(260d) Solar-Based Hydrogen Production and Storage System Utilizing Auto-Cascade and Mixed Refrigeration Cycles

Numerous countries based on the Paris Agreement have committed to significantly decrease carbon dioxide (CO₂) emissions and achieve net-zero carbon emissions by 2050. The signatories of the Paris Agreement are interested in increasing the use of hydrogen (H₂) as a clean fuel alongside other energy carriers. Large-scale storage and distribution of H₂ is a major challenge due to its low energy density in gas form. The main challenges of liquid H₂ storage as one of the most promising techniques for large-scale transportation and long-term storage include high specific energy consumption (SEC), low exergy efficiency, high total costs, and boil-off gas losses. In this study, an integrated structure of an auto-cascade and a multi-component refrigeration cycle is used for H₂ pre-cooling. Also, the Joule-Brayton process is employed to liquefy pre-cooled H₂. Parabolic trough collectors and photovoltaic panels are utilized to provide heat and electricity for the H₂ production and storage structure based on the energy potentials of Arkansas, USA. The proposed integrated structure utilizes a proton exchange membrane electrolysis electrolyzer for H₂ production. Utilizing the auto-cascade refrigeration cycle to recover solar energy in the form of refrigeration during the H₂ pre-cooling process results in a reduction of SEC. Pinch analysis is utilized to design heat exchanger networks effectively and reduce energy consumption. The exergy analysis of the proposed system provides valuable insights into the efficient use and loss of input exergy. Exergy loss, which acts as an irreversibility index, quantifies the inefficiencies within the system. In this research, the sensitivity analysis phase aims to investigate the effect of design variables on various output parameters, such as major energy factors (e.g., SEC and net power consumption) and exergy (e.g., exergy destruction and exergy efficiency).