Page 84 - Alternative Energy Systems in Building Design

60 SOLAR POWER SYSTEM PHYSICS AND TECHNOLOGIES

Figure 3.23 A MARTIFER two-axis sun tracker. Photo courtesy of MARTIFER.

sun’s rays to a central focal point. A solar cell is mounted at this focal point and con-
verts the sun power into electric power. A number of Fresnel lenses are manufactured
as a single piece or parquet (Fig. 3.24).
The solar cells are mounted on a plate at locations corresponding to the focus of
each Fresnel lens. A steel C-channel structure maintains the aligned positions of the
lenses and cell plates. The lenses, cell plates, and steel structure are collectively
referred to as an Amonix MegaModule. Each MegaModule is designed to produce
2
5 kW of dc power at 850 W/m direct normal insolation and 20°C ambient temperature
(IEEE standard). One to seven MegaModules are mounted on a sun-tracking structure
to obtain 5 kW of dc power.
Recently Amonix announced the release of the series 7700 MegaConcentrator dual
tracking system shown in Fig. 3.21. The company’s seventh-generation field-proven
solar power generator is capable of converting one-fourth of the sun’s energy into usable
power. At 53 kW, representing a 50 percent increase over the previous system, the 7700
MegaConcentrator is designed to be the world’s most powerful and cost-effective PV
system.
The 7700 is made up of seven of Amonix’s proprietary MegaModules and uses mul-
tijunction solar cells. When mounted on the dual-axis tracker, it delivers an ac effi-
ciency approaching 25 percent, resulting in 122,000 kWh of electricity generated
annually. At present, the Amonix 7700 MegaConcentrator is the most efficient PV system
in the world.