Heat pipe

Heat pipe, device that moves heat while keeping the temperature relatively constant. A heat pipe consists of a sealed metal tube with a porous lining that holds a boiling liquid. To transfer heat, one end is immersed in the heat source, and the liquid's temperature is gradually brought to boiling, which forces the vapor to move to the colder end of the pipe. The vapor then condenses and releases the heat. Heat pipes are extremely efficient because they can transfer large amounts of heat over long distances and keep the temperature constant without using an external power supply.