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ABSTRACT
Now-a-days, dealers of natural resources like fuel, coal etc. are facing a hard
time to keep pace with the increasing demand. Therefore, to carry out this
demand it is quite necessary to make a new exploration of natural resource of
energy and power. Therefore sunlight is now-a-days considered to be a source of
energy which is implemented in various day to day applications. Solar energy is
being used to produce electricity through sunlight. With the help of this
technology we aim to make solar energy powered car in our project. The main
component to build a solar car is the solar panel. The solar cells collect a portion
of the sun’s energy and store it into the batteries of the solar car. Before that
happens, power trackers converts the energy collected from the solar array to the
proper system voltage, so that the batteries and the motor can use it. After the
energy is stored in the batteries, it is available for use by the motor & motor
controller to drive the car. We are going to use two set of batteries; one of which
will get the electrical energy from the panel to drive the motor and another will be
used as a back-up source of energy which will provide required power when
there is no sunlight. A microcontroller can be used in this purpose which can
switch to the fully recharged battery when it senses that another battery is empty
or not providing enough power to drive the motor. Again, we used a complete
circuitry to solve the problem of voltage fluctuation due to movement of the sun,
earth or cloud etc. We used a voltage comparator, a relay circuit for and a
transistor along with a diode for this purpose. Comparator compares the voltage
of solar panel and the battery and then it provides the higher voltage to the
transistor to activate the relay which provides the required and stable voltage to
the car. However, after all these being proceeded, the motor controller adjusts
the amount of energy that flows to the motor to correspond to the throttle. The
motor uses that energy to drive the wheels. Preliminarily our objective would be
to implement our idea on a remote control toy car and afterwards with help of this
prototype we can extend our future work on building a actual car powered by the
solar energy.
INTRODUCTION
1.1 A Preview on the Necessity of Solar Energy at Present Situation
There must be some limits to the ability of the earth to sustain a growing
population. Fortunately, population models suggest that the world's population
will probably level out at about two to three times the present numbers over the
next hundred years. The question is whether the earth's resources are sufficient
to sustain that population at a high standard of living for all. In this the key issue
is energy.
Now-a-days, dealers of natural resources like fuel, coal etc. are facing a hard
time to keep pace with the increasing demand. At one hand, there are more cars
or motor vehicles are dominating the transport medium, on the other hand these
cars are being dominated by the fuel. As a result, the limited resources are being
quashed by the producers and dealers to satisfy this need which is leading us to
an uncertain future with having the scarcity of fuel and minerals. So, it is clear
that present trends in energy consumption, especially oil, cannot be sustained
much longer. Again, in view of the possibility of global warming, these resources
are playing a negative role. Therefore, under this circumstances, it is quite
necessary to make a new exploration of natural resource of energy and power.
But why exploration when the resource is in front of our bear eye. It is effective,
less expensive and above all, it is an endless source of energy. With greatly
improved energy efficiency, a transition to this energy based economy capable of
sustaining the anticipated growth in the world economy, is possible. This effective
source is “Solar Energy”.
1.2 What is Solar Energy?
Solar energy is radiant energy that is produced by sun. Everyday the sun
radiates, or sends out, an enormous amount of energy. The sun radiates more
energy in one second than people have used since the beginning of time!
Where does the energy come from that constantly is being radiated from the
sun? It comes from within the sun itself. Like other stars, the sun is a big ball of
gases- mostly hydrogen and helium atoms. The hydrogen atoms in the sun’s
core combine to form helium and generate energy in a process called nuclear
fusion.
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During nuclear fusion, the sun’s extremely high pressure and temperature
causes hydrogen atoms to come apart and their nuclei (the central cores of the
atoms) to fuse to become one helium atom. But the helium atom contains less
mass than the four hydrogen atoms that fused. Some matter is lost during
nuclear fusion. The lost matter is emitted into space as radiant energy.
It takes millions of years for the energy in the sun’s core to make its way to the
solar surface, and then just a little over eight minutes to travel the 93 million miles
to earth. The solar energy travels to the earth at a speed of 186,000 miles per
second, the speed of light.
Only a small portion of the energy radiated by the sun into space strikes the
earth, one part in two billion. Yet this amount of energy is enormous. For
instance, everyday enough energy strikes the United States to supply the
nation’s energy needs one and a half years!
Where does all the energy go? About 15 percent of the sun’s energy that hits the
earth is reflected back into space. Another 30 percent is used to evaporate water,
which lifted into the atmosphere, produces rainfall. Solar energy is also absorbed
by plants, the land, and the oceans. The rest could be used to supply our energy
needs.
Recent Research on Utilization of Solar Energy
Solar energy refers primarily to the use of solar radiation for practical ends.
However, all renewable energies, other than geothermal and tidal, derive their
energy from the sun.
Solar technologies are broadly characterized as either passive or active
depending on the way they capture, convert and distribute sunlight. Active solar
techniques use photovoltaic panels, pumps, and fans to convert sunlight into
useful outputs. Passive solar techniques include selecting materials with
favorable thermal properties, designing spaces that naturally circulate air, and
referencing the position of a building to the Sun. Active solar technologies
increase the supply of energy and are considered supply side technologies, while
passive solar technologies reduce the need for alternate resources and are
generally considered demand side technologies.
Now-a-days, solar technology is being used in so many aspects of our day to day
lives such as-
• Architecture and urban planning
• Agriculture and horticulture
• Solar lighting
• Solar thermal
• Water treatment
• Electrical generation
• Solar vehicles etc.
1.5 Research Objective
Sunlight is now-a-days considered to be a source of energy which is
implemented in various day to day applications. Solar energy is being used to
produce electricity through sunlight. With the help of this technology we aim to
make solar energy powered car. Preliminarily our objective would be to
implement our idea on a remote control toy car and afterwards with help of this
prototype we can extend our future work on building an actual car powered by
the solar energy which is both cost effective and of course environment friendly.
We also intend to solve the problem of voltage fluctuation due to the fact of
cloud, earth movement, sun movement etc.
ANALYSIS
2.1 Effect of Load (Weight) on the Toy Car
To successfully complete the whole project, initially we need to choose the
proper solar panel with appropriate power rating and weight. Because, these
things are directly related to the efficiency of the car. So, we did an experiment
which involved the load management of the car while driving along with the V-I
rating.
Here, we chose a random car and put different bars with different weights on
different position (i.e. front hood, roof top/ seat, back hood) of that car. Then we
connected the multi-meter to the respective input pins (‘+ve’ and ‘-ve‘) of the
battery of that particular car in parallel. Through this process we found out the
voltage required to drive the motor of the car at different situation. Again, after
that, we connected an ammeter with those respective in series to find out the
current flow required to drive the motor of the car.
By the way, the battery of that random car was providing 9.6V and 600mAh,
voltage and current rating respectively. This experiment gave us the idea about
the solar panel we should collect for our future project implementation.
2.2 Choosing the Solar Panel
Since we got the idea about the solar panel we should collect, we spent no time
to grab it from the store. In our case, we used a 3W solar panel to drive our
handmade three wheeler toy car. We also measured the weight of the solar
panel which was about 500gm. We ripped out border coating of the panel to
further lessen the weight. This would give the three wheeler less load to take and
move more freely.
2.3 Characteristics of Solar Panel
2.3.1 Measurement of voltage rising with respect to time
Now we have the solar panel, so it is important to measure the rise time of the
voltage of the panel. As a result we can get the idea about how much time it will
take to charge up the battery and use it for further application.
Characteristic
After collecting the solar panel it is important to measure the V-I rating of the
panel for further implementation. So, we went outside in an open place under the
sunlight at midday and did the job. We connected different loads with the panel to
measure the voltage and current at different loads. But at first we found out the
voltage and current at ‘without any load’ situation.
INITIAL CONCEPT
3.1 The Plan
In our project we are attempting to build a solar car that converts the sunlight into
electrical energy. The main component to build a solar car is the solar panel. The
solar cells collect a portion of the sun’s energy so that power trackers can
convert the energy collected from the solar array to the proper system voltage.
After the energy is collected in the panel, it is available for use by the motor &
motor controller (which was connected to the panel). After all these being
proceeded, the motor controller adjusts the amount of energy that flows to the
motor to correspond to the throttle. The motor uses that energy to drive the
wheels.
3.2 Challenges
As stated before, this process has some limitations with it. They are-
• Taking the input from the panel
It is not safe to connect the solar panel directly to the motor input. The sun
does not provide the same heat to the solar cells so that it is quite impossible
to get a constant voltage from the panel. This sudden rise and fall of the
voltage may hamper the motor so that the car may not work properly.
• No back-up source
There is no back-up source included here. That means, while there is no
sunlight the car will not move a bit. This is a serious drawback of this process
as we cannot get sunlight all the 24 hours. Then how can we expect it to use
in our day to day proceedings?
• Ensuring bi-input supply
Even if we use a back-up source like a battery, there is no such way shown
here to connect it to the motor of the car. So, having a back-up is not the only
solution, ensuring the supply of both the solar and back-up input is also
important.
• Controlling voltage fluctuation
As stated before, the sun cannot give us a constant voltage all day long.
There might be cloud, movement of earth, movement of sun etc. can change
the voltage level rapidly which we call fluctuation. As we all know, voltage
fluctuation is always a threat to any electrical device, but there is no such way
defined here to solve this problem in this plan.