Performance evaluation and optimization of encapsulated cascade PCM thermal storage

•A mathematical method is implemented in order to model a Latent Heat Packed Bed Storage System.•A Cascade Latent Heat Storage System (CLHS) is optimized in two different cases.•Optimized storage systems performance in charge and discharge cycle is improved 5% compare to single-PCM storage systems.•The performance of optimized storage systems in charge and charge-discharge phase is analyzed.

One of the main components of any solar power plant is its thermal heat storage system. Heat storage reduces the cost of power generation by increasing the capacity factor of the system. This paper aims to model and optimize the operation of a consecutive multi-layer Phase Change Material (PCM) thermal heat storage system, named Cascade Latent Heat Storage (CLHS), using the method of characteristics and genetic algorithm. The model is validated through comparison with experimental data available in the literature. The model can predict fluid and PCM temperature, PCM phase and the energy absorbed by PCM. A sensitivity analysis is employed for both the PCM and the fluid parameters. The PCM types, placement, and quantity are optimized in two different cases. Optimization results in comparison with the best case of a Single-PCM storage show an improvement of the system performance. In the first case, the stored energy of a CLHS during a 4-h charge period is maximized by increasing 5.12%, while in the second case, the discharged energy maximized during an 8-h charge-discharge cycle by 5% increase. This achievement can outperform current storage systems capabilities in different applications such as building and solar power plants.