Analytic optical evaluation of linear aplanatic solar Fresnel reflectors

Leonardo F.L. de Souza, Naum Fraidenraich, Chigueru Tiba, Jeffrey M. Gordon

Research output: Contribution to journalArticlepeer-review


Linear Aplanatic Fresnel Reflectors (LAFRs) were recently presented as a novel and viable dual-mirror solar concentrator. Within a vast parameter space, a few promising designs were identified and evaluated via raytracing. This cumbersome, time-intensive exploration left unresolved whether configurations with superior optical performance remained undiscovered. Here, we present analytic methods for all inherent optical losses for the LAFR - results that are equally valid for almost all sources of optical loss in all linear Fresnel reflector solar concentrators. The loss modes include the separate contributions linked to the transverse and longitudinal projected incidence angles. This permits exact rapid comparisons among the wide range of possible aplanatic designs in a physically transparent manner that quantifies each mode of optical loss. These analytic derivations subsume blocking of rays reflected from the primary mirror segments, radiation that misses the primary and strikes the ground, shading of the primary by the secondary, end losses, and rays reflected from the primary that either miss the secondary (spillage) or enter it and miss the absorber tube (ray rejection). LAFR designs superior to those determined previously, in terms of higher intercept factor and higher concentration, are found and evaluated.

Original languageEnglish
Pages (from-to)107-121
Number of pages15
JournalSolar Energy
StatePublished - 1 Jan 2023


  • Aplanatic
  • Incidence angle modifier
  • Linear Fresnel
  • Optical losses
  • Solar concentrator

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science (all)


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