Thermochemical Energy Storage (TCES) with metal oxide particles is a promising technology for renewable energy dispatchability. TCES involves a two-step redox process in which the particles are charged under inert gas by means of a high-temperature heat source such as concentrated solar (~1500 °C) while the discharge occurs under an oxidative atmosphere, at temperatures typically above 900 °C. Discharging requires precise temperature, atmosphere and flow control for efficient oxidation and heat extraction. Moreover, the scalability of TCES reactors depends on technical prerequisites including spatial and temporal decoupling of charge and discharge steps with low-cost storage between them, and the use of a heat transfer fluid (HTF) for power block integration. Presented here is our development of a 1 kW discharge/oxidation reactor for TCES. The concept includes a counter-flow reactor/heat exchanger positioned between two moving beds. The design seeks to promote the exothermic oxidation reaction, and effective heat extraction and utilization. Our experimental campaigns so far have achieved sustained HTF outlet temperatures of ~900 °C with thermal efficiencies of ~38 %, and oxidation conversions of ~66 %. Further improvements aim at increasing oxidation conversion and thermal efficiency.
Juve Ortiz-Ulloa is a Ph.D. student in Chemical Engineering working under the advice of Dr. Nick AuYeung. He previously obtained a master’s degree in Energy Systems from the University of Melbourne. His work focuses on developing effective and scalable TCES materials and reactors for high temperature applications such as concentrated solar power and industrial heat.