Dynamic Modeling and Control of a Two-Reactor Metal Hydride Energy Storage System

Dynamic Modeling and Control of a Two-Reactor Metal Hydride Energy Storage System

Event Date: November 1, 2022
Authors: P. Krane, D. Ziviani, J.E. Braun, A.M. Marconnet, and N. Jain
Journal: Applied Energy
Paper URL: Link to Full Text
Applied Energy, vol. 32, p. 119836, 2022. DOI:10.1016/j.apenergy.2022.119836

Metal hydrides have been studied for use in energy storage, hydrogen storage, and air-conditioning (A/C) systems. A common architecture for A/C and energy storage systems is two metal hydride reactors connected to each other so that hydrogen can flow between them, allowing for cyclic use of the hydrogen. This paper presents a nonlinear dynamic model and multivariate control strategy of such a system. Each reactor is modeled as a shell-and-tube heat exchanger connected to a circulating fluid, and a compressor drives hydrogen flow between the reactors. We further develop a linear state–space version of this model integrated with a model predictive controller to determine the fluid mass flow rates and compressor pressure difference required to achieve desired heat transfer rates between the metal hydride and the fluid. A series of case studies demonstrates that this controller can track desired heat transfer rates in each reactor, even in the presence of time-varying circulating fluid inlet temperatures, thereby enabling the use of a two-reactor system for energy storage or integration with a heat pump.