Numerical analysis of demolition waste-based thermal energy storage system for concentrated solar power plants

Thermal energy storage (TES) is an enabling system that provides uninterrupted energy from concentrated solar power (CSP) plants. Packed-bed TES systems have great opportunity to significantly enhance the cost-effectiveness, efficiency, and sustainability of CSP plants by employing an affordable and sustainable packing material. The objective of this study is to design a demolition waste-based packed bed TES system with a maximum storage capacity of 40 kWh, specifically tailored to store heat within the temperature range of 290 degrees C to 565 degrees C using solar salt as heat transfer fluid (HTF), thereby making it suitable for integration into CSP plants. Performance and thermal behavior of demolition waste-based packed-bed TES system was assessed through numerical analysis. The results demonstrate that a high discharging efficiency of 76.0% was achieved when the HTF flow rate was set at 100 kgh-1. However, it is important to note that at lower HTF flow rate, heat loss increases, leading to a decrease in discharging efficiency to 70%. The experiment also revealed a uniform thermal gradient within the packed-bed TES system, up to a fluid flow rate of 300 kgh-1. It is worth mentioning that lower flow rates can further improve the stratification effect; however, they may also result in increased heat loss and reduced storage capacity. Based on these findings, an optimal flow rate range of 100 to 200 kgh-1 is recommended to achieve the best performance for the packed-bed TES system.

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