Numerical Analysis of the Thermal Behavior of a Latent Thermal Storage Unit Utilized for Solar Tower Receiver Protection

Abstract

The high-temperature solar central receiver is a pivotal component in solar power plants, requiring efficient thermal management to ensure both longevity and performance. This study employs a two-dimensional computational fluid dynamics framework based on FEM to analyze five central receiver designs under both uniform and interrupted incident radiation conditions. Phase change phenomena are modeled using the apparent heat capacity method during charging and discharging cycles. The objective is to compare absorber models, with and without phase change materials (PCMs), to identify the optimal configuration that enhances the receiver’s life cycle. Numerical results indicate that integrating a thermal energy storage (TES) unit with fins into the absorber is the most effective design. Specifically, Model d, which incorporates metallic fins and an optimized TES compartment, achieves higher outlet temperatures (>1,000 K) and improved storage stabilization with increasing incident solar flux compared to other configurations. This model also demonstrates faster PCM melting and liquid fraction stabilization, completing these processes within 550 seconds at flux densities≥350 kW/m2. Furthermore, during periods of interrupted solar flux, the TES-integrated models effectively maintain the heat transfer fluid temperature above 400 K for 10 to 15 mins, showcasing their protective capabilities. These findings underscore the critical role of integrating high-melting-point PCMs and metallic fins in central receiver designs to optimize thermal performance.