Field weighting model for tracking-integrated optics

Brian Wheelwright, J Roger P Angel, Blake Coughenour, Kimberly Hammer, Andrew Geary, Thomas Stalcup

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The emergent field of tracking-integrated optics enables a potentially low cost concentrating photovoltaic (CPV) implementation, where single-axis module tracking is complemented by an additional degree of freedom within the module [1,2,3,4,5]. Gross module tracking can take on multiple configurations, the most common being rotation about a polar or horizontal North-South oriented axis. Polar-axis tracking achieves >95% sunlight collection compared to dual-axis tracking[6], leaving the tracking-integrated optics to compensate for +/-23.5° seasonal variations. The collection efficiency of N-S horizontal axis tracking is latitude-dependent, with ~90% collection relative to dual-axis tracking at 32.2° latitude. Horizontal tracking at higher latitudes shifts an increasing burden to the tracking-integrated optics, which must operate between two incidence angle extremes: summer solstice sunrise/sunset to winter solstice noon. An important aspect of tracking-integrated lens design is choosing a suitable field weighting to appropriately account for annual DNI received at each angle of incidence. We present a field weighting model, generalized for polar or horizontal module tracking at any latitude, which shows excellent agreement with measured insolation data. This model is particularly helpful for the design of tracking-integrated optics for horizontally-tracked modules, where the correct field weighting is asymmetric and significantly biased away from the normal incidence.

Original languageEnglish (US)
Title of host publication10th International Conference on Concentrator Photovoltaic Systems, CPV 2014
EditorsDaniel Riley, Sarah Kurtz, Geoffrey S. Kinsey, Kenji Araki, Mathieu Baudrit
PublisherAmerican Institute of Physics Inc.
Number of pages5
ISBN (Electronic)9780735412538
StatePublished - 2014
Event10th International Conference on Concentrator Photovoltaic Systems, CPV 2014 - Albuquerque, United States
Duration: Apr 7 2014Apr 9 2014

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Other10th International Conference on Concentrator Photovoltaic Systems, CPV 2014
Country/TerritoryUnited States


  • Insolation
  • Solar concentration
  • Solar tracking
  • Tracking-integrated optics

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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