Influence of Thermal Conductivity on the Thermal Behavior of Intermediate-Temperature Solid Oxide Fuel Cells

Aman, Nurul Ashikin Mohd Nazrul; Muchtar, Andanastuti; Rosli, Masli Irwan; Baharuddin, Nurul Akidah; Somalu, Mahendra Rao; Kalib, Noor Shieela

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Research Article

DOI: https://doi.org/10.33961/jecst.2019.00276 Published online May 6, 2020.

Influence of Thermal Conductivity on the Thermal Behavior of Intermediate-Temperature Solid Oxide Fuel Cells

Nurul Ashikin Mohd Nazrul Aman¹, Andanastuti Muchtar^1,2, Masli Irwan Rosli³, Nurul Akidah Baharuddin¹, Mahendra Rao Somalu¹, Noor Shieela Kalib^1,4

¹Fuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
²Centre for Materials Engineering and Smart Manufacturing (MERCU), Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
³Centre for Sustainable Process Technology (CESPRO), Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600, UKM, Bangi, Selangor, Malaysia
⁴School of Engineering and Physical Sciences, Heriot-Watt University Malaysia, Precinct 5, 62200 Putrajaya, Malaysia

Correspondence: Andanastuti Muchtar,
Email: muchtar@ukm.edu.my

Received: 30 May 2019 • Accepted: 14 October 2019

Abstract

Solid oxide fuel cells (SOFCs) are among one of the promising technologies for efficient and clean energy. SOFCs offer several advantages over other types of fuel cells under relatively high temperatures (600^oC to 800^oC). However, the thermal behavior of SOFC stacks at high operating temperatures is a serious issue in SOFC development because it can be associated with detrimental thermal stresses on the life span of the stacks. The thermal behavior of SOFC stacks can be influenced by operating or material properties. Therefore, this work aims to investigate the effects of the thermal conductivity of each component (anode, cathode, and electrolyte) on the thermal behavior of samarium-doped ceria-based SOFCs at intermediate temperatures. Computational fluid dynamics is used to simulate SOFC operation at 600^oC. The temperature distributions and gradients of a single cell at 0.7 V under different thermal conductivity values are analyzed and discussed to determine their relationship. Simulations reveal that the influence of thermal conductivity is more remarkable for the anode and electrolyte than for the cathode. Increasing the thermal conductivity of the anode by 50% results in a 23% drop in the maximum thermal gradients. The results for the electrolyte are subtle, with a ~67% reduction in thermal conductivity that only results in an 8% reduction in the maximum temperature gradient. The effect of thermal conductivity on temperature gradient is important because it can be used to predict thermal stress generation.

Key Words: Computational Fluid Dynamics, Modeling, SOFC, Thermal Conductivity, Thermal Behavior