Thermoelectric Devices: is the devices for direct conversion of heat to electricity.
How they work:
Heating one end of a thermoelectric material causes the electrons to move away from the hot end toward the cold end. When the electrons go from the hot side to the cold side this causes an electrical current, which the PowerPot harnesses to charge USB devices. The larger the temperature difference the more electrical current is produced and therefore more power generated.
The tricky part about thermoelectric generators is that as you heat the hot side, the cold side of the generator heats up too. In order to generate power with the a thermoelectric generator you need both a heat source and a way of dissipating heat in order to maintain a temperature difference across the thermoelectric materials. This is done with no moving parts by heating water in the PowerPot. Water holds several times more heat than aluminum per pound, so it makes a wonderful heatsink. Also, water never gets hotter than 212 F (100 C) at a boil, effectively limiting the maximum temperature of the “cold” side of the thermoelectric generator.
Their Application
Thermoelectric power generation requires three major pieces of technology: thermoelectric materials, thermoelectric modules and systems that interface with the heat source.
HOW THERMOELECTRIC MATERIALS WORK
Thermoelectric materials generate electricity while in a temperature gradient. In order to be a good thermoelectric, materials must have the unique combination of both high electrical conductivity and low thermal conductivity.
HOW THERMOELECTRIC MODULES WORK
A thermoelectric module is a circuit containing thermoelectric materials that output usable electricity. There are several types of efficient thermoelectric materials, but not all are capable of operating in a power generation circuit, or “module,” under typical waste heat recovery conditions.
HOW THERMOELECTRIC POWER GENERATOR (TEG) SYSTEMS WORK
A thermoelectric power generation system takes in heat from a source such as hot exhaust, and outputs electricity using thermoelectric modules.
Example:
The PowerPot is a thermoelectric generator that uses heat to generate electricity. The PowerPot has no moving parts or batteries, and since the thermoelectric technology is built into the bottom of the pot it can produce electricity from a wide variety of heat sources. Simply add water and place the PowerPot on a fire (e.g. wood, propane, butane, alcohol, gas) and it will start generating electricity within seconds. Just plug in the high temperature cable to the back of the pot and watch your USB devices safely charge from a fire.
The larger the temperature difference between the water in the pot and the bottom of the pot, the more electricity the PowerPot will produce. For example, melting snow in the PowerPot is a great way to generate electricity, because snow is so much colder than a flame. However, you don’t have to worry about overpowering your device, because the PowerPot has a built in regulator which insures that you safely charge your USB devices. The regulator outputs 5 volts (USB standard) and up to 1000 milliAmps of current, which is the most any smartphone/MP3 player on the market can handle. This means when you’re charging your USB device with the PowerPot, you will get the same charging time as you would from your wall outlet at home.
https://powerpractical.com/pages/how-do-thermoelectrics-work
http://www.globaltcad.com/en/solutions/application-tutorials/thermo-electric-device/01-thermo-electric-device.html
https://www.alphabetenergy.com/how-thermoelectrics-work/