Numerical study of porous media thermoelectric converter

Abstract

The efficiency of the conventional bulk semiconductor thermoelectric device is about 20% for ideal theoretical calculation, and less than 5% for an actual application. It is because the heat conduction in the device and the Joule loss are too large compared with the Peltier heat which is changed into the electric power, that the efficiency is very low. In the thermoelectric conversion which used a bulk device, the heat conduction loss in the device can not be avoided. On the other hand, the thermoelectric device made by porous media is heated by the radiation and maintains a large temperature difference by the gas which passes in the porous device. Therefore, the influence of the heat conduction in the thermoelectric device is small and the improvement of the conversion efficiency can be attempted. In this paper, we report the calculated result of performance of a thermoelectric converter made of porous media. The phenomenon which we considered in this analysis is radiation heat in the porous media and the increment sensible heat of passage gas, in addition to the heat conduction, the Joule heat generation and the Peltier effect. We assumed that the porous media device is a gray body for radiation and calculated the heat balance of the thermoelectric heat, the radiation heat absorption and sensible heat of gas in one dimension of the direction of the thickness. We examined the influence which gas flow rate and module thickness device porosity give the module performance.