Light (particularly sunlight) can be used to create heat or generate
electrical power. This is referred to as solar energy.
It is a clean form of energy production, which doesn't pollute the
environment as some other forms of energy production do.
There are two forms of solar energy. The first is solar thermal
conversion, which uses sunlight to create heat and then electrical
power. The second is photovoltaic conversion, which uses sheets of
special materials to create electricity from the sun. "Photo-" means
"light," and "voltaic" means "producing electricity."
Solar Thermal Conversion
Solar thermal conversion systems use reflectors or mirrors to
concentrate sunlight to extremely intense levels of heat. (Solar means
"of the sun," thermal means "of heat" and conversion means "changing
something from one form to another.")
You can understand this better if you consider the example of using a
magnifying glass to start a fire. You may have heard of this or even
tried it before. You can hold a magnifying glass under the sun, and
concentrate the light on a small pile of flammable materials. The
magnifying glass will make the sun's heat much stronger, and will light
the materials on fire. It has been said that a magnifying glass one
meter in diameter, held under the sun, will create a ray hot enough to
melt stone.
If you would hold a magnifying glass flat under the sun and put your
hand under it, you would need to move your hand away very quickly in
order to avoid burning yourself.
Solar thermal conversion systems use mirrors or reflectors to
concentrate sunlight onto containers full of liquid. Sometimes water is
used. Sometimes other liquids are used, which retain heat better than
water.
The liquids are heated up to high temperatures, and this produces
steam. The steam is used to turn a turbine. The turning motion of the
turbine is used to create electricity.
How does a rotating motion create electricity? When you set up a coiled
wire or similar device to rotate between two magnets, it generates an
electric current. This is how electric generators work, as well as
windmills, nuclear power plants, and other energy plants which use such
things as coal, gas, or petroleum.
Windmills use the wind to create the turning motion. Nuclear power or
fossil fuels are used to heat water up, thus creating steam to turn the
turbines.
Solar heating is another form of solar thermal conversion. In solar
heating, an absorber is used to take in sunlight and convert it to
heat. The absorber could be something simple, like black paint, or it
could be a special ceramic material. A heat absorber is considered to a
be good one when it collects at least 95 percent of the sun's radiation.
The absorbers are then used to heat a fluid, which is then circulated
to warm up buildings or to create hot-water supplies.
Photovoltaic Conversion
As covered above, photo means "light." It comes from the Greek word
"phos," which means "light."
"Voltaic" means, "producing electric current." The word comes from the
name of Alessandro Volta, an Italian physicist who was a pioneer in the
field of electricity during the 1700's. (His name is also where the
word "volt" comes from.)
Photovoltaic means, "creating electrical energy when exposed to light."
A "cell" is a device that produces electricity. An example of an
electrical cell is a flashlight battery.
Photovoltaic cells produce electricity when they are exposed to light.
They usually consist of panels. The panels contain two layers of
different materials.
When light hits these two layers, one of the layers becomes positively
charged, and the other becomes negatively charged.
This works similarly to a regular flashlight battery, which has a
positive end and a negative end. When a wire connects the two ends,
they produce an electric current.
When the two layers of material in a solar cell are exposed to light,
they create an electric current.
The AMOUNT of electricity generated by a solar power cell depends on
several factors. Mainly:
-How big is the solar power device, and how much surface is exposed to
the sun? -How strong is the sun? (This depends on time of day, weather,
latitude, etc.) -How long is the solar power device exposed? -How much
impediment is there to the light? (Clouds, mist, dust, dirt, etc.)
In other words, a solar power cell generates electricity faster when
the sun (or light) is brighter. A device with larger solar panels will
produce more electricity than one with smaller panels. Exposing the
cell for a longer period of time will create more electricity than
exposing it for a shorter period of time. A panel near the equator will
be more effective than one in an arctic region. A solar panel in misty
or dusty conditions does not create as much electricity as it would in
full, unobstructed sun.
Some solar cells produce only enough current to power small electronic
devices, but can be "daisy-chained" (connected together) in order to
create more electricity for other items.
Solar cells which produce enough electricity to run larger equipment
(such as laptops) may be larger, more expensive, or heavier than the
others.
But there are many varieties available. Individuals and companies are
consistently striving to create lighter and more efficient portable
solar cells.
Solar Energy and the Future
An advantage to solar power is that it can reduce expenses. It can also
be portable. When one is backpacking in the wilderness or traveling far
from power grids, solar power can provide a means of powering
electronic equipment.
Another advantage is, of course, the lack of pollution created by solar
energy production. In fact, if all of our electrical energy were
produced by such means, we might not be worrying about global warming
and the other destructive effects of pollution on our environment.
These threats to our environment also pose a threat to mankind. Solar
power could be developed to a point where it, along with other forms of
renewable energy, would replace harmful means of electricity production.
It isn't necessarily impossible to have a clean and safe Earth. We just
have to work on it.
Article Source: http://www.solarpanelarticles.com
About the Author: Anna Stone is an educator and is also a photography student, with an interest in finding ways to use solar power to help photographers and backpackers run their equipment when they are far from city power grids. She is the webmaster of the website www.findportablesolarpower.com Article Source: www.goarticles.com
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