Owners use the red side as a drinks coaster to place a hot drink on it, and the blue side as for a cooling drink such as a beer.
It uses something called a Stirling engine to turn heat into energy.
US company Epiphany Labs, based in New Castle, Pennsylvania, has built a working prototype and hopes to have it on the market early in 2014.
The company is still vague on just how long it takes for the device to charge up a phone because there are a lot of variables at play, including how hot or cold the source is.
Any source of heat that can fit on the Puck will work.
It works best with something that's very warm like a steaming cup of tea or coffee, or very cold like a well chilled beer or soft drink.
Epiphany is aiming to raise 63,000 pounds on fund raising website Kickstarter to turn the prototype into a gadget that can be mass-manufactured.
By Feb 8, more than 25,000 pounds had been raised, and early birds can still get in for a 62-pound pledge price.