ENTECH's SOLAR ENERGY TECHNOLOGY –

ENTECH's patented terrestrial products offer unique benefits:

• Modularity: outputs from 1 kilowatt to multi-megawatts
• Economy: highly competitive pricing
• Technology Transfer: available outside the U.S. for certain applications
• Flexibility: produce electricity, hot water, or both
• Heritage: PV industry leader in system performance since 1980. For example, compare the long-term independent performance data from the PhotoVoltaics for Utility Scale Applications (PVUSA) program, sponsored by the U.S. Department of Energy, National Renewable Energy Lab, Sandia National Laboratories, Electric Power Research Institute, California Energy Commission, Sacramento Municipal Utility District, and other organizations.

ENTECH's silicon cell based concentrator is one of the world's largest PV modules, with an aperture area of 3 square meters (m²) and a rated power output of 500 watts. This PV module uses a large acrylic plastic Fresnel lens to focus sunlight onto small silicon cells. Concentrating the sunlight to 20 times its normal intensity reduces the use of expensive silicon cell material by 95%, compared to conventional flat-plate PV modules. The solar cells are mounted to an extruded aluminum heat sink which keeps the cells about as cool as conventional 1-sun cells. The solar cell assemblies, electrically insulated and encapsulated for durability, use a unique patented optical device called a prism cover to boost performance. An aluminum housing supports and encloses the module. Each module is 0.9 m (3') wide, 3.7 m (12') long, and 0.9 m (3') high.

ENTECH's uniquely designed PV concentrator cell is a modified version of the crystalline silicon cell used in flat plate PV panels. The major difference is that the metallized grid on the concentrator cell's surface conducts over 20 times more electrical current. Consequently, the cell has a larger metallized conductive grid.

ENTECH's optically clear prismatic cell cover is bonded to the cell to refract incoming light away from the grid onto the silicon.

Each module has 30 solar cells electrically connected together like the positive and negative connections of batteries, to provide about 15 volts DC, depending on the cell temperature.

Support bearings are located at each end of the module housing so that it can roll from east to west. Modules are mounted in a supporting frame which tilts from north to south tp provide z-axis tracking.

The support structure is made from readily available structural steel materials. This simple durable structure enables the modules to move about the tilt axis up to 75^o, and to roll east to west through 150^o. All steel components are galvanized to ensure the 30-year design life of the system.

The combined roll and tilt motion enables the modules to stay aligned with the sun throughout the day. The two tracking drive actuators, one for the roll axis and one for the tilt axis, are common DC motor-driven linear actuators. The motors are controlled by a microprocessor unit with a built-in clock, that computes the position of the sun based on the unit's geographic location, day of the year and time of day. In stow position the structure can withstand wind speeds up to 129 kilometers per hour (80 mph) while being ready to start tracking the sun automatically when the wind diminishes.