One of my neighbors has a very cool gizmo: an “Eco Fan” that sits on top of the wood-burning stove. It’s a solid, cast-iron construction that conducts heat from the wood stove into the body of the fan. There’s a thermoelectric module inside that converts heat into electricity ~ and the small current powers the fan. Very ingenious. Slick design, too (image from the manufacturer’s website below).
The warmer the stove, the faster the fan spins. You know with just a glance if you need to put another log into the stove because the fan slows down.
I have wood-burning fireplace insert in my house (pity it’s flush to the wall so there’s nowhere for an Eco Fan). My hearth has a fan that circulates air around the body of the hearth ~ a couple of logs keep the whole house warm all day, on the coldest winter days.
The eco fan does more than just blow warm air into the room. When the warm air is whisked away, it draws cooler air around the body of the wood-burning stove. Heat transfer is directly proportional to the temperature difference, so more heat is extracted from the woodstove (instead of being lost out of the chimney) when the air is cooler.
Great conversation piece ~ especially when energy conservation geeks like me come for a visit! (Next winter, when I see smoke coming out of their chimney, you can be sure I’ll stop by for a visit to see the Eco Fan in operation.)
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Excerpted from Going Green, available as an eBook at this list of eBook retailers online.