Coupling of an Electrolyzer with Rankine Cycle for Sustainable Hydrogen Production via Thermal Solar Energy

Abstract

Due to the global challenges faced everyday by our planet earth, several groundbreaking energy solutions are needed to reduce the environmental pollution caused by fossil fuels and improve energy sustainability for the future generations. The increase in fossil fuel prices, environmental pollution, and limitations in fossil fuel reserves, stresses the need of an alternative energy source that is clean, not hazardous, and dependable. Hydrogen is believed to be the future energy carrier that will reduce environmental pollution and solve the current energy crises especially when produced from a renewable energy source. Solar energy is a renewable source that has been used in the production of hydrogen for years because it is inexhaustible, clean, and a free energy source. Hydrogen is produced by a means of a water splitting process, mainly electrolysis, which requires energy input provided by harvesting solar energy. The proposed model integrates the solar harvesting system to a conventional Rankine cycle, producing electric and thermal power, used in domestic applications, and production of hydrogen by high temperature electrolysis (HTE) using a solid oxide steam electrolyzer (SOSE). The objective of this research is to carry out thermodynamic energy analysis on the proposed system to study the performance and efficiency of the system. The system is divided into three subsystems; solar collector(s), steam cycle, and electrolysis subsystem, where thermodynamic analysis is done using equations from the literature and Engineering Equations Solver (EES). Moreover, parametric analysis will be carried out with the results obtained from EES to study the performance of the system under different conditions. The analysis that will be carried out is to study the effect of varying the solar flux and varying the area of the solar collector on the rate of hydrogen produced. Finally, a comparative analysis will be done with a parabolic trough and heliostat field to investigate which works most effectively with the plant and has the highest rate of hydrogen produced.