**4. Conclusions**

The behavior of maximum power, maximum efficiency, and maximum thermal stress was investigated numerically and theoretically for a thermoelectric module with various combinations of leg geometry, material, segmentation, and two-stage arrangement. From the conducted numerical and theoretical analysis, the following critical observations are summarized:


the intensity of stress in the thermoelectric module with the SiGe+Bi2Te<sup>3</sup> material could be reduced by using soldering layers without affecting maximum power and maximum efficiency.

(d) The segmented arrangement of the thermoelectric module showed a higher maximum power and maximum efficiency and lower maximum stress in all combinations of the thermoelectric module. Therefore, the segmented arrangement of the thermoelectric module with cylindrical leg geometry and a combination of SiGe+Bi2Te<sup>3</sup> materials was selected as the optimum configuration for the thermoelectric module with maximum power of 0.73 W, maximum efficiency of 13.2%, and maximum thermal stress of 0.69 GPa.

**Author Contributions:** Conceptualization, M.-Y.L.; J.-H.S., and K.S.G.; methodology, M.-Y.L., J.-H.S., H.-S.L., and K.S.G.; software, M.-Y.L., J.-H.S., and K.S.G.; validation, M.-Y.L., J.-H.S., and K.S.G.; formal analysis, M.-Y.L., J.-H.S., H.-S.L., and K.S.G.; investigation, M.-Y.L., J.-H.S., H.-S.L., and K.S.G.; resources, M.-Y.L., J.-H.S., and K.S.G.; data curation, M.-Y.L.; writing—original draft preparation, M.-Y.L., J.-H.S., and K.S.G.; writing—review and editing, M.-Y.L., J.-H.S., and K.S.G.; visualization, M.-Y.L.; supervision, M.-Y.L.; project administration, M.-Y.L.; funding acquisition, M.-Y.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** This work was supported by the Dong-A University research fund.

**Conflicts of Interest:** The authors declare no conflict of interest.
