High temperature systems using solid particles as TES and HTF material: A review

Thermal energy constitutes up to 90% of global energy budget, centering on heat conversion, transmission, and storage; therefore, the technology for harvesting solar energy worth to be developed. One of them is the concentrated solar power (CSP) solar towers where sun-tracking heliostats reflect solar radiation to the top of a tower where the receiver is located. The great advantage of CSP over other renewable energy sources is that energy storage is feasible, particularly when the heat transfer fluid (HTF) is also used as thermal energy storage (TES) material which is the case of solid particles. A lot of development efforts are under way for achieving commercial direct solar solid-particle systems. Solid particle systems for transferring high temperature thermal energy are purposed for increasing the efficiency of these systems when converting heat into electric power. This review recapitulates the concept of these systems taking into account the main receiver designs, particle conveyance, particle storage systems and components, the heat exchanger, and the main challenges that must be overcome to split this technology as a commercial one, especially from the materials availability point of view. This review summarizes the actual status of the use of solid particles for TES and as HTF for CSP Tower, and condenses all the available information and classifies them considering the main functional parts and remarking the current research in each part as well as the future challenging issues.