Numerical analysis on inlet position and orientation for enhanced thermal performance of a solar thermochemical reactor for two-step WS cycle for hydrogen production

Abstract

This study presents the effect of inert gas flow inlet positioning and orientation on the conversion efficiency of the proposed solar thermochemical reactor for hydrogen production. The nitrogen gas was used as (i) a reducing agent, (ii) a cooling agent to control the porous matrix temperature and (iii) removing oxygen from the STCR chamber. The result of the study demonstrates that the highest average temperature yield of 1570 K occurred at an inlet position of 10 mm with a 75° inclination, while 1665 K was obtained at an inlet position of 10 mm with a 90° inclination. Additionally, a temperature of 1353 K was achieved at an inlet position of 12 mm with a 75° inclination, both radially (for 20 mm thickness) and axially (over 80 mm length) along the centerline of the STCR chamber (extending 125 mm in length). The optimized inlet positioning and orientation provided the improved design of the solar thermochemical reactor (STCR) chamber capable of achieving the uniform solar flux profile and high-temperature distribution in the porous media to successfully carry out the redox reactions and achieve high solar-to-fuel conversion efficiency.