Wednesday, January 8, 2014

No. 825: Thermoelectric generation develops fast (January 7, 2014)

Thermoelectric generation that changes heat to electricity with the help of temperature difference attracts wide attention. NEC and NEC Tokin developed an element by applying the physical phenomena called the spin Seebeck effect discovered by EijiSaitoh of Tohoku University. They adopted a bendable thin resin for the substrate of the element and built a magnetic film by spraying a solution that contains nickel, zinc, and iron. And they attached a metal film on the magnetic film to build a sheet-like thermoelectric conversion element that is about 30 micrometers thick and several millimeters vertically and horizontally. They confirmed that electric current flowed along the metal film should temperature difference exists between the front and back of the element.

Although the new element has the same generation efficiency as the existing elements, it does not need a complicated production process: the spray temperature is between 90 and 100 degrees centigrade and materials of the new element are inexpensive. They wish to reduce the production cost of the element to one tenth of the production cost of the existing elements, and plan to utilize it for waste heat lower than 150 degrees centigrade.

Panasonic developed a thermoelectric conversion tube made of bismuth telluride that can be installed on the piping of refuse disposal facilities. In the experiment conducted in a refuse disposal plant in Kyoto, the company successfully generated more than 400 W per cubic meter using heat as low as 80 degrees centigrade. This is eight times more electricity generated by the existing technology and two times more electricity generated by photovoltaic generation per installation area. Currently, 70% of heat generated in a refuse disposal plant is discarded, but Panasonic’s technology can theoretically utilize 1 percent of the discarded 70% for generation. Panasonic plans to review material cost and production process to reduce the cost per generation to make it cheaper than photovoltaic generation. Please click here for further information on Panasonic’s thermoelectric generation.   

   Panasonic's efforts to materialize a
 thermoelectric conversion tube

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