Performance analysis of thermoelectric generator system in different aspect ratio collector channels

Rectangular collector channels are widely used in thermoelectric generator (TEG) systems. The aspect ratio greatly influences the heat transfer of the channel and thus affects the TEG output performance. However, the effect of aspect ratio on TEG output performance has not been intensively analyzed. Thus this paper studies the effect of aspect ratio on TEG output performance under the same heated area for the first time and clarifies the reasons for the high output power of low aspect ratio channels. A numerical model of the TEG system is developed, and the model's accuracy is verified. Then, the output performance of the collector channel TEG system with different aspect ratios, such as output power, net power, and heat conversion efficiency, is investigated to obtain the optimal channel aspect ratio. Finally, the effects of the fin number and the load resistance on the output performance of the TEG system are further analyzed. The results show that the TEG system with low aspect ratio channels exhibits better output performance; the TEG system with an aspect ratio of 0.1 has an 18.3% higher output power than the TEG system with an aspect ratio of 1. When the Re number is 2400, the TEG with an aspect ratio of 0.1 has the highest net power of 2.77 W. The lower aspect ratio reduces the collector channel's hydraulic diameter and improves the TEG's heat transfer performance. When the fin number is increased from 16 to 34, the output power increases by 10%, but the lower number of fins exhibits a higher heat conversion efficiency. This study provides some new ideas for improving the output performance of TEG systems.