High performance solar receiver-reactor for hydrogen generation

This paper reports on the numerical analysis of a volumetric solar receiver-reactor for hydrogen pro-duction, using the 2-step reduction-oxidation cycle. A detailed parametric sweep covering hundreds of various parameter combinations is performed for a large solar reactor, using a transient physical model. We generate performance maps which are currently cost prohibitive via experimental or high -fidelity simulation studies. The following performance metrics are evaluated: solar to fuel efficiency, hydrogen yield, conversion extent and specific hydrogen yield. We show that the relations between the different performance metrics are complex, leading to different optimal points depending on the metric pursued. The daily hydrogen yield for a single reactor varied between 0.89 kg for an absorber thickness of 30 mm, and up to 1.04 kg for a 60 mm thick receiver, with solar to fuel efficiency values of 3.84% and 3.81% respectively. For a case with 45 mm thick receiver, an intermediate hydrogen yield of 0.94 kg is calcu-lated, while exhibiting the highest efficiency (4.05%). The efficiency can be further increased to 5.86% by using a simple heat recovery system, and reach an upper limit of 21.16% with a more sophisticated heat recovery method. (c) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study conducted a numerical analysis of a volumetric solar receiver-reactor for hydrogen production, evaluating performance metrics such as solar to fuel efficiency and hydrogen yield. The research found complex relationships between different performance metrics, leading to different optimal points depending on the metric pursued. The study demonstrated the potential for further increasing efficiency through heat recovery systems, with the highest efficiency reaching 21.16% through a sophisticated method.