It was fabricated by General Motors in USA in 1942
for heatradiation of spaceship and it was
commercialized since 1963.
The inner surface of the tube is lined with a porous material that is filled with a vaporizable liquid. When heat is applied to the outer area of the tube, the liquid inside the tube boils and vaporizes into a gas that moves through the tube seeking a cooler location where it condenses. When the liquid circulating inside sealed area performs phase conversion between liquid and vapor continuously, it has high heat efficiency using latent heat.
Using the characteristics of high conductivity which is hundreds times greater than the conductivity of copper,it is applied in various fields such as electronic parts,
equipment cooling,air conditioning system and solar collector.
Materials of main body are copper, stainless steel,
ceramics and tungsten, and porous fiber is used for
inside wall,Ethanol,aceton,water and mercury are used
for inside volatile materials.