REVIEW OF LITERATURE

The solar energy is a clean, freely and abundantly available alternative energy source in nature.
Capturing solar energy from nature is an advantageous task for power generation. Conversion
of sun energy into another form is a highly complex phenomenon. For this purpose, Photo-
Voltaic (PV) panels are used which convert Sun energy to Direct Current (DC) electrical energy.
Conventional fixed type PV panels extract maximum energy only during 12 noon to 2 PM which
results in less efficiency. Therefore, building of an automatic solar tracking system is the need of
an hour. PV panels have to be perpendicular with the sun for maximum energy extraction
which can be fulfilled by automatic tracking. This project includes the design and development
of Arduino based automatic solar tracking system. Photo voltic cells are used to sense the
intensity of sunlight and hence the sun’s position in the sky. Arduino is used for controlling the
movement of PV panel. The mechanism uses geared DC motors to rotate the PV panel. DC
motors are controlled by the Arduino with respect to signals from pv cells. Liquid Crystal Display
(LCD) is used to display the output DC voltage and current on site.

This literature review reveals the detailed work that has been carried out till date on the topic
of Solar Tracking. N. Othman, M. I. A. Manan, Z. Othman, S. A. M. AlJunid have designed a two-
axis sun tracking system with the use of five LDRs and an Arduino UNO controller [1]. The
objective of this research is to design and construct the automatic dual axis solar tracker for
maximum sun energy utilization. The only point of worry is that this system should consume
energy as minimum as possible so that the difference between power conversion and power
consumption would increase and hence the net profit of the system. Arduino UNO controller
has been used and it is programmed in C language. LDRs are used to detect the maximum
sunlight position in the sky and the program written performs calculations and drives the servo
motors to make PV panels perpendicular to the sun [1]. The sun not only travels from east to
west but there is a change of angle in north to south direction also. So the north and south
directions should also be taken care of. Dual axis trackers do that. These trackers track the sun
on a horizontal as well as vertical axis. Because of this operating ability the dual axis trackers
have more output power than the single axis trackers. Light Dependent Resistors are used to
find the brightest spot of the sun in the sky. LDRs are connected to Arduino UNO controller
which gets to know the position of the sun in the sky and hence rotates the motors towards the

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sun. Two Servo motors are used for panel rotation which also fulfils the low cost and
lightweight criteria [1]. Md. Tanvir Arafat Khan, S.M. Shahrear Tanzil (2010) have designed and
constructed a microcontroller based solar tracking system using LDRs to sense the intensity of
sunlight and stepper motors to move the Photo-Voltaic (PV) panels in accordance with the sun
[2]. Fabian Pineda, and Carlos Andres Arredondo (2011) have designed and implemented a two-
axis sun module positioning by sensing the maximum brightness point in the sky. A geodesic
dome based sensor has been built for the bright point tracking [3].Authors Salabila Ahmad et al.
have designed and constructed an open loop two axes sun tracking system with an angle
controller. r. The hardware is selected such as it will maximize the power collected and
minimize the power consumed as the efficiency parameter lies in between these two power
parameters [4]. Solar tracking also helps in transmitting sunlight to dark area like basement.
Authors Jifeng Song et al. have implemented the high precision tracking system based on a
hybrid strategy for concentrated sunlight transmission via fibres [5]. Author Cemil Sungur
(2008) has presented the multi-axes sun tracking system with PLC control.

Robert H. Dold describes a two axis solar tracker capable of withstanding the extreme weather
conditions. The solar tracker includes a solar array, a frame, a base, a pivot frame, and a first
and second actuator. The solar array is mounted to the frame and captures sunlight. The base is
pivotally connected to the frame and defines a pivot axis for elevational movement of the solar
array. The pivot frame is also pivotally connected to the frame and defines a pivot axis for
azimuthal movement of the solar array. The base is pivotally connected to the frame and
defines a pivot axis for elevational movement of the solar array. The pivot frame is also pivotally
connected to the frame and defines a pivot axis for azimuthal movement of the solar array. The
first actuator controls elevational movement of the solar array and the second actuator
controls azimuthal movement of the solar array.The solar tracker is pivotable between a raised
position and a stowed position

Ronald P Corio claims as an object of the his invention to mechanically link multiple solar
trackers in a large array configuration so that they may operate in unison, driven by a single

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motor and tracker controller, whereby the mechanical linkage system is designed such that it
must only be capable of withstanding the relatively low forces required to effect movement of
thetrackers without the requirement to resist larger wind forces acting on the array of
trackers.Another Object of his invention is to apply the drive principles to various solar single-
axis tracking geometries to maximize the economic performance for each solar tracking
application. Multiple gearboxes can be mechanically linked by drive shafts and driven by a
single motor. The drive shafts may incorporate universal joints for uneven terrain or staggered
configurations. Harmonic dampers can be affixed to the solar panels to decouple wind forces
which allow the use of larger solar panels.

S.Abdallah Desalination ELSEVIER has presented a computerized sun tracking device for rotating
the solar still with the movement of the sun. A comparison between fixed and suntracked solar
stills showed that the use of sun tracking increased the productivity to around 22%, due to the
increase of overall efficiency by 2%. It showed that the sun tracking is more effective than fixed
system and is capable of enhancing the productivity

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