VOLUMETRIC RECEIVER DEVELOPMENT - A HEAT TRANSFER AND DESIGN EVALUATION OF AN ADVANCED AIR HEATING SOLAR THERMAL CENTRAL RECEIVER CONCEPT (ENERGY, NUMERICAL ANALYSIS, FLUID DYNAMICS, SIMULATIONS, MONTE CARLO)

The volumetric receiver is an advanced solar central receiver concept designed to produce high temperature air. This document presents the results of a heat transfer and performance evaluation of the volumetric receiver concept.;The unusual features of the volumetric receiver required the development of analytical models for radiation heat transfer, convection and receiver performance. Radiation heat transfer was calculated using a Monte Carlo model where an innovative numerical scheme was used to improve computation speed. Convective heat transfer correlations used were obtained from a review of existing literature. The receiver performance was predicted using a transient simulation which calculated the equilibrium temperature distribution.;The results of an extensive parametric investigation of five volumetric receiver design variations are reported and the most attractive design is identified. This design consists of a large number of small diameter ceramic fibers enclosed in a shroud. Convection from the fibers is enhanced by inducing a swirl in the incoming ambient air. The combination of small ceramic fibers and the induced swirl produces very efficient heat transfer. Performance results showed that the volumetric receiver has a predicted efficiency of 86% as compared to other high temperature receivers where the efficiency is estimated to be 81%.;The volumetric receiver consists of an array of ceramic fins or fibers arranged in concentric rows around a central manifold. Solar energy is absorbed on the fins or fibers and is used to heat ambient air which is drawn into the receiver by an induced draft fan.