I gave my friend an ECOFan fan that does not consume electricity. This concept is pretty cool, so I plan to copy one from scratch. A reverse-mounted semiconductor refrigeration fin supplies energy to the fan through temperature difference power generation. In other words, as long as it is placed on a warm stove, it will absorb heat to drive the fan to rotate.
I have always wanted to be a Stirling engine, but it is a bit more complicated. However, this small fan for thermoelectric power generation is very simple and suitable for a weekend.
Principle of thermoelectric generator
Thermoelectric power generation relies on the Peltier effect, which is often used on cpu radiators and semiconductor cooling chips in pocket refrigerators. In normal use, when we apply current to the cooling plate, one side will become hot and the other side will become cold. But this effect can also be reversed: as long as there is a temperature difference between the two ends of the cooling plate, a voltage will be generated.
Seebeck effect and Peltier effect
Different metal conductors (or semiconductors) have different free electron densities (or carrier densities). When two different metal conductors are in contact with each other, the electrons on the contact surface will diffuse from a high concentration to a low concentration. The diffusion rate of electrons is directly proportional to the temperature of the contact area, so as long as the temperature difference between the two metals is maintained, the electrons can continue to diffuse, forming a stable voltage at the other two ends of the two metals. The resulting voltage is usually only a few microvolts per Kelvin temperature difference. This Seebeck effect is usually applied to thermocouples to directly measure temperature differences.
Post time: Dec-31-2021
