I want to with several Peltier elements build a kind of generator. However, I have not yet figured out the respective ideals interaction between the heating and cooling on the sides. Unfortunately, the efficiency is very low. (With candle and PC fans) 5 volts and a few mA I want to generate order to possibly charge a smartphone.
Is anyone familiar?
The best answer
In comparison to other thermal elements ( https://de.wikipedia.org/wiki/Thermoelement#Energiewandlung ) Peltiers have the worst efficiency (1/10 of the Carnot efficiency).
Guess that your device might reach 2%. That is at 5V and 10mA charging current (50mW power approx.) You have 50 times of thermal power out. Since you will not get along with a candle. And with the power of the PC fan verbrät ready several phones at the same load.
For the charge control of your smartphone you'll need you then buy or tinker a charging voltage. But it must be noted that these elements have been optimized for the active function of an untensioned heat pump. The temperature difference between the two sides is approx 60-70 degrees (and which must be continuously maintained). The solder itself absorb approximately to max. + 175-225 degrees. So you should first measure once that maximum voltage at which current falls at 60 degrees temperature difference between the two ceramic plates. Only then can you continue testing. But remember that a candle produces very little heat energy (joules) and also soot. And a soot layer is in turn a good thermal insulator. The heat generated is therefore likely to flow to your building upward past. The following proposal for a test setup: on each side of a sufficiently massive heatsink. Up Once cooled with an external power source via the fan, the lower radiator is in a 90 degree bain. Then you can determine the short-term occurring electrical values (voltage / current) before. Note the operating voltage / current of the element at operating correctly according to the datasheet.
to be cooled side an old CPU cooler and fan, ev. extends the voltage before the part is there too hot to supply the fan. I just noticed that the fans something chase in coolers if you separate the box from power. The performance is higher, the higher the temperature difference tw. Both sides is