For the solar thermochemical gasification of coal coke to produce CO + H-2 synthetic gas using concentrated solar radiation, a windowed reactor prototype is tested and demonstrated at laboratory scale for CO2 gasification of coal coke using concentrated Xe light from a 3-kW(th) sun simulator. The reactor was designed to be combined with a solar reflective tower or beam-down optics. The results for gasification performance (CO production rate, carbon conversion, and light-to-chemical efficiency) are shown for various CO2 flow rates and ratios. A kinetics analysis based on homogeneous and shrinking core models and the temperature distributions of the prototype particle bed are compared with those for a conventional fluidized bed reactor tested under the same Xe light irradiation and CO2 flow-rate conditions. The effectiveness and potential impacts of internally circulating fluidized bed reactors for enhancing gasification performance levels and inducing consistently higher bed temperatures are discussed in this paper. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.