miller60 writes "How do you cool a high-density server installation inside a high rise in Hong Kong? You dunk the servers, immersing them in fluid to create an extremely efficient HPC environment in a hot, humid location. Hong Kong's Allied Control developed its immersion cooling solution using a technique called open bath immersion (OBI), which uses 3M's Novec fluid. OBI is an example of passive two-phase cooling, which uses a boiling liquid to remove heat from a surface and then condenses the liquid for reuse, all without a pump. It's a slightly different approach to immersion cooling than the Green Revolution technique being tested by Intel and deployed at scale by energy companies. Other players in immersion cooling include Iceotope and Hardcore (now LiquidCool)."