Investigation of thermodynamic performances of particle/supercritical CO₂ fluidized bed heat exchanger integrated with supercritical CO₂ recompression Brayton cycle for concentrated solar power

The supercritical carbon dioxide (sCO₂) Brayton cycle is gaining momentum as a potential alternative for power generation in concentrated solar power plants. Solid particles can be a suitable heat transfer and energy storage medium to achieve high temperatures exceeding 1000 ℃. However, the research on concentrated solar power systems that utilize solid particle/sCO₂ fluidized bed heat exchanger to drive high-performance power cycles is limited. This study presents a comprehensive model of a concentrated solar power system that integrating a sCO₂ recompression Brayton cycle and a particle/sCO₂ fluidized bed heat exchanger. Sensitivity analysis investigates the effects of various parameters such as the number of tubes, particle diameter, fluidization air inlet temperature, and fluidization air velocity on the performance of the fluidized bed heat exchanger. Furthermore, thermodynamic analysis and economic assessment are performed on the integrated system. Results indicate that the overall thermal efficiency of the system increases with the turbine inlet temperature, decreases with the main compressor inlet temperature, and reaches a peak value of 0.35 with increasing recompression fraction. The thermal efficiency of the fluidized bed heat exchanger is 99.1 %, the power cycle efficiency is 50.5 %, and the overall thermal efficiency of the system is 32.2 %. These research findings provide a promising alternative for the efficient utilization of solar energy.