This project designs, develops, and tests novel particle receivers with configurations that use light-trapping geometries. Particle receivers drop sand-like ceramic particles through a beam of concentrated sunlight atop a power tower. The particles absorb heat at temperatures near 800°C, then store the heat in an insulated container below the receiver. This thermal energy can be converted into electricity using a traditional power cycle at a later time. By capturing more sunlight, researchers increase the effective solar absorbance and efficiency of high-temperature particle receivers. Zig-zag release patterns and multi-drop curtain configurations will be compared to baseline planar curtain configurations. This project builds off of the High-Temperature Falling Particle Receiver project in the 2012 Concentrating Solar Power (CSP) SunShot R&D funding program. Using particles as the heat transfer media provides an opportunity to integrate with high-temperature, high-efficiency power cycles. Furthermore, particles remain stable at ultra-high temperatures and avoid corrosion concerns that plague many liquids above 700°C.
The research team uses computer simulation to demonstrate that zig-zag and/or multi-drop particle curtains increase thermal efficiency relative to baseline planar curtains. They are also modifying existing particle receiver systems to accommodate zig-zag patterns for on-sun testing. This includes performing unheated tests to demonstrate that new particle curtain geometries are stable and performing 1 MW on-sun tests to demonstrate thermal efficiency of new particle release configurations is higher than baseline planar curtains.
This project addresses the efficiency of the thermal receiver using particle based heat transfer media, one of the most critical obstacles facing CSP. By taking advantage of light trapping and volumetric heating, this work will explore novel methods of maximizing thermal receiver efficiency and help particle-based CSP plants become cost competitive. By utilizing the National Solar Thermal Test Facility and Sandia National Laboratory, the project will demonstrate its results at scale so they are ready for hand-off to the solar industry.