Design of 24/7 continuous hydrogen production system employing the solar-powered thermochemical S–I cycle

Abstract We propose a system design for continuous and emission-free hydrogen production using the thermochemical Sulfur–Iodine cycle. Process heat required for the sulfuric acid decomposition is exclusively generated by a combination of concentrating solar thermal parabolic trough and solar tower systems, which are operated during the daytime only. The proposed design relies on the decoupling of the high temperature section from the rest of the process through material and energy storage for continuous operation. We conceptually design the whole process via steady-state simulation and assess its thermal efficiency and economics. We reveal that the proposed system is comparable to its alternatives in terms of the heat-to-hydrogen efficiency (38.0%) and the levelized cost of hydrogen 10.4 $/kg H 2 . Since the levelized cost is primarily attributed to the capital investment, enlarging the proposed system will lead to significant cost reduction due to economies-of-scale.