A heat pipe is a highly efficient heat transfer device that uses a combination of conduction and convection to transfer heat. The heat pipe consists of a sealed tube filled with a working fluid, typically a liquid metal or a refrigerant. When heat is applied to one end of the heat pipe, the working fluid evaporates, creating a pressure gradient that drives the fluid through the tube. As the fluid condenses at the other end, it releases heat, creating a highly efficient heat transfer mechanism. T