High-Flux Solar Absorber Concept for Central Receiver Power Plants

Abstract

For cylindrical receivers with a capacity of about 400 MW/t, an aim-at-the-belt focusing strategy can produce average fluxes the order of 0.5 MW/m2 with peaks as high as 2 MW/m2. An absorber concept is described which uses liquid sodium coolant and a three-header configuration to efficiently capture this solar power. The mechanical design of this absorber is discussed and thermal performance estimates are presented showing the solar-capture efficiency over a range of solar intensities. The sodium-flow characteristics and some potential flow-control problems are also described. A thermal-stress analysis is presented which shows that a limiting factor on the flux capability may be tube-wall creep/fatigue failure and not the heat-transfer capability of sodium.

Limits of the cylindrical absorber design for a sodium receiver

“…Liquid sodium has been shown to enable CSP system operation under high incident radiative flux when used as a heat transfer fluid (HTF) for solar receivers 5 . Values of 1.8 MW.m -2 of peak incident flux have been suggested in the literature for sodium receivers as acceptable design limits for 30 years lifetime 6 , which compares to 1.2 MW.m -2 molten salt receivers 7 . Billboard, cavity and cylindrical type receivers have been suggested as candidate geometries for liquid sodium receivers 4,8 .…”