Optimization of silver-based heat mirrors using a genetic algorithm

Thomas Eisenhammer; Michel P. Lazarov; R. Sizmann

doi:10.1117/12.130491

25 November 1992 Optimization of silver-based heat mirrors using a genetic algorithm

Thomas Eisenhammer, Michel P. Lazarov, R. Sizmann

Proceedings Volume 1727, Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XI: Selective Materials, Concentrators and Reflectors, Transparent Insulation and Superwindows; (1992) https://doi.org/10.1117/12.130491
Event: Optical Materials Technology for Energy Efficiency and Solar Energy, 1992, Toulouse-Labege, France

Abstract

Heat mirrors based on thin silver and dielectric films for thermal solar energy applications at elevated temperatures (200 - 300 degree(s)C) are studied numerically. The well known three layer design dielectric/silver/dielectric can be improved by additional anti-reflective films. Thicknesses and selection of dielectrics of these more complex designs are optimized with a genetic algorithm. At absorber temperatures above 200 degree(s)C and for bulk optical constants the optimal sequence with five layers contains two silver films: dielectric/silver/dielectric/silver/dielectric. This design is compared to optimal designs with four and five layers, but only one silver layer. The five layer design with two silver layers allows a reduction in hemispherical emittance in comparison to the design with only one silver layer. An improvement of 14% in the figure of merit at a solar radiant flux of 500 W/m² and an absorber temperature of 300 degree(s)C is possible. However, optical constants of thin silver films differ substantially from bulk optical constants. Thickness dependent optical constants modeling experimental data were evaluated within a Drude model. The figure of merit is generally smaller than for bulk optical constants. For the design with two silver layers, the figure of merit is smaller than for designs with one silver layer, except at the highest investigated absorber temperature of 300 degree(s)C.

Citation Download Citation

Thomas Eisenhammer, Michel P. Lazarov, and R. Sizmann "Optimization of silver-based heat mirrors using a genetic algorithm", Proc. SPIE 1727, Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XI: Selective Materials, Concentrators and Reflectors, Transparent Insulation and Superwindows, (25 November 1992); https://doi.org/10.1117/12.130491

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available