I found an article this morning on C|NET about a startup company, GMZ Energy, that has received venture funding. They've developed some nanotechnology that improves the efficiency of the thermoelectric effect and they're looking to build a power generator that more efficiently captures 'waste heat' turning it into electricity. I found a bunch of related articles and posted on 7gen.com (link below).
The Thermoelectric Effect is what drives the Peltier cooler technology that is sometimes used in portable coolers, or in CPU coolers. I remember a couple years ago a couple teenagers in Utah won a prize for developing a car air conditioner powered by this same technology. In any case it appears the idea is when you heat a wire the electrons run to the other end, maybe electrons don't like heat? Somehow they're able to capture the electrons and make them into electrical current. I've only briefly glanced over the articles, so if you're interested I've got a whole bunch of links on my other site.