Comparison of Segmented and Traditional Thermoelectric Generator for Waste Heat Recovery of Diesel Engine

Abstract

This paper established a mathematic model of segmented thermoelectric generator (TEG) based on low-temperature thermoelectric material bismuth telluride and medium-temperature thermoelectric material skutterudite. The performance of segmented TEG and traditional TEG has been compared using this model under different conditions, such as heat source temperature, cold source temperature, heat transfer coefficient, and length and cross section area of thermocouple. The results show that the maximum output power and conversion efficiency of segmented TEG are higher significantly using exhaust of diesel engine (DE) as heat source and coolant as cold source. The results also show that the trends of maximum output power and conversion efficiency are contrary with increment of thermocouple length. The trends of maximum output power is linear with increment of cross section area, and the conversion efficiency is constant. Finally, the segmented TEG has a more potential to recover waste heat than tradition TEG. The performance of segmented TEG is decided by the ratio of materials, the optimum design of segmented TEG should base on the crossing point of ZT value for two materials.