Abstract
A 1 MWth high-temperature falling particle receiver was constructed and tested at the National Solar Thermal Test Facility at Sandia National Laboratories. The continuously recirculating system included a particle elevator, top and bottom hoppers, and a cavity receiver that comprised a staggered array of porous chevron-shaped mesh structures that slowed the particle flow through the concentrated solar flux. Initial tests were performed with a peak irradiance of similar to 300 kW/m(2) and a particle mass flow rate of 3.3 kg/s. Peak particle temperatures reached over 700 degrees C near the center of the receiver, but the particle temperature increase near the sides was lower due to a non-uniform irradiance distribution. At a particle inlet temperature of similar to 440 degrees C, the particle temperature increase was 27 degrees C per meter of drop length, and the thermal efficiency was similar to 60% for an average irradiance of 110 kW/m(2). At an average irradiance of 211 kW/m(2), the particle temperature increase was 57.1 degrees C per meter of drop length, and the thermal efficiency was similar to 65%. Tests with higher irradiances are being performed and are expected to yield greater particle temperature increases and efficiencies.