Enhancement of Hydrogen Production Using an Integrated Evacuated Tube Solar Collector and PEM Electrolyzer With Al2O3 and SiO2 Hybrid Nanofluids

Abstract

The motivation for this study stems from the global demand for clean energy solutions and the limitations of conventional fluids in hydrogen production systems. By exploring hybrid nanofluids, this research aims to enhance efficiency and sustainability in solar-thermal energy applications. An evacuated tube solar collector (ETSC) with a polymer electrolyte membrane (PEM) electrolyzer efficiently harnesses solar energy for hydrogen production. The ETSC's vacuum design minimizes heat loss, providing consistent thermal performance. This system enables clean hydrogen generation, reducing emissions. This study investigated the integration of an ETSC with a PEM electrolyzer and organic Rankine cycle (ORC) for efficient hydrogen production. Water as the working fluid in the ETSC circuit resulted in lower hydrogen production rates, prompting the introduction of Al₂O₃ and SiO₂ hybrid nanoparticles at a 50:50 ratio to form an enhanced hybrid nanofluid. The resulting various volume concentrations (0.5%, 1%, 1.5%, and 2%) of the hybrid nanofluid were tested, yielding energy gains of 13.22%, 21.37%, 30.38%, and 48.52%, respectively, compared to water. The ORC efficiency enhanced by 12.29% at 0.5 vol.%, 23.10% at 1 vol.%, 34.15% at 1.5 vol.%, and 48.40% at 2 vol.%. The PEM electrolyzer produced a maximum hydrogen yield of 3105.6 g, with an overall system efficiency of 71.3% and hydrogen production of 2156.7 g at 2 vol.%, demonstrating the significant performance enhancements achieved with hybrid nanofluids. The results demonstrated the effectiveness of hybrid nanofluids in enhancing system efficiency and hydrogen output, underscoring their importance in promoting sustainable hydrogen production technologies.