An epitrochoidal rotary reactor for solar-driven hydrogen production based on the redox cycling of ceria: Thermodynamic analysis and geometry optimization

A novel epitrochoidal rotary reactor was proposed to perform efficient solar-driven water-splitting based on thermochemical redox cycling of ceria. This study is focused on the geometry optimization of the epitrochoidal rotary reactor to achieve the optimal thermodynamic solar-to-fuel energy conversion efficiency. The mathematical descriptions of kinematic synthesis of the conjugate rotor and stator profiles are derived in detail. The geometric compression ratio is statistically estimated using a hit-or-miss Monte Carlo method. A thermodynamic model considering the solid and gas phase heat recovery is developed to evaluate the performance of the epitrochoidal rotary reactors in various geometries. Among all geometrical parameters instigated, the cam-to-rotor size ratio and the number of rotor sides are found to have the most significant impact on the solar-to-fuel energy conversion efficiency. The optimal design of the epitrochoidal rotary reactor with a curved triangle rotor offers a geometrical compression ratio of 13 and a solar-to-fuel efficiency of 17% under a concentrated solar radiative flux of 3000 suns.