Combined heat and mass transfer analysis of solar reactor integrating porous reacting media for water and carbon dioxide splitting

• Published in: Solar energy 2022-08, Vol.242, p.130-142
• Main Authors: Shuai, Yong, Guene Lougou, Bachirou, Zhang, Hao, Han, Dongmei, Jiang, Boshu, Zhao, Jiupeng, Huang, Xing
• Format: Article
• Language: English
• Subjects: Heat transfer in porous media; Mechanism and kinetic; Solar fuel; Thermochemistry
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2022.07.017

•Solar in-situ heating and thermal coupling chemical micro-mass transport are typical phenomena observed in the reactor.•Reacting media permeability influences thermal and chemical conversion performances.•Most of the heat losses were associated with re-radiation on the reactor front face.•Synergistic activity of Fe and Co at CuO interface exhibited significant fuel yield.•Higher solar fuel conversion efficiency of up to 33.52% was obtained. Radiative heat flux transfer across a chemical reacting media is a complex system mostly characterized by phenomena including in-situ heating and chemical species micro-mass transport. To solve simultaneously the issue associated with radiative heat transport and chemical conversion intensification, this study developed a combined heat and mass transfer process of a solar reactor integrating Fe-Co-CuO coated SiC porous reacting media. It is demonstrated providing a larger convective heat transfer interface in the oxidation region could result in excessive solar energy absorption with a significant reduction in H2O and CO2 conversion. From the mechanistic aspect, there exists a trade-off between heat transfer enhancement and chemical conversion performance improvement. While re-radiation heat loss at the reactor front face was found as a major factor affecting efficient solar energy conversion, the performance indicators of the reactor are strongly influenced by the permeability of the reacting media. The higher the chemical products evolution in the reacting media, the higher the solar fuel conversion efficiency of up to 33.52% can be gained using a cavity having a porous media of Ф = 0.9 porosity and dp = 0.019 mm under 30 kW/m2 radiative heat flux. This study provided comprehensive insights into solar in-situ heating and thermal transport combining chemical species micro-mass transport mechanisms in a thermochemical reactor.