This 5W thermoelectric generator converts heat from a chimney or camp stove into electricity for charging USB devices.
Small-scale electricity production can be a complete gamechanger for off-grid communities and emergency preparedness, and there are a number of fairly well-known options for generating enough juice from the sun, wind, and water to keep crucial portable electronics, such as phones, charged. However, there's another method of producing your own electricity, which is using a thermoelectric generator that runs on 'waste' heat that would normally just fly up the chimney and escape. We've covered a few previous thermoelectric devices meant for personal use, but there's a new entry in the market from a company that also sells "a tiny hydropower turbine in a can."
The FireBee Power Tower can make use of some of the heat produced for cooking food or warming a home to yield an additional harvest of clean electricity for keeping small electronics charged up, either for off-grid, home use, or both. The new device, from Seattle's HydroBee, is designed to generate electricity from the heat already being produced by a camping stove, propane stove, or in the chimney of a woodstove or fireplace, but can also be operated with a small alcohol burner. The company claims its Power Tower can produce up to 7 watts of electricity, which is dispatched to two output options, a 5V 2A USB port for portable electronics, and a 12V 125mA terminal that can be used to trickle charge 12V batteries.
Heat from the stove or fire is absorbed by radiator fins inside the device, which then passes through a pair of thermoelectric modules and eventually into the cooling tank, which is full of water. The thermoelectric modules generate the electricity from the temperature difference between the heated fins and the cooler water tank, and this electricity is then converted into the common 5V 2A USB format that most portable devices use.
But wait, there's more! Because the Power Tower requires a cooling tank full of water to operate, which eventually comes to a boil, a spigot on the device makes it easy to pour out that hot water for washing or cooking. Essentially, users can get a hot meal, charge their device, and heat the dinner cleanup water all at the same time. Because power production comes from the temperature difference, optimal generation happens with a hotter heat source and the coolest water, and draining the boiling water and replacing it with cooler water will 'refuel' the device.
"The FireBee Power Tower is the most powerful thermoelectric generator of its kind. Even a small amount of heat makes a lot of power. You can customize it to use with a small alcohol or propane camp stove, or inside a chimney pipe." - FireBee
Although the simplest option would seem to be to use the $159 Power Tower with a gas campstove, the folks at HydroBee also suggest mounting the device inside a woodstove chimney to generate electricity while heating your home or cabin.
"To attach the Power Tower to a wood stove chimney, use a hacksaw to remove the base below the thermoelectric generator, cut a square that is 2 13/16 inches wide and 4 inches tall in the chimney, and simply slide the Power Tower into the slot."
When paired with a 12V battery bank, that approach might be a great way to power more than just LED lights and portable electronics during winters in a cold climate, as the device could conceivably trickle charge the battery bank around the clock. However, in warm and sunny locations, that wouldn't be very handy, but I couldn't help but wonder what would be possible if you aimed a highly-efficient solar cooker/concentrator at a Power Tower, which would then convert it into a truly clean and renewable electricity solution.