Effect of vehicle driving conditions on the performance of thermoelectric generator

Abstract

Thermoelectric generators (TEGs) have become a promising technology for vehicle exhaust heat recovery. Although the complex vehicle driving conditions may lead to significant variation of TEG performance, such influence was rarely paid attention to. In this study, a numerical model of thermoelectric generator (TEG) based on vehicle waste heat recovery is developed. When the acceleration duration is short, the hot side temperature increases quickly at first with an overshoot phenomenon. When the acceleration durations increase or the acceleration range becomes smaller, the overshoot phenomenon becomes weaker. The change of the voltage and power generally follows the same trend. The performance variation of TEGs becomes more significant with faster acceleration or deceleration. The transient response of the hot and cold side temperatures, voltage and power in deceleration is less significant than acceleration, because in deceleration, the cold side temperature increases first due to the weakened heat convection. For the step change of vehicle speed, when the speed is low, the voltage and power curves and the speed curve are more consistent, and a longer step duration leads to better consistency. A higher road grade can increase the power output of TEG significantly, and lead to a faster transient response. The Japanese 10–15 cycle, New European Driving Cycle (NEDC) and Urban Driving Dynamometer Schedule (UDDS) are selected to evaluate the impact of different driving cycles. The results suggest that a highly frequent change of driving condition may have a negative effect on the TEG performance.