Peltier effect is a thermoelectric phenomenon where, by allowing direct current to flow through different metals or semiconductors, a heat pump can be produced that cools on one side of the element and heats on the other. Modern Peltier elements usually use bismuth telluride (Bi2Te3). The phenomenon was discovered in 1834 by the French physicist Jean Peltier. Seebecke effect is based on the same technology, where you can instead generate direct current by exposing the element to temperature differences. The phenomenon was discovered by the Tallinn-born German physicist Thomas Seebeck in 1821.
Currently (2006) you can find simple wine refrigerators and soft coolers on the market that use Peltier elements. The Seebeck effect is used for temperature measurement in thermocouples, but is unrealistic for practical electricity production as the efficiency is very low (approx. 2-3%). There are fans that are operated with the Seebeck effect. Such fans should be placed on a very hot surface, e.g. on a fireplace.
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