Mehmet Aygun

Date of Graduation


Document Type


Degree Type



Statler College of Engineering and Mineral Resources


Mechanical and Aerospace Engineering

Committee Chair

Ismail Bektas Celik

Committee Co-Chair

Ismail Bektas Celik

Committee Member

Xingbo Liu

Committee Member

Terence Musho


Fossil fuel based power generation causes air pollution and climate change. The consequences of these two factors are of at most importance for future generations. Thus, renewable energy sources can play a significant role by reducing the dependence on fossil fuels. However, if the energy storage problem is not solved renewable sources will not be useful. Sodium sulfur battery (NaS) is one of the practical solutions to store wind and solar energy. A NaS battery is comprised of two liquid electrodes and one solid electrolyte which operate between 300-350 °C. The molten sodium is in anode electrode, the molten sulfur and sodium-polysulfide are in cathode electrode, and solid electrolyte, which is made out of beta-alumina or Nasicon material is between anode and cathode.;The purpose of this study is to develop a computational model for a NaS battery block which includes multiple cells and to predict the temperature inside the block during the operation cycles. The temperature distributions are calculated using a newly developed three-dimensional thermal model which takes cell temperatures as input from a lumped electrochemistry model. The properties required for solving governing equations are calculated and updated as a function of time and temperature based on the composition of each control volume. The lumped model is validated against experimental results from the literature. The 3D thermal model is used to perform a parametric study on key stack properties. The newly developed algorithm is robust and can be used for stack design analysis and improvement.