We illustrate a process for designing solar thermal chemical reactors for industrial applications. The process is iterative and involves developing a numerical model of the reactor that links the radiation heat transfer to the other modes of heat transfer and the kinetics of the chemical reaction. Reactors that effectively convert solar energy to chemical energy match well the solar flux entering the reactor to the rate of the reaction being effected in the reactor. The design parameters controlling this match include the reactor's geometry, the reactant feed condition, and the form of the reactants. (C) 2003 Elsevier Ltd. All rights reserved.