Thermodynamic investigation of a novel hydrogen liquefaction process using thermo-electrochemical water splitting cycle and solar collectors

• Published in: Energy conversion and management 2021-08, Vol.242, p.114318, Article 114318
• Main Authors: Ebrahimi, Armin, Saharkhiz, Mohammad Hossein Monajati, Ghorbani, Bahram
• Format: Article
• Language: English
• Subjects: Alternative energy; Chlorine; Climatic conditions; Cogeneration; Electrochemistry; Energy sources; Energy storage; Heat; Heat exchangers; Hydrogen; Hydrogen liquefaction cycle; Hydrogen production; Liquefaction; Liquid hydrogen; Magnesium; Oxygen; Parameters; Pinch analysis; Power consumption; Process integration; Renewable energy; Renewable energy sources; Renewable resources; Sensitivity analysis; Solar collectors; Solar energy; Solar parabolic dish collector; Splitting; System effectiveness; Thermo-electrochemical water splitting cycle; Thermodynamic efficiency; Water splitting
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2021.114318

•A novel integrated system for liquid hydrogen production is developed.•This system consists of the thermo-electrochemical and hydrogen liquefaction cycles.•Solar dish collectors are used for supplying the system required heat demand.•Pinch method on multi-stream exchangers to achieve heat exchanger networks is used.•The total thermal efficiency of the integrated system is 71.4% Hydrogen production and liquefaction using solar thermo-electrochemical water splitting systems can as an effective method for long-term renewable energy source storage are suggested. In this paper, a novel integrated configuration for the cogeneration of liquid hydrogen and oxygen by magnesium-chlorine thermo-electrochemical water splitting cycle, hydrogen liquefaction unit, and solar dish collectors is developed. The novel integrated structure produces 7116 kg/h liquid hydrogen and 57597 kg/h oxygen. Through the magnesium-chlorine cycle, pure hydrogen is produced and the required energy is supplied through solar renewable energy based on the climatic conditions of Isfahan city in Iran. Then the produced hydrogen enters the liquefaction process to generate liquid hydrogen. The heat and power consumption of the whole system for the cogeneration of liquid hydrogen and oxygen are 207.9 MW and 373.9 MW, respectively. The heat waste of the integrated structure is used to produce hot water as a by-product. The specific power consumption of the liquefaction cycle is 7.6 kWh/kg LH2 and also the total thermal efficiency of the whole integrated system is 71.4%. Through the pinch method, heat exchanger networks related to multi-stream heat exchangers of the present system are extracted. Sensitivity analysis is used to investigate the effects of changes in major parameters including operating conditions of the thermo-electrochemical cycle as well as changes in the solar dish collector main parameters and the results are reported.