Solar Energy

What is Solar Energy?

-Concepts behind solar energy

- How solar energy is used in solar cars

What is It? (solar energy)

Renewable energy source that converts heat & light into energy

More common than we realize

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 sun’s heat to do work)

Sun is responsible for making other forms of renewable energy (biomass, wind, fossil fuels)

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

The Basics

The photovoltaic cell• Building block of

solar-electric system

Let’s look at what’s happening

Sun’s rays knock electrons off of Atoms

Electrons are pulled from bottom material to top material

Electrons flow through the motor producing power

Looks a little like this…

Let’s build one…shall we?

5 components of Solar Race Car;

• Chassis• Wheels & Bearings• Power Source• Transmission• Body/Shell

1. Chassis…

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

together

Some Possible Chassis…

Designing & building will involve trade-offs

There is no one ideal design

What to consider?

Is your car to heavy?

In solar cars, efficiency is very important

Don’t want to waste energy

Materials

For solar cars, stiffness is very important

E.g.. Stiff, light materials include styrofoam, balsa wood and cardboard

Shape

Paper is not stiff

Redesigning it’s shape, you can make paper stiffer

Orientation

Take an ordinary wood/plastic ruler

• Try to bend it in both directions

Stiffen you chassis by adding strips?

2. Wheels & Bearings

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

Wheels can be large, small, narrow or wide…

What to consider?

Weight Distribution and Traction

Bearings

Components that allow relative motion between the axel and the chassis

Holds axel and wheels to the chassis but reduces their friction

3. The Power Source

How the solar panel and motor work- solar power

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

Let’s look at a mechanical example

Water wheel:– Power coming out

depends on 2 things1. How high the water

falls2. How much water

(how many buckets) is poured over the wheel

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

Maximizing Power…

Which car will have more power?

Tilt the panel towards the sun? Add reflectors?

4. Transmission

How to transfer power from the motor to the wheels

There are different ways to transfer power to the wheels

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

5. Body/Shell

How the Shell effects car performance?

& - protects passengers - safety in case of crash - looks

Some ideas for the Shell…

Main concept….. Aerodynamics

How much force does air have?

How about when bicycling?

Think about these for your own design…

Fast cars shaped to move easily through the air

Tractor-trailer trucks with big air deflectors

Your Task…

Design & Construct a solar vehicle

Remember to give careful consideration to your choice of:

ChassisWheels & BearingsPower SourceTransmissionBody/Shell