(242c) Numerical Simulation of Concentrated Solar Energy Absorption in Packed and Fluidized Bed Systems

Concentrated solar energy (CSE) is an excellent source for thermal energy storage medium in packed bed of near-blackbody particles. In addition, CSE is capable of directly providing the required clean energy for many chemical, pharmaceutical, and biological processes. Thus, understanding and searching for the most efficient way to store concentrated solar radiation and transfer the stored energy is very important. In this study, we attempt to gain a better understanding of the radiation energy by CSE received by packed and fluidized bed systems, using our Computational Fluid Dynamic (CFD) model to simulated radiative energy received and distributed in our fluidized and packed bed systems. In the fluidized bed system, gas enters the bottom of the fluidized through a distributor, specially designed to eliminate the large bubbles that cause gas bypassing and loss of particles by entrainment. Inside the fluidized bed, particles receive concentrated solar power, while the gas directly removes the heat from the high-temperature particles. Drag forced modification was developed based on the Clark sub-gird model for fluidized beds. The radiative heat transfer was modeled as an effective conductivity based on the Breitbach and Barthels study and the conductive heat transfer was modeled using Zehner-Bauer-Schlünder (ZBS) conductivity model. The numerical simulation results were compared with experimental data of Tregambi et al (2016). The result of our two-dimensional simulation agreed well with thermal measurement by infrared cameral on a directly irradiated packed bed and fluidized bed solar absorber experiments by Tregambi et al.

Tregambi, C., Chirone, R., Montagnaro, F., Salatino, P., Solimene, R., 2016. Heat transfer in directly irradiated fluidized beds. Solar Energy, 129, pp.85-100.