Page 56 - Solar Power in Building Design The Engineer's Complete Design Resource

26 SOLAR POWER TECHNOLOGIES

Figure 2.4 Silicon ingot production chamber.
Photo courtesy of SolarWorld.

WHY CONCENTRATION?
Before photovoltaic systems can provide a substantial part of the world’s need for
electric energy, there needs to be a large reduction in the cost. Studies conducted by
the Department of Energy (DOE), Electrical Power Research Institute (EPRI), and
others show that concentrating solar energy systems can eventually achieve lower
costs than conventional PV power systems. The lower cost results from:

■ Less expensive material. Because the semiconductor material for solar cells is
a major cost element of all photovoltaic systems, one approach to cost reduction is
to reduce the required cell area by concentrating a relatively large area of solar inso-
lation onto a relatively small solar cell. The solar power concentrator technology
developed by Amonix deploys low-cost Fresnel lenses to focus the sun power onto
the cells, which reduces the required cell area and material by nearly 250 times.
A 6-in wafer used in a flat-plate PV system will produce about 2.5 W, but will pro-
duce 1000 W in the Amonix system as illustrated in Figure 2.7.