Optimization of length ratio in segmented thermoelectric generators for engine’s waste heat recovery

Abstract

Abstract This paper established a three-dimensional numerical model of segmented thermoelectric generator (TEG) for engines waste heat recovery. The thermoelectric materials are low-temperature Bi2Te3 and medium-temperature skutterudite. Two modes of segmented ratios of p-leg and n-leg are analyzed based on different boundary conditions, such as heat source temperature, cold source temperature and ratios of two thermoelectric materials. Suggestions on improving the output power and conversion efficiency are given based on the analysis. Results show that the performance of a segmented TEG with higher ratios of skutterudite is significantly better than that of a traditional TEG under larger temperature gradient. Enhancing the heat transfer from the heat source is a more effective method of improving the output power. Considering different thermal conductivity, the optimal Bi2Te3 ratio of p-leg is a little higher than that of n-leg. In addition, the design of segmented TEG should consider the temperature range of the heat and cold source to improve the output power and conversion efficiency to the utmost extent.