There are 12 volt picnic coolers that use pn silicon junctions to change electricity to cool or heat. They are reversible so they can make electricity from a temperature difference at about 10% efficiency which is better than therocouples. The RTG = radiological thermal generators make electricity for many of our space craft. Body heat however is not hot enough to make even one watt, unless the cold side is very cold, so you would not want to give up much body heat. You can however get enough electricity to light one or two LED with a few milliwatts each.
Here is a link of a girl ,that won a science fair for her flashlight powered by the heat from her hand
http://energyblog.nationalgeographic.com...
if ur body heat can convert the water into superheated steam then the steam can be harnessed to run the generators to produce electricity.
Use thermocouple..........
i wanna use heat from my body.
