Aicha EDDEMANI, Omar ACHAHOUR, Hayat El BAAMRANI, Ahmed AHAROUNE, Lahcen BOUIRDEN, Ahmed IHLAL
A rock-bed provides a highly efficient and cost-effective heat storage solution for solar concentrators employing air as the heat-conducting fluid. This pioneering technology was first deployed on an industrial scale at the Ait Baha concentrated solar plant in Morocco, delivering a thermal storage capacity of 100 MWh. This work aims to explore the thermal behavior of large-scale reservoir under real operating conditions and also to explore the impact of pre-charging on system performance. For this purpose, a Computational Fluid Dynamics (CFD) model, rigorously validated through experimental measurements, is employed. Based on the number of Pre-Charging Cycles (PCCs), scenarios with 0, 1, 3, 4, 5, 6, and 7 PCCs were analyzed over 30 days of system operation and compared to the reference case characterized by 0 PCCs. The results demonstrate that starting the system with PCCs significantly improves performance during the early cycles, effectively mitigating initial inefficiencies, enhancing operational efficiency, and reducing the duration of transient behavior during energy input and output phases. The analysis identifies six PCCs as the optimal balance for this system, delivering high efficiency and stabilizing performance with the minimal fluctuations by the 5th operational cycle. Furthermore, a comprehensive guideline is proposed to determine the optimal number of PCCs, ensuring the prevention of system overload and the minimization of energy waste during the pre-charging process.