Improving TEG power density through integrated heat pipe structure
The TEG device with integrated heat pipes improves the heat transfer performance between cold/heat sources and thermoelectric modules. Researchers have introduced heat pipe structures into traditional stacked designs, utilizing the high thermal conductivity of heat pipes to change the direction of heat transfer, making the stacking direction consistent with the direction of heat flow, which helps integrate more thermoelectric modules in limited space. Through bench experiments, under the heat flow of 650 K and 50 m s-1, the TEG device can generate an output power of 848.37 W and an ultra-high system level power density of 48.22 W L-1, achieving a significant improvement in power density. Meanwhile, it can be extended to different application scenarios by changing the stacking structure.
The TEG structure presents a hexagonal configuration as a whole, assembled by stacking hot end plates, cold end plates, and thermoelectric modules between the two. Each hot end plate is equipped with 12 hot end heat pipes, which are arranged in a staggered manner between different layers to ensure the heat transfer performance between the heat pipes and the high-temperature exhaust gas; Each cold end plate is equipped with 12 cold end heat pipes inside, which transfer heat to the defects in the hexagonal configuration for cooling and improve space utilization.
TEG engineering applications need to meet two requirements simultaneously: generating sufficient output power in a limited space, and avoiding excessive exhaust back pressure. The author used a combination of CFD and thermoelectric coupling models to conduct finite element simulations on the thermodynamic and power generation performance of TEG integrated with heat pipes. Research has shown that the thermoelectric generator can build a sufficiently high temperature difference at both ends of the thermoelectric module while ensuring a small exhaust back pressure, with a single module output power of 3.89 W.
The researchers first integrated the heat pipe with the hot/cold end flat plate to form a hot/cold end unit; Then, starting from the first layer of hot end flat plate with exhaust inlet, assembly is carried out layer by layer, and finally a complete prototype with 240 thermoelectric modules is produced. During the assembly process of different components, thermal grease is applied to the contact interface to eliminate gaps. The TEG device produced by this method can adjust the stacking layers according to different application scenarios to generate sufficient output power and has a wide range of applicability.
If higher performance thermoelectric materials and thermoelectric modules with higher operating temperatures are used, the TEG device will be able to withstand greater heat transfer, thereby achieving higher output power and power density.
