Performance improvement of a solar volumetric reactor with passive thermal management under different solar radiation conditions

To alleviate the effect of solar radiation fluctuation on the solar volumetric reactor, phase change material (PCM) is applied to buffer the temperature vibration and improve the stability of thermochemical reactions. In this work, we analyzed the heat flow and dis-tribution characteristics of the conventional double-walled volumetric reactor filled with PCMs (SVR1). We then proposed a novel solar volumetric reactor design (SVR2) to solve the problems of local high temperature, slow charging-discharging rate, and fluctuating methane conversion in various radiation conditions. The heat and mass transfer model coupled with thermochemical reaction kinetics was established to compare the perfor-mance of SVR1 and SVR2 under steady state, heat charging-discharging mode, and actual solar radiation fluctuation, respectively. The results show that compared to SVR1, the maximum temperature of SVR2 decreases by 106.3 K, and the minimum methane con-version rate increases from 77.4% to 93.6% under natural solar radiation fluctuation.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

In order to counteract the effects of solar radiation fluctuation, phase change material (PCM) was employed in the solar volumetric reactor. A new design, SVR2, was proposed to address issues of high temperature, slow charging-discharging rate, and fluctuating methane conversion. Simulation results showed that SVR2 achieved a lower maximum temperature and higher methane conversion rate compared to the conventional SVR1 under natural solar radiation fluctuation.