Alternate EnergyUsing Solar Power

Solar Energy

Solar energy: is energy that is created through the use of the sun. Solar energy can be used for heating and electrical production

Using Solar Energy

Just how much Energy do we get from the sun?

About 1300 Watts/Meter2

Like 13, 100 watt light bulbs, for every square meter!

Or about 1.8 hp for every meter2 of the earth

OR

Enough to power a hair dryer- for every meter2 of the earth

OR

So How Do We Use All This Energy?

In what ways, can we make use of solar power?

Heat water- like the roof of a house Heat air-like a trombe wall( big and dark, “mass”)

Generation stations boil water (think lots of mirrors focused on a single point)

Photovoltaic cells(make electricity)

Active Solar Energy Active Solar heating systems use fans or

pumps to move the heated air or heat absorbing fluid

Collector to absorb and collect solar radiation.Energy storage system (like a water tank).

Solar Energy Generating Systems (SEGS)Solar Hot Water

Passive Solar

Passive solar is the use of the sun’s energy for the heating of living spaces. Mechanical equipment is not used to move the heated air or liquid

Passive space heating is what happens to a car on a hot summer day.

South Facing Home Solar Oven

Passive Solar Energy

Anasazi Indians used passive heating for hundreds of years

Convection

Convection: is where less dense warm air rises while more dense cooler air moves downward. Example: Hot Air Balloon

Photovoltaic cells(PV) change sunlight into Direct Current(DC) electricity.

Direct Current: Is Electricity that travels in only one direction when connected to a circuit.

Photovoltaic Cells-Where can they be

used

Load

Basic Theory of Operation

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N-type

P-type

Path for E-

Returning E-

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Photon of light

Photovo-what?

Photo·volt·aic cell Photo- meaning light Voltaic- volt, a unit of electricity Cell- a single unit used to create electricity

Semi·Conductor:

Semiconductor materials can both resist or allow the movement of electrons depending on the circumstances.(light/dark)

Typically we use Silicon as our primary semiconductor material

Where can silicon be found?

Solar Vehicles

Any Vehicle that uses solar power as its energy source.

Solar Cars

Electricity from the solar cells is directed to the cars batteries or to the electric motor

Electric motor then drives the cars wheels

Only about 24% of the sun’s energy can be used by the PV cells

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Electric MotorsA machine that changes electrical energy into mechanical energy.

Vehicle Body Design

• Solar cars are emission free, and do not continually deplete the Earth's natural resources

• Sunlight is free

• The energy supply is locally produced

Advantages of Solar Energy

Disadvantages Solar cars are very expensive

Only 14 - 24% of the Sun’s solar energy is able to be utilized by the PV cells so they must be very large to generate enough energy

Solar cars must be very light and aerodynamic Designs still need to overcome power to weight

problems

History of Photovotaic cells

Charles Fritts- First Solar Cell 1883,made of Selenium (semiconductor) and a

thin layer of gold,<1% efficient

Russell Ohl- Silicon solar cell 1941,similar to modern construction,~6% efficient

Today- 24% efficiency

Solar Energy Weather Issues:

Northeast - only 4 of 10 are sunny :( Southwest- 8.5 of 10 days are sunny :) Snow? Rain? Clouds? Seasons?

Installing a Solar Collector:

1. Face the collector south (in northern hemisphere-sun

rises in east-travels across southern sky-and sets in west)

2. The sun light rays must hit collector at right angles. Why?

3. Look up your Latitude- 430 Niskayuna 4. Calculate the optimal angle-

Latitude +10 = winter angle (12/22)Latitude -10 = summer angle(6/21)Latitude =/- 0 =sping/fall (3/21,9/22)

5. Time of day factor- am sun is low (east )noon-mid sky (south)pm- sun is low (west)

Basic Electric Terms Current: Flow of electricity- specifically the flow of electrons, a sub-atomic

particle

Polarity: The electrical charge coming from the terminal on a power supply

or the charge applied to the terminal of a component.

Conductor: When a material is able to pass electrical current

 Insulator: When a material is unable to pass electrical current

Semi-Conductor: A class of materials that can either act like a conductor

or an insulator, depending on conditions