Heat Transfer Characteristics Of Automotive Exhaust-based Thermoelectric Generator Cooling Units

A considerable amount of the energy generated by the internal combustion engine is wasted through the exhaust gas.The thermoelectric power generation technology can effectively convert the low-quality thermal energy in the exhaust into high-quality electrical energy for energy recovery,improving vehicle fuel economy.Meanwhile,the cooling units play an important role in maintaining the temperature difference between the hot and cold sides of the thermoelectric module,and thus has a crucial influence on the overall performance of the thermoelectric generator.Firstly,based on the theory of thermoelectric power generation and heat transfer,the heat transfer model of the thermoelectric module and the cooling units are established.The performance evaluation index of the cooling units is proposed,which lays the foundation for the research of the heat transfer characteristics of cooling units.Secondly,through the combination of computer simulation and scientific experiments,the influence of different internal structures,including fin structure and groove structure,on the heat transfer characteristics of the automobile exhaust-based thermoelectric generator cooling units is studied.The results are analyzed from the aspects of fluid mechanics,heat transfer and thermoelectric power generation performance.The internal structure of different cooling units are compared by the comprehensive efficiency factor and power comprehensive performance evaluation factor.It is found that the groove structure has the best comprehensive performance and the groove structure has an increase of 38.4% in comprehensive efficiency factor compared to the smooth structure.Finally,the influence of thermoelectric module layout and cooling fluid condition on the heat transfer characteristics of the cooling units is studied.The thermal resistance of the system and power generation characteristics under different module numbers and arrangement spacing are compared and analyzed,and an optimal module arrangement is found.Through the reasonable module arrangement,the overall performance of the thermoelectric generator can be effectively improved.In addition,in order to analyze the influence of cooling fluid on the heat transfer characteristics,a response surface methodology(RSM)model is established based on the approximate model theory,and the synergetic influence of the cooling fluid inlet velocity and temperature on the heat transfer characteristics of the cooling units is found out.The research on the heat transfer characteristics of the thermoelectric generator cooling units is significant for the application of thermoelectric generator in vehicle and the development of automobile energy conservation and emission reduction technology.