**ABSTRACT**

The aim of this paper is to evaluate numerically the effect of varying the electrochemical model and its parameters on the performance and entropy generation of a mono-block-layer build type (MOLB-type) geometry of a solid oxide fuel cell (SOFC). Particularly, the influence of the exchange of current density, the electrical conductivity of the electrodes and the electrolyte has been studied and the prediction of the thermodynamic irreversibility by means of an entropy generation analysis is considered. The numerical analysis consider a three-dimensional CFD model that takes into account the mass transfer, heat transfer, species transport and electrochemical reactions. Several numerical simulations were performed and each contribution to the local entropy generation rate was computed. The results show different trends of the current density, temperature, species, activation loss, ohmic loss and concentration loss along the fuel cell. Also, the results show strong variations of the local and global entropy generation rates between the cases analyzed. It is possible to conclude that the fuel cell performance and the prediction of thermodynamic irreversibilities can be significantly affected by the choice of the electrochemical models and its parameters, which must be carefully selected.

**KEYWORDS**

PAPER SUBMITTED: 2015-12-21

PAPER REVISED: 2017-05-20

PAPER ACCEPTED: 2017-05-20

PUBLISHED ONLINE: 2017-06-04

- Subhash C. Singhal, Kevin Kendall. High temperature solid oxide fuel cells: Fundamentals, design and applications. Elsevier Ltd, 2003.
- Massardo AF, Lubelli F. Internal reforming solid oxide fuel cell-gas turbine combined cycles (IRSOFC-GT): part A - cell model and cycle thermodynamic analysis. Journal of Engineering for Gas Turbines and Power 122 (2000), pp. 27-35.
- Ferguson J.R., Fiard J.M., Herbin R. Three-dimensional numerical simulation for various geometries of solid oxide fuel cells. Journal of Power Sources, 58 (1996), pp. 109-122.
- A.A. Kulikovsky, A model for SOFC anode performance, Electrochemica Acta, 54 (2009), pp. 6686-6695.
- Andersson Martin, Paradis Hedvig, Yuan Jinliang, Sundén Bengt. Three dimensional modeling of an solid oxide fuel cell coupling charge transfer phenomena with transport processes and heat generation. Electrochim Acta 2013; 109:881-93
- S.C. Kaushik, V. Siva Reddy, S.K. Tyagi. Energy and exergy analyses of thermal power plants: A review. Renewable and Sutainable Energy Reviews. 15 (2011), pp. 1857-1872.
- F. Calise F.,M. Denticed'Accadia M., Palombo A., Vanoli L. Simulation and exergy analysis of a hybrid Solid Oxide Fuel Cell (SOFC)-Gas Turbine System. Energy, 31 (2006), pp. 3278-3299.
- Naterer G.F., Tokarz C.D., J. Avsec J. Fuel cell entropy production with ohmic heating and diffusive polarization. International Journal of Heat and Mass Transfer, 49 (2006), pp. 2673-2683.
- Baniasadi E., Dincer I. Energy and exergy analyses of a combined ammonia-fed solid oxide fuel cell system for vehicular applications. International Journal of Hydrogen Energy, 36 (2011), pp. 11128-11136.
- F. Calise, G. Ferruzzi, L. Vanoli. Parametric exergy analysis of a tubular Solid Oxide Fuel Cell (SOFC) stack through finite-volume model. Applied Energy, 86 (2009), pp. 2401-2410.
- V.H. Rangel-Hernandez V.H., Damian-Ascencio C., Juarez-Robles D.,Gallegos-Muñoz A., Zaleta-Aguilar A., Plascencia-Mora H. Entropy generation analysis of a proton exchange membrane fuel cell (PEMFC) with a fermat spiral as a flow distributor. Energy, 36 (2011), pp. 4864-4870.
- Li X., Faghri A. Local entropy generation analysis on passive high-concentration DMFCs (direct methanol fuel cell) with different cell structures. Energy, 36 (2011), pp. 403-414.
- Gorte RJ. Recent developments towards commercialization of solid oxide fuel cells. AIChE J , 51 (2005), pp. 2238-377.
- Bove R., Ubertini S. Modelingsolid oxide fuel cell operation: Approaches, techniques and results. Journal of Power Sources, 159 (2006), pp. 543-559.
- Bird RB, Steward WE, Lightfoot EN. Transport phenomena. John Wiley & Sons, New York, USA, 1960.
- Costamagna P, Honegger K. Modeling of solid oxide heat exchanger integrated stacks and simulation at high fuel utilization. J Electrochem Soc 145(1998),11, pp. 3995-4007.
- R.B. Bird, W.E. Stewart, E.N. Lightfoot. Fenómenos de transporte. Reverté, S.A., 1992.
- Chan S.H., Khor K.A., Xia Z.T. A complete polarization model of a solid oxide fuel cell and its sensitivity to the change of cell components thickness. Journal of Power Sources, 93 (2001), pp. 130-140.
- Gellings PJ, Bouwmeester HJM, editors. in: The CRC handbook of solid state electrochemistry. CRC Press, Boca Raton, FL, 1997. pp. 269-94 and pp. 407-480.
- Bejan A. Advanced Engineering Thermodynamics. Wiley, 2006.
- De Groot S.R., Mazur P. Non-equilibrium thermodynamics. Dover Publications, New York, 2011.
- Campanari S., Iora P. Definition and sensitivity analysis of a finite volume SOFC model for a tubular cell geometry. Journal of Power Sources, 132 (2004), 1/2, pp. 113-126.
- Pei-Wen Li, Minking K. Chyu. Simulation of the chemical/electrochemical reactions and heat/mass transfer for a tubular SOFC in a stack. J. of Power Sources 124 (2003), pp. 487-498.
- Yunzhen Yang, Guilan Wang, Haiou Zhang, Weisheng Xia. Comparison of heat and mass transfer between planar and MOLB-type SOFCs. J. Power Sources 177 (2008), pp. 426-433.
- Yuzhang Wang, Jianguo Yu, Shilie Weng. Numerical investigation of differents load effect on the performance of planar electrode supported SOFC with syngas as fuel. I. J. Hydrogen Energy, 36 (2011), pp. 5624-5631.