I’m not the first to have thought of this, but since I didn’t know that when I did so, I’m adding my voice to the other proponents of, and researchers working on, wearable heat engines. Take a full-body, insulating, form-fitting suit, and run wires from all parts of its interior to a thermoelectic generator in the suit, whose low temperature side is exposed to outside air, 30 degrees cooler. This could provide power to, for instance, recharge pacemakers, or insulin pumps, or personal electronic devices. And if I’m understanding their operation correctly, generators would actually reduce the warm (so the human’s) temperature, cooling the body, and forcing it to burn more calories to compensate.
From what I’m reading the hardest part of making this idea work is developing materials that are electrically, but not thermally, conductive. Here’s hoping they’re able to do so, with resultant efficiencies high enough that production is viable. I want my calorie-burning, cell phone-charging super suit. :)