A CFD and thermal-electric coupled analysis of a kW-level automobile thermoelectric generator for automotive exhaust recovery

The application of thermoelectric generators for harvesting automobile exhaust heat is constrained by their low output and substantial size. To tackle this challenge, we propose a novel solution: the stacked automobile thermoelectric generator integrated with heat pipes (HPATEG). This study also introduces a method that combines a CFD model and a thermal-electric coupling one to analyze the HPATEG's behaviour. Results reveal that the use of heat pipes and a stacking design creates a significant temperature difference at both ends of TEMs, resulting in substantial electricity generation. However, there is a notable temperature and output drop from the first-layer TEM to the last layer. Additionally, the HPATEG's output performance is markedly affected by changes in exhaust temperature and flow rate. The ideal power generation may reach 1510.73 W under a flow rate of 600 g/s and a temperature of 700 K, however, energy losses caused by the interconnection topology of TEMs become significant, particularly for a system with numerous TEMs. Through optimizations, the suggested optimal structure parameter, where 4 units with 9/10/11/12 TEM layers per unit, series within units, and parallel between units, reaches a power output of 1406.91 W, surpassing the traditional series topology connection by 12% and reaching 93% of the ideal output power.