Physical property design of multi-component particle systems as heat transfer medium for directly irradiated solar receiver

Abstract

• New particle candidates considered as the HTM for directly irradiated SPSRs. • The different particles mixed to form novel multi-component particle systems. • The absorption property increases with the addition of dark colored materials. • Thermal performance of particle systems enhanced in a falling quartz tube SPSR. In directly irradiated solid particle solar receivers (SPSRs), the performance of the heat transfer and thermal energy storage medium is a hot research topic. Herein, the thermophysical properties, thermal stability, surface morphology, element compositions and absorptivities of 16 kinds of candidate particles are studied and evaluated. Considering that the performance of homogenous particles as heat transfer medium (HTM) is not ideal, a novel concept of multi-component mixed particle systems with different mass ratios is proposed for the first time. To explore the effect of the particle systems on the receiver performance, a quartz tube falling receiver numerical model is applied. The results indicate that the absorption performance of the particle systems have increased with the addition of dark colored materials, but this effect becomes less obvious with the amount of additive, especially for quartz sand-silicon carbide particle systems. A quartz sand-silicon carbide particle system with a mass ratio of 7:3 may be the optimal choice for high receiver outlet temperature and low mass flow rate. Compared to that of pure silicon carbide particles, this system can achieve a 64.47% reduction in the material cost with only a 4.11% reduction in receiver thermal efficiency. This work provides ideas for the design of multi-component particle systems, which may open a significant development for next-generation concentrated solar power station.