Page 58 - Solar Power in Building Design The Engineer's Complete Design Resource

28 SOLAR POWER TECHNOLOGIES

Figure 2.7 Flat-plate PV solar ray impact.

■ Higher efficiency. Concentrating PV cells achieve higher efficiencies than do non-
concentrating PV cells. Flat-plate silicon cells have efficiencies in the range of 8 to
15 percent, while the Amonix concentrating silicon cell has an efficiency of 26 percent.
Concentrating multijunction cells presently under development are expected to achieve
an efficiency greater than 34 percent.
■ More annual energy. Further increased annual energy production is achieved by the
incorporation of a two-axis sun-tracking system. All high-concentration system
technologies require a sun-tracking control system. A computerized tracking sys-
tem periodically adjusts the MegaConcentrator platform to optimize the insolation
angle that results in additional annual energy generation production. The average
annual energy for 19 different fixed flat-plate installations under test conditions in
Phoenix, Arizona, ranged from 1000 to 1500 kWh per rated kilowatt. The same
equivalent power-rated Mega Concentrator manufactured by Amonix generated in
excess of 1900 to 2000 kWh per rated kilowatt.

Amonix Megaconcentrators

SYSTEM DESCRIPTION
The solar PV concentrator technology described here is a proprietary patented prod-
uct of Amonix Corporation located in Torrance, California. Essentially the solar power
system referred to as a Mega Concentrator consists of six specific components that
have resulted in a reduction in product cost:

1 MegaModule subsystem. Concentrates the sun’s energy on a solar cell that converts
it into electric energy. It consists of Fresnel lenses, solar cells, and the support struc-
ture. Each system consists of five to seven MegaModules.
2 Drive subsystem. Rotates the MegaModules in azimuth and elevation to track the
sun. The drive system consists of a foundation, pedestal, rotating bearing head,
hydraulic actuators, and torque tube.