A Novel Iris Mechanism for Solar Thermal Receivers

Cédric Ophoff, Nesrin Ozalp

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Variable aperture mechanisms are being used in many fields including medicine, electronics, fluid mechanics, and optics. The main design characteristics of these aperture concepts are the use of multiple blades regulating aperture area and consequently the incoming medium flow. Manufacturing complexities primarily depend on the concept geometry, material, and the process application requirements. Design of a variable aperture demands meticulous methodology and careful consideration of the application field. This paper provides an in-depth methodology on the design of a novel iris mechanism for temperature control in high temperature solar thermal receivers and solar reactors. Such methodology can be used as a guideline for iris mechanisms implemented in other applications as well as in design of different apparatuses exposed to high temperature. Optical simulations in present study have been performed to demonstrate enhanced performance of the iris mechanism over conventional Venetian blind shutter serving as optical attenuators in concentrating solar power systems. Results showed that optical absorption efficiency is improved by 14% while reradiation loss through the aperture is reduced by 2.3% when the iris mechanism is used. Correlation for adaptive control of aperture area was found through computational surface area measurement. Experimental testing with a 7 kW solar simulator at different power levels demonstrated the performance of the mechanism to maintain stable temperature under variable flux.

Original languageEnglish (US)
Article number061004
JournalJournal of Solar Energy Engineering, Transactions of the ASME
Issue number6
StatePublished - Dec 1 2017

Bibliographical note

Funding Information:
This research has been funded by Impulse Fund Project No. IMP/14/049 of KU Leuven. We express our appreciation to Dr. Patrick Van Rymenant for his support during manufacturing and technical discussions.

Publisher Copyright:
© 2017 by ASME.


  • Iris mechanism
  • aperture area
  • design methodology
  • motion analysis
  • solar reactor


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