The Power Of Waste Heat

Scientists from South Korea used 3D printing to develop thermoelectric inks, which helped design tubes that can convert waste heat into electricity.

AsianScientist (Jan. 19, 2022) – Harmful factory smoke and car exhaust may soon serve as a power source. Using 3D printing techniques, researchers from South Korea have developed high-performance thermoelectric tubes that can convert waste heat into electricity. The study was published in Advanced Energy Materials.

Most industries still rely on burning fossil fuels to generate electricity. As much as 80 percent of the global energy demand is being supplied by fossil fuel sources. In the process, a significant amount of heat energy is produced. Similarly, automobile combustion engines burn dirty fuel to generate mechanical power, which emits high-temperature gases through the vehicle’s exhaust pipe.

Thermoelectric technology could potentially make good use of such heat and convert the polluting waste products into electrical energy instead. However, conventional thermoelectric devices are built through bulk-scale manufacturing, which limits design flexibility.

Generally, these devices often come in rectangular shapes that may not fit well with existing systems, like tubular exhaust pipes in vehicles and factory chimneys. This mismatch fails to maximize the area of contact for transferring heat, leading to inefficient power output. Moreover, fashioning the device into a tube-like shape often means adding heavy materials just to facilitate integration with exhaust pipes.

Scientists have been exploring 3D printing techniques to precisely craft power-generating tubes. With the same goal, Professor Chae Han Gi from Ulsan National Institute of Science and Technology in South Korea led a research team that  developed thermoelectric ink containing lead and tellurium metals that were modified to improve the ink’s viscoelasticity—a dual property, which provides both viscous and elastic characteristics.

Those advances made the assembled device stable and easily moldable into the desired tubular shapes, avoiding the need to add other materials during the engineering process.

In the study, when the researchers matched the structure of the pipes, the 3D-printed thermoelectric tubes could collect heat more efficiently than the conventional devices. The direct collection and transfer of heat then enabled the technology to exhibit nearly triple the power output of typical devices upon testing between 400 and 800 degrees Kelvin—the temperature range of car exhaust gases and industrial waste heat.

The design flexibility offered by the thermoelectric ink and 3D printing method holds promise for cost-effective manufacturing of high-performance, customizable power generators. The researchers hope that with further developments such as integrating anticorrosive coating, the technology can eventually be scaled up to industrial applications.

“If we use 3D printing technology in the production of thermoelectric materials, we will be able to overcome limits of conventional materials,” said Chae.

The article can be found at: Lee et al. (2022) Doping-induced viscoelasticity in PbTe thermoelectric inks for 3D printing of power-generating tubes.


Source: Ulsan National Institute of Science and Technology; Photo: Shutterstock.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Asian Scientist Magazine is an award-winning science and technology magazine that highlights R&D news stories from Asia to a global audience. The magazine is published by Singapore-headquartered Wildtype Media Group.

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