Steel and glass manufacturing generates large amounts of waste heat that’s not easy to capture – devices that do the job are either prohibitively expensive or don’t work in the requisite high temperatures. But a team of three Massachusetts Institute of Technology (MIT) researchers have created a device that solves both issues at once. The high-temperature liquid thermoelectric device, which converts industrial waste heat into energy, could be a game-changer.
Converting waste heat to electricity is often accomplished through solid-state thermoelectric devices, but at certain high temperatures they just don’t work, or are so expensive they can’t be used in much other than spaceships. In contrast, the MIT liquid thermoelectric device could pave the way for affordable conversion of waste heat into electricity. It includes a molten compound of tin and sulfur much cheaper than the solid-state bismuth telluride found in many commercial thermoelectric devices. That material is around 150 times more expensive than tin sulfide per cubic meter, according to MIT, and it only operates at temperatures of around 500 degrees Celsius.
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The new MIT device, built by graduate student Youyang Zhao, operates at temperatures of 950 to 1,074 degrees Celsius. And as he changed the temperatures in which the device operated, he saw no significant performance drop.
The researchers, however, don’t think most glass or steel plants would adopt the device simply to save the planet. But assistant professor of metallurgy Antoine Allanore, of whose research group Zhao is a part, said they might be interested if heat management could enable them to operate at even higher temperatures – allowing them to increase productivity or lengthen the lifespan of their equipment.
According to MIT, thanks to the molten compounds in the new device, managing heat at high temperatures is now a possibility. The two scientists were joined by recent PhD graduate Charles Rinzler for a paper published by ECS Journal of Solid State Science and Technology.
Via MIT News
Images via Youyang Zhao and Denis Paiste/Materials Processing Center
