I am interested in generating heat manually by rubbing two materials together. I am trying to find the most efficient way to generate the most heat. I've read a little about thermoelectricity where if a current flows in a circuit consisting of two different conductors then one of the junctions is heated and the other is cooled. My question is, would it be possible to rub two conductors together to generate electricity from friction, and use that electricity to generate heat? I don't need to generate a huge amount of heat, just *more* heat than friction alone would generate. Thanks.