Exergy effeciency and local heat production in solid oxide fuel cells

Kjelstrup, Signe; Møller-Holst, Steffen

doi:10.1016/0013-4686(93)85164-t

Cited by 23 publications

(2 citation statements)

References 17 publications

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“…In rSOC reactor, only the electrochemical reactions contribute to the work term (

W_{rev}

) in both fuel cell and electrolysis mode. The reactions, RWGS ((R3)) and SMR ((R2)), do not take part electrochemically and hence the work potential of these reactions is lost . Therefore, theoretical work term (

W_{rev}

) in Equation is evaluated by Equation .

W_{rev, fc} = - false(G^{2} - G^{1} false) - false(- Δ_{normalR 2} G false)

…”

Section: Resultsmentioning

confidence: 99%

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Electricity Arbitration and Sector Coupling with an Experimentally Validated Reversible Solid Oxide Cell Reactor System Connected to the Natural Gas Grid

2020

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Chemical energy storage offers an attractive solution for the arbitration of intermittent renewable electricity due to its higher energy storage capacity and storage duration. Reversible solid oxide cell (rSOC) reactor systems can efficiently operate in electrolysis operation to convert electrical energy to chemical energy or in fuel cell mode to convert chemical energy back to electrical energy. Natural gas is widely used in the chemical industry as a source of energy and hydrogen. Hence, storing electrical energy in the form of synthetic natural gas can couple electricity arbitration with chemical process industries. A methane‐based rSOC system concept for the purpose of energy storage and sector coupling is investigated. A process system analysis is performed based on an experimental study of a commercially available rSOC reactor. A validated rSOC reactor model is used to identify optimal system operating conditions. The proposed system concept achieves a chemical to electrical energy conversion efficiency of 57% and electrical to chemical energy conversion efficiency of 93% based on first law and lower heating value. A net electrical storage efficiency of 53% can be achieved.

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“…In rSOC reactor, only the electrochemical reactions contribute to the work term (

W_{rev}

W_{rev}

) in Equation is evaluated by Equation .

W_{rev, fc} = - false(G^{2} - G^{1} false) - false(- Δ_{normalR 2} G false)

…”

Section: Resultsmentioning

confidence: 99%

“…The reactions, RWGS ((R3)) and SMR ((R2)), do not take part electrochemically and hence the work potential of these reactions is lost. [36,37] Therefore, theoretical work term (W rev ) in Equation (4a) is evaluated by Equation (5).…”

Section: Ideal Performance With and Without Heat Storagementioning

confidence: 99%

Electricity Arbitration and Sector Coupling with an Experimentally Validated Reversible Solid Oxide Cell Reactor System Connected to the Natural Gas Grid

2020

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Low temperature fuel cells

Divišek

2010

Handbook of Fuel Cells

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The principle of energy conservation determines the energy balance equation, which can be generally formulated as the sum of single rates of energy input and output, energy production and accumulation. In a fuel cell, the balance takes into account the thermal and the electrical energy. There are three modes of heat transfer process occurring in a fuel cell: conduction, convection and radiation. The fundamentals of these processes are discussed together with the heat transfer occurring with the change of state, such as evaporation, condensation and additional chemical reactions. The general energy balance equation is analyzed with respect to the heat sources, energy balances for single phases, boundary conditions and parameter definition. An approach for the delocalization of reaction entropy in fuel cells is also given. Based on the general heat transfer equations, water and heat management for low temperature fuel cells (hydrogen and direct methanol) is discussed considering cell structure, current density and temperature distribution. Heat transfer in high temperature fuel cells (HTFCs) is extremely important for the system evaluation. Heat management for high temperature fuel cells (molten carbonate fuel cells (MCFCs) and solid oxide fuel cells (SOFCs)) is analyzed. Heat generation in HTFCs is strongly influenced by chemical reactions, such as methane/water reforming. Thermodynamic analysis and reaction kinetics of the reforming reaction are presented. A performance analysis of MCFCs and planar and tubular SOFCs is made considering the cell geometry, current density and temperature distribution. Finally, heat removal for cogeneration in SOFCs is dealt with.

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A thermodynamically consistent framework for non‐isothermal modelling of local heat generation and electromotive force in SOFC single electrodes

Amiri

Hayes

Sarkar³

2019

Can J Chem Eng

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Mathematical models for single electrode reversible heat and non‐isothermal electromotive force (EMF) of a solid oxide fuel cell (SOFC) are developed. These models estimate the volumetric reversible heat generation and EMF of electrochemical reactions, within each electrode at local conditions of temperature and pressure, based on entropy change of half reactions. The resulting equations are thermodynamically consistent. They inherently obey the conservation of energy law as the electrochemical energy released added to the heat of reactions at each electrode equate the enthalpy change of the reacted species. The equations are implemented to model electrodes in a tubular micro‐ solid oxide fuel cell (TμSOFC). The thermodynamic consistency of the model is numerically confirmed as the enthalpy of the reactants equates the electric energy released by the cell plus the sum of electrode heats plus electrolyte Ohmic heat. The effect of thermal gradients on the cell's overall EMF is found to be negligible. The reversible and irreversible heat generation of each electrode are distinguished. Overall, the anode is found to be endothermic, and the cathode exothermic.

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Exergy effeciency and local heat production in solid oxide fuel cells

Cited by 23 publications

References 17 publications

Electricity Arbitration and Sector Coupling with an Experimentally Validated Reversible Solid Oxide Cell Reactor System Connected to the Natural Gas Grid

Electricity Arbitration and Sector Coupling with an Experimentally Validated Reversible Solid Oxide Cell Reactor System Connected to the Natural Gas Grid

Low temperature fuel cells

A thermodynamically consistent framework for non‐isothermal modelling of local heat generation and electromotive force in SOFC single electrodes

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