Development of a double-helical thermal matching reactor for enhanced solar green hydrogen production

The complementary use of various renewable energy sources exhibits carbon–neutral potential in the field of green hydrogen preparation; therefore, to effectively reduce carbon emissions, promoting the development of hydrogen production technology from renewable energy sources has become an inevitable trend. Solar-powered biogas reforming for hydrogen production effectively utilizes discontinuous and unstable solar energy. However, uneven temperature distribution from the solar collector can adversely affect the reaction process, catalyst performance, and reactor lifespan. To address this, the study introduces a double-helical flow channel thermochemical reactor. This innovative design achieves effective thermal matching between the reaction flow channel and the heated surface, ensuring continuous heating of the reaction gas. It is found that the double-helical structure increases solar-thermochemical energy conversion efficiency to 31.41%, which is 26.36% higher than single-helix structures and significantly better than traditional straight-tube reactors through a multi-physical field coupling analysis. The double-helix reactor is also found to be more environmentally friendly compared to the single-helix reactor. The energy analysis shows that adding a vacuum cavity layer around the reactor effectively reduces convective heat loss to the air. This improvement increases the solar-thermochemical energy conversion efficiency to 34.51%, a 9.87% enhancement over the previous design's 31.41%. The study offers a novel approach for designing multi-energy complementary hydrogen production thermochemical reactors.