Proposal and investigation of a novel hybrid hydrogen production and liquefaction process using solid oxide electrolyzer, solar energy, and thermoelectric generator

In this research, an integrated system of large-scale hydrogen production and liquefaction has been introduced. Conceptual configurations for the hydrogen liquefaction cycle are designed, modeled, simulated, optimized, and analyzed for energy, and the most appropriate ones are selected for use in system. A combination of several units is provided together to produce and then liquefy hydrogen utilizing solar energy. The designed system uses linear Fresnel collectors in combination with a solid oxide electrolyzer set, thermoelectric generator, and Rankine cycle to form the hydrogen production section. The proposed system has a production capacity of 6400 kg of liquid hydrogen each hour. The specific energy consumption and coefficient of performance of the proposed refrigeration cycle were calculated for mass flows rates of 1 kg/s, 1.5 kg/s, and 1.77 kg/s. These values at best were 5.72Kwh/Kg(LH2) and 0.1804, respectively. Declared values are significantly better than the corresponding values of similar and reference liquefaction cycles. The energy efficiencies of the electrolyzer, LFR, Rankine cycle, and thermoelectric generator were calculated as 71.18%, 21.42%, 46.64%, and 12.4% respectively. Also, the effect of operational parameters of each subsystem, including temperature and pressure of the input current to the electrolyzer and the total area of the solar reflector on the overall proficiency of the system was researched and the results are presented. The energy efficiency of the hydrogen production sector was 15.98% and the system's total solar fraction was 0.86.

Automated summary

This research introduces an integrated system for large-scale hydrogen production and liquefaction, using solar energy. The system combines multiple units to produce and liquefy hydrogen. The system has high energy efficiency and performance compared to similar liquefaction cycles. The operational parameters of each subsystem and their effects on the overall system efficiency were also studied.