Particle residence time distributions in a solar vortex receiver

Abstract

There is a growing interest in the use of solid particles as the absorber of concentrated solar thermal radiation, due to their high surface area per unit mass and compatibility with direct irradiation. A solar particle receiver technology that has received recent attention features direct irradiation of particles that are transported by a carrier gas and suspended in a vortex within a cylindrical cavity, termed the solar vortex receiver, SVR. To support the development of vortex-based particle receiver systems, new understanding of the particle residence time distributions within the receiver and their influencing factors is required. In the present paper, a method has been developed for measuring particle-phase residence time distributions in a laboratory-scale vortex-based solar particle receiver using a modified tracer pulse method. The measurements quantify the influence of both air volumetric flow rate and particle size on the particle residence time distribution, with trends that are consistent with expectation. Both an increase in the air flow rate and a decrease in particle size result in a shorter, narrower distribution of residence times.