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POLITECNICO DI TORINO
DOCTORAL PROGRAM IN ENERGETICS
Ph. D. THESIS PROPOSAL
Subject
Optimal design of a novel MCFC stack for micro-cogeneration
List of proponents (with e-mail address of the responsible person)
Michele Calì
[email protected]
Vittorio Verda
[email protected]
Description of the international background of the proposal
Among high temperature fuel cells, Molten Carbonate Fuel Cells (MCFC) have reached nowadays an advanced
industrial development. In particular, the integration of this technology with microturbines, which represents a major
option for future distributed generation, has been already obtained in various full scale demonstration plants. Despite
these results, large efforts are still required to improve performances and reliability and to reduce costs.
Only few papers are available on MCFC modeling. Most of them are black box models developed for control system
design purposes (see for example [Fan et al. 2007]). Concerning detailed modeling, in [He and Chen, 1998] a coarse
transient tridimensional model is considered. The domain is constituted of a single repeated cell. A similar work is
proposed in [Yu et al. 2008], where an experimental validation of the cell model is proposed. In [Brouwer et al.
2006] a nodal model of a single cell is proposed together with an experimental validation. Yoshiba and co-workers
[Yoshiba et al., 2000] have proposed a one dimensional thermal model of a stack, including radiation heat transfer, to
calculate temperature distributions for diagnosis purposes. Marra has recently proposed a fluid-dynamic
characterization of the anodic and cathodic gas distributions using a FEM model [Marra, 2008].
Research program objectives (intermediate and final) and expected results
This research project aims to optimize the geometry of a stack prototype constituted of 15 molten carbonate
fuel cells built by Fabbricazioni Nucleari.
The first part of this work is focused on the fuel cell performance improvements through re-design of the
fuel distribution, with the aim of maximizing the homogeneity of the reactants concentration on the active
surfaces. The analysis will be conducted using a CFD model and is applied to the circular shaped fuel cell
prototype. The model will account for heat transfer, fluid flow, mass transfer, current transfer, chemical
and electrochemical reactions. The model will be validated using the experimental data obtained in the
tests.
The optimization is then conducted by modifying the configuration of the distribution system inside the
cell. To achieve the goal, the tree shaped channels will be considered for the fluid supply and various
number of outlet channels will be considered. A fluid network model is used to select the optimal
configurations, then the system optimization is conducted using the CFD model. The entropy generation
analysis is used as the tool for system optimization.
In the second part of the research, the analysis will be focused on the fluid distribution within the stack. A
full CFD model of the entire stack will be considered and various designs, obtained by modifying the
geometry of the distribution channels as well as the recirculation system will be analyzed. Different
operating conditions will be also considered in order to optimize the cell operation. The entropy generation
minimization technique will be used to identify the main source of irreversibilities and then to select the
most effective ways to conduct the optimization.
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List of publications of the proponents and/or specific references (with titles)
W. He, Q. Chen (1998). Three-dimensional simulation of a molten carbonate fuel cell stack under
transient conditions. Journal of Power Sources 73: 182–192
L.Yu, G. Ren, X. Jiang (2008). Experimental and analytical investigation of molten carbonate fuel
cell stack. Energy Conversion and Management 49: 873–879
J. Brouwer, F. Jabbari, E.M. Leal, T. Orr (2006). Analysis of a molten carbonate fuel cell:
Numerical modeling and experimental validation. Journal of Power Sources 158: 213–224
D. Marra (2008). Gas distribution inside an MCFC. International Journal of Hydrogen Energy, 33:
3173 – 3177
F. Yoshiba, T. Abe, T. Watanabe (2000). Numerical analysis of molten carbonate fuel cell stack
performance: diagnosis of internal conditions using cell voltage profiles. Journal of Power
Sources 87: 21–27
C. Massano, A. Sciacovelli, V. Verda (2009). Detailed Model of Molten Carbonate Fuel Cell
Stacks. 22nd International Conference on Efficiency, Cost, Optimization Simulation and
Environmental Impact of Energy Systems. August 31 – September 3, 2009, Foz do Iguaçu,
Paraná, Brazil
Sciacovelli A., Verda V. (2009) Entropy generation analysis in a monolithic-type solid oxide fuel
cell (SOFC). Energy 34. 850-865.
January 8, 2004