Modeling a Reversible Solid Oxide Fuel Cell as a Storage Device Within AC Power Networks

Abstract

A reversible solid oxide fuel cell (RSOFC) system, consisting of a RSOFC stack, heat store, and electrical inverters to convert DC to AC power, is shown by computer modeling to have the potential to efficiently store electrical energy. This paper describes the modeling of a single RSOFC, based on a proposed cell geometry, empirical data on the resistivities of the components, and calculation of activation and diffusion polarization resistances from electrochemical theory. Data from ac impedance spectroscopy measurements on symmetrical cells are used to model RSOFC impedance. A RSOFC stack is modeled by electrically linking the individual cells inside a pressurized vessel. A phase change heat store is added to improve energy storage efficiency. The model is implemented in MATLAB®/Simulink®. Two competing inverter control schemes are compared, trading off DC bus ripple against AC power quality. It is found that selection of appropriate DC bus capacitance is important in certain scenarios, with potential system cost implications. It is shown that the system can store electrical energy at an efficiency of 64% over a single discharge–charge cycle, i.e., hydrogen to electricity and heat to hydrogen.

Design and Optimization of a Fuel‐ and Air‐Preheater for Reversible Solid Oxide Fuel Cells

“…Thermal diffusivity / m 2 s -1 q 1 Inlet temperature of hot side / K q 1 Outlet temperature of hot side / K q 2 Inlet temperature of cold side / K q 2 Outlet temperature of cold side / K r Fliud density / kg m -3 Heat transfer coefficient between hot side and wall a 2 Heat transfer coefficient between cold side and wall l…”

“…Heat transfer coefficient between walls V Drag coefficient c 1 Correction factor for hot channels c 2 Correction factor for cold channels…”

The performance of thermal based modified solid oxide fuel cell (SOFC) model under different DC load conditions

“…SOFC models, which concentrate on effects of temperature dynamics, were previously investigated in the literature (Sedghisigarchi & Feliachi, 2004;Goel et al, 2006;Wang & Nehrir, 2007a;Wu et al, 2008a;Ren et al, 2010;Gebregergis & Pillay, 2010;Yang et al, 2009). The output power of fuel cell is closely related to the temperature of the fuel cell unit (Sedghisigarchi & Feliachi, 2004).…”

La2NiO4+δ as oxygen electrode in reversible solid oxide cells

“…Reversible solid oxide cells capable of working in solid oxide fuel cell (SOFC) mode for power generation from fuel and as solid oxide electrolysis cell (SOEC) mode for fuel generation form the electrolysis of steam and CO 2 have generated widespread interest for the development of environmentally friendly ways of energy storage and electricity generation [1,2], because a RSOC system could provide effective and flexible power delivery and has the potential to be used as an efficient electrical energy storage device at the power plants based on intermittent renewable energy sources [3,4], and also provides the possibility of utilization of waste heat generated by high temperature industrial processes and excess electricity produced in off-peak hours at conventional power plants and renewable sources for steam electrolysis or steam/CO 2 co-electrolysis in SOEC mode [5,6].…”