Thermal conductivity measurement of sunlight absorbers by digital interferometry


Principal investigator



Sunlight absorber coatings in concentrating solar power (CSP) convert focused solar radiation into heat. These coatings have an intrinsic thermal barrier, which increases the thermal loss of the solar thermal receiver. The thermal barrier increases with coating thickness and decreases with thermal conductivity. Therefore, an accurate measurement of the thermal conductivity of thin CSP coatings is essential to better estimate the thermal losses of the receiver. However, conventional methods to measure the thermal conductivity are note reliable for high-temperature light-absorber coatings, as these coatings are complex in structure and composition while being attached to a metallic substrate. In this project, we will develop an optical method, called phase-shifting interferometry, to accurately measure the thermal conductivity of light-absorber coatings.


To develop a method that accurately measures the thermal conductivity of light absorber coatings. These coatings may have a hierarchical morphology and multilayer arrangement.


  • Interest in developing new experimental methods.
  • Completion of the course Fluid Mechanics and Heat Transfer is preferred.

Background Literature

Scientific papers by Torres et al.

  • Development of phase-shifting interferometry for measurement of isothermal diffusion coefficients in binary solutions (link)
  • Degradation mechanisms and non-linear thermal cycling effects in a high-temperature light-absorber coating (link) ← from an Honours thesis
  • Measurement of Soret and Fickian diffusion coefficients by orthogonal phase-shifting interferometry and its application to protein aqueous solutions (link)
  • Optical Method for Simultaneous High-Resolution Measurement of Heat and Fluid Flow: The Case of Rayleigh-Bénard Convection (link) ← from two Honours theses


phase-shifting interferometry; concentrating solar power; light-absorber coatings; thermal conductivity

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