Unformatted text preview: logies. A Stirling engine/parabolic dish system
holds the world’s record for converting sunlight into
electricity. In 1984, a 29% net efficiency was
measured at Rancho Mirage, California .
measured 3.3. Power tower system
A heliostat uses a field of dual axis sun trackers that
direct solar energy to a large absorber located on a
tower. To date the only application for the heliostat
collector is power generation in a system called the
power tower .
The Power tower system is
shown in the figure 3.3.1 below.
shown Figure 3.3.1 Power tower system . Heliostats are shown in
the figure 3.3.2 below.
the Figure 3.3.2 Heliostats . A power tower has a field of large mirrors that follow the
sun's path across the sky. The mirrors concentrate
sunlight onto a receiver on top of a high tower. A
computer keeps the mirrors aligned so the reflected
rays of the sun are always aimed at the receiver, where
temperatures well above 1000°C can be reached. Hightemperatures
reached. Highpressure steam is generated to produce electricity .
The power tower system with heliostats is shown in the
figure 3.3.3 below.
figure Figure 3.3.3 Power tower system with heliostats . 3.4. Stationary concentrating
Stationary concentrating collectors use compound
parabolic reflectors and flat reflectors for directing solar
energy to an accompanying absorber or aperture through
a wide acceptance angle. The wide acceptance angle for
these reflectors eliminates the need for a sun tracker.
This class of collector includes parabolic trough flat plate
collectors, flat plate collectors with parabolic boosting
reflectors, and solar cooker. Development of the first two
collectors has been done in Sweden. Solar cookers are
used throughout the world, especially in the developing
countries 4. Working principles of
concentrating Unlike solar (photovoltaic) cells, which use light to produce
electricity, concentrating solar power systems generate
electricity with he...
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- Spring '14
- ........., Concentrating solar power, power tower