Concentrating photovoltaic (CPV) technology has recently gained interest based on their expected low levelized cost of electricity, high efficiency, and scalability. Many CPV systems use Fresnel lenses made of poly(methyl methacrylate) (PMMA) to obtain a high optical flux density. The optical and mechanical durability of such components, however, are not well established relative to the desired service life of 30 years. Specific reliability issues may include: reduced optical transmittance, discoloration, hazing, surface erosion, embrittlement, crack growth, physical aging, shape setting (warpage), and soiling. The initial results for contemporary lens- and material-specimens aged cumulatively to 6 months are presented. The study here uses an environmental chamber equipped with a xenon-arc lamp to age specimens at least 8x the nominal field rate. A broad range in the affected characteristics (including optical transmittance, yellowness index, mass loss, and contact angle) has been observed to date, depending on the formulation of PMMA used. The most affected specimens are further examined in terms of their visual appearance, surface roughness (examined via atomic force microscopy), and molecular structure (via Fourier transform infrared spectroscopy).

Date Published: 19 August 2010
PDF: 12 pages
Proc. SPIE 7773, Reliability of Photovoltaic Cells, Modules, Components, and Systems III, 777303 (19 August 2010);

Published in SPIE Proceedings Vol. 7773:
Reliability of Photovoltaic Cells, Modules, Components, and Systems III
Neelkanth G. Dhere; John H. Wohlgemuth; Kevin Lynn, Editor(s)