(1) astronomical positioning and
(2) a solar sensor that seeks to position the trackers precisely perpendicular to the sun to ensure optimum system performance.
The entire trackers module assembly dimensions are approximately 48 feet across by 25 feet tall. Each tracker would be mounted on a 28-inch steel mast (steel pole), which, depending on wind loading and soil conditions at the site, would be installed by: (1) inserting the mast into a hole up to 20 feet deep and encasing it in concrete, (2) vibrating the mast into the ground up to 20 feet deep, or (3) attaching the mast to a concrete foundation sized to adequately support the trackers.
The ultimate height of each tracker in its most vertical position depends on how it is installed because installing the mast into a concrete foundation may increase the tracker height. In its most vertical position and assuming the use of a concrete foundation, however, the top of each tracker would not exceed 30 feet above grade, and the lower edge would not be less than 1 foot above ground level. In its horizontal “stow” mode (for high winds), each tracker would have a minimum ground clearance of 13 feet, 6 inches.
Soitec’s Concentrix modules, which are manufactured in San Diego County (Rancho Bernardo), are made up of a lens plate (Fresnel lens) and a base plate on which high-performance solar cells are mounted. The Fresnel lens focuses sunlight concentrated by a factor of 500 on the solar cells beneath.
The solar cells are optimized multi-junction solar cells (GAInP/GaInAs/Ge) in which three different types of solar cells are stacked on top of one another. Each cell is designed to convert a certain range of the solar spectrum: short-wave radiation, medium-wave radiation, and infrared. For almost 20 years, multi-junction solar cells have been used in space applications.
The solar modules are lightweight and surrounded by airflow both inside and outside the module. As a result, heat dissipates quickly from a solar panel. The normal operating temperature for solar modules is 20 degrees Celsius (°C) above ambient temperature; therefore, on a typical summer day at 40°C (104°F), the panel temperature would be approximately 60°C (172°F). When accounting for irradiance (a measure of solar radiation energy received on a given surface area in a given time), wind, and module type, it is expected that the peak module temperatures in the summer would be between 65°C and 70°C (149°F and 158°F), and the peak module temperatures in the winter would be between 35°C and 40°C (95°F and 104°F).
Although the CPV panels would be hot to the touch as a result of solar energy absorption, CPV panels are designed to absorb light energy inwards towards the panel to produce electricity. As opposed to mirrors which redirect the sun, CPV modules use Fresnel lenses to concentrate sunlight inside the module to produce electricity, and therefore, they would not noticeably affect the temperature of the surrounding area; temperatures below the modules would be nearly the same as ambient temperatures in ordinary shade.
