Test results on a thermo-syphon concept to high-power cool desktop computers and servers

This paper reports measured thermal performance of two prototype thermo-syphon devices designed to cool desktop computers and servers. The prototype was designed to reject 100 W with 35 K CPU-to-air temperature difference using an 80 mm 3350 rpm fan for air flow. One prototype is aluminum and uses R-134A, while the other is copper and uses water. The working fluid boils at the CPU and is condensed in tubes of an air-cooled heat exchanger, based on automotive technology. The frontal areas of the heat exchangers are 97 /spl times/ 70 mm (aluminum) and 54 /spl times/ 70 mm (copper). The thermo-syphon device uses high-performance heat transfer technology, consisting of louvre fins (air-cooled unit), and a sintered boiling surface. The experimental results of the aluminum/R-134A prototype are in good agreement with the previously published predicted thermal resistance. The performance of the prototype systems are believed to provide the highest performance of any published air-cooled heat rejection system.