The idea behind the Epiphany onE Puck is to use a stirling engine powered solely by heat disparities, such as a hot or cold drink, a candle, ice, etc. These heat sources will provide enough power to the stirling engine to fully charge your cell phone battery. The charger works best in extremes, so the colder or hotter the drink, the quicker your phone charges.
You place a hot or cold beverage on the surface and let your drink do all the work. Check out the video for more.