Peltier or Seebeck? Seebeck or Peltier?
As we have already heard in our article about the thermal power units, the Peltier effect is “the thermoelectric phenomenon whereby an electric current flowing between two different metals or semiconductors into contact produces a heat transfer” (Wikipedia ): in other words, it’s possible to obtain heat through the use of electric current only. And since the heat is released from the surrounding environment is possible to use the laws of physics both for heating and for cooling an environment or object.
But… it can happen the other way? That is, could you get electricity through the sale of heat? Certainly!
This is called “Seebeck Effect”, always as stated in Wikipedia, a thermoelectric effect whereby, in a circuit formed by metallic conductors or semiconductors, a temperature difference generates electricity.
Where you can apply the Seebeck effect?
One of the most common applications is in thermocouples. These sensors are constituted by a pair of electrical conductors of different materials joined together at a point, the hot junction, and is the point in which is applied the temperature to be measured. The free ends of the two conductors, however, are called cold joint.
In industrial plants, thermocouples are widely used because of economical, easily replaceable and capable of measuring a wide range of temperatures: are inserted into protective sheaths, which penetrate inside the equipment of which one wants to measure the temperature and, when there is a temperature difference between the area of the hot junction and the cold junction area, it can detect an electrical potential difference between the free ends of the cold junction. This potential difference is due to the temperature difference, and then measured.
Moreover, we find its application in thermoelectric generators. These generators, however, have an efficiency quite low, converting about 7% of the thermal power into electrical power. A turbine engine is able to reach 20%. The game is not worth the candle, then? It is said, because science is always in motion: they are products were made which are able to use the temperature difference between the outside and the inside of a pot containing boiling water, which, connected to a particular device, can generate enough electricity to recharge a mobile phone.
Perhaps, the next technological gadget, will leverage its... the Seebeck effect!