ICT2014 Abstracts

Thermoelectric (TE) performance depends on the elements shape as well as material properties, and the elements with the tilted laminate structure have the good mechanical stability and efficient heat transferring ability from the hot fluid. Our previous work reported TE behaviors for the parallelogram elements, and here we propose a conceptual shape of TE elements by removing the parts near the edges mechanically from the parallelogram elements in order to save the TE materials. As the fundamental trials to improve TE performance, two identical and triangular prisms were cut off from the both terminals of parallelogram elements, and the element with the shape of polyhedron was designed. TE performances in the module consisting of these polyhedron elements were numerically simulated under the condition of constant temperature difference by using the finite-volume method. The output power, voltage and current from the module are higher than those before cutting. The polyhedron shape affects the heat transfer and the flow of electric charges. By varying the shape of triangular prisms, we found that an optimal shape existed and made the heat flux more uniform, where the thermal energy dissipates slowly to produce the high conversion efficiency. This is one of the advantages obtained by the favorable TE configuration. Even after cutting off, some parts with the low current density still exist in the polyhedron because the current preferentially flows through the shortest path in the TE module. Two novel models are designed for the optimal usage of the polyhedron elements: (1) the serial combination of p- and n-type polyhedron elements with the symmetrical arrangement in a single pair, and (2) the serial connection of p- and n-type materials using the unsymmetrical shape of polyhedron elements, which were cut off the parts of low current density.