Session: 05-02 Metrology in CSP

Paper Number: 107402

107402 - Stability Assessment of High Temperature Coatings for Flux Measurement Applications 

Clean energy technologies are necessary to decarbonize industrial processes and power generation. Concentrated solar power (CSP) technology harvests concentrated solar energy as a heat source in applications such as heating, cooling, process heat, material processing, power generation, and chemical cycles. CSP technologies require accurate measurement of high solar flux to improve system efficiency and enable automation. Circular foil gauges, or Gardon gauges, are low-cost flux sensors that are commonly used for flux measurements >1000 kW/m². Failure modes and effects analysis have identified Gardon gauge foil coating as a critical component for the development of a robust flux gauge for high intensity broadband flux measurements. Degradation of coating optical properties and physical condition impact flux gauge calibration and lead to errors in flux measurements. This finding has prompted a series of tests to investigate the viability of multiple flux gauge foil coating candidates for future flux gauge development. Four off-the-shelf coating candidates are exposed to high intensity solar flux and high temperature environments to assess coating optical property degradation and delamination. Samples are exposed to many solar and thermal cycles to simulate real-world aging. State-of-the art solar furnace, solar simulator, and wind tunnel facilities at the National Solar Thermal Test Facility (NSTTF) are utilized to gather experimental data. The solar absorptance and hemispherical total emissivity of samples are characterized before and after testing, and the state of coating delamination is assessed qualitatively using microscope images. The degradation of coating candidates is compared during each test campaign, and an ideal coating for flux gauge applications is identified.

Presenting Author: Luke McLaughlin Sandia National Laboratories

Presenting Author Biography: Luke is a R&D Mechanical Engineer at the National Solar Thermal Test Facility at Sandia National Laboratories. His research focuses on development of energy storage systems, high temperature processes, and concentrated solar thermal technologies.