Publications

High Temperature Silicon Carbide Receiver Tubes for Concentrating Solar Power

Walker, Matthew W.; Armijo, Kenneth M.; Yellowhair, Julius; Ho, Clifford K.; Bohinsky, Amy B.; Halfinger, Jeff H.; Feinroth, Herb F.

In order for Concentrating Solar Power plants (CSP) to achieve the desired cost breakpoint, significant improvement in performance is required resulting in the need to increase temperatures of fluid systems. A US DOE Small Business Voucher project was established at Sandia to explore the performance characteristics of Ceramic Tubular Products (CTP) silicon carbide TRIPLEX tubes in key categories relating to its performance as a solar receiver in next generation CSP plants. Along these lines, the following research tasks were completed : (1) Solar Spectrum Testing, (2) Corrosion Testing in Molten Chloride Salt, (3) Mechanical Shock Testing, and (4) Thermal Shock Testing. Through the completion of these four tasks, it has been found that the performance of CTP's material across all of these categories is promising, and merits further investigation beyond this initial investigation. Through 50 solar aging cycles, the CTP material exhibited excellent stability to high temperatures in air, exhibited at or above 0.95 absorptance, and had measured emittances within the range of 0.88-0.90. Through molten salt corrosion testing at 750degC it was found that SiC exhibits significantly lower mass change (-- 90 times lower) than Haynes 230 during 108 hours of salt exposure. The CTP TRIPLEX material performed significantly better than the SiC monolithic tube material in mechanical shock testing, breaking at an average height of 3 times that for the monolithic tubes. Through simulated rain thermal shock testing of CTP composite tubes at 800degC it was found that CTP's SiC composite tubes were able to survive thermal shock, while the SiC monolithic tubes did not. ACKNOWLEDGEMENTS * US Department of Energy Office of EERE for sponsorship of this project * Andrew Dawson of the DOE Office of EERE for Project Management, including the excellent technical insights that he provided throughout the project * Ken Armijo lead the Thermal Shock Testing activities * Cliff Ho and Julius Yellowhair led the Solar Spectrum Testing activities * Jeff Halfinger prepared the CTP specimens for each of the research tasks * Herb Feinroth provided guidance and input into the preparation for the test specimens and the associated research tasks * Alan Kruizenga collaborated with CTP to apply for and be awarded this project from DOE EERE. The scope for the project was developed by Alan together with CTP. * Rio Hatton and Jesus Ortega (student interns) helped with portions of the solar simulator testing, reflectance/emittance data collection, and image (including microscope) collection. * Kent Smith helped design and fabricate the high temperature molten salt corrosion setup * Jeff Chames and Javier Cebrian completed the microscopy for the molten salt corrosion test specimens * Amy Bohinsky (student intern) and Kevin Nelson helped complete the mechanical shock testing for the monolithic and composite tubes, including organizing the results for the final report. * Josh Christian and Daniel Ray helped with portions of the Thermal Shock Testing * Mark Stavig completed the polyethylene plug testing associated with the Thermal Shock Testing