Ecofan - physics in action!

On the narrow boat there is a wood burning stove, and on top of that stove is this fan which distributes the heat. At first I assumed that the fan blades were driven by convective air current, but then found that the blades are connected to a small motor. No batteries or mains connection - how does it work? PHYSICS!

The base of the fan is heated by being in contact with the fire, and a thermal gradient develops along the height of the base. In the base is a thermoelectric material - a semiconductor tha demonstrates the Seebeck effect. The Seebeck effect is the generation of an electric current by a heat gradient. BRILLIANT. Semiconductor physics used in a narrow boat. Conincidentally we have begun to study a version of this effect at work, great to know of a real world application of the research.