Optimization study of the produced electric power by SOFCs Youcef Sahli a,b,* , Hocine Ben Moussa b , Bariza Zitouni b,c a Unit e de Recherche en Energies Renouvelables en Milieu Saharien, URERMS, Centre de D eveloppement des Energies Renouvelables, CDER 01000, Adrar, Algeria b D epartement de M ecanique, Facult e de Technologie, Universit e de Batna 2, Algeria c Institut des Sciences V et erinaires et des Sciences Agronomiques, Universit e de Batna 1, Algeria article info Article history: Received 19 April 2018 Received in revised form 15 July 2018 Accepted 24 August 2018 Available online xxx Keywords: SOFC Thermodynamic Power density Current density Over-potential and optimization abstract In this work, an optimization study of the delivered power density by the solid oxide fuel cells is presented according to a thermodynamic model. The power density is defined by the current density, the Nernst potential and the three losses: concentration, activation and ohmic. A comparison between the Tafel and Butler-Volmer formulations was per- formed to quantify the activation loss. A program in FORTRAN language was developed locally for the resolution of the mathematical equations representing the used physical model. The obtained results show that the SOFCs power density is inversely proportional to the anode thickness, electrolyte thickness and cathode thickness. The optimum fuel water content ensures the maximum power density is 6.25%. The cell power density is propor- tional to the oxygen concentration in the oxidant, the operating temperature and the operating pressure. © 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Introduction SOFC is one of the fuel cells family; it is characterized by a high overall efficiency (90%), a solid electrolyte and a high oper- ating temperature (600e1050  C). The high overall efficiency and operating ability by various fuels have given a very good status for SOFCs in the clean energy production family. Cur- rent SOFC developments are focused on reducing their very high operating temperature which leads to the fast aging of these components and maximizing the electrical energy pro- duction of this cells. In this context, the SOFCs energy pro- duction optimization has been conducted by several researchers. Several optimization methods are used in this contexts. The most used optimization methods are divided into three types: meta-heuristic, deterministic and stochastic methods [1]. Shi et al. [2] have optimized the electrodes porosity (pore size and porosity distribution) by a meta- heuristic method to maximize the fuel cell output power. Moller et al. [3] have used a genetic algorithm that based on a meta-heuristic method for optimization of several operating parameters of a coupled system (solid oxide fuel cell and gas turbine). Goyal et al. [4] have used a deterministic method to optimize the produced energy of coupled system SOFC-PEM. Wen et al. [5] have optimized the electrical power of a single SOFC cell using a deterministic method. Francois et al. [6] have exposed a real-time optimization using a stochastic method to realize an optimization of SOFCs electrical efficiency. Cheddie [7] has used a thermo-economic study that based on a * Corresponding author. Unit e de Recherche en Energies Renouvelables en Milieu Saharien, URERMS, Centre de D eveloppement des Energies Renouvelables, CDER 01000, Adrar, Algeria. E-mail address: sahli.sofc@gmail.com (Y. Sahli). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy xxx (2018) 1 e10 https://doi.org/10.1016/j.ijhydene.2018.08.162 0360-3199/© 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Please cite this article in press as: Sahli Y, et al., Optimization study of the produced electric power by SOFCs, International Journal of Hydrogen Energy (2018), https://doi.org/10.1016/j.ijhydene.2018.08.162