Modeling and Optimization of a Multi-Flow Falling Particle Receiver for Generation 3 CSP

Generation 3 Concentrating Solar Power (CSP) systems use solid particles for heat transfer and thermal energy storage. Particle-based systems can use a falling particle receiver with an open cavity that allows particles to flow as a curtain. The particle curtain is directly exposed to solar radiation, which is absorbed by the particles as they descend through the receiver. This research presents a free-falling particle receiver with optimized particle supply via ten individually controlled valves. In a uniform mass flow rate curtain, the hottest particles accumulate in the center due to non-uniform flux distribution, which leads to higher radiative and advective losses. Accordingly, lower flux levels at the periphery of the curtain result in lower temperature particles. The modular valve design described here improves the solar receiver efficiency and varies the particle curtain opacity in key areas to prevent back wall overheating. The outer valves have the lowest mass flow rate, while the valves near the center have the highest, allowing for a more uniform heating of the particle curtain. Engineering Equation Solver (EES) is used to analyze the efficiency and performance of the falling particle receiver. The performance of the receiver is optimized by adjusting the mass flow rate in each curtain section. The study aims to determine the ideal mass flow rate for each of the particle curtain valves to augment receiver performance and evaluate back wall temperature under different input flux conditions.