Use of imaging refractive secondaries in photovoltaic concentrators

Technical Report · Sat Jul 01 00:00:00 EDT 1989

DOI:https://doi.org/10.2172/5962798· OSTI ID:5962798

James, L. W.

A new type of secondary optical element for two-axis photovoltaic solar concentrator systems is described. This optical system is known as the double-imaging concentrator system because the sun is imaged by the primary Fresnel lens onto the secondary lens, and the primary lens is imaged by the secondary lens onto the cell. The secondary lens can take two forms. An egg-shaped (ellipsoidal) glass secondary is suspended above the cell in one implementation. The alternative configuration, called the SILO secondary, allows gluing the secondary lens directly to the cell. The SILO lens is a glass cylinder or cone with a molded half-ellipsoidal top surface. In both cases, the fact that the primary lens is imaged onto the cell means that if the primary lens is uniformly illuminated, then the cell is uniformly illuminated, independent of first-order of tracking errors, mounting errors, and primary Fresnel lens aberrations. Monte Carlo ray trace modeling of these systems with the ''FgImgSec'' computer code shows significant advantages over other optical systems in the important areas of photon flux uniformity over the solar cell surface, and maximum allowable mounting and aiming tolerances. Parametric studies of concentration ratio and primary lens f-number show the limits in system design and give guidance for system optimization. 2 refs., 44 figs.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5962798
• Report Number(s): SAND-89-7029; ON: DE89014376
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
SOLAR CONCENTRATORS
DESIGN
COATINGS
COMPUTERIZED SIMULATION
COST
ERRORS
F CODES
FRESNEL LENS
OPTICAL SYSTEMS
SOLAR FLUX
SOLAR TRACKING SYSTEMS
TESTING
TRANSMISSION
COMPUTER CODES
EQUIPMENT
HELIOSTATS
LENSES
SIMULATION
SOLAR CELL ARRAYS
SOLAR COLLECTORS
SOLAR EQUIPMENT
SOLAR TRACKING
141000* - Solar Collectors & Concentrators