Abstract: A heat-generating apparatus comprising a friction chamber immersible in a fluid reservoir. A drive shaft is supported in the friction chamber and is rotationally driven by a power assembly. Shoe members engaged with an operating plate secured to the drive shaft are urged into friction-generating engagement with the friction chamber in response to drive shaft rotation. Heat thus generated is channeled to the fluid reservoir. The power assembly may comprise a windmill assembly, responsive to wind movement, which drives a rotary shaft engaged with the drive shaft.