Calyos, founded in 2012 in Brussels, Belgium, has become a leader in advanced two-phase cooling systems for electronics in a very short time thanks to its expertise in loop heat pipe technologies that utilizes continuing passive cycles of vaporization and condensation to cool power electronics.
Calyos of Belgium has designed a two-phase heat pipe loop. (YouTube)
The company was recently featured on KitGuru.net in an article that asked if Calyos was the world leader in two-phase cooling. The author examined the company’s loop heat pipe system to find out the details behind its success.
The company insists that the underlying technology behind its loop heat pipe systems was developed in 1971 but that the current iteration is far smaller than the massive systems used on French metro trains and also more efficient and reliable.
The article explained, “Imagine you have a bunch of electronics inside the tank that requires cooling. You clamp on a heat pipe cooling system that bolts to the side or roof of the tank and use the 60 tonne chassis as a passive heat sink. This works well in Europe but rather less well in the heat of a desert as the sun makes the top of the tank very hot.
“Switching to a loop heat pipe system solves the problem as you can simply bolt the cold end to the bottom of the tank where it is protected from the sun. Remember, a loop heat pipe system doesn’t care about the orientation of its installation so ‘down’ works equally as well as ‘up’.”
The author learned that the porous material attached to the copper heat sink is nickel and sintered to the cooper plate. The sintering process was kept secret, although Calyos does have a furnace that can heat the assemblies to 900°C and can hit an exact temperature within a tolerance of 3°C.
The article concluded, “In many respects the least interesting fact about Calyos loop heat pipe cooling systems is the point that the heat exchangers can be cooled either actively or passively. Instead you should focus on the absence of a pump and the way the cooling fluid circulates without any mechanical assistance.”
According to the Calyos website, the process works under three physical principles. The first is capillary pumping that uses a metallic foam with micron level pores. When the foam absorbs fluid, it naturally creates pressure that circulates the fluid inside the loop without requiring outside energy.
The second principle is vaporization. The fluid that is being pumped fully vaporizes when it absorbs the heat being dissipated from the component. The final principle is condensation. The vapor passively flows over a condenser where it is turned back to liquid and heat is dissipated outside the system through a heat exchanger.
Having separate pipes for vapor and for liquid is a significant point of separation for Calyos compared ot many of its competitors.
Learn more about Calyos in the video by KitGuru below: