In a thermocouple under a thermal gradient, i.e., with a hot junction and a cold junction, there are 4 electromotive forces as shown in figure 1, (E1
If material B (in blue) is a P-type semiconductor, the electromotive force E4
will have the opposite direction.
Traditional thermoelectric modules, type TEG (Thermoelectric Generator fig. 2), are constructed with P-type semiconductors and N-type semiconductors, forming several series interconnected thermocouples. These modules exploit the electromotive force generated by electron diffusion along the thermocouple legs
, figures 1 and 2). This diffusion, however, only happens when the junctions are subjected to a temperature difference.
Unlike traditional thermoelectric modules, the VHETM exploits the electromotive force generated at the junctions of the thermocouples and not in their legs. Electrons excited thermally (above 0 Kelvin) tend to invade border regions that have lower electron density. Therefore, when we join two dissimilar metals, the electrons of the "stronger" (higher energy) material invade the boundary of the "weaker" material thus establishing two electromotive forces, E1
. However, under normal conditions, they cancel each other out because they have opposite directions and the same intensity. See figure 3.
The innovation in VHETM thermocouples lies in the fact that one of its junctions has an electronic nano device that simulates 0 Kelvin. This is why E1
behave as if they are under a thermal gradient around 300 Kelvin. Thus, the electromotive force generated at the "hot" junction, even at room temperature, is greater than the electromotive force generated at the "cold" junction, which is under the effect of the "0 Kelvin" simulator. With this innovation, the sum of the two forces (E1
) is nonzero and can then be used externally.
For reasons linked to trademarks and patents, I cannot yet publicize the structure of the "0 Kelvin" simulator used in the cold junction. But I will give details of its design, and construction technique, to the person or institution that becomes my partner. Learn more at: Thermoambient Energy Project