FIR – Solar Thermal Power Source Study

Brightleaf CPV Technology History…

…CPV was developed in the 1950’s as a power source for the American space program. Spectrolab, a Boeing subsidiary, has produced this technology from inception. CPV uses lenses or mirrors and tracking systems to focus a large area of sunlight on small photovoltaic surfaces which generate electricity. This technology is ideal for space use, since the size of the solar array can be small (transportable into space) and there is no problem with heat dissipation from the concentrated sunlight. Unfortunately, the thermal transfer problems on earth have created huge difficulties. In a conventional dense array, the solar concentration would melt traditional cells. In recent years, Spectrolab has developed multijunction cells (cells designed to take advantage of different portions of the solar spectrum) which are optimized for the terrestrial spectrum. The efficiencies of these cells are triple those of conventional photovoltaics (35-40% with the current generations of cells and 50%+ with the imminent next generation). By mounting small cells (approx. 0.5-1 cm. square) in dispersed arrays, the thermal issues can be managed in a satisfactory and cost-effective fashion.

Brightleaf Sun Tracking

The efficiency of the cells is highly dependent on accurate solar tracking. Fortunately, these tracking systems have become relatively inexpensive and reliable in recent years. Commercially available systems are neither as simple nor as cost-effective as they should be. It appears that this has been a high profit-margin portion of the conventional photovoltaic business. brightLeaf has designed a system with minimal mechanical complexity in order to keep the acquisition and maintenance costs of its systems as low as possible, rather than using an off-the-shelf unit. brightLeaf’s system will employ an astronomical algorithm, which will define solar positioning for all latitudes and longitudes throughout daylight hours. The system will have a periodic feedback mechanism to confirm that the cells are indeed focused on the sun and thus give maximum power yield.

brightLeaf’s proprietary technology: Non-parabolic Collector

brightLeaf's proprietary technology: Non-parabolic Collector

brightLeaf's proprietary technology: Non-parabolic Collector

• Only two functional parts

brightLeaf’s proprietary technology: Auto-aligning geometry

brightLeaf’s proprietary technology: Auto-aligning geometry

brightLeaf’s proprietary technology: Auto-aligning geometry

• Direct longest rays to center of cell

• Invert half of ray bundles so ray bundles move in opposing directions

RESULT: 0.5º system tolerance

brightLeaf’s proprietary technology: No Gaps, No Shadows™

brightLeaf’s proprietary technology: No Gaps, No Shadows™

98.5% of Sunlight reaches collector