfoundation.org/practical-physics/motion-sun]
Solar tracking theory
Since both sun and earth don’t have a fixed position, a solar energy system, using the
mechanical advantages provided from a solar tracker, can face the sun directly and
continuous, thus optimize the operation of solar energy receivers. A solar tracker can
increase the sufficiency of a solar energy system by an extra 30%.
Figure 3- Solar Tracker [Available from:http://www.projectfreepower.com/solar-power/building-a-sun-tracker.html]

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Advantages and Disadvantages of solar tracking systems
Solar tracking systems have the following advantages:
• Improves the efficiency of the photovoltaic system by 30% for single axis and an
additional 16% for dual axis.
• Reduces the number of panels required in a system; thus reducing the cost of the overall
investment.
• Environmentally friendly technology since no pollutants are caused by power generation.
• There is no need of electricity; instead solar energy is used for the system to operate.
• With proper control of algorithms inputted in the system, tracking is done automatically.
• Cheap and easy to install compared to other methods of improving a solar energy system.
• Investment is only required once.
• Long lasting.
• Low maintenance is needed in order to ensure the accuracy of the system.
Solar tracking systems have the following disadvantages:
• Large surface area is essential.
• Expensive investment.
• Maintenance is needed in order to ensure the accuracy of the system.
• Extra costs and expenses to a solar energy system.
Literature Review
Solar energy system timeline
Going back to 1830, the first solar cell technology research was initiated by Edmond
Becquerel (1830). After 9 years, he was eventually credited with the “Solar Panel
Research” after observing the photovoltaic effect.
However this technology was not applied in real life until 1860s. Auguste Mouchout
(1860) a French mathematician, he was funded by the French monarch for further research
in solar energy. He designed the first motor that could operate with solar energy systems.
In addition he also invented the first solar- powered steam engine.

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Charles Fritz, in 1883, was named as the first person to create a solar energy system that
would turn solar energy to electricity. He used junctions that were created when the
semiconductor was coated by a thin layer of gold.
The solar energy development was an on-going challenge, and around 1904, Henry
Willsie, was accredited with the honours of the first person who managed to store energy
for later use.
In 1941, Russel Ohl accidentally discovered the potential of silicon for use in solar
technology at Bell Laboratories. The first silicon solar panel had an efficiency of 1%.
By 1956, commercial solar cells were available in the market. However they were
extremely expensive at that time ($300 per watt).
Continues researches and developments related to solar energy systems all over the world
lead us to 1999 were photovoltaic capacity reached 1000 megawatts.
The low efficiency solar energy systems have is still an issue in nowadays. Today solar
cells have an efficiency of 15-17%. They highest efficiency achieved was 40% by HEMM
solar cells created in 2007 by the National Renewable Energy Laboratory and Boeing
Spectrolab.
Prior Art on Solar Tracking Systems
Technology is surrounded by constrains. Similarly, a solar energy systems encompass
various obstacles. The main challenge faced by solar energy system researches is to
increase the overall efficiency. This can be achieved the contribution of a solar tracker to
the system, as already mentioned. The way the solar tracker contributes with the system is
divided into the following aspects: Tracking techniques (dynamic or fix control algorithm),
tracking system (single or dual axis), Sensors justification and Solar tracking motion.

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Tracking Techniques
Control signals of solar tracker are inputted via 2 techniques: fix controls algorithms and
dynamic tracking.
Fix control algorithms use a controller, which works along with control algorithms that are
set according to the geographical position and current time of the system. Records of the
intensity the sun has throughout the year are used as an input for the fixed controlled
algorithms method. A controller device is used to move the system to the position that
faces the maximum intensity of solar radiation at specific times.
The second method is dynamic tracking, which operates using photo sensors. These photo
sensors can instantly determine the current latitude of the radiation source where the higher
energy emission can occur. Signal from the photo sensors are sent to the controller and the
motor drives accordingly. If earth was flat and did not rotate, the fix control algorithm
would have been as accurate as dynamic tracking. Depending on your geographical
position, azimuth angle varies. You can also lose up to three hours of charging, due to the
unpredictable exact time of sunrise and sunset. Thus dynamic tracking is more efficient
than fixed control algorithms, since tracking is done instantly according to the photo
sensors. Additionally, dynamic tracking is more reliable in unexpected climates compared
to fix control algorithms. This is because fix control algorithms are set according to the
expected weather conditions.
In 2009, Nelson A. Kelly and Thomas L. Gibson, made a research called “Improved
Photovoltaic Energy Output for Cloudy Conditions with a Solar Tracking System”; a
research regarding the benefits a solar tracker can provide to a solar energy system. A
detailed description of the theoretical and experimental procedure is included, where a
fixed control algorithm dual –axis solar tracker was used to determine the operating mode
that a solar tracker should run during overcast condition. Referred to the features of a fixed
controlled algorithm method, a FCA system will not be able to produce peak energy at
times where unexpected climate conditions can limit significantly the light intensity
received from the sun to the earth. Concluding with the analysis of data demonstrated;
during overcast conditions, solar panels tilting away from the zenith-axis will cause

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irradiance to decrease in the horizontal configuration and thus improve the overall
efficiency of fixed control algorithm solar energy systems. In order to avoid complexity,
while producing a more efficient solar energy system, fixed controlled algorithm method
should be replaced by dynamic tracking.
In addition,Azhar Ghazali M. and Abdul Malek Abdul Rahman, in 2012, also made an
efficiency research called “The performance of Three Different solar Panels for Solar
Electricity Applying Solar Tracking Device under the Malaysian Climate Condition”. A
dynamic, single axis solar tracker was used to determine the efficiency of poly-crystalline,
mono-crystalline and amorphous silicon solar panels, which were tested under the hot and
humid climate in Malaysia. Poly-crystalline photovoltaic panels have shown better
performance ratio and average panel efficiency. As mentioned previously, Mono-
crystalline PVP provides us with higher efficiency, contrariwise, in Malaysia’s weather
conditions Polly-crystalline PVP performs best. In UK, where the climate is cooler, Mono-
crystalline PVP would function best.
Figure 4-Dynamic Solar tracking diagram
Solar panels
Motors Photo-sensor
Controller
Radiation source
sunlight is emitted
from the solar
panels
Photo sensors
determining
radiation source
Motors rig with two
axis
Motors rotating the
photo sensor
Provides signal to
turn the motor and
solar panels
Signals sent to
controller when
sensor detect
sunlight
Power supply
Power suply
Excessive energy
stored for later use
Power Supply for
solar tracking
system

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Dynamic tracking operation is divided into three main functioning operations. These
operations are: tracking system, justification of solar sensors, and solar tracking motion.
All three operations are described in detail below.
Tracking system
This operation includes a device, which orients solar panels towards the sun. Trackers are
added to a solar energy system in order to increase the output of the system. There are two
common designs for tracking: single axis and dual axis.
Single axis solar trackers track the sun in only one direction. Axis direction is determined
according to the geographical position of the system. In tropical regions, where the sun
gets very high at noon but the days are short, horizontal axis is used. Meanwhile, vertical
axis is used in high latitudes, where the sun does not get very high and days are longer.
Single axis tracker can increase the annual output of a solar energy system by a minimum
of 30%.
Figure 5- Single-axis Solar Tracker [Available from: http://www.solarchoice.net.au/blog/solar-trackers]
On the other hand, dual axis solar trackers, involves tracking the source of radiation in
both horizontal and vertical axle. This type of solar trackers can operate with the same
efficiency all over the world due to the dual-axis commands it can receive. Dual-axis
tracker can increase the annual output efficiency by a minimum of 36%. However, they are
more mechanically complicated in designing and installation. Two motor are usually used
for dual axis instead of one for a single axis.

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Figure 6- Dual-axis solar tracker [Available from: http://www.solarchoice.net.au/blog/solar-trackers
Francisco Javier Gomez-Gil, Xiaoting Wang and Allen Barnett, in “Energy Production of
Photovoltaic Systems”, in 2012 demonstrated a comparison of energy production and
performance ratio of three photovoltaic system configurations: fixed, 1-axis and 2-axis
tracking flat plate, and concentrating photovoltaic. Detailed analysis and real time
performance of these types of PV system configurations were tested in Spain; Gain in the
annual energy production: 22.3% for single-axis, 25.2% for dual-axis and 16.1% (close to
fixed position) for CPV. A dual axis solar tracker will provide you with the higher energy
production, where a single axis solar tracking system follows with a small difference of
2.9%. The difference between the two moving systems and the CPV is significantly large.
Thus, according to your design principles, a choice between the two systems that are in
motion should be taken.
Solar sensors
Light sensors detect and determine the solar radiation source for a solar tracker. Feedback
from the sensors is then sent to the controller for process. The output of this process is
used to control the movements of the motor accordingly. In a dynamic tracking system the
following sensors are used for both absorbing energy and determining the solar source.
The types of sensors, which are functionally preferred for a solar tracker, are:
• LDR - light Dependent Resistors: This type of sensors response to light visible on
the human scale. Their resistance increases as light intensity increases. This sensor,
also known as photo-resistor, is useful for detecting light. It will fit in a dynamic
tracking system for providing signals for the movements of the motor. LDR are

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small, cheap and low power users. They are also simple and liable. LDR are mostly
used as automatic switches for devices, such as outdoor lights.
• Photovoltaic light sensors are also called solar cells. This type of sensor is
responding to light intensity by converting sunlight energy into electrical energy.
Energy is then stored in silicon cells. Solar cells provide us with DC current and
the efficiency is about 30%. They have a life expectancy of 25 to 30 years. Solar
cells are mostly used in watches and calculators due to their small size and the low
wattage they provide. However, they can be combined together to provide large
amounts of current. A combination of solar cells is used in solar panels for a solar
energy system. Again these types of sensors respond to light visible on the human
scale.
Other types of sensors:
o Photodiode is a PN junction diode, which has a transparent casing in order for
light to be able to reach the junction. When light is received from the junction,
either current or voltage is generated. Photodiodes have very fast response;
however the current flow is relatively small.
o Phototransistor is a photodiode, which operates with amplification. It is an
NPN transistor and is more sensitive than photodiode. The frequent response of
a phototransistor is not good; however, it can provide 50-100 times greater
output than a photodiode.
In 2011, as a part of Renewable Energy, C.S. Chin, A. Babu and W. Mcbride wrote a
thesis called “Design, modelling and testing of a standalone single axis active solar tracker
using MATLAB/Simulink”. Different operating modes are provided to the user based on a
dynamic tracker. Two light-dependent resistors (LDR) sensors were installed on the
surface of the PVP. The system was also designed in MATLAB in order to predict the
outcome. Experimental testing agreed partially with the expected outcome. Mainly, the
reliability of the solar tracker to follow the sun continuously was not at a high level
resulting to less energy production.

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Solar Tracking Motion
Signals provided from photovoltaic light sensors are sent to the controller for analysis. The
output of the analysis is used as instructions, which are forwarded to the motor. Motors are
used to drive solar panels at the direction of the sun in a solar tracking system. The most
common types of motors used for solar trackers are stepper motors. A stepper motor is a
brushless DC electric motor that moves in steps. They are made of permanent magnets and
coils surrounding the magnets. As a result an electromagnet is produced. Magnets rotate in
a rotating shaft called rotor. The operation of stepper motors is easy, and the number of
steps performed can determine the distance travelled. Signals received from the controller
of the motor are used to control the speed. The most common and basic type of stepper
motor in the market is the Permanent-magnet stepper motor. The rotor of the permanent
magnet motor has a permanent magnet with two or more poles, in the shape of a disk.
Coils surrounding the magnet will attract or repulse the permanent magnet and as a result
torque is generated. Permanent-magnet stepper motors are divided into two types of motor:
• Unipolar stepper motor: A rotating permanent magnet that is surrounded by four
coils. The controller needs four output lines to operate. It also contains four
electromagnets. Current flows in one direction through each coil in repeating
patterns.
• Bipolar stepper motor: On the other hand, this type of permanent-magnet motors
requires two coils, half required for the unipolar. This specification makes it
cheaper than unipolar stepper motors. However, bipolar stepper motors lack centre
taps and as a result bipolar motors require a different type of controller to operate.
They need a controller that can reverse the current flow through the coils by
alternating the polarity of the terminals. Higher torque is achieved using bipolar
stepper motors.
Other types of motors:
o DC motor: Direct motor is one of the simplest motors existing. They work with
a direct current supply. A permanent magnet is coiled up with loops of wires to

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the stator. Current flows through the field of coils; from the negative to the
positive terminal. As a result, voltage is induced in the windings opposing the
current flow. It is not easy to determine the control of the speed of such a motor
because a DC motor spins very fast and insufficient torques are created. The
fast spin it provides is used for applications that require fast speed.
o Servo motor: A servo motor contains a DC motor. Electric input is used to
determine the position of the armature of a DC motor. As the motor rotates, a
variable resistor changes; and as a result the direction and position of the
motor’s shaft can be detected. If the desired position is achieved, the motor’s
power supply is stopped. The speed of the motor varies according to the
difference between the current position and the desired position of the motor.
The speed is proportional with this difference. Servo motor is popular due to its
small size and its accuracy. However, full revolutions are not applicable
(usually between 180-270 degrees).
Paraphernalia
In addition to the above mechanisms and systems required to drive and operate the solar
energy system, more equipment are essential, mainly for adjusting the configurations of
the voltage:
• Inverter - the electricity generated by a solar cell comes in the form of DC current.
Special equipment designed to transform the output voltage into AC voltage is
used. As a result, a solar energy system can provide energy to equipment running
with an alternative current.
• Storage batteries - electricity generated by the solar panels is stored in batteries.
Batteries can be connected in series or parallel in order to achieve the desired input
voltage for the inverter. The most common battery used is the deep cycle lead acid
battery. This type of battery is divided into:
1) Flooded type, also known as wet cells, that is filled with fluid. The main
advantage of a flooded battery is that despite being bulky, it is very

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economical. They are commonly used as solar batteries since they can
provide the required energy for an off-grid system or high power loads.
2) Sealed type, also known as absorbed gas mat batteries. They have pads
that were previously soaked in fluid. These pads are structured between
the plates of the battery. They are small and mainly used for lower
power equipment. Voltage of sealed batteries is lower than voltage of
flooded batteries, due to the limited fluid existing in the flooded type.
• Charge controllers - Charge controllers are used to prevent overcharging and
discharging the batteries. This is because excessive voltage can result in the
damage of the battery. A charge controller maintains the rate of charging the
batteries. Proper charging will avoid damage and increase the life and performance
of the batteries. Charge controllers are divided into three stages:
1. Bulk Stage- the voltage steadily increases to the bulk level (usually14.4-
14.6 volts) while the batteries draws maximum current.
2. Absorption Stage - voltage is maintained at bulk level for a specified time.
Meanwhile current gradually tapers off as the batteries charge up.
3. Float Stage - after the absorption stage, voltage is lowered to float level
(usually 13.4-13.7 volts) and batteries draw a small maintenance current
until the next cycle.
Application of Solar Energy Systems
Since the early stages of solar energy’s development, the range of application has never
been limited. In fact, in the early years of solar energy, 1955, William G. Cobb of the
General Motors Corp. (GM) displayed his 180 mm “sunmobile”, the first solar energy
automobile.

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The everyday use of systems powered by solar energy is increasing day by day. Solar
energy systems are now added in many systems due to the reduction in cost over the years.
Such systems are listed below:
1. Cell phone charger
2. Notebooks
3. Radio
4. Solar calculators
5. Auxiliary power in boats and cars
6. LCD displays
7. Traffic lights
The low efficiency solar systems have, limits the range of application in systems that
require a higher amount of power to operate such as cars. However solar energy system
can be connected to electric network grids. Photovoltaic parks are becoming popular since
the investor can sell the stored electricity. In addition, due to the environmentally friendly
behaviour of solar energy systems, government funds are available encouraging the
investor for a higher net profit. In 2012, in USA, Youma country, AZ, the biggest
photovoltaic park was installed. It generates a power of 250MW.
Furthermore, extra add-ons appear in modern designs such as strength kits and wind
turbines while, other designers provide us with portable designs in a variety of shapes and
sizes. Designs to fit caravans (Figure 7- Portable solar energy system [Available from:
http://www.patriotsolargroup.com]) and portable aluminium solar energy cases are two
examples of the expansion in the market solar energy gained over the years. These lead
one to conclude that designers of solar tracking systems aim to produce designs that have s
stable, reliable and accurate design alignment, while costing less to the customer and
performing as effectively as possible, according to the consumer’s needs.

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Solar panel fitting in trucks are available from Patriot solar group. Panels are installed on
trucks replacing fuel generators.
Figure 7- Portable solar energy system [Available from: http://www.patriotsolargroup.com]
A bag designed mainly for campers. Solar panels fitted on the bag provide the user of the
bag with energy. The bag is available in the web community, where more unique solar
energy designs are available.
Figure 8-Solar panel bag [Available from: http://www.voltaicsystems.com/fuse4w.shtml]

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Solar Tracking System Methodology and
Design
Methodology
Design can be defined as a drawing or model. However, through the vision of an engineer
design is defined as problem solving process; art with a purpose. The following design
principles demonstrated in the diagram below, were used to derive the concept requirement
and produce a final design.
Figure 9- Methodology diagram
Concept & Idea
Output
Requirements
Mechanical and
Electrical
Design
Modifications (if
required)
Physical Model
Testing Output Results

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Concept & idea / Output Requirements
The main concept and idea of this thesis is to design an efficient Solar Tracking System.
Solar energy and solar tracking systems were examined in detailed and meanwhile
overview assumptions were recorded. The next step will determine the output
requirements that are necessary for this system. Table 2- Aspects and Features indicates
the main design features that will form the foundation of the design.
Aspects and features Explanation
Dynamic Tracking Photo Sensors are used for tracking instead
of fixed control algorithms.
Dual-Axis Earth and Sun both rotate.
Cheap Product Cheap components, reduce raw material.
Display the increase in efficiency of the
overall system
Dual- axis, dynamic tracking. Best proposed
method in solar tracking.
Stability Stiff product, wind resistance, raw material
used.
3- mode system Fixed, Single Axis, Dual-axis functions.
Display the investor’s benefit. Energy used to drive the system< excess
energy provided from the solar tracker.
Foundation for extra PV panels. Availability for the user to add more PV
panels on the system.
Universal solar tracker Being able to work both in the northern and
southern hemisphere
Table 2- Aspects and Features

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Alternative designs and Design Selection
Having in mind the features mentioned above, three proposed concepts of dual- axis solar
tracking system were designed, using SolidWorks. Each of the design can track the solar
radiation using different techniques. A design selection process is vital in order to
determine the best suitable design this project. A description of the proposal designs is
provided below.
Design 1: Two Rotational Actuators
The first design involves two rotational actuators for controlling both axes. Design 1’s
main disadvantage is the limitation in support for the solar panel thus external forces such
as wind can force the solar panel to rotate and loose accuracy.
Figure 10- Design 1

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Design 2: Two Linear Actuators
The second design involves two linear actuators for controlling both axis. It is consider to
be an effective and simple design.
Figure 11- Design 2
Design 3: One Rotational and One Linear Actuator
The third design includes one linear actuator, for controlling the movements of the system
along the azimuth-axis, and one rotational actuator, for rotating along the x-axis. This
design is integrated by using the main benefits and ideas from design 1 and 2. It has a
stable and accurate approach of tracking sunlight.
Figure 12- Design 3

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Moving on, a criteria analysis was undertaken in order to display the advantages and
disadvantages of each design, in order choose the most appropriate one. Stuart Pugh, in
1996, published a criteria analysis procedure through the book called “Creative Innovative
Products Using Total Design”. The criteria analysis performed for the solar tracker is a
simplified procedure to the one written by Stuart Pugh. A choice of criteria were used and
credits were acknowledge to each feature according to their significance; not significant: 1,
significant: 2 and very significant: 3. Eventually an average score was calculated to
determine the most suitable design. An excel database was created for the feature analysis.
The Display sheet shows the score that each design achieved on each criterion from with a
scale out of 10. The score is discussed and backed up in the respective sheet of each
criterion [Appendix B].
Criteria Design 1 Design 2 Design 3 Credits
Risk of Failure 6 8 9 3
Power Consumption 7 9 8 3
Cost 9 6 8 2
Life Span 5 7 9 2
Maintenance requirements 6 7 9 2
Weight 9 8 7 2
Ease of Manufacturing 6 8 7 1
Raw material 8 7 6 1
Installation 7 9 8 1
Potential extension 6 5 9 1
Average Score out of 10 6.9 7.6 8.2 18
Table 3-Design selection score

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Design 3 obtained the highest average score. It provides us with an efficient method of
alignment both in stability and reliability. Additionally, it achieved the highest score in 4
out of 9 of the criterion and most importantly for the one regarding the risk of failure. Thus
the next stage was to mainly concentrate on the disadvantages of design 3 and attempt to
create an improved and more effective system.
Computer- Aided and Physical Design
Computer-Aided Design
The proposed design needs further improvement in order to produce a mechanical system
that will be as efficient as possible. SolidWorks allows the user to produce detailed designs
and simulations to display the output performance in different aspects and condition. The
final design of the dual-axis solar tracking system is shown below.
Figure 13- Suitable design
The design can be divided into the bottom part and top part. The bottom part involves a
cylindrical tube, which can be used as a protective case for electronic miscellaneous. The
tube also supports the whole system by applying a vertical force to the base (balance the
system). A shaft installed at the centre of the tube is rotated by the gearbox attached to it.
On the top edge of the shaft, a disc is placed that rotates the top part.

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Figure 14-Bottom part
Regarding the top part of the design, two isosceles rectangular tubes are used as a support
for the PVP. An extra support tube is used to connect the two diagonal tubes. Hinges
connect the tubes with the PVP allowing circular motion. Meanwhile, a linear actuator,
which stands on the disc, is hinged to the centre of the lower part of the PVP forcing it to
move along the azimuth axis when operating. The shaft rotates all three components.
Initially, a ball groove bearing was installed at the top part of the cylindrical tube.
However, the diameter of the tube requires a bearing with a significantly large diameter;
thus, increasing the total cost. As a result, bearings were relocated. A deep groove ball
bearing and a thrust ball bearing were fitted in the bottom edge of the shaft. Finally,
compared to the proposed design 3, the linear actuator is now positioned on the cylindrical
tube. Due to the limitations in the range of movements allowed to the linear actuator when
placed in the tube, the linear actuator is now fixed perpendicular to the disc. This
modification increases the total height of the design. In addition, as mentioned above, a
horizontal tube is connected perpendicular to the isosceles tubes, providing support to
them and reducing the overall stresses across the design. These were the most important
changes made to the design
Cylindrical
tube
Shaft

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Figure 15-Top part
Furthermore, design embodiment procedures were undertaken in order to ensure that the
system would not fail. The most significant component of the system is the shaft, since
both vertical and torsional forces are acting on it with the possibility of failure. The most
important specification of the shaft needed to be determined was its diameter.
Since we know that
𝜎! =
!
!
and 𝐹𝑂𝑆 =
!!
!!
Equation 1
Where σz is the normal stress, F is the force, A is the area and Sy is the Yield strength.
Then minimum diameter of the shaft is 2 mm [Appendix D] from the equation shown
below:
𝐷
!!
!×!
!×
!!
!"#
Equation 2
Using the minimum diameter and the total weight of the top part of the system, which is
22.88Kg the system can be manufactured with a minimum FOS of 3.
Hinges
Horizontal tube

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Implementation and Manufacturing Process
Having available a workshop in Sharjah, UAE, for the needs of “Harwal group of
Companies”, I was able to understand and apply in real time different types of
manufacturing processes and procedures in order to create a physical model of the
designed solar tracker. Through the use of existing components, manufactured by the
factory, a solar tracker was built at a low cost.
As an initiating step, a shaft was chosen. The diameter of the shaft used is 44mm and it has
a height of 500mm. It is made of mild steel. Yield strength and Young modulus were taken
according to the specifications of SolidWorks for Cast Carbon Steel as 248MPa and
200GPa respectively. The diameter of the shaft is 44mm, which is 22 times greater than
the minimum diameter required in order for the system not to fail. The reason behind this
is mainly due to the small range of gears available on the shelves of the workshop. The
driven gear was welded on the shaft to a height parallel to its driven gear.
Figure 16-Shaft
A bearing case consists of a deep groove ball bearing and a thrust ball bearing was used as
a base while also supporting for the shaft. The bearing case was screwed on a square base
with dimensions 520*520 mm. The square base was initially made of steel. However, the
steel was replaced by PVC due to the lighter weight properties it has. PVC is suitable for

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all weather conditions; thus, avoiding the need for galvanising the steel. The same applies
for the choice of the cylindrical tube, which is used as a protective case for electronics and
as an overall support for the system. The cylindrical PVC tube used was an existing pipe
manufactured by the factory. The cylindrical PVC tube and the square PVC base were
joined together by welding.
Figure 17-Exploded assembly shaft and bearing case
The final stage regarding the manufacturing of the bottom part of the system had to do
with a cylindrical disc made of steel, which was welded at the top part of the shaft. The
disc has 4 symmetric holes and a bigger hole located at the centre of its cross sectional
area. The four symmetric holes were used in order to screw the disc with a PVC disc,
which functions as a countersunk for the cylindrical PVC pipe. The centre hole was used
to fit the shaft in. Due to the fact that the diameter of the shaft was greater than the fitting
diameters of the bearing case and the steel disc, the shaft was grinded at its two edges in
order to fit the steel disc centre hole and the bearing case respectively.
Shaft
Bearing Case
Cap
Thrust
Ball
Deep Groove
Ball Bearing
Bearing Case

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Figure 18-Bearing case 2D drawings
The construction of the bearing case was the most complicated part this project. For that
purpose, lathe, drilling and grinding were required. A cylindrical steel beam was used with
a diameter of 136mm. The beam was then turned by lathe with a depth of 14mm and a
height of 43mm. A drilling machine was then used to create holes according to our needs
as indicated in Figure 18-Bearing case 2D drawings. The diameters of the Bearing and the
shaft, determined the internal diameters of the holes, in order for them to fit in. Eventually,
holes were drilled in order to connect the case with the PVC base and a cap was attached
on the top of the bearing case to hold it stable.
Figure 19-Bottom part annotations
Steel Disc
(welded to
the shaft)
PVC Disc
(screwed to the
steel disc)
PVC Cylindrical
Tube
PVC
Square
Base

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Additionally, regarding the top part of the system, two hollow rectangular steel tubes were
cut, de-burred and finally welded on a flat steel sheet in an angle, so that the horizontal
distance of the two top edges of the tubes would be equal to 1165 mm, which is the
distance between the two hinges. The hinges were then bolted on the PVP and the steel on
the PVC cap accordingly. A third tube was cut, which was welded at an angle of 26
degrees to the isosceles tubes as an extra support, reducing the overall forces acting in the
structure. All three tubes and the sheet of steel were galvanized; thus, preventing
corrosion.
Tube Length (mm) Angle at the edge (degrees) Quantity
1 1205.5 26 2
2 614 26 1
Table 4-Tubes
Figure 20-Top part annotations
Tube 1
Tube 2
Hinges screwed on the
solar panel (1165 mm)
Welded
joints
Steel sheet

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The next step included drilling of the PVC disc. Holes were drilled in order to meet the
dimension criteria of the linear actuator and the isosceles rectangular beams. The
horizontal distance (passing through the centre) between the isosceles legs and the linear
actuators’ position (which was perpendicularly hinged on the PVP when the PVP was at an
angle of 45 degrees) was measured to be 295.5mm. Thus, holes were drilled accordingly.
Eventually the hinges were welded on the top horizontal edges of the two beams.
Figure 21-PVC disc 2D drawing
Finally, assembling the bottom part and the top part resulted in a dual axis solar tracking
mechanism. The limitation in the range of components determined the overall size of the
system. The overall mechanism size, which was mainly integrated by the shaft’s diameter
and the linear actuator’s height, appears to be overdesigned as it has the tolerance in
reducing the overall size of the design, thus decreasing raw materials/manufacturing cost.

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Shaft
A shaft can be described as a mechanical component, which transmits rotational motion. It
is essential for mechanical systems that are rotated by a motor or an engine. A static
analysis is crucial in order to display the combined stresses, because of the existence of
torsional shear and normal stresses due to bending.
As an initiating step, the minimum diameter of the shaft was calculated to be 2mm. A shaft
of 44mm diameter and 0.5m height was used.
Euler Buckling and J.B. Johnson procedures were then performed in order to prevent
failure.
𝐸𝑢𝑙𝑒𝑟 𝐵𝑢𝑐𝑘𝑙𝑖𝑛𝑔!
!!!
!"
!!
Equation 3
Where:
𝐼!
!!!
!
Equation 4
And
!.!.!"!!"#!(!"#)
! !
𝑆! −
!!
!!
∗
!
!
!
∗
!
!"
Equation 5
Where: I-second moment of inertia, L-length of shaft, K-radius of gyration, E-young
modulus, T-Torque and C can be obtained from the table below:
Table 5-Constant C
Furthermore, the torque of the shaft was calculated in order to find its efficiency.
𝑇𝑜𝑟𝑞𝑢𝑒(𝑇!)!
!∗!!∗!
!
Equation 6

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𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦!
!"#$% !"#$%& (!!)
!"#!"# (!!
Equation 7
Where 𝑓! is the friction coefficient and𝑇!!
!∗!
!!
.
Finally, the Factor of Safety (FOS) of the shaft was evaluated using the Von Misses
Stresses Procedure. The Von Misses stresses acting on our shaft are calculated below:
𝜎! =
!
!
Equation 8
𝑡!" =
!∗!
!
Equation 9
𝑉𝑜𝑛 𝑚𝑖𝑠𝑠𝑒𝑠 𝑠𝑡𝑟𝑒𝑠𝑠𝑒𝑠(𝜎!
=
!
!
[𝜎!
!
+ 𝜎!
!
+ 6 ∗ 𝑡!"
!
]
!
! Equation 10
𝐹𝑂𝑆 =
!!
!!
Equation 11
Where s’ is the Von misses stresses and J is the Polar moment of inertia and it’s calculated from: =
!
!
∗ 𝜋𝑟!
(𝑚!
).

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Equations and known values were input in an Excel database and a simulator was created
to calculate the output values. The crucial values of the simulation are displayed in the
table below:
Shaft
Input Force N 224.5
Material module of elasticity ( E) GPa 200
Material Yield Stress MPa 248
Minimum Diameter m 0.002
Length of the shaft (l) m 0.5
F ( Critical) - Euler N 1801324.775
F ( Critical) - J.B Johnson N 673.339
f ( coefficient of friction) 0.11
Diameter m 0.044
Torque Nm 0.543
e (efficiency) 32.883
σy MPa 0.148
τxy MPa 0.032
Von Misses Stress MPa 0.158
FOS 1569.80
Table 6- Excel template results for shaft

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In addition, an FEA (Finite Element Analysis) analysis was performed in SolidWorks to
demonstrate the statics of the shaft. FEA is a common design procedure used by designers
in order to perform complex mathematical expressions, where solutions are hard obtained.
By using Meshing technique, which breaks the system down according to your desired
percentage, results can be obtained for any point of the part. An FEA analysis is crucial in
where large stresses are acting on the component. In our case, stresses acting on the shaft
appear to be very small, as calculated from the Von Misses Stress equation; thus
performing an FEA analysis it would indicate stresses to be at their minimum.
Figure 22- Shaft FEA analysis
The first step requires to denoting the forces acting on the shaft. A vertical force of 224.5N
and a torsional force of 0.543 Nm were used for the FEA analysis. The next step required
meshing of the component. Eventually results were demonstrated using a scale of stresses,
denoting a colour for a range of stresses acting on it. Starting from the minimum stress
occurring in our design which is 10,882.9 N/m^2 indicating blue and ending with the
maximum stress of 2,522,566.0 N/m^2 indicated in red. As shown in the Figure 22- Shaft
FEA analysis above, the majority of the system appears to be blue verifying the
calculations in Table 6- Excel template results for shaft.

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Gear Box
Gears can be defined as components used to transmit motion between two parts. Gears are
crucial parts for a mechanical device. They can be found in everyday mechanism used, as
well as in complex machines used in factories. There are many types of gears according to
your desired output available. The most common types of gears are shown in the table
below:
Type of Gears Description
Spur Gears Have teeth parallel to the axis
of rotation and are used to
transmit parallel motion
http://students.autodesk.com/?nd=showcase_
detail_page&gallery_id=14153&jid=191413
Helical Gears Have teeth inclined to the axis
of rotation in order to develop
thrust loads and bending
couples. Due to the gradual
engagement of the teeth during
meshing, noise is limited.
http://www.enterprise-europe-
network.ch/marketplace/index.php?file=bbs-
show.php&bbsref=07%20GB%20EAST%200IBL
Bevel Gear Have teeth formed on conical
surfaces. Mainly transmitting
motion between intersecting
shafts. http://www.beam-
wiki.org/wiki/Compound_gear#Compound_Gears
Worm Gear Mainly used when the speed
ratios of the two shafts are
quite high.
http://www.stepanlunin.com/Worm_Gear_software.html
Table 7-Types of gears

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A set of Spur gears was used to transmit parallel rotational movement for the solar tracking
system. Spur gears are the simplest gears; thus, reducing the complexity of the overall
assembly. The gears used/available in the workshop matching our requirements are
displayed below:
Table 8- Chosen gears specifications
Using the above parameters, the train value was calculated to be 0.4 using the following
formula:
𝑇𝑟𝑎𝑖𝑛 𝑉𝑎𝑙𝑢𝑒!
!"!"#$%"
!"!"#$%&
Equation 12
Since 1892, engineering designers have used the Lewis bending equation in order to
estimate the stress in gears. By dividing the Yield strength of the gears by the calculated
LBS, the Factor of safety of the gears can be determined.
𝐿𝑒𝑤𝑖𝑠 𝐵𝑒𝑛𝑑𝑖𝑛𝑔 𝑆𝑡𝑟𝑒𝑠𝑠!
!!!!
!"#
Equation 13
𝐹𝑂𝑆!
!!
!
Equation 14
Where Kv is the Dynamic factor, w is the angular velocity, T is the torque and Wt is the tangential
transmitted load.
The final FOS was calculated to be 1260.377, as shown in Table 9-Excel template for the
bending stress of gears. The factor of Safety calculated is too high. A significantly lower
FOS would have been sufficient in our model.
Gear Driver Driven
Pitch Diameter (mm) 60 150
Module 3 3
Number of teeth (Nt) 20 50
Pressure Angle (deg) 20 20
Face Width (mm) 30 30

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Bending Stress Analysis
GEAR Driver Driven
Torque 0.000109 0.54322302 Nm
Wt tangential transmitted
load 0.003621 7.24297359
N
Wn 0.001318 2.63622679 N
W angular velocity 1.047198 0.83775804 Rad/s
V- velocity 0.031416 0.06283185 m/s
Kv- dynamic Factor 1.000000 1.00000000 Low speed
Lewis bending equation stress 0.000125 0.19676647 MPa
FOS from Lewis 1984555.076 1260.377
Table 9-Excel template for the bending stress of gears
An AGMA stress procedure and a Bending stress calculations were performed [Appendix
D] where the final results are shown in the table below:
Driver Driven
Bending FOS 144554.479 125.6846804
AGMA stress Equation 0.003 3.788
Table 10-AGMA stress equation
Eventually, by calculating the FOS from Lewis bending stress and AGMA stress equations
we can ensure that gears will not fail and that they can transmit the required torque. The
next step involved the assembly of the gears. A base was created, which will hold the
rotary actuator and the gears at a fixed position, as indicated in Figure 23-Gear assembly .
In addition, a solenoid was added on the base which will be activated when the gears are

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not in motion in order to hold the gears still and avoid motion caused by external winds
acting on the solar panel.
Figure 23-Gear assembly
Linear Actuator
A linear actuator was used for tilting the PVP along the azimuth axis. A relatively cheap,
low weight and meanwhile powerful linear actuator was desired. The linear actuator used
in the design, was bought from Actuator Zone, a company selling mechanical components
online [Available from: http://www.actuatorzone.com/actuator-linear-actuator-pa-02-24-400-24-inch-
stroke-400-lbs-force-actuator.aspx ]. Specifications of PA-02-24-400 actuator:
• Stroke: 0.6 m
• Weight: 2.72 Kg
• Speed: 0.015 m/s
• Force: 1780 N
• Voltage: 12Volts
• Price: 90 UKP

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The linear actuator was the most expensive investment of the project. The price of linear
actuators are higher compared to prices for rotational actuators. However, despite its high
cost, the linear actuator was preferred in order to reduce support tubes which would have
been necessary without the linear actuator’s present and to provide accuracy.
The choice of the linear actuator was crucial in meeting the requirements of this system.
The linear actuator provides one with a very high value of stroke force (1780 N). One solar
panel (7.5 Kg) was installed to the system, thus the minimum stroke force required was
calculated using the equations below.
Figure 24
Since x=y
𝐹!"# + 𝐹! = 𝐹 Equation 15
so
𝐹!"# ∗ 0.27 = 𝐹! ∗ 0.27
Where F is the force applied by the solar panel: 7.5 ∗ 9.81 = 73.58𝑁, Fact is the stroke Force and Fs is the
force applied by the two rectangular beams.
Finally substituting the two equations, we obtain 2𝐹! = 𝐹 which allows us to calculate the
Fact which is 18.395N.
Thus, apart from satisfying requirements, it also gives us the potential to add more PVP to
the system with the help of an extension kit. Due to the fact that the sun moves very slowly
along the day, the small velocity (0.015m/s) the linear actuator has increase the overall
accuracy of the system. In addition, the mounting brackets at the two edges of the linear

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actuator provide a simple assembly to the user. Concluding, a smaller in size (mainly in
height) and stroke force linear actuator could have been used. However, due to the
limitation in time and the fact that the company was out of stock in smaller linear
actuators, I had to choose the specific one. The difference in size for linear actuators does
not affect the price, as it is the same despite the size. A smaller in size linear actuator could
have only reduced the overall height of the system.
Figure 25-Linear actuator
Rotational Actuator
A rotational motor can operate as a prime mover for the shaft; thus rotating the whole
system. The motor must drive the solar panel in small angles between 0 and 180 degrees at
a low speed.
The DC motor used is of unknown properties due to the fact that it was removed from an
existing machine. A multi meter was connected parallel to the DC motor in order to
identify its voltage which is of 12 volts.
Bearings
By the time the first wheel was invented, people realised that motion can be achieved
easier on rollers. In addition, lubrication is another way to reduce the relative motion
between surfaces. These two features were combined together to form bearings. A bearing
is a mechanism, which is used in mechanical systems to support relative motion between

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moving parts. Even though is not viable to everyday life, bearings are ubiquitous in our
everyday life; automobile, computers, electrical appliances, tools, etc.
Figure 26-Bearing acting loads [Available from: http://www.rbcbearings.com/ballbearings/selguide.htm]
The main benefits that bearings provide to a system are listed below:
• Power saving
• Lubrication and labour saving
• Reliability
• Cleanliness
• Reduced fire hazards
• Increased production
• Life span
A range of bearings, in sizes and dimensions, are available in the market functioning to the
desired application. The most common types of bearings available in market are listed in
the table below:
Type of Bearing Features Application
Deep groove ball • High speed and precision
• Average radial and thrust load
Automobiles, cutting tools,
water pumps, machinery.
Self-aligning ball • Support radial and thrust load where shaft and
housing are subjected to misalignment
Rubber mixers, vertical
pumps.
Thrust ball • Support thrust load Automobile, gauges and

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instruments.
Needle roller • Support of radial load where radial dimension
is limited
Oil pumps, harvesters.
Cylindrical roller • Low speed and heavy load
• Support only radial load
Machine tools, tractor,
motors.
Spherical roller • Support radial and thrust load.
• For long shafts
Mill machinery, air
compressors, cranes.
Table 11-Types of bearings
This project involves both a thrust and a radial load acting on the shaft. Radial load is the
torque applied by the driver gear to the driven gear in order to rotate the system. The
weight of the top part of the system acts perpendicular to the shaft. Two bearings were
installed in the system in order to reduce friction reduction; thus less power required to
rotate the system and more reliable design. Table 12-Chosen bearings specifications
indicates the specifications of the two bearings used.
Type Internal diameter (mm) External diameter (mm)
Deep Groove Ball bearing 40 68
Thrust Ball bearing 30 48
Table 12-Chosen bearings specifications
A deep groove ball and a thrust bearing were placed accordingly. The deep grove ball
bearing was used to enable motion along the shaft and overcome the radial force. This type
of bearing operates with the need of high precision in the rotation of the shaft. In addition,
it can accept average thrust loads. The second bearing is a thrust ball bearing that
overcomes the vertical forces acting on the shaft. Thus a thrust ball bearing is installed
onto the shaft in order to co-operate with the deep groove bearing and produce a reliable
design. The assembly of the bearings with the shaft is displayed below using SolidWorks.

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Figure 27-Bearing assembly
In addition, calculations were made in order to predict the life expectancy of the bearings.
These were based on a life expectancy of 60 million revolutions. Using the formula below,
the basic dynamic load rating (C kN) was calculated.
𝐿!" = 10!
∗ 𝑎! ∗ 𝑎! ∗ 𝑎! ∗ (
!
!
)!
Equation 16
Where the equivalent dynamic load = 𝑋𝐹𝑟 + 𝑌𝐹𝑎 , L10 is the basic rating life and p,a1,a2 and a3 are
provided by the manufacture booklet of the bearings.
Calculations were performed in excel and results are shown in the table below:
BEARING LIFE
Deep Groove Ball Bearing
L10- basic rating life 1.752 revolutions
C- basic dynamic load rating 0.0087316 KN
P - the equivalent dynamic load 0.0072430 KN
p 3
a1- Reliability life factor 1
a2- materials life factor 1
a3- debris life factor 1

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Thrust Ball Bearing
L10- basic rating life 1.752 revolutions
C- basic dynamic load rating 0.205 KN
p 0.170 KN
p 3
a1- Reliability life factor 3
a2- materials life factor 1
a3- debris life factor 1
Table 13-Bearing life calculations
PVP (photovoltaic Panel)
Solar panels or PVP are identified based to their raw material: Thin amorphous, mono-
crystalline and poly-crystalline photovoltaic panels. Furthermore, the amount of power
capable to produce is another criterion for a PVP. A 100watts PVP made of mono-
crystalline solar cells was selected. It weight 7.5Kg with dimensions of 1200 × 500 × 30
mm. The PVP was bought online at the price of 90 UKP from the following link:
[Available from: www.ebay.co.uk]
The PVP’s dimensions were an initiating integrating factor for the top part of the design.
The width of the PVP, as mentioned above, determined the distance between the top edges
of the two rectangular tubes in order for the hinges to connect the PVP to the tubes and
allow it to tilt.
Figure 28-PVP 2D drawings

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Electronic Design
In order to produce an effective solar tracker based on the principles of a dynamic solar
tracking system analysed in the literature review, an accurate control system is required to
reliably track the sun by exposing it to the point of peak light intensity for the longest
possible time. With the aid of electronics, a dynamic solar technique system will be
designed. The performance of the controlling system will be demonstrate with the aid of
real life testing. Results will prove that a solar panel using a solar tracker provides more
power compared to a fixed position solar system.
Micro-controller Board
A controller board is used to interface with peripherals and act depending on these. The
aim is to be able to read the LDR sensors (input signals) on top of the panel and make
some basic calculations (output instructions) to finally drive the motors accordingly to
make the panel face the sun; Thus a dynamic solar tracking system.

Figure 29- Arduino micro-controller [Available from: http://www.arduino.cc/]

To achieve this, an Arduino Duemilanove board is used due to its simplicity interfacing
with the hardware which is supported worldwide and has a big community which is always
there to help.

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The USB connection used to program the Arduino board is also used to gather data from
the sensors and is able to log important data onto the computer through UART (Universal
Asynchronous Receiver/Transmitter) to later on graph it and obtain feasible results. The
microcontroller in the Arduino board will hold the algorithm which is written in C, a
coding language, [Appendix E].
Motor-driver Board
An Ardumoto Shield [Available from: https://www.sparkfun.com/products/9815] is
directly connected to the Arduino board in order to control the two actuators in the design.
The Ardumoto is based on an L298 H-bridge which will give power to the motors. Two
LEDs in the board indicate the direction of each actuator which is helpful for testing and
debugging purposes.

Figure 30-Ardumoto

LDR (Light Dependant Resistors)
LDRs are sensors that vary their resistance depending on the light intensity. Four of these
are positioned in each corner of the panel to measure the light difference between. This
light difference will tell the direction at which the motors should move. To achieve a good

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performance, a voltage divider was built with each photo resistors as per the picture.

Figure 31-Resistance VS Light intensity graph [Available from: http://www.kitronik.co.uk/resources/understanding-
electronics/how-a-ldr-light-dependent-resistor-works]
In order to achieve a good performance, a voltage divider was built with each photo
resistors as in Figure 32-Voltage divider . The voltage divider converts the resistance to a
voltage so that the Arduino can read the input from the LDRs. In addition LDRs are
calibrated in order that to for all four of them to give the same value in different light
conditions.
Figure 32-Voltage divider

Voltage
divider

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Software
The Arduino is a micro-controller which allows a
user friendly interfacing. A software was uploaded
and calibrated in order to function the mechanical
part of the system. The software [Appendix E]
functions by recording the values of the sensors
and basic mathematics are performed to identify
the direction and magnitude of the signals sent to
the actuators accordingly.
When the sum of right hand side sensors is
deducted from the sum of the left hand side
sensors [(1+2)-(2+3) =x-axis], the difference will
determine the direction for the x-axis (rotary
actuator) whereas the same procedure is performed
to determine the y-axis (linear actuator) direction
[(2+3)-(1+4) =y-axis] as shown in Figure 33.
This will then select which direction the motors
should move. Later on the Arduino will send
PWM signals to the Ardumoto to drive the motors
in an accelerated and pulsed pattern.
The current sensed obtained from the ADCs
(analogue to digital converters) will be sent to a
host PC through serial and saved in text files.
Excel would then be used to graph this data.
Figure 34-Dynamic tracking methodology
32
1 4
Figure 33- LDR’s alignment
Read
sensors

Calculate
light

diﬀerence

Select
motor

direc5on

Move
motors
if

needed

Stop
motors

Send
current

sense
values

through
serial

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Remarkable Outputs and Experimental
Results
Cost Analysis
A cost analysis procedure was performed where the retail price of the solar tracker was
calculated. One of the initiating objectives of the project was to manufacture a
significantly cheap solar tracker. Solar trackers available in the market of United
Kingdom, range from 600UKP to 2000UKP. Thus, our aim was to build a solar tracker,
whose price would allow the seller to add an extra 25% profit. The 25% profit was
calculated by comparing retail prices of products manufactured by Harwal Group of
Companies with the selling prices used by distributors of their products. The choice of
materials were chosen in such a way so that the retail price will range between £400- £600.
A detailed costing datasheet is provided below where shipping is excluded.
MATERIAL Price
PV PANEL £ 90.00
SUPPORT BEAM DIAGONAL (2) £ 3.00
SUPPORT BEAM HORIZONTAL £ 1.00
PVC DISC £ 5.00
PVC CYLINDRICAL TUBE £ 15.00
PVC SQUARE BASE £ 6.00
SHAFT £ 5.00
BEARINGS £ 7.00
ACCESSORIES £ 5.00

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FASTENERS £ 3.00
ARDUINO MICRO-CONTROLLER £ 15.00
ARDUMOTO £ 10.00
ELECTRONIC PERIPHERALS £ 5.00
LDR SENSORS £ 2.00
12 VOLT POWER SUPPLY £ 15.00
LINEAR ACTUATOR £ 90.00
ROTARY ACTUATOR £ 30.00
OTHER (INCLUDING PACKING COST) £ 12.50
TOTAL MATERIAL COST £ 319.50
LABOUR & OVERHEADS (15% LABOUR + 5% OVERHEAD) £ 63.90
TOTAL COST £ 383.40
GROSS PROFIT 15% (ROUNDED) £ 57.51
RETAIL PRICE £ 440.91
Table 14-Costing Datasheet
The solar tracker’s selling price with an additional 15% Gross profit for the manufacturer
was calculated to be £440.91, ranging between the set margins of £400-£600. This will
allow the distributor to add a 25% profit for himself. Thus a solar tracking system with a
100Watt PVP can be sold at the price of £551.14. The costing datasheet above was based
on a similar procedure used by “Harwal Group of Companies” to calculate their selling
prices. Comparing this price to the one of solar trackers available online, it is cheaper by

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approximately £50. Thus our 100W solar tracker prototype can be described as relatively
cheap.
As previously mentioned, the most expensive equipment bought for this project was the
linear actuator. The linear actuator was bought at a price of £90; thus, is the component
that significantly increased the selling price. Instead of using a linear actuator, a second
rotary actuator could have been used with modifications to reduce the cost. However the
retail cost will range about the same price calculated, £440,91, due to the fact that an
improved controller should be replace for more accurate and effective output results
Additionally, the same costing datasheet was used to calculate the cost without the solar
panel. The new raw material cost was calculated to be £229.50, the retail price £263.92
and the selling price £329.90.
In addition, the payback period for the solar tracker was calculated. Using figures provided
by Sunrise Sunset [Available from: http://www.projectbritain.com/weather/sunshine.htm] the average
hours of daylight was calculated. The cost of electricity in the UK is 15.32 Pences/Kw
according to energysavingtrust.org.uk. Thus using the following equation an estimated
payback time was calculated.
!"#$
!"#$"%& !"#$
= 𝑓 ∗ 𝑃 ∗ ℎ𝑜𝑢𝑟𝑠 𝑜𝑓 𝑑𝑎𝑦𝑙𝑖𝑔ℎ𝑡!"# !"#$ ∗
!"#$!%# !!"#$ !" !"#$%&!!
!"#
∗ 𝑐𝑜𝑠𝑡 𝑜𝑓 𝑒𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑖𝑡𝑦
Equation 17
Where f is the efficiency and P is the power of the solar panel.
Since the cost of our solar energy system is £440.91, substituting in the formula above an
estimated payback time of 14.34 years
An excel spreadsheet simulator was used to calculate the payback time, and a scenario of a
solar tracker with a higher output power was performed in order to calculate the payback
time for it. It was assumed that 4 solar panels of 150Watts were operating installed in our
system. The total cost of the system will increase to £1,292.89 and the total power will
now change to 600W. Substituting our new criteria in the payback template, the payback
time is now 5.61 years.

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It is crucial to mentioned that the payback period is based on theoretical assumptions.
However the overall costing price ranges low compared to the solar tracking system’s
market.
Do-It-Yourself Product
A DIY (do-it-yourself) product was manufactured. One of the principles followed to
integrate the prototype is to provide an easy assembly to the buyer. This is a modern
business strategy used by one of the biggest and most profitable manufacturing company
in the word, IKEA. A self-assembly solar tracking energy system will not require the need
of a technician thus reducing the overall cost of the investment. In addition this feature
allows the user to maintenance the system in case of any malfunction by replacing only the
damaged part.
Figure 35-Exploded assembly
Assembling the mechanical and the electronica components of the solar tracker (for a
second time) took me approximately 18 and 13 minutes respectively total of 31 minutes.
For an everyday user who is not familiar with the design, a period of one hour would be

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sufficient in order to assembly a stiff and robust system with the help of a manual booklet.
This is one of the biggest advantage of the product.
Real time-Testing of the Universal Solar Tracker
Testing in real time was performed in order to demonstrate that the solar tracker was
operated based on the principles of a dynamic solar tracking system. Two scenarios were
tested: 1) the photovoltaic panel was at a fix position at an angle of 45 degrees facing south
–west and 2) a dual axis solar tracker- between 12:00 and 13:00 o clock mid-day in two
consecutive days. This two experimental scenarios allows us to display difference between
the overall performances of a solar tracking system and fix position solar system. The
figure below demonstrates the power output analysis for a solar tracking system compared
to a fixed mounting position performed by POWERWAY [Available from:
http://www.pvpowerway.com/news/829.html].
Figure 36- POWERWAY power chart for a period of a day
Method and Calibration of testing
In order to be able to calculate the power that the electronics are using at any given time, a
current sense resistor was used. To make calculations easy, a 1 ohm 50w power resistor
was connected in series at the output of the power supply at which the electronics were

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connected. Current will be then calculated depending on the voltage difference across it, as
follows: 𝑉 = 𝐼 ∗ 𝑅, Where V is the voltage, I is the current and R is the resistance.
As we know the resistance is 1ohm we can deduce that and we end up with a simple
formula we can use to convert the voltage measured: V=I*1 à V=I
Figure 37-Current Sense resistor
Finally a dummy load was used to be able to draw a constant amount of current from the
solar panel. Thus current can be measured easily with a similar approach as described
above. The dummy load is available
by:http://www.arachnidlabs.com/blog/2013/02/05/introducing-re-load/. The figure below
shows the basic circuit for building a constant current load provided by the manufacturer
in the left hand side and on the right hand side is the load connected to the Arduino micro-
controller. Finally the load needs to be calibrated so that it actually gives 1mV for every
amp.

Figure 38 Dummy Load and schematic diagram[Available

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Summarizing from the approach taken to test the
• Connect the four resistors to “ADC0”, “ADC1”, “ADC2”, “ADC3”.
• Arduino is connected to pins 3, 11, 12 and 13 on the Ardumoto.
• The panels is connected with “resistor 1” next to it and the yellow resistor to ADC4.
• Connect the power supply with “resistor 2” and the 2 wires on the ardumoto (“ADC5)
Figure 39- Experimental Approach
Fix position solar system Scenario
The solar panel mounting position was set in

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Figure 40-Fix position current Graph
Graph as expected, has an increasing linear pattern between 12:00 and 12:33 o clock,
where the sun was moving in a position closer to it’s the systems ideal position (direct
exposure). Coming next, a stable current between 12:33 and 12:45 was observed. The
stability in current received is due to the fact that sun, over this period of time, hits the
solar panel directly. In addition peak current of 4.2 Amps was achieved between 12:33 and
12:45, validating the statement that more power can be received by a solar energy system
when exposed to direct sunlight, as It appears to be at that period. Finally between 12:45
and 13:00 o clock, even though the graph is still in a constant pattern, a slight reduction in
current was observed. This is due to the fact that sun’s magnitude is moving, slowly, away
from the direct exposure angle.
Universal Solar Tracker Scenario
The second experimental test involved recordings of the current received by the solar panel
with the aid of the universal solar tracker, during the same period of time on a different
day.
The current sense resistor was now connected

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Figure 41-Universal Solar Tracker Current Graph
A constant curve was formed from the data
Power produced: Fix position Vs. Universal Solar Tracker
It is significant to calculate the total power produced by a solar energy system, an
important specification. Power=Current*Voltage in Watts, using this equation the power
produced for each system was calculated. Voltage was recorded in time intervals of 10
minutes with the aid of a multi meter due to the fact that the Arduino micro-controller
didn’t have any ADCs left on. Out of the recordings an average value of 18.7 Volts was
calculated and used in order to predict the likely power output in each scenario and be able
to compare them.

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Figure 42-Fix position Vs. Universal Solar Tracker
The graph above shows the predicted pattern
Once again, comparing a solar tracking system to a standalone solar energy system with
the aid of Figure 42-Fix position Vs. Universal Solar Tracker, effectiveness and overall
performance between the two of them proves the literature review and proposed methods
of tracking. The area under each curve denotes the net power production of each scenario.
The area covered by a solar is much higher compare to the fix position system. It is
important to be mentioned that the day on which the Universal solar tracker scenario was
tested was a cloudy day which directly affects the performance of a solar energy system. In
addition, the fix position solar panel maximum output is higher compared to the other
scenario. This statement should have been opposite and shows the lack in accuracy
provided by the controlling system.
Expanding the graph in Figure 42-Fix position Vs.
Future Modifications and Conclusion
Extension kit Scenario
As already stated, the linear actuator used provides us with a stroke force of 1780N. This
high stroke force are capable of accepting an extension kit stand on which more solar
0.00

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90.00
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12:58

12:59

13:00

Power
(Wa*s)

Time

Fix
Posi2on
Vs
Universal
Solar
tracker

Universal
Solar
Tracker
Fix
Posi5on

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panels can be install on the system. As calculated above, the linear actuator used requires
only 18.395N in order to tilt the solar panels. Calculations were made in order to check the
feasibility of replacing our solar panel with four 150W panels. Assuming that the average
weight of a 150W solar panel is 12Kg and the stand used is 5Kg, then the total required
stroke force is calculated using the same procedure as in 𝐹𝑎𝑐𝑡+𝐹! = 𝐹
Equation 15 and is 129.98N. This modification directly
affects significant forces acting on our system thus it was crucial to calculate the new
Factor of safety for the shaft. By replacing once again our new criteria in the excel
spreadsheet [Appendix D], our new FOS is 525.29, which again is very high. The stand
kit, together with the four 150W panels, was designed in SolidWorks and they replaced the
solar panel, as shown in the picture below.
Figure 43- 600W solar tracker
In addition, an FEA analysis was performed under the 4 solar panel scenario, in order to
verify that the two isosceles rectangular beams would not fracture due to overloading.
Results of the FEA analysis are demonstrated in Error! Reference source not found.,
where maximum stresses appear to take place at the point of joint between the horizontal
and the diagonal beams.

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Figure 44-FEA analysis
Conclusion
After examining the information obtained by the real time testing of the prototype, it can
be said that the proposed way of a dynamic solar tracking system, is a practicable method
of maximizing the mean intensity of sunlight received by a solar energy system. The
limited knowledge I have on electronics and controlling system commands makes the solar
tracking system incomplete. As already mentioned, the micro-controller used is not
reliable. The principle of dynamic tracking of the sun was achieved however it lacked of
accuracy and effectiveness due to electronic limitations.
The concepts which integrated the mechanical part of the Universal Solar Tracker
appeared to be effective. A product which can be assembled by the user in only one hour, a
robust structure. Additionally the significantly low angular velocity that was achieved by
the gear box combined with the low linear velocity provided by the linear actuator increase
the accuracy of the system. Even though the system is over-designed, with the appropriate
reductions in dimensions such as tube length and shaft diameter would decrease the raw
material required; thus, an even cheaper product can be created.
The linear actuator, which was the most expensive component used for this project, was
worth the money spend on it because of its various benefits, as previously identified. Some
of these are its high stroke force, its accuracy, the fact that it is easy to install and finally its
ability to function straight away. Therefore, the linear actuator has directly affected the

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design as a whole, as well as the performance of the tracker. Moreover, despite its price, it
was appropriate to choose and use the actuator in order to tilt the solar panel.
Concluding, as proved while having in mind that this is the prototype of the Universal
Solar Tracker, the overall system with the following modifications can compete in the
market of solar trackers as an effective, low cost, DIY solar tracker:
• Reduce raw materials by decreasing the overall size.
• Installation of an effective controlling system.
• Design a stand kit in order for the system to accept more solar panels.
• Supply the system with a battery and an inverter
Reflective Statement
This project has provided me with a priceless experience, which will unquestionably be of
great benefit in my future career as an engineer, as well as assist me in the areas of
industry and business. Having to produce such a big piece of work for the first time taught
me various things, amongst which are time management, finding effective methods for
problem solving, and generally enriched me with great knowledge. By completing this
project, I also gained experience in overcoming unpredictable obstacles; such as using an
unfitting mechanical part in manufacturing a product, having to come up with a practical
solution and learn to reschedule task’s deadlines.
Having worked hard, mainly by consulting and experimenting on various principles and
strategies that have been used for years from a range of companies, designers and
engineers, my project, was successfully built and functioned to a satisfying point. This
project, namely ‘The Universal Solar Tracker’, was my first engineering design model,
which I built from scratch.
A better and more critical knowledge and understanding of the areas of solar energy and
solar tracking system was achieved by the aid of the literature review. The various
resources of current awareness, which I have read indicated that it is important for an
engineer to have knowledge of the market surrounding his research areas. This is mainly

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because nowadays, customers’ demands are high due to the evolution of technology. Thus,
it is important for an engineer to make an adequate research based on the current market,
otherwise, the manufacture of products that do not meet the ends of the consumers will end
up in being a failure in the market.
Having to design a model of the product enriched me with experience and confidence in
working with SolidWorks, an engineering design software. Additionally, using the
Arduino micro controller in order to design the electronics provided me with adequate
knowledge of the programme, which I had never used before. Finally, the manufacture of
the product itself gave me the opportunity to use old-fashioned and modern manufacturing
processes and understand their importance. In addition I strongly feel that this project is
actually an engineering design project. The mechanical parts of the system, on which
through my Mechanical Engineering degree I gained rich full skills and confidence on this
area, were approached, investigated and manufactured as an amateur engineering designer
would have done.
Having tested the Universal Solar Tracker verified the research outputs. The researches
made and the design proved to have been successful as more power was gained with the
use of a solar tracker, as compared to a fix position solar system: Dynamic solar tracker.
Despite that, I honestly don’t feel satisfy from the electronic area of the project, since I
have never before worked on electronics and at this stage I believe I should have read and
worked on it even harder. In my opinion, this is an area where the prototype lacks in
competence. A short and unprofessional video was recorded while testing the system and
is available from: http://www.youtube.com/watch?v=KtwnweP7T-A . Additionally, the
prototype of Universal Solar Tracker is located in room 1N25 at the University of the West
of England, which it would be appreciated and respected if you investigate it and provide
me with feedback.
In conclusion, despite the exhaustion and stress that I have felt over the past six months, I
have now realised that this project assisted me in improving my confidence and making
me a more responsible person. Most importantly, my knowledge in this area has reached
an advanced level.

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Appendices
See the CD submitted for the appendices
Appendix A- Gantt chart
Appendix B- Design Selection
Appendix C- SolidWorks 2D/3D Drawings and Simulations
Appendix D- Solar tracking system calculations [Excel template]
Appendix E- Arduino Code
Appendix F- Experimental results [Excel template]
Appendix G- Cost Analysis

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