Solar energy

by

Siva shankar P G

WHAT IS SOLAR ENERGY?

Solar energy is the ultimate source of

energy from millions of years and it is

a renewable energy.

This energy consists of radiant light

and heat energy from the sun.

Out of all energy emitted by sun only a

small fraction of energy is absorbed

by the Earth.rgy

How is Solar energy is used?

We can use solar energy by converting

it to electrical energy . So we must use

a device called solar panels which can

convert the light energy into electrical

energy.

Solar panel is a group of solar cells.

Solar cells works on the principle of

photoelectric effect.

Photoelectric effect

When a light of certain

frequency falls on the

surface of a metal ,

electrons will absorb the

energy . If incident light

energy is greater than the

work function of the metal

,then the photo electrons

will be emitted and the

excess energy is converted

to the kinetic energy of

electron

photovoltaics

generating electrical power by converting

solar radiation into dc electricity using

semiconductors that exhibit the photovoltaic

effect

The photovoltaic effect is the creation

of voltage or electric current in a material

upon exposure to light

first observed by Alexandre-Edmond

Becquerel in 1839

the photovoltaic cell also called solar cell, is an electrical device that

converts the energy of light directly into electricity by

the photovoltaic effect

made of monocrystalline silicon or polycrystalline

silicon or amorphous silicon or cadmium telluride,

or copper indium selenide/sulfide

first built by Charles Fritts in1883 by coating

the semiconductor selenium with an extremely thin

layer of gold

the photovoltaic cell

the photovoltaic cell cont.

photons in sunlight hit the solar panel and are

absorbed by semiconducting materials, such

as silicon

electrons are knocked loose from their atoms,

and current starts flowing through the

material and this electricity is captured

an array of solar cells converts solar energy

into a usable amount of direct current [DC]

electricity

“nellis solar power plant” contains 70,000 solar panels

that will generate 25 million kilowatt-hours

“solar one”, california 1,800 sun-tracking mirrors reflect

heat to a central collector

a solar farm in the philippines…

pisay

advantages

solar energy is a renewable source of energy

in the presence of solar power, use of non-

renewable sources of energy like petroleum

can be lessened which also lessens pollution

unlike others, solar energy can be harnessed

and used in remote locations like mountains

even though solar panels are expensive, the

total amount that would be saved makes the

price of the panels will seem small

disadvantages solar panels are expensive

solar power is inefficient in cloudy areas

batteries and solar panels occupy morespace

solar power maintenance is a problemespecially to those who doesn’t know theproper technician

disposal is difficult for the batteries and solarpanels when they have broken downbecause they contain toxic chemicals likelead, sulfuric acid & cadmium telluride

sources

http://www.solarenergy-solarpower.com

http://www.wikipedia.org [wikipedia]

http://www.google.com [google images]

the world of science, vol 10, technology of change