National Renewable Energy Laboratory
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Two types of methods were evaluated for correcting the short-circuit current of photovoltaic (PV) modules for variations in the solar spectrum under clear skies: (1) empirical relationships based on air mass, and (2) use of spectral irradiance models and PV module spectral response data. Methods of the first type were the Sandia absolute air-mass function, or f(AM(a)), and the CREST air-mass function, or f(AM). The second type used SEDES2 and SMARTS spectral irradiance models. The methods were evaluated using data recorded during June, September, and December 2008 at the National Renewable Energy Laboratory and during June 2008 at the Florida Solar Energy Center.
For predicting the short-circuit current for a multi-crystalline silicon PV module and an amorphous silicon PV module, the methods using spectral irradiance models and PV module spectral response data performed better than the empirical air mass methods. This is attributed to the empirical air mass methods not accounting for variations of aerosols and water vapor. For the multi-crystalline silicon PV module, applying a correction with any of the methods was not significantly beneficial when compared to not applying a correction.
Photovoltaics; Short-circuit current; Solar energy; Solar spectrum variations
Oil, Gas, and Energy
Preliminary investigation of methods for correcting for variations in solar spectrum under clear skies.
Available at: http://digitalscholarship.unlv.edu/renew_pubs/16