Aplanatic beam-down solar towers

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

4 Scopus citations


The pragmatic virtues of ground-level receivers in solar towers have long been recognized, but the associated beam-down optics reduce concentration, resulting in higher heat loss and cost, or the need for an actively-cooled tertiary concentrator that incurs additional optical losses. Here, we describe the concept of an aplanatic beam-down solar tower, where concentration can be increased without the need for a tertiary concentrator, while retaining a ground-level receiver. The basis for satisfying aplanatism constitutes tailoring the contour of a stationary secondary mirror atop the tower with a distinct heliostat tracking strategy. Conflating the aplanatic solar tower with the option of multiple towers, where a heliostat can be aimed at different targets depending on solar geometry, can markedly reduce shading, blocking and cosine losses. Also, a system of many mini-towers each of which is only a few meters in height could enable systems that are more modular, efficient and easily-maintained.

Original languageEnglish
Title of host publicationNonimaging Optics
Subtitle of host publicationEfficient Design for Illumination and Solar Concentration XVI
EditorsRoland Winston, Eli Yablonovitch
ISBN (Electronic)9781510629332
StatePublished - 1 Jan 2019
EventNonimaging Optics: Efficient Design for Illumination and Solar Concentration XVI 2019 - San Diego, United States
Duration: 11 Aug 201912 Aug 2019

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceNonimaging Optics: Efficient Design for Illumination and Solar Concentration XVI 2019
Country/TerritoryUnited States
CitySan Diego

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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