Page 60 - Solar Power in Building Design The Engineer's Complete Design Resource

30 SOLAR POWER TECHNOLOGIES

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
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5 kW of dc power at 850 W/m direct normal insolation and 20 degrees Celsius (°C)
ambient temperature (IEEE standard). One to seven MegaModules are mounted on
a sun-tracking structure to obtain a 5 kW of dc power.

SYSTEM OPERATION

The Mega Concentrator solar power systems are designed for unattended operation for
either grid-connected or off-grid applications. As described previously, the system
moves automatically from a night stow position to tracking the sun in the early morn-
ing. The system tracks the sun throughout the day, typically generating electric power
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whenever the direct normal irradiance (DNI) is above 400 W/m , until the sun sets in
the evening. The controller monitors the sun position with respect to the centerline of
the unit and adjusts the tracking position if required to maintain the required pointing
accuracy. If clouds occur during the day, sun-position mathematical algorithms are
used to keep the unit pointing at the expected sun position until the clouds dissipate.
Figure 2.9 depicts Amonix MegaConcentrator module assembly and Figure 2.10 is a
photograph of the two axis hydraulic tracking system.
A central unattended remote monitoring system provides diagnostic information that
can be retrieved from a central or distant location. In addition to providing system oper-
ational diagnostics, the monitoring system also provides solar power output information
such as currents, voltages, and power data that are stored in the central supervisory sys-
tem memory. The cumulated data are then used to verify if there are any performance

Figure 2.9 MegaConcentrator module assembly. Photo courtesy of Amonix.