A high thermal stability core-shell aerogel structure for high-temperature solar thermal conversion

Silica aerogel can be applied to the concentrated solar power (CSP) plants to achieve a high operation temperature due to the high optical transparency and thermal insulation properties. However, the insulation capacity of aerogel at high-temperature will deteriorate rapidly due to the damage of the porous structure. In present study, a transparent aerogel consisting of SiO2/Al2O3 core-shell particles was proposed. The structure-dependent radiative properties were predicted through the combination of Discrete Dipoles Approximation (DDA) and Monte Carlo (MC) method. The core-shell aerogel achieves a higher solar transmittance than the alumina aerogel. The evaluation parameter of greenhouse selectivity was introduced to assess the aerogel performance by considering the solar transmission and infrared extinction simultaneously. An optimal design of SiO2/Al2O3 core-shell aerogel at different temperatures was conducted. Compared with the pure alumina aerogel, a maximum enhancement of 22.6% in greenhouse selectivity was achieved by the core-shell aerogel with phi = 95% and r(1)/r(2) = 0.4 at 700 degrees C. This work provides a promising method to achieve a high-efficient transparent thermal insulating aerogel for high-temperature CSP plants with high thermal stability.