Structural design and analysis of a solar thermochemical reactor partially filled with phase change material based on shape optimization.

[Display omitted] • A solar parabolic trough reactor shape optimization model is developed. • Catalytic tube shape described by Bézier parameterization curve. • Optimize the catalytic tube shape to enhance the methanol conversion efficiency. • Filling with metal foam reinforced PCM to improve reactor transient performance. • Less catalyst and higher overall performance are achieved in optimized reactor. Solar parabolic trough thermochemical reactor (SPTR) exhibits poor comprehensive performance due to the intermittent solar influence. In this work, a Bézier parametric curve-based shape optimization model is presented for designing the methanol steam reforming reaction-based SPTR filled with metal foam enhanced phase change material. Combined with the SPTR multi-field model, the catalytic tube shape in SPTR is well optimized by Globally Convergent Method of Moving Asymptotes, and finally an optimized rose-shaped catalytic tube with maximum methanol conversion efficiency is obtained. The SPTR performances of unoptimized original, customized and optimized tubes under constant and fluctuating solar flux are also analyzed and discussed in detail. The results show that the optimized tube and the small inlet cone-frustum tube have a better overall performance than the original tube, with about 67% reduction in catalyst usage. Especially for the optimized tube with optimal steady performance, methanol conversion efficiency, solar thermochemical efficiency and hydrogen yield are relatively improved by 4.3%, 8.2% and 2.4%, respectively, as compared to the original tube. The transient performance of the optimized tube also shows a relative increase of 8.6% and 8.2% in average conversion and hydrogen yield, and the reaction is more stable and safe in flux fluctuations. [ABSTRACT FROM AUTHOR]