ADVANCED COOLING TECHNOLOGIES, INC. (ACT) HAS WORKED EXTENSIVELY ON HEAT PIPE PRODUCT RELIABILITY. This guide provides information for designing, modeling, and practical reliability surrounding copper/water heat pipes.

A heat pipe is a two phase heat transfer device with very high “effective” thermal conductivity. It is a vacuum tight device consisting of an envelope, a working fluid, and a wick structure. As shown below, the heat input vaporizes the liquid working fluid inside the wick in the evaporator section. The saturated vapor, carrying the latent heat of vaporization, flows towards the colder condenser section. In the condenser, the vapor condenses and gives up its latent heat. The condensed liquid returns to the evaporator through the wick structure by capillary action. The phase change processes and two phase flow circulation continue as long as the temperature gradient between the evaporator and condenser are maintained.