Development of the thermoelectric system using porous media

提高材料性能和热电器件/系统性能对热电能量转换系统的应用具有重要意义。本研究的重点是通过提高器件与冷却/加热流体之间的交换效率来提高功率密度，(I)多孔介质的制造，(Ii)部分多孔器件/模块的制造，以及(Iii)多孔器件/模块的评价。首先，开发了一种利用脆性热电材料制备多孔介质的新工艺。利用该工艺制备了部分多孔型热电器件和组件，并对所研制的热电器件进行了性能评价。实验结果表明，当冷热源为导热系数较低的气体时，采用多孔介质强化换热是有利的。在这种情况下，部分多孔器件的功率密度可以比常规型器件的功率密度高10倍。例如，使用FeSi2的多孔热电器件通过优化多孔介质的物理性质显示出更高的功率密度。

It is important to improve both of the materials properties and the thermoelectric device/system performance for application of the thermoelectric energy conversion system. This study focused on enhancement of the power density by improving exchange efficiency between the device and cooling/heating fluids, (I) Fabrication of the porous media, (ii) Production of the partially porous devices/modules, and (iii) Evaluation of the porous devices/modules were studied.Firstly, a new process to fabricate porous media using brittle thermoelectric materials was developed. By using the process, partially porous thermoelectric devices and modules were fabricated.Performance of the developed thermoelectric devices was evaluated. The experimental results indicated that enhancement of the heat exchange by using porous media was beneficial when heating/cooling sources are gas which thermal conductivity was low. In the case, power density of the partially porous device may be 10 times higher than that of the conventional type devices. For example, porous thermoelectric devices using FeSi2 exhibited higher power density by optimizing physical properties of porous media.