Pp t Proposal

7/27/2019 Pp t Proposal

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DUAL AXIS

SOLAR RADIATION

TRACKER

Proponents:

Espedillon, Marigold May L.

Estrella, Recuerdo C. Jr.

Grageda, Glenda Mae V.

Herrera, Erika Claudine G.

Lalo, Erika Gayle E.

BSECE 5-1


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INTRODUCTION

These factors have led the proponents to come up with a project that

can make use of the abundant commodity available at present (The

Sun), harness it and make use of it to power up a household who

cannot afford to buy and were not privileged enough to be included in

the electric distribution by power companies

We uses electric energy

to power up the appliances

which emit greenhouse

gases

which causes global

warming

they are also expensivemaking other people

unable to afford this


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INTRODUCTION

The sun is an unlimitedcommodity that can be

adequately sourced from

many locations

avoids the price

manipulations politics that have more

than doubled the price

of many fossil fuels

Although an immense amount of energy is constantly coming from

the sun to the earth, all that energy is spread out over a very large

area. Solar energy also does not work at night. The sun moves

both throughout the day as well as throughout the year


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INTRODUCTION

A solar panel must be

able to follow the suns

movement to produce

the maximum possible

power

The goal of this project was to design an active, dual axis

solar tracker that will have a minimum allowable error of

tracking to get the maximum solar energy possible and also

be economically feasible to market towards people living in

the rural locations to be used as their power generator in

their household


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BACKGROUND OF THE STUDY

Solar powered equipment works best when pointed at or near thesun, so a solar tracker can increase the effectiveness of such

equipment over any fixed position, at the cost of additional

system complexity. The sun's position in the sky varies both with

the seasons and time of day as the sun moves across the sky.

A Solar tracker is a device for

orienting a solar photovoltaic

panel or concentrating solar

reflector or lens toward the sun.

A solar electric module (also

known as a panel) is made up of

many PV cells that are wiredtogether in a series to achieve

the desired voltage. The thin

wires on the front of the module

pick up the free electrons from

the PV cell.


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One way to do this is with a use of a light sensor. A light sensor isemployed to control the solar cell tracking system. If the light

sensor is not aligned with sun rays, then it could turn on the

motor until it is once again aligned. If the motor is attached to the

frame holding the solar cell, then the solar cell could be moved to

face the sun

If we could configure a solar

cell so that it faces the suncontinually as it moves across

the sky from east to west, we

could get the most electrical

energy possible

The use of a tracking

system greatly improves the

power gain from solar

radiation


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THE SOLAR TRACKER electrical system contains the sensor and the comparator circuit

which give the tracker the capability to compare the amount of solar

radiation that is being directed towards the panel

mechanical system is responsible for the rotation and the tilting of

the solar panel as it tracks the best angle that will provide the highestpossible amount of solar radiation.

Build an automated system ofour own, using a motor and is

capable of recharging on its

own when the battery level is

running low without

compromising the amount ofsolar energy we are

harnessing


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STATEMENT OF THE PROBLEM

The sun is an unlimited commodity that can be adequately

sourced from many locations, meaning solar avoids the price

manipulations and politics that have more than doubled the price of

many fossil fuels in the past decade

Although an immense amount of energy is constantly coming

from the sun to the earth, all that energy is spread out over a very

large area. And also solar energy is directly dependent with the lightintensity that the sun gives and as we all know the Sun moves

constantly in bell shape throughout the day. Solar panels are also

bulky and the main hindrance to solar energy going widespread is the

cost of installing solar panels. Capital costs for installing a home solar

system are high.

The proponents will use a tracking device to be mounted in

the solar panel to be able to follow the Sun to attain the maximum

amount of energy that can be harness to supply the household.


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SIGNIFICANCE OF THE STUDY

In lieu of the gradual increase in the risks of Global

Warming, this study is timely enough to push

through. In recent years, our country have launched

many studies in the aspect of aiding rapid increase

of the risks of Global Warming and made a lot ofachievements. Many organizations around the

globe are prioritizing the movement towards green

technology and this study is our contribution. The

project is free from harmful emissions and it is alsoless expensive than those that are present in the

market today, for the project harnesses and

produces low-cost and renewable energy.


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The amount of solar energy available on the earth

depends on the geographical latitude and the time

of day and year at a given location, and this source

of energy is abundant in nature, so nobody is going

to take advantage and monopolize the supply ofthis.


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The use of solar tracking system would greatly

improve the power gain from the solar radiation

compare to the fixed or immobile solar panel. And

also the project would not only focus on making the

project more efficient than what is available inmarket but also make it economically feasible to

market so that underprivileged people can also

afford it.


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REVIEWOFRELATEDLITERATURE

Immobile Versus Mob ile Panel

Different power applications require different tracking systems. Forcertain applications a tracking system is too costly and will decrease themax power that is gained from the solar panel. Due to the fact that theearth rotates on its axis and orbits around the sun, if a PV cell/panel isimmobile, the absorption efficiency will be significantly less at certaintimes of the day and year. The use of a tracking system to keep the PV

cell/panel perpendicular to the sun can boost the collected energy by 10- 100% depending on the circumstances.

If a tracking system is not used, the solar panel should still be oriented inthe optimum position. The panel needs to be placed where no shadowwill fall on it at any time of the day. Additionally, the best tilt angle shouldbe determined based on the geographical location of the panel. As a

general guideline for the northern hemisphere, the PV panel should beplaced at a tilt angle equal to the latitude of the site and facing south.However, for a more accurate position and tilt angel a theoretical modelof the suns iridescence for the duration of a year is created and the angeland position is matched to the model.


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Overview of Current Tracker Drive Types

After classifying the solar panel into mobile or immobile wehad determine that it is best to use a tracker or mobile panelto be able to follow the sun throughout the day to capture themaximum solar energy.

Solar trackers can be divided into three main types dependingon the type of drive and sensing or positioning system thatthey incorporate. Passive trackers use the suns radiation toheat gases that move the tracker across the sky. Active

trackers use electric or hydraulic drives and some type ofgearing or actuator to move the tracker. Open loop trackersuse no sensing but instead determine the position of the sunthrough pre-recorded data for a particular site.


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Gas Trackers (Passive Trackers)

- Passive trackers use a compressed gas fluid as a means oftilting the panel. A canister on the sun side of the tracker isheated causing gas pressure to increase and liquid to be pushedfrom one side of the tracker to the other. This affects the balance

of the tracker and caused it to tilt. Active Trackers

- Active trackers measure the light intensity from the sun todetermine where the solar modules should be pointing. Lightsensors are positioned on the tracker at various locations or in

specially shaped holders. If the sun is not facing the trackerdirectly there will be a difference in light intensity on one lightsensor compared to another and this 11 difference can be usedto determine in which direction the tracker has to tilt in order tobe facing the sun.


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REVIEWOFRELATEDLITERATURE Open Loop Trackers

Open loop trackers determine the position of the sun using computer controlledalgorithms or simple timing systems.

Timed Trackers

These use a timer to move the tracker across the sky. Incremental movementthroughout the day keeps the solar modules facing the general direction of the sun.Trackers of this type can utilize one or two axes depending on their application. Themain disadvantage of timed systems is that their movement does not take intoaccount the seasonal variation in sun position. Unless measures are taken to adjustthe tracker position seasonally, there will be a noticeable difference in efficiencydepending on the season.

Altitude / Azimuth Trackers

Uses astronomical data or sun position algorithms to determine the position of the sunfor any given time and location. Tracker location, date and time are used by a microcontroller to fix the position of the sun. Once the position has been calculated, themodules are moved using servo motors and there position measured by encodersbuilt into the tracker frame.


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METHODOLOGY

To be able to meet the goal of the proponents to build an active, dual

axis solar tracking device that will increase the efficiency of the fixed

solar panel, to attain the maximum energy that could be harness from

the sun, for the purpose of supplying household of under-privileged

people in rural areas


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METHODOLOGY

The tracking system is the one responsible for determining and

moving which position or tilting of the panel would capture the

highest amount of solar energy

The harvesting system is the one responsible for the

distribution of the captured energy to the household


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METHODOLOGY

Tracking System

Mounted PV sensors around the Solar Panel receiving the intensity of

light at the same time

4 sensors would be place at top, bottom, left side and right side of the

panel respectively to be able to determine the position of the sun

As the sensors receive intensity of light, the comparator circuit whichconsists of a differential amplifier will identify which of the 4 sensors is

receiving the highest amount of light

Comparator circuit as the brain of our tracking system which is

responsible for the decision making of the movement of the tracker

When the comparator circuit has determine which sensor is

receiving the highest amount of light this will drive the motor to start

moving the gears/arm to move the panel to the position of the sun


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METHODOLOGY

Harvest ing System

By integrating the panel with the tracking device, the amount of solar energy thatpanel would capture will increase thus making the panel more efficient as a source

of electricity for the rural areas out of reach of the distribution grid of the electric

companies.

Charge controller will be inserted to the system to regulate the excessivevoltage that solar cells would produce and maintain the proper charging

voltage on the batteries

Battery bank would be included in the system to be able to store some

amount of solar energy at day time to be use at night time

The switch will act as a light sensing circuit, it will determine what would be

the power source that the household will use


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METHODOLOGY

System Design o f the Tracker

The purpose of the solar tracker is to accurately determine the position of the sun.This enables solar panels interfaced to the tracker to obtain the maximum solar

radiation. With this particular solar tracker a closed-loop system was made

consisting of an electrical system and a mechanical system.


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METHODOLOGY


Mechanical System

Uses 2 DC motors for the tilting of the panel one is for the verticalaxis tilting(top and bottom) and the other is for the horizontal tilting(left and

right). And a worm gear is chosen because it is capable of high speed-

reduction ratios as well as ensuring that there is no inertial backlash to the

driving source. This is ideal for a solar tracking system as the tracker

needed to move both slowly and with minimal influence from inertia.


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METHODOLOGY


Electrical SystemTo produce a useful solar tracker the electrical system needs to

give accurate control signals to the mechanical system, be reliable, and

have low power consumption. The electrical system will consists of solar

sensors, a comparator circuit and an H-bridge.


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METHODOLOGY


A battery to power the tracking system. Taking into consideration that the

tracker would be operating in remote parts of the world and the battery

would have to be replaced eventually. The proponents would put abattery recharging circuit that would recharged by the solar panel

mounted on the tracker so that the system would be self-sufficient.


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METHODOLOGY


As described previously, the motor chosen was a

DC motor. This motor can rotate in both directions by

reversing the direction of the current supplied. Becausethe power supply on the tracking system has only one

pole, a circuit was needed to switch

the direction of the current to the motor. The most

power efficient way to accomplish this is with a circuit

known as an H-bridge.


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METHODOLOGY


MOSFETs were chosen for their high

power efficiency compared to other

transistor technologies like the BJT

which actively draws current in addition

to the current flowing through the

device. Within the range of MOSFETs

there are also power MOSFETs with a

different internal construction that give

them high current and/or high voltage

capabilities. These power MOSFETs

generally have a much lower on-resistance than standard MOSFETs and

therefor have a lower power dissipation

and higher efficiency.


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METHODOLOGY


To provide an interface from the PV

sensors to the H-bridge, a circuit that

compares the voltage of 4 sensors

and outputs a control signal to eachof the four MOSFET inputs of the H-

bridge had to be designed. This

circuit design needed to accurately

sense the voltage difference

between the sensors and provide

reliable inputs to the H-bridge


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METHODOLOGY


Photovoltaic sensors are chosen

because it is more sensitive or

responsive to the change in intensity

of light it receive. The sensor tilt angle

was chosen that obtained the highest

angular response. The LM741 is chosen as the

comparator because it is a common

operational amplifier with a power

dissipation of low power dissipation of

only 500 mW. Two LM741 were

connected to the two sensor voltage

dividers and configured in the no-

feedback, comparator setup. This

comparator setup has an overall

power dissipation of 1 W.

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