Grooved Heat Pipes for Efficient Thermal Solutions
Helically or axially grooved heat pipes (also known as thermal siphons or thermo-siphons) do not have a wick structure and rely on gravity to return the fluid to the evaporator end. They can only transfer heat “upward” or away from the acceleration vector. Thus, orientation is much more important for helically grooved heat pipes than for sintered wick structured heat pipes. They are also easier to manufacture and less expensive, and are typically used in applications with radial heat fluxes up to 40 W/cm2.
Grooved heat pipes have a circle of grooves in their interior wall acting as the wick, increasing its surface area and enhancing heat transfer. The grooves efficiently pull the condensate back to the evaporator from cooler surfaces where the working fluid had condensed.
Grooved constant conductance heat pipes are ideal for satellite thermal management applications. They are also used for electronics enclosure cooling, as their long-range heat transfer capabilities offer more design flexibility, providing a variety of options for cooling electronic components in various challenging locations.
One of the important applications of helically grooved heat pipes is in solar water heaters, where solar energy is harnessed. The heat is transported to the water in a tank by using a type of thermosiphon arrangement in vacuum tubes, reducing the consumption of electricity. The demand for solar water heaters is increasing every day, especially in developed countries, due to the power savings, some countries going so far as to make this mandatory for every household.