At its National Solar Thermal Test Facility, Sandia National Laboratories recently completed a 3½-year project funded by DOE’s SunShot Initiative to develop a high-temperature falling particle receiver, in which sand-like ceramic particles are heated as they fall through a beam of highly concentrated sunlight focused by an array of mirrors.  The falling-particle receiver enables concentrated solar power with thermal storage for on-demand electricity production and process heat at significantly higher temperatures (up to 1000 °C and higher), which can increase power cycle efficiencies and reduce levelized costs.  Sandia constructed and successfully demonstrated the world’s first continuously recirculating high-temperature 1 MWt falling particle receiver, achieving peak particle temperatures over 900°C and bulk temperatures over 800°C.  The particle heating rate reached 100–300°C per meter of illuminated drop distance at concentrated solar irradiances of ~1,000 kW/m2 and thermal conversion efficiencies of ~80%.  The particle receiver is being considered for next-generation solarized supercritical CO2 Brayton cycles.  A new project through the SunShot National Laboratory Multiyear Partnership (FY16–FY18) was awarded to Sandia to develop a particle/sCO2 heat exchanger for this concept.