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The Solar Energy is not something new; it was
used for many centuries ago. But it was replaced for crude oil in the
Industrial Revolution.
Currently due to high crude oil costs and its
major environmental impact, has decided to return to the use of solar
energy.
If crude oil did not exist, now we would have more technology about
renewable
energy.
There
are
a lot of kinds of Solar Energy; probably the most popular is the
photovoltaic energy
which is a way to obtain electrical energy by photovoltaic panels. But
there
are another ways to obtain electrical energy by solar light and
probably with
better results.
One example is the Solar Thermal energy, which
transforms the Solar
Energy into Electric Energy. The Solar Thermal Power Plants work by a
thermodynamic cycle, which consists of a set of mirrors (heliostats);
located
on land and properly oriented to reflect sunlight that strikes them,
all this
radiation is delivered to a receiver so all the energy is transported
at the same
time.
History of Photovoltaic Solar Energy.
In 1893, Edmond Becquerel (French physicist)
discovered the photovoltaic
effect, noted that some materials transforms the light into electric
current.
In 1887, through several
experiments, Heinrich Hertz was able to produce
photovoltaic cells which process light into electricity.
Albert Einstein could not miss in the history
of Solar Energy; in 1905
he talked about the photo electric effect, associated with the
generation of
electricity in solar cells.
The Czochralski process (method to obtain
crystals of high purity
silicon) increased the PV Market. In 1954 scientist at Bell
Laboratories
produced the first silicon solar cell capable of creating a controlled
electric
current. During the Cold War took place solar cells on airplanes and
satellites.
In 2002, Japan installed 25, 000 solar panels
on the roofs of houses
across all the country.
In 2003, investments in solar energy a wind
energy exceeded 20 000
million per year.
In 2006, in the world are more than 25 0000
megawatts in photovoltaic
energy.
History of Solar
Thermal Energy
In China and in the ancient Greece, people used
the sunlight with
mirrors or glass for making fires. During war time, the same technique
was used
to set fire to enemy ships. In the early twentieth century had already
been
invented simple machines that could run from the concentration of heat
from the
sun.
In 1931, Frank Shuman (American) developed the
first solar thermal pumping
station in Meadi, Egypt. This system worked with 5 large reflectors,
each one
had 62 meters long and contained glass mirrors forming a cylinder like
parable.
The modern history of Solar Thermal Energy
began in the crude oil crisis
of the 70s. Jimmy Carter, then president of the U.S., boosted the
concentrated
solar power plants, SEGS and decided to install solar thermal
collectors on the
roof to heat water from the White House.
In 1984, California built the first plant-1
SESGS (Solar Energy
Generating System). These kinds of plants operate with a parabolic
trough
collector system. The SEGS consist of a solar field with parallel
rows of parabolic trough
collectors connected in series to convert solar energy into heat,
warming the
oil passing through the absorber tubes of solar collectors. The hot oil
is sent
to a heat exchanger where it generates superheated steam required to
drive a
turbo-alternator, and that is how it produces electricity.
SEGS
plants began with a power of 14MW and ended
with an output of 80MW, with a total installed capacity of 354 MW.
These plants
continue to operate successfully until 2003.
The
record with this type of plants inspired Spain
to continue with its investigations, opening in 2009 the thermal plant
in
Aldeire Andasol-1, Granada.
The project aims Andasol-1
is to convert solar energy into electrical energy through a solar field
of
parabolic trough collectors, a thermal storage system capacity of 6
hours plus
25% confidence based on molten salts and a steam cycle 49, 9
MV-building.
Andasol-1 process: when the
sun shines field collectors concentrate solar radiation on the absorber
tubes
and heat the fluid to a temperature of 393 °. In the fluid are
inorganic salts
such as sodium nitrate and potassium nitrate, when they reach the
higher
temperature fluid is transported to a hot tank. At night, the hot tank
to tank
transfers the cold fluid, hence the hot salt transfer energy to the
fluid and
generate steam
Andasol-1 achieved an
efficiency of 16% average annual conversion of solar radiation into
electrical
energy.
We should
also highlight the PS10 and PS20 solar
power plants created by the Abengoa Solar Company.
The
PS10 is the first solar tower plant that
produces electricity in a stable way and commercial. It consists of 624
heliostats to focus solar radiation incident on the receptor that is
found on
top of a tower 115 meters high.
The
receiver is responsible for generating
saturated steam directly, consists of 4 vertical panels 5.5 m wide and
12 m in
height. PS10 contains 30 minutes of storage even at low irradiation.
The solar
plant is capable of supplying 5500 homes and save 6700t of CO2 per year.
The PS20
is the second plant in the world with
this technological system. It consists of 1 255 heliostats to reflect
solar
radiation received on the receiver on the tower of 165 meters of height
which
produces steam to generate electricity in the turbine. The plant can
power 10
000 homes and save 12 000t of CO2 per year.
Currently the
researches about solar thermal energy are growing, maye a Solar Thermal
Plant construction costs more than a typical thermal plant, but
eventually they be the only alternative because we are killing our
planet and we must act fast to reverse.
UPCOMING COURSES ON RENOVETEC solar
thermal power plants:
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A
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