Thermoelectric Analysis for Helical Power Generation Systems

Suzuki

2015

Mater. Trans.

Self Cite

Our previous work showed that the utilization of polyhedron elements has better advantages than the parallelogram elements in the thermoelectric (TE) generation. Especially a high efficiency of converting heat into electricity can be achieved at an optimal shape. This study proposed new TE module configurations consisting of polyhedron elements, and examined the TE performance of them by conducting the finiteelement analysis. The simulation results show that the performance of TE module in the case of symmetrically arranging the polyhedron elements is slightly higher than that of arranging elements in parallel because of the more homogeneous heat flux and current density. The heat transfer and electric resistance, respectively, depend on the module configuration and element shape, and affect the TE performance simultaneously. TE performance increases significantly when the internal resistance becomes smaller and the heat diffuses slower.

Section: Constitutive Equationmentioning

confidence: 99%

Performance Analysis of Thermoelectric Modules Using Polyhedron Elements

Suzuki

2015

Mater. Trans.

Self Cite

“…By referring to the reported codes [12,13] , we evaluated the current density via our custom-written C program [7,14] , and subsequently, our codes were combined with the conventional functions of FLUENT because this commercial package does not account for this TE phenomena. The final results were obtained after several thousand iterations until sufficient convergence was achieved for each complex calculation of the entire TE process.…”

Section: Constitutive Equationmentioning

confidence: 99%

“…As shown in Figure 5, low-current-density regions in the parallelogram elements appear at the two small areas close to the terminals lying at either end of the long diagonal, although the polyhedron design leads to a more homogenous distribution in current density than that obtained with parallelogram elements. This is because the current preferentially flows through the shortest path available to form a primary current stream, and this path is determined by the configuration of the TE module [7] .…”

Section: Module Featuresmentioning

confidence: 99%

“…The preferential flow of current in a given three-dimensional (3D) TE system can be studied via analysis of the TE modules consisting of p-and n-type elements, which are connected thermally in parallel and electrically in series [7] . This current path is formed spontaneously, causing electric charges to flow through the shortest path, and regions with high current density are formed at the diagonal corners of TE elements.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Simulation Analysis of Tilted Polyhedron-Shaped Thermoelectric Elements

Suzuki

2014

Journal of Elec Materi

Self Cite

The generation of thermoelectricity is considered as a promising approach to harness the waste heat generated in industries, automobiles, gas fields, and other man-made processes. The waste heat can be converted to electricity via a thermoelectric (TE) generator. In this light, the generator performance depends on the geometric configuration of its constituent elements as well as their material properties. Our previous work reported TE behaviors for modules consisting of parallelogram-shaped elements because elements with tilted laminate structures provide increased mechanical stability and efficient heat transferring ability from the hot surface to the cold surface. Here, we study TE elements in the shape of a polyhedron that is obtained by mechanically truncating the edges of a parallelogram element in order to further enhance the generator performance and reduce TE material usage. The TE performance of the modules consisting of these polyhedron elements is numerically simulated by using the finite-volume method. The output power, voltage, and current of the polyhedral TE module are greater than those of the parallelogram-element module. The polyhedron shape positively affects heat transfer and the flow of electric charges in the light of increasing the efficiency of conversion from heat to electricity. By varying the shape of the truncated portions, we determine the optimal shape that enables homogeneous heat flux distribution and slow diffusion of thermal energy to obtain the better efficiency of conversion of heat into electricity. We believe that the findings of our study can significantly contribute to the designing policy in TE generation.

“…Our previous works discussed the basic TE phenomenon under constant thermal conditions for various module designs, i.e. fixed the temperature or the heat flux on hot and cold surfaces and analyzed TE performance of the helical and conventional straight panels, as well as modules consisting of tilted parallelogram-and polyhedron-shaped thermo-elements [5][6][7][8][9] . However, the most likely approach to utilize the residual heat of waste fluids is to allow the high-temperature gas and liquid to flow on module surfaces.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric Generation Using Counter-Flows of Ideal Fluids

Zhu

et al. 2017

Journal of Elec Materi

Self Cite

Thermoelectric (TE) performance of a three-dimensional (3D) TE module is examined by exposing it between a pair of counter-flows of ideal fluids. The ideal fluids as thermal sources of TE module flow in the opposite direction at same flow rate and generate temperature difference on the hot and cold surfaces due to their different temperature at channel inlet. TE performance caused by different inlet temperature of thermal fluids are numerically analyzed by using finite-volume method on 3D meshed physical models and then compared with those of using constant boundary temperature. The results show that voltage and current of TE module increase gradually from a beginning moment to a steady flow and reach a stable value. The stable values increase with inlet temperature of hot fluid when inlet temperature of cold fluid is fixed. However, the time to get the stable values is almost consistent for all the temperature differences. Moreover, the trend of TE performance using fluid flow boundary is similar to that of using constant boundary temperature. Further, 3D contours of fluid pressure, temperature, enthalpy, electromotive force, current density and heat flux are exhibited in order to clarify the influence of counter-flows of ideal fluids on TE generation. The current density and heat flux homogeneously distribute on entire TE module, thus indicating that the counter-flows of thermal fluids have high potential to bring fine performance for TE module.