Direct Solar Thermal Hydrogen Processes

Baykara SZ (2004) Hydrogen production by direct solar thermal decomposition of water, possibilities for improvement of process efficiency. Int J Hydrogen Energy 29 1451-1458... 

Solarization process increases soil temperatures up to levels lethal to many plant pathogens and pests and, therefore, direct thermal inactivation is the most important and normally expected mechanism. Some studies on the biochemical bases of sensitivity of organisms to high temperatures hypothesized that heat sensitivity is related to small differences in cell macromolecules, leading to a lethal increase of intra-molecular hydrogen, ionic, and disulfide bonds (Brock 1978). Sundarum (1986) suggested a reduced cell membrane function beyond an upper limit fluidity... 

Many other methods for hydrogen production, suitable for coupling with solar or other renewable energy technologies, have been investigated and developed to at least a pilot demonstration stage. These include direct thermal decomposition or thermolysis [24], thermochemical cycles [25], and photolysis (photochemical, photoelectrochemical, and photobiological processes) [26,27]. Unfortunately, all of these processes have severe technical difficulties, many of them have been abandoned, and all of them are far from industrial use. 

---