Characteristics of solar to hydrogen-rich fuel production integrating parabolic trough collectors with partially rotatable tracking strategies

Abstract

To achieve carbon neutrality, hydrogen and solar energy are receiving increasing attention. Concentrated solar thermal energy by parabolic trough collectors can be used to drive methanol cracking reactions for distributed hydrogen-rich syngas production. In this scenario, the collector is characterized by its small size and easy to integrate with hydrogen utilization equipment. However, parabolic trough collectors use a single-axis strategy with inherent large cosine loss, resulting in a low annual efficiency. The partially rotatable tracking is an advanced tracking strategy, which considers the trade-off between performance and cost compared to double-axis tracking strategies, and shows great potential for applications in distributed solar thermochemical reactions. In this study, solar to hydrogen-rich fuel production integrating parabolic trough collectors with the partially rotatable tracking strategy is proposed. The effect of the partially rotatable tracking strategy on the solar thermochemical conversion of methanol cracking is revealed. An annual normalized optical improvement of 40%∼54% is realized over a latitude range of 0∼50° by means of an optimal daily rotation angle. The solar thermochemical reactor with the partially rotatable tracking strategy has the less irreversibility loss during the concentrating process and the higher thermochemical efficiency. The results show that in three Chinese cities (Beijing, Lhasa and Guangzhou) with different latitudes and irradiation conditions, a partial north-south rotation strategy yields an additional 17.42%, 11.62% and 6.22% of chemical energy per year from the sun, while a partial east-west rotation strategy yields an additional 14.91%, 19.35% and 15.37% per year from the sun. The encouraging results indicate a promising method for the effective conversion of solar energy to chemical energy of hydrogen-rich fuels.