DIRECT SOLAR THERMAL SPLITTING OF WATER AND ON-SITE SEPARATION OF THEPRODUCTS - II - EXPERIMENTAL FEASIBILITY STUDY

The development of a process of hydrogen production by solar thermal w ater splitting (HSTWS) presents a formidable technological task. The p rocess has, however, great potential from the thermodynamic point of v iew and, when combined with fuel cell technology, it can lead to effic ient conversion of solar energy to power. In the process under develop ment at the Weizmann Institute of Science, water vapor is partially di ssociated in a solar reactor at temperatures approaching 2500 K. Hydro gen is separated from the hot mixture of water splitting products by g as diffusion through a porous ceramic membrane. The paper describes th e problems encountered during the development of the HSTWS process. Th e following topics are discussed in some detail: (a) achievement of ve ry high solar hydrogen reactor temperatures by secondary concentration of solar energy; (b) materials problems encountered in the manufactur e of the solar reactor; (c) development of special porous ceramic memb ranes that resist clogging by sintering at very high temperatures. (C) 1997 International Association for Hydrogen Energy.