TERM PAPER

On

Title : Solar Car

Submitted to

AMITY SCHOOL OF ENGINEERING

AND TECHNOLOGY

Guided by: Submitted by

Dr.Rashmi Singh Udayan Bhattacharya

ECE-2 A2305109128

ASET Roll No.- 1111

Acknowledgements

Any attempt at any level cannot be satisfactorily completed without the support and guidance of learned people. I would like to express my immense gratitude to Dr. Manmit Sakia ; Dr. Alpana Goel for their constant support and motivation that has encouraged me to come up with this project. I also thank Dr.Rashmi mam for checking and rechecking the project which has helped me to bring perfection in my work.

I would be failing in my duty, if I do not express my indebtedness to the principals and teachers of those institutions who cooperated in data collection work joyfully. Without whose cooperation it would never been possible to collect the valuable data. I am also thankful to library staff for providing me necessary reading material for my study.

I express my thanks to the Administration and Management of Amity University, for extending her support. I would also thank my Institution and my faculty members without whom this project would have been a distant reality.

I am also thankful to my parents MR. Swadesh Bhattacharya and Mrs. Sujata Bhattacharya and my class fellows who have rendered their whole hearted support at all times for the successful completion of this project.

CERTIFICATE

This is to certify that Mr. UDAYAN BHATTACHARYA ,student of B. Tech. in ECE (Department) has carried out the work presented in the project of the term paper entitle “SOLAR CAR” as a part of First year programme of Bachelor of Technology in “ECE” from Amity School of Engineering and Technology, Amity University, Noida, Uttar Pradesh under my supervision.

Dr. RASHMI SINGH

Deptt. Of Applied Sciences

ASET, Noida.

Table of Contents:

1) Introduction.2) What is solar energy?3) Background.4) How is solar energy used to run a “solar car”?5) Solar Cell.6) Basic components of a “solar car”.7) Kit Materials.8) Vehicle Specification.9) Building a “solar car”.

a)Construct the body.b)Mount the wheels.c)Mount the motor.d)Prepare the solar panels.e)Mount the panels.

10) Testing. 11) Conclusion. 12) References

ABSTRACT:

A solar vehicle is an electric vehicle powered by solar electricity. This is obtained from solar panels on the surface (generally, the top or window) of the vehicle or using a solar jacket in electric bicycles. Photovoltaic (PV) cells convert the sun's energy directly into electrical energy.

Solar vehicles are not sold as practical day-to-day transportation devices at present, but are primarily demonstration vehicles and engineering exercises, often sponsored by government agencies. However indirectly solar-charged vehicles are widespread and solar boats are available commercially.

Solar cars combine technology typically used in the aerospace, bicycle, alternative energy and automotive industries. The design of a solar vehicle is severely limited by the amount of energy input into the car. Most solar cars have been built for the purpose of solar car races. Exceptions include solar-powered cars and utility vehicles.

Solar cars are often fitted with gauges as seen in conventional cars. In order to keep the car running smoothly, the driver must keep an eye on these gauges to spot possible problems. Cars without gauges almost always feature wireless telemetry, which allows the driver's team to monitor the car's energy consumption, solar energy capture and other parameters and free the driver to concentrate on driving.

Solar cars depend on PV cells to convert sunlight into electricity. In fact, 51% of sunlight actually enters the Earth's atmosphere.[1] Unlike solar thermal energy which converts solar energy to heat for either household purposes, industrial purposes or to be converted to electricity, PV cells directly convert sunlight into electricity. [2] When sunlight (photons) strike PV cells, they excite electrons and allow them to flow, creating an electrical current. PV cells are made of semiconductor materials such as silicon and alloys of indium, gallium and nitrogen. Silicon is the most common material used and has an efficiency rate of 15-20%.

INTRODUCTION

What is solar energy?

Solar energy is a renewable energy source that converts the sun’s heat and light into energy. It is more common than people realize. For example , the food we eat to give us energy comes from plants. Plants use sunlight for photosynthesis which makes them grow and produce food. The sun is also responsible for making other forms of renewable energy. Biomass energy, for example, is made by converting organic materials— like plants—into energy. The sun is needed to grow the plants, or biomass, that are converted into energy. Wind energy is also created by the sun. When the sun heats up the earth’s atmosphere, it causes certain areas to be warmer than other areas. When cool areas collide with the warm areas, wind is produced. Without the sun, there would be no wind. Solar energy is also connected to the creation of fossil fuels. Millions of years ago, plants died and were buried undertons of pressure. After millions of years coal, oil and natural gas were created from these plants. Fossil fuels can be considered ‘fossilized’ or stored-up solar energy.

Background:

Not only is the sun a source of heat and light, it’s a source of electricity too! Solar cells, also called photovoltaic cells, are used to convert sunlight to electricity. Solar cells are used to provide electricity all kinds of equipment, from calculators and watches to roadside emergency phones and recreational vehicles.

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Solar cells are most commonly made from silicon, the same material used to make computer chips. Silicon is one of the Earth’s most common elements, and is a major component of sand and many kinds of rocks. A solar cell is built like a sandwich, with two layers of silicon separated by a thin layer of insulating material. All three layers work together to convert sunlight into electricity. When sunlight falls onto the solar cell, it produces a small electric charge. Like a battery, the charge is positive on one side of the cell, and negative on the other. A wire connects the two sides of the cell, allowing electricity to flow. This flow, or current, of electricity can be used to power a small light bulb, turn an electric mot motor, or recharge a battery.

Solar cells are often used in locations where there isn’t any electricity and where electricity is needed in small amounts. In such cases, solar cells are usually connected to batteries, allowing electricity to be stored for use during times when the sun isn’t shining.A single solar cell is able to produce only a small amount of electricity. But solar cells can beconnected together on a multi-cell panel to produce larger amounts of electricity. As with batteries, the more cells that are connected to one another, the greater the current of electricity that can be produced.1 Solar panels can produce enough electricity to power satellites, recreational vehicles, and equipment for other applications where electricity is used in large amounts. For this project, you will be using the electricity from solar panels to power a small car. Your challenge will be to build a solar car that travels as fast and straight as possible.

How is solar energy used to run a solar car ?

The basic building block of a solar-electric system is the photovoltaic cell. The amount of electrical power created by the photovoltaic cell var- Sun’s Rays KnockElectrons off of Atoms Top Material, Bottom Material Electrons Close-Up View Electrons Flow Through the Motor, Producing Power Electrons are Pulled From Bottom Material to Top Material Motor.

Solar Cell

A photovoltaic cell is a sandwich made up of materials called semiconductors. The cells are thin silicon wafers with a positively charged impurity deposited on the surface. As you might already know, atoms have a positively charged nucleus and negatively charged electrons which spin around the nucleus. When these two materials are put together in a sandwich, an interesting thing happens--the electrons are pulled from the bottom half of the sandwich to the top half. But there’s a problem. The electrons are attached to the atoms, and the atoms won’t let go very easily. This is where the sun’s energy helps out. When sunlight shines on these materials, thesunlight has enough energy to knock the electrons off the atoms These electrons arethen free to be pulled to the top of the sandwich. Now, if we connect a wire from the solar panel to a motor, electrons will flow from the solar panel, through a wire, into the motor and then back to the solar panel through another wire. As more photons, or the tiny units of radiant energy released by the sun, hit the surface of the photovoltaic cell, more electrons are freed and more electrical charges are sentthrough the wire directly. The power coming from the solar panel is the product of voltage times the current—or the number of electrons flowing”.

Basic Components of a Solar Car

Aerodynamic Drag : The shape of the car’s body determines the amountof aerodynamic drag on the car. Fast cars are shaped so that, when moving quickly, they “cut” more easily through the air . To make sure your car moves more quickly, you can streamline the body, especially in the front area. Also, by choosing a body or shell that deflects air around the car, you can reduce the force of the air. The materials listed in the options below should be tested carefully to find a body design that will lessen the car’s drag. To test the aerodynamic drag on your solar car, use the roll-down test that car manufacturer’s use. The idea is to roll your car down an incline and see how far it rolls. A car with more drag will roll to a stop faster than a streamlined, low drag car.

W heels: Wheels are circular objects attached to the axle that allow the car to roll forward.

Wheel Size : The larger the wheel, the more energy it takes to turn it. A large wheel will allow the axle to rotate more slowly and will waste power in the bearings.

Wheel Alignment : Properly aligned wheels all move in the same direction. Improperly aligned wheels will slide sideways and cause friction. This wastes energy. Friction can be reduced by taking the time to align wheel properly the first time. Make sure all four tires move straight and that no wheels slide sideways.

Tire Traction : Traction is what keeps tires from slipping on a surface. It transmits the force from the wheels to the road. Traction is important, but the more traction you have, the more energy you lose (see Illustration 5). Conversly, if there is too little traction on a tire, the car will slide. Students need to find a level of traction that won’t cause the car to slip, but won’t waste valuable energy.

Weight Distribution - Students can increase traction by redistributing existing weight This will solve the traction problem without adding additional weight.

Suggested m aterials for wheels :Thin plywood, Balsa wood, foam core, stiff plastic sheet, Styrofoam, toy/ model wheels, tape spools, brass tubes, wood dowels, cardboard tubes, tin can, thread spool or plastic pipe.

BearingsBearings are the components in the wheel that allow the relative motion of two parts. They also support the axle with the wheels attached to it.

Lubrication : Lubrication helps parts slide against each other and it is used to reduce friction in the bearings. Good lubricants for solar car bearings include light oil, light grease or graphite powder (crushed pencil lead). Students should experiment with different lubricants to see which works best for their car.

Thrust Bearings : These bearings keep the axle from falling out the side of the car. If the edges of a wheel rub on the body of the car, it creates a lot of drag. If there is something around the axle that lets the center portion of the wheel touch first, the drag will then be reduced.

Suggested m aterials for the bearings :Screw-eyes/eye bolts, brass tubing, hard materials with a hole drilled in it, brackets with screw holes pre-drilled or holes drilled into the chassis.

Axle : The axle holds the wheels and supports the car’s frame.

Friction in Diameter of the Axle : The larger the diameter of your axle, the harder it is to turn. A larger axle takes more energy to turn than a smaller one.

Axle Bearings : Choose axle materials that create the least amount of friction. Surface finish is critical, so make sure all of the running surfaces are as smooth as possible.

Suggested m aterials for the axle : Nails, brass rods, brass tubing or coat-hanger wire.

Transmission:

The transmission connects the motor shaft to the wheel or axle. In general, a transmission is any device which transmits mechanical power from one place to another. Power is the product of force x speed (or torque x rotational speed). Transmissions are also used to change the speed and force proportions while transmitting mechanical power.

Gears: A gear is a wheel with teeth on the outer edge. When it is teamed up with other gears, it provides torque.

Pitch : Refers to the number of teeth that can be put on a 1-inch diameter gear. Gears with different pitches will not fit together well, so the same pitch must be used throughout the transmission. Gears in 48 and 64 pitch are used most often in solar cars.

M otor:

The motor uses the electrical energy provided by the solar panels to power the wheels. Pitsco motor 280 or its equivalent is recommended, and may not be altered.

Solar Panels:

Solar panels create energy that is used by the motor to move the car.Tiltable panels are useful for changing panel direction on the race day to receive the maximum amount of sunlight, but they are heavier and cause aerodynamic drag.

Positioning Solar Panels : Students will need to determine where to position the solar panels on their cars to collect the most sunlight. The top part of the car is probably the best and nothing should cast a shadow over the panel.

Panel Efficiency : Because solar panels only convert about 10% of the light that hits them, students will want to make sure the panels are as efficient as possible. Students should keep their panels clean and cool. Solar panels work best when they are not hot.Pitsco solar panel 3V 1100MA or its equivalent is recommended .

Kit Materials:

- 1 Pitsco Ray Catcher Solar Panel (2.76V, 1, 100 mA) - 1 White Sheet of Plastic Coated Paper

• 2 Balsa Sheets (10-1/2”x4”x3/16”)• 2 Alligator Clips• 2 Pitsco GTF Wheels• 2 Pitsco GTR Wheels• 1 Straw• 1 No. 280 Motor• 4 Nylon Spacers• 2 Plastic Delrin Axles• 1 Plastic Gear Font• 4 Rubber bands (2 No. 14 Rubber Bands and 2 Wide Rubber Bands)

- Junior Solar Sprint Rules and Regulations

Vehicle Specification

1. The vehicle must be safe to contestants and spectators, e.g., no sharp edges, projectiles, etc.

2. The vehicle must fit the following dimensions: 30 cm. by 60 cm. by 30 cm.3. Decals of the sponsor organizations (provided by JSS) must be visible from

the side on the body of the car. A 3 cm. by 3 cm. space must be left for the assigned car number.

4. The sun’s light is the only energy source that may be used to power the vehicle. No other batteries or energy storage devices are permitted.

5. Any energy-enhancing devices, like mirrors, must be firmly attached to the vehicle.

6. The vehicle must be steered by the guide wire using one or more eyelets affixed to the front of the vehicle. The vehicle must be easily removable from the guide wire, without disconnecting the guide wire.

7. The body of the car must be three dimensional. The solar cell cannot be used as the body of the car.

Building A Solar Car

A. Construct the Body

1. Using the utility knife, cut the foam board into three pieces — one measuring 20 cm by 7 cm, and two measuring 2 cm by 7 cm. Use the metal ruler to guide your cuts.

2. Glue the two smaller foam board pieces to the large foam board piece as shown in the illustration below.3. Using a ruler, carefully mark the positions of the screw eyes on the two smaller pieces as shown in the illustration below

3. Using a ruler, carefully mark the positions of the screw eyes on the two smaller pieces as shown in the illustration below.

4. Turn the screw eyes into the foam board pieces. Be sure the screw eyes penetrate both layers of foam board.

5. Slip an axle through the screw eyes to check their alignment. The axle should beparallal to the end of the foam board. If necessary, adjust the screw eyes.

B. Mount the Wheels

1. Slip a rubber tire onto each of the two large wheels, and two of the small wheels. The smallest wheel will be used later.

2. With scissors, cut the vinyl tubing into small sections approximately 5 mm in length. These will be used as spacers on the car’s axles.

3. Test the fit of the wheels and axles. The wheels should grip the axles firmly. If the wheels cannot be pressed onto the axles, try sanding the ends of the axles to reduce their thickness slightly, and check again for fit.

4. Assemble the rear axle as shown in the illustration. Do this by slipping the axle through the screw eyes, then adding the spacers followed by the drive pulley (the third small wheel) and wheels. You may need to sand the axle a little to allow the drive pulley to slide on.

5. Add the front axle with its wheels and spacers, as shown in the illustration.

6. At this point, check your car to see how well it rolls. Put the car on the floor and give it a gentle push. Make sure it rolls easily and in a fairly straight line. Adjust the axles slightly to get a better alignment, if necessary. If the screw eyes seem loose, carefully place a drop of hot glue where the screw eyes come through the foam board to hold them in position.

C. Mount the Motor

1. Push the small black pulley onto the shaft of the motor, as shown on the next page. Slip the motor into its clip.

2. Stretch the elastic band over the rear wheel and place it on the axle-mounted drive pulley.

3. Position the motor so that the elastic band makes good contact with both pulleys without being stretched more than 5 mm. Once you know where the motor should fit, mark that location on the foam board with a pencil. Remove the backing from the self-adhesive motor clip, and press the clip and motor onto the foam board in the position that you marked.

D. Prepare the Solar Panels

1. On the back of each solar panel you will find a metal connecting bar and two threaded metal contacts. Each contact is equipped with a small washer and a nut. The metal bar and contacts are used to connect the panels together, and to connect wires to the panels. Remove the nuts, washers and metal bars from the connectors and set these aside, being careful not to lose them.

2. Connect the two solar panels using one of the metal connecting bars, as shown below. Be sure the bar connects the positive terminal on one panel to the negative terminal on the other. Secure the connecting bar using washers and nuts, tightening them gently using the pliers.

4. Use scissors to cut the alligator clip test lead into two pieces of equal length. Strip about 1 cm of insulation from the two cut ends, and in each case twist the exposed copper wires tightly together.

5. Using the pliers, carefully bend the spare connecting bar to form an angledsupport for the solar panels, as shown below.

6. Position the second connecting bar on the threaded metal contact, as shown below. This will be used to help support the panels in a later step.

7. Loop the bared ends of each test lead over the threaded contact and screw a nut onto each. Gently tighten each nut using pliers, making sure the wire is well secured.

E. Mount the Panels

1. Use the utility knife to carefully cut a small slot in the large foam board section as shown below.

2. Use the brass paper fastener to secure the connecting bar to the foam board. Push the fastener through the hole in the bent connecting bar, and spread the tabs where they poke through the slot in the foam board.

3. Arrange the panel and its support so that it sits at an angle on the body of your solar car. Use a small piece of clear tape to fasten the lower end of the panel assembly to the foam board..

4. Use the alligator clips to connect the wires to the terminals on the electric motor. If necessary, tape loose wires to the body of the car to keep them from touching either the ground or moving parts of the car.

Test It!

Test your car by placing it in bright sunlight, or under a bright (150 watt or greater) light bulb. The wheels should begin to spin quickly. If the wheels are turning the wrong direction, switch the wires connected to the motor. This will reverse the direction of the motor. You can make small adjustments to the angle of the panels, the alignment of the wheels, and the position of the motor to reduce friction, increase the power from the panels, and improve the speed of your car.

CONCLUSION:

Future Of Transportation:

In the coming decades, transportation in the U.S. is expected to change radically in response to environmental constraints, fluctuating oil availability and economic factors.

The transportation systems that emerge in the 21st century will be defined largely by the choices, skills and imaginations of today’s youth.As scientists and engineers, they will develop new vehicle and fuel technologies. As citizens, they will make decisions balancing mobility, environmental, and economic needs.

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Wikipedia.

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Study of electronic components by J.A. Smith (2nd edition) , 1999.

"Practical Photovoltaics" by Richard Komp PhD,

Battery Science: Make Widgets That Work. by Doug Stillinger

Electronic circuit analysis and design by Donald A. Neumann, Mc Grawhill Book Company, USA 1996.

Amplifiers comparators and special functions, Texas instrument, Data book volume B, Custom Printing Company’s,1997.