How can you turn the heat from burning wood into electricity using a device that fits inside a shoe box?

Traditional thermo-electric power plants do just that, but they are huge, require loads of space and require enormous investments. They are certainly not something that you can bring along, in your backpack, on a camping trip.

The solution is called a Peltier device and it’s not really anything new. They have been around for a long time, indeed. However, the introduction of smartphones have, in recent years, created a need for portable power plants that we seemed to be fine without just a few years ago.

How a Peltier device operates

Peltier devices, or Peltier elements, are semiconductor components that have traditionally been used for enhanced cooling.They are flat, with a hot and a cold side and two wires, for connecting them to electric power.

By applying an electric current, the device will start moving heat from the cold side, that will get cold, to the hot side, which will get hot. Exactly how this works is beyond the scope of this article, but by applying the cold side to something that needs cooling, such as an electric component, and cooling the hot side, you will get an overall cooling effect that is way bigger than what you would otherwise have.

So, a Peltier element is heat pump with no moving parts, requiring only electricity to work.

The really interesting thing is that you can run it in the opposite direction. By heating one side and cooling the other you will cause an electric current to flow in the connectors.

Camping stoves that charge your phone

This is why you can use camping stoves from BioLite and such companies, to charge your mobile phone, by burning a few sticks while, at the same time, you can use it to prepare your lunch.

It’s genius, really, and very simple. It’s so simple, in fact, that you could build your own thermoelectric power plant from a few components that you can easily buy for a few dollars from eBay.