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By: mat
Solar Energy The Word solar comes from the Latin word solaris, which means
sun. Solar Energy is the act of catching light from the sun and converting it
in to energy. This is not new many ancient people used solar energy. The
Egyptians, the Greeks, the Romans and American Indians used the sun to warm
their homes. There are two types of solar energy, passive and active. If no
mechanical devices are used in a solar energy system it is called passive
solar energy. This is an appealing energy alternative because it is pollution
free. It requires little maintenance, and needs no energy source other than
sunlight. There are two categories of passive systems. One is direct solar
gain, which allows plenty of direct sunshine. The windows, walls, and floor
all serve as healing traps and storage centers. A second type of passive solar
energy is indirect solar gain. Sunlight first strikes a thermal mass than
transfers its heat to energy If mechanical devices are used it is active solar
energy. These devices help collect, store, and distribute energy. The basic
components include solar collectors, a heat exchange tank, pumps, fans,
valves, controls devices, and a system to transport the energy. Active solar
has a higher cost than passive systems. The key point of an active system is
the collector. The process of making electricity from the suns energy is done
by photovoltaic cells also called solar cells. Solar cells are made of brass,
mica, silicon, an iron plate, and a light sensitive film. The cells are
usually square in shape, and many cells are combined to form a panel. On a
Sunny day these panels of cells can produce about 100 watts of electricity per
square yard. A solar panel works by having light pass through, which causes
electrons to leave the selenium and enter the center of the film. Therefore,
the film has an abundance of electrons compared to the iron plate. When the
iron plate and film are connected electric current is generated. Which can be
used or stored for latter use, the stored energy is stored chemically. Solar
panel can be made to produce different voltages for different uses. The first
modem solar cells were developed in the 1880's. There is ever increasing
interest in solar energy. Most of the energy we now use comes from the three
types of fossil fuels found on Earth oil, coal, and natural gas. Supplies of
fossil fuels that took millions of years to build up are being used at the
rate of over a half million tons an hour. At this rate all the supplies of
fossil fluels will be gone by the year 2040. These organic fuels also cause
serious damage to the environment when the are consumed. The cost of using
these fluels is increasing all the time. The sun's energy is plentiful,
renewable and free. Devices for collecting the suns energy uses no fluel,
causes no environmental damage, and are easy to maintain. Bibliography Solar
Energy At Work David Petersen Children's Press 1985 Solar Energy John Hoke
Impact Books 1978 Solar Energy Graham Rickard G. Stevens Children's Books
Solar Energy Bradley M. Franklyn Thomas Y. Crowell Company The Energy Crisis
Bruno Leone &Judy Smith Greehaven 1981 Harnessing The Sun David C. Knight
Morrow Eagle Publications, Inc 1976 Exploring Solar Energy Allan Kaufman
Prakken Publications, Inc 1989 Solar Power Robin Mckie Gloucester Press
1985 The World Book Encyclopedia 1992 Volume 6 Various Web Sites
_Bibliography _
Solar Energy Graham Rickard G. Stevens Children's Books Solar Energy Bradley
M. Franklyn Thomas Y. Crowell Company The Energy Crisis Bruno Leone &Judy
Smith Greehaven 1981 Harnessing The Sun David C. Knight Morrow Eagle
Publications, Inc 1976 Exploring Solar Energy Allan Kaufman Prakken
Publications, Inc 1989 Solar Power Robin Mckie Gloucester Press 1985
The World Book Encyclopedia 1992 Volume 6
Word Count: 578
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