Multiscale thermomechanical assessment of silicon carbide-based nanocomposites in solar energy harvesting applications

Abstract

Increasing the operating temperature of concentrating solar power plants beyond 650 °C is crucial for increasing their efficiency and energy storage capability, and thus pushing their market penetration. However, one of the main drawbacks that arise with an increase in temperature is material degradation. Ceramic materials are an interesting alternative to nickel–chromium superalloys due to their high thermal resistance and low expansion capabilities. In this work, we characterize the thermomechanical behavior of a silicon carbide-based ceramic material for receiver tubes up to 750 °C. For this purpose, we develop a multiscale simulation framework, combining studies at different scales of observation (i.e., material, and component) using different simulation tools. At the material scale, we generate virtual microstructures that are subject to thermomechanical tests using the lattice model. The material properties obtained at this scale of observation are subsequently used at component level simulations, which are carried out by means of the finite element method. This allows the exploration of new materials designed in silico and the prediction of their performance in solar energy applications. In this work, we use our methodology to assess the thermoelastic behavior of SiSiC tubes at high temperatures and obtain temperature-dependent material properties. At the material level, we report elastic moduli in the range of 250–500 MPa and coefficients of thermal expansion in the range of 6–12·10−6 1/°C, under operation conditions. Regarding the component, we found that SiSiC tubes with a thickness-to-diameter ratio of 0.15 or larger are safe at operating temperatures up to 750 °C.