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 things 1.How high the water falls 2.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: Chassis Wheels & Bearings Power Source Transmission Body/Shell