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Unformatted text preview: at. Concentrating solar collectors use
mirrors and lenses to concentrate and focus sunlight onto
a thermal receiver, similar to a boiler tube. The receiver
absorbs and converts sunlight into heat. The heat is then
transported to a steam generator or engine where it is
converted into electricity. There are three main types of
concentrating solar power systems: parabolic troughs,
dish/engine systems, and central receiver systems.
These technologies can be used to generate electricity for
a variety of applications, ranging from remote power
systems as small as a few kilowatts (kW) up to grid
connected applications of 200-350 megawatts (MW) or
more. A concentrating solar power system that produces
350 MW of electricity displaces the energy equivalent of
2.3 million barrels of oil .
2.3 4.1. Trough Systems
These solar collectors use mirrored parabolic troughs to
focus the sun's energy to a fluid-carrying receiver tube
located at the focal point of a parabolically curved trough
reflector .It is shown in the figure 4.1.1 below.
reflector Figure 4.1.1 Parabolic trough with mirrored parabolic troughs . The energy from the sun sent to the tube heats oil
flowing through the tube, and the heat energy is then
used to generate electricity in a conventional steam
generator. Many troughs placed in parallel rows are
called a "collector field." The troughs in the field are all
aligned along a northsouth axis so they can track the
sun from east to west during the day, ensuring that
the sun is continuously focused on the receiver pipes.
Individual trough systems currently can generate
about 80 MW of electricity.
about Trough designs can incorporate thermal storageTrough
setting aside the heat transfer fluid in its hot phase
allowing for electricity generation several hours into
the evening. Currently, all parabolic trough plants are
"hybrids," meaning they use fossil fuels to
supplement the solar output during periods of l...
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- Spring '14