Multi-Flow Falling Particle Receiver Modeling

Abstract

Generation 3 Concentrating Solar Power systems use solid particles for heat transfer and thermal energy storage. Particle-based systems use a falling particle receiver with an open cavity where particles flow together as a curtain that is directly exposed to solar radiation absorbed by the particles as they descend. The efficiency of the receiver depends on curtain opacity (influenced by the particle mass flow rate), the average particle temperature, and environmental factors. We present a free-falling particle receiver design that incorporates ten individually controlled valves for precise particle supply management. Each valve is equipped with a slide gate and an actuator, ensuring a consistent mass flow rate. In a uniform mass flow rate curtain, the hottest particles accumulate in the center due to non-uniform flux distribution, leading to higher radiative and advective losses. Accordingly, lower flux levels at the periphery result in lower temperature particles. Our modular valve design enhances receiver efficiency by improving curtain opacity in key areas. The outer valves have the lowest mass flow rate, while the center valves have the highest, allowing more uniform heating. The 10-section model outperforms the 1D model by reaching a maximum efficiency of 85%, compared to 84%.