Exergy and engineering analyses of hybrid thermochemical solar hydrogen production

A hybrid thermochemical solar hydrogen producing process has been developed and evaluated using the first and second laws of thermodynamics. The cycle is based on sulfuric acid decomposition and the synthesis processes developed earlier. The process has been improved by producing mechanical power using additional primary energy as well as excess process heat generated within cycle. The thermal and exergetic efficiencies of a daily cycle have been determined as 58.24 and 35.80 per cent, respectively. For a plant producing 0.66 × 106 GJ H2 per year, the typical levelized costs of hydrogen for 15.9% capital charge rate are 40.92$ (1988) per GJ energy and 49.72$ (1988) per GJ exergy.