Simulation study of semiconductor thermoelectric power generator for waste heat recovery and energy harvesting

• Main Author: Chan, Murphy Kim Hua
• Other Authors: Wong Kin Shun, Terence
• Format: Thesis-Master by Coursework
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/170607
• Institution: Nanyang Technological University

Global warming has a huge impact on our daily life which many countries are trying to reduce their carbon footprint in a bid to reduce pollution. One of the proven initiatives is to perform waste heat recovery using thermoelectric generators (TEGs) in wide variety of applications including space, solar photovoltaic, automotive, smelting and more. To understand key aspects of TEG performances such as power output and efficiency, the study of thermoelectric material with respect to applied temperature is also another important consideration. While there is no single compound that exhibits a high figure of merit, power output and efficiency over a wide range of temperatures, it is of interest to understand the material’s behaviour towards these performance indices. In this report, investigation of conventional and emerging thermoelectric materials is carried out using online simulation tool called ADVTE [105] to predict their performances with power output, efficiency, power density and material thickness. These conventional materials include n-type BiTeSe, MgSiSn & SiGe, and p-type BiSbTe, PbTe & SiGe, while the merging materials are n-type CuSeS & SrBaCoSb. Among the conventional materials, the figure of merit, ZT of p-type PbTe remained the highest, 1.99 and 2.09 at heat source temperature 700K and 900K respectively while n-type CuSeS fared the better in the emerging materials with 0.98 and 1.51. Combination of n-type MgSiSn and p-type PbTe displayed the highest power output value of 106mW at 800K. While n-type CuSeS and p-type SiGe only achieved 2mW, n-type SrBaCoSb and p-type SiGe fared better with 100mW at 900K. Combination of n-type MgSiSn and p-type PbTe remained having the best conversion efficiency of 3.09% at 800K, followed by n-type SiGe and p-type PbTe of 3.08% at 900K. A reduction in surface area of TEG was observed to lower the power output and vice versa. But this had no impact on conversion efficiency and material thickness. This behaviour was verified using surface area of 100mm2 and 3,721mm2 while main study was carried out with surface area of 2,601mm2 based on commercial sample of TEG in Figure 2.6. This observation also applied to the materials, CuSeS and SrBaCoSb. Another observation made was that peak power output did not occur at the same thickness as maximum efficiency predicted. TEG dimension size must also be taken into consideration as it impacted the power output as shown in Table 4.9.