Solar Energy

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Solar Energy
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What is Solar Energy?

• Concepts behind solar energy
• How solar energy is used in solar cars

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What is It? (solar energy)

• Renewable energy source that converts heat
  light into energy
• More common than we realize

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Just how common is it?

• The food we eat to give us energy comes from
  plants that use sunlight (photosynthesis)
• We hang laundry out to dry in the sun (using
  suns heat to do work)
• Sun is responsible for making other forms of
  renewable energy (biomass, wind, fossil fuels)

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How is Solar Energy used to run a Solar Race Car?
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The Basics

• The photovoltaic cell
• Building block of solar-electric system

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Lets look at whats happening

• Suns rays knock electrons off of Atoms
• Electrons are pulled from bottom material to top
  material
• Electrons flow through the motor producing power

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Looks a little like this
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Lets build oneshall we?

• 5 components of Solar Race Car
• Chassis
• Wheels Bearings
• Power Source
• Transmission
• Body/Shell

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1. Chassis

• How to build the frame of the car?
• -Holds all of the main parts together

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Some Possible Chassis

• Designing building will involve trade-offs
• There is no one ideal design

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What to consider?

• Is your car to heavy?
• In solar cars, efficiency is very important
• Dont want to waste energy

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Materials

• For solar cars, stiffness is very important
• E.g.. Stiff, light materials include styrofoam,
  balsa wood and cardboard

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Shape

• Paper is not stiff
• Redesigning its shape, you can make paper stiffer

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Orientation

• Take an ordinary wood/plastic ruler
• Try to bend it in both directions
• Stiffen you chassis by adding strips?

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2. Wheels Bearings

• How to make wheels that turn
• - support the chassis and allow the car to
  roll forward

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Wheels can be large, small, narrow or wide
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What to consider?

• Weight Distribution and Traction

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Bearings

• Components that allow relative motion between the
  axel and the chassis
• Holds axel and wheels to the chassis but reduces
  their friction

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3. The Power Source

• How the solar panel and motor work
• - solar power

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How does a solar panel create power?

• The solar panel captures energy from the sun and
  turns this energy into electrical energy
• Electric motor uses this energy to power the
  wheels of the car

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Lets look at a mechanical example

• Water wheel
• Power coming out depends on 2 things
• How high the water falls
• How much water (how many buckets) is poured over
  the wheel

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Back to the solar thing

• Solar panel
• Very similar to water wheel concept
• Instead of height we have voltage
• Instead of buckets of water we have an electric
  current
• Power voltage x current

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Maximizing Power

• Which car will have more power?
• Tilt the panel towards the sun? Add reflectors?

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4. Transmission

• How to transfer power from the motor to the
  wheels

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There are different ways to transfer power to the
wheels
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Selecting the proper gear ratio

• Each rotation of the front sprocket will make the
  back wheel rotate
• Once in combo 1
• Twice in combo 2
• 4 times in combo 3

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5. Body/Shell

• How the Shell effects car performance?
• - protects passengers
• - safety in case of crash
• - looks

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Some ideas for the Shell
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Main concept.. Aerodynamics

• How much force does air have?

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How about when bicycling?
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Think about these for your own design
Fast cars shaped to move easily through the air
Tractor-trailer trucks with big air deflectors
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Your Task

• Design Construct a solar vehicle
• Remember to give careful consideration to your
  choice of
• Chassis
• Wheels Bearings
• Power Source
• Transmission
• Body/Shell