Abstract
The problem of scaling the impinging solar radiation spectrum, to the excitance of blackbodies on earth at moderate temperatures is discussed. Typically diagrams with these two kinds of spectra are used to demonstrate wavelength separation as the background for solar, optical selectivity. All spectra can satisfactorily be approximated with Planck curves, but the solar spectrum must be reduced in intensity because of the long distance Earth - Sun. Some difficulties with using astronomical data for this scaling are noted. As an alternative, the T5-dependence of the Planck curve maxima, when drawn on a wavelength axis, is used to demonstrate that the curves can be scaled based on their total energy and solar absorber stagnation. The ratios of the peaks of the impinging solar radiation to the excitance spectra for black surfaces on earth at various ordinary temperatures are reported. It is pointed out that the choice of independent variable effects the positions of the Planck function peaks, as well the shape of the spectra. The peak values increase proportionally to T3 when frequency is used instead of wavelength and the width of the curves grows linearily with temperature. Effects of using a logarithmic wavelength scale are also noted.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Carl-Gustaf Ribbing, Carl-Gustaf Ribbing, } "Getting the sunshine right", Proc. SPIE 3789, Solar Optical Materials XVI, (11 October 1999); doi: 10.1117/12.367568; https://doi.org/10.1117/12.367568
PROCEEDINGS
7 PAGES


SHARE
RELATED CONTENT

A nano-satellite to study the Sun and the Earth
Proceedings of SPIE (June 02 2014)
Design and test of a new facility for assessing spectral...
Proceedings of SPIE (February 23 2016)
Parabolic solar concentrator
Proceedings of SPIE (September 13 2006)
The FES Delta Focusing Solar Collector
Proceedings of SPIE (March 15 1976)

Back to Top