Background
The generation of electricity from sunlight is currently not cost-effective in many situations because of the inherent limitations of photovoltaic (PV) cells and typical lighting conditions. Increase PV cell efficiencies and minimizing the use of costly materials and fabrication techniques will reduce costs. One promising way to accomplish this is to raise light intensities at the PV cell surface with concentrator PV (CPV) systems, where an inexpensive optical element covering a large sun-lit area is used to greatly concentrate the light onto a small PV cell.
However, a critical problem with many CPV systems is the expense of mounting and moving a CPV array to track the sun. Fixed concentrator arrays do not concentrate light as effectively as tracking arrays, thereby dissipating much of the efficiency gains associated with using concentrators in conjunction with PV cells.
Description
A University of California, Merced researcher has invented a fixed CPV system that can achieve higher light concentrations and therefore greater PV efficiency than existing fixed concentrator designs.
The fixed CPV system is similar to conventional trough-shaped reflector concentrators, but features an unusual geometric arrangement of PV cells that significantly increases the average light intensity at the PV cell surface.
Overall, there is a five-fold concentration of light and ten-fold increase in power output relative to fixed PV panels without any concentrator, and a large enough acceptance angle (65 degrees east/west, and 15 degrees north/south) that only rough seasonal adjustments of the concentrator are required. Because it relies on reflective elements, the optical efficiency of this CPV system is on the order of 90%, substantially better than many tracking CPV systems.
Applications
This fixed CPV system may become an preferred design for CPV systems, helping make fixed CPVs more competitive relative to fixed nonconcentrator PV arrays and relative to tracking CPV arrays.
Advantages
This invention eliminates the need for costly tracking systems, while achieving useful increases in light concentration for increasing PV efficiencies and high optical efficiencies.
Patent Status
Patent Pending
Inventor
Roland Winston
Weiya Zhang
