Friday, January 10, 2014

Fun with thermopile generator

Got a bag of Peltier cooling elements (thanks Dan) and experimented with using them as thermoelectric generators. These devices will generate an electric current when subjected to a temperature difference.
When placed on a hot oven they will generate about 1,8V and 650mA for a few seconds and then fade out due to heat conducting through the element and cancelling out the temperature difference.
I found a really fancy heat sink from an old server. By placing the heat sink on top of the element I was able to sustain generation for a much longer time.
Even the heat sink eventually gets hot causing the power output to decrease. Sitting on top of the oven in a column of warm air it is not able to dissipate heat well.
I found that blowing cold(er) air from the surroundings onto the heat sink increased the efficiency dramatically.
As a small cooling fan I used a motor/prop assembly from one of the HCD's, powered directly from the Peltier element. This allows sustained power generation.
Just for fun I connected a color changing LED (Thanks Jim), powered by modified Joule Thief circuit:

Video of the thing going.

Update: Picked up the cold generator and held it in my hand. After a few seconds the fan started just from the heat of my hand!


  1. Thermoelectric generators are very cool. I'm using one in a wood stove invention called the Humid-i-Fire. It is an ornamental fountain and humidifier that operates on the top of wood or gas stoves without any power cord or batteries. I've just started a 30 day Kickstarter campaign to test the market. I would love to know if you liked the product.

  2. Interesting Blog .When heat is applied to the thermophile, an electric current is generated in the range of 450mv to 750mv. When the valve coil reaches the minimum required Milli volts, the valve will open and gas will flow to the main burner and ignite.

    Radiator Fan & Condenser Fans