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The Power Source of the Future: Thermoelectric Energy Harvesters

Transforming thermal pollution, one of the biggest and most-often overlooked forms of waste, into an emission-free power source would usher humanity into an energy revolution. Thermal waste, also known as “waste heat,” is intrinsic to all industrial manufacturing and is released to the environment through stacks, vents, flares and bodies of water. Capturing and reusing that waste heat is both a valuable alternative approach to improving overall energy efficiency, and could also reinvigorate American manufacturing by creating jobs, lowering the cost of energy and reducing overall emissions from electric generation.

Thermoelectric energy harvesters have ability to convert thermal energy to usable electricity by promoting the flow of electrons, thus creating an electric current. These energy generators do not consist any moving parts and fluids systems and therefore they are very compact and, most importantly, require no maintenance. These qualities set the thermoelectric energy harvester apart from any other energy conversion systems.

Traditional fabrication methods limit their geometric designs and are far too expensive and time-consuming for practical implementations. Therefore, NASA, which has been the leading agency in promoting and using thermoelectric devices, seeks to discover novel thermoelectric materials and fabrication technologies for future space missions. This is where Dr. Emrah Celik, an assistant professor in the Department of Mechanical and Aerospace Engineering, and his team of undergraduate researchers come in.

NASA’s Florida Space Grant Consortium (FSGC) awarded Celik scholarship money for two undergraduate students to investigate the additive manufacturing – more commonly known as 3-D printing – of thermoelectric modules and generators. “3-D printing of thermoelectric generators allows us to fabricate and print all the complex structures of the generator – semiconductors, ceramics, etc. – using the same tool, which decreases the time and cost it takes to create a generator,” Celik explains.

Specifically, Celik and his team are using a 3-D printing mechanism that fuses thermoelectric powders and thermoplastic materials called fused deposition modelling. Compared to other additive manufacturing methods – such as stereolithography and screen printing – fused deposition modelling is highly flexible in terms of both the printing materials that can be utilized and the geometry of the printed device.

The undergraduate students will work in Celik’s Advanced Nano Systems Laboratory (ANSyL) characterizing the qualities of different materials created by the laboratory’s custom Fused Deposition Modeling (FDM) 3-D printer and ranking their feasibility for thermoelectric energy harvesters.

Max Rosenfeld ’18, a University of Miami College of Engineering mechanical engineering major, is one of two students who received the scholarship from FSGC. Rosenfeld says that he is “very excited to assist with innovative thermoelectric research, because it is an interesting, unconventional technology. More importantly, though, it is one step towards a society that is based on sustainable energy, which is paramount.”

“Thermoelectricity is such a promising field,” explains Mitchell Hamann ’18, also a CoE mechanical engineering major and the second awardee for the scholarship. “The idea of combining additive manufacturing and thermoelectrics could dramatically reduce the cost of producing thermoelectric modules, which could become a larger source of power on spaceflight missions.” Hamann adds, “I’m very happy to be engaging in research that aligns so much with my interests. … I plan to get a master’s degree in aerospace engineering at some point in my life, and being able to do this research on thermoelectricity has sparked an interest I may carry into graduate school.”

The research project is officially titled, “Fabrication of Thermoelectric Energy Harvesting Materials by Additive Manufacturing.” To learn more about Celik’s research and his laboratory, please click here.