Incidence-Angle Modifier and Average Optical Efficiency of Parabolic Trough Collectors

[+] Author and Article Information
H. Gaul, A. Rabl

Solar Energy Research Institute, 1536 Cole Boulevard, Golden, CO 80401

J. Sol. Energy Eng 102(1), 16-21 (Feb 01, 1980) (6 pages) doi:10.1115/1.3266115 History: Online November 11, 2009


The incidence-angle modifier for parabolic troughs is investigated in order to clarify the connection between collector tests and prediction of long-term energy delivery by collector arrays. The optical efficiency of a parabolic trough collector decreases with incidence angle for several reasons: the decreased transmission of the glazing and the absorption of the absorber; the increased width of the solar image on the receiver; and the spillover of the radiation from troughs of finite length. In order to be able to apply test results from a short collector module to collector arrays of arbitrary length, it is necessary to separate analytically the end loss from the first two effects. This analysis is applied to several collectors that have been tested at Sandia Laboratories and at the Solar Energy Research Institute (SERI). The measurements of the incidence-angle modifier at SERI were, carried out at low temperature with an open water test loop for improved accuracy. The results are presented in two forms: as a polynomial fit to the data; and as a single number, the all-day average optical efficiency for typical operating conditions.

Copyright © 1980 by ASME
Your Session has timed out. Please sign back in to continue.





Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In