Optimization of thermoelectric generator module spacing and spreader thickness used in a waste heat recovery system

► We provided a 3D numerical model of a TEG module used in a waste heat recovery system. ► The effects of temperature difference and waste gas heat transfer coefficients were investigated. ► The power density for a TEG module is the objective function to be maximized. ► The numerical data are in good agreement (within 8%) with the experimental data. ► The optimum TEG module spacing and spreader thickness are strongly dependent on the waste gas heat transfer coefficient.