Study and multi-objective optimization of integrating an energetic solar thermal application, a supercritical process, and a high-temperature electrolyser

Abstract

Supercritical processes using carbon dioxide reached suitable sustainability in previous research. Hence, the current paper proposes and examines a recompression supercritical carbon dioxide Brayton cycle integrated with a solar power tower. To improve the stability of the solar subsystem for continuous daily operation, two energy storage stages are employed innovatively. In addition, the whole scheme embraces a solid oxide electrolyzer. Therefore, a novel combined electricity and hydrogen cogeneration model based on solar energy is evaluated here. To this end, the energy-, exergy-, sustainability-, and economic-based parametric sensitivity study is implemented comprehensively. Net present value is another performance metric investigated in this paper. Besides, a novel multi-objective approach utilizing an artificial neural network combined with a multi-objective grey wolf optimization is performed. Considering four different decision parameters, optimum objectives include exergy efficiency, hydrogen production rate, and products’ unit cost. From the parametric sensitivity study, it is inferred that the outlet pressure of the low-pressure turbine significantly affects performance metrics. Also, from the optimization, the optimum values of mentioned objectives equal 2587 kg/day, 20.89%, and 17.25 $/GJ, respectively. Moreover, the net present value indicates that the payback period can be reduced up to 8.1 years corresponding to optimum operational conditions.

Keywords

• Supercritical process
• Solar power tower
• Electrolyzer
• Sustainability
• Multi-objective optimization