Solar-powered hybrid energy storage system with phase change materials

•A 25kWh encapsulated LTES is investigated using CFD.•Data from CFD is fed into a scheme to investigate the yearly charging performance.•Performance differs seasonally, with varying temperatures impacting the operation.•Optimization reduces cooling unit heat dissipation and maximizes stored heat. Solar energy's growing role in the green energy landscape underscores the importance of effective energy storage solutions, particularly within concentrated solar power (CSP) systems. Latent thermal energy storage (LTES) and leveraging phase change materials (PCMs) offer promise but face challenges due to low thermal conductivity. This work comprehensively investigates LTES integration into solar-thermal systems, emphasizing medium-temperature applications. It introduces an innovative LTES tank design with encapsulating tubes modeled through computational fluid dynamics (CFD). The system employs a novel hybrid thermal storage approach, enhancing thermal output through a high-temperature heat pump (HTHP) before storage. This approach aligns with future energy systems, emphasizing energy vector integration. The study offers realistic LTES modeling, accounting for natural convection effects, and integrates LTES within solar thermal systems by taking advantage of time dependent CFD results. Real-world solar irradiance data for an Italian city is integrated into the investigation, providing insights into LTES performance and its role in sustainable solar energy solutions. A multi-objective optimization process follows the year-round simulations to maximize the amount of stored heat and minimize the electric input. This approach facilitates better system sizing and performance evaluation, contributing to the advancement of solar thermal technology.