(488h) Analysis of Concentrated Solar Energy Storage Using Packed and Fluidized Bed Systems

Concentrated solar energy (CSE) is capable of providing the energy needed for the majority of chemical, pharmaceutical, and biological processes. One of the challenges in using CSE is the development of innovative fluids or mixtures of fluid and particle systems to efficiently adsorb concentrated solar radiation and transfer the stored energy for utilizations. In this presentation a radiative heat transfer model was developed and linked to computational fluid dynamics (CFD) model to analyze CSE absorption by both packed and fluidized bed of silicon carbide (SiC). The results of our simulation agreed well with temperature measurement by infrared camera on a directly irradiated packed and fluidized bed solar absorbers experimental data in the literature. Our simulation showed that the fluidized bed reduces the surface temperature by convective energy transfer for the bubbling fluidized bed due to the mixing created by bubbles. The lower temperature on the surface significantly decreases the radiative energy loss from the surface to the environment, which results in larger energy absorption by the bubbling fluidized bed compared with similar packed bed system. Furthermore, using a wider incident radiative energy flux distribution would increase the energy absorption by both packed and fluid bed systems. Our numerical simulations showed that a packed bed system with a novel design of an optical quartz tube, where the radiative energy from the bed surface meets the surface of the optical tube at the center of the packed bed, results in additional distributed concentrated solar energy on the tube and an increase in energy absorption, storage capacity, and energy storage at higher temperature.