The Beginnings of 2-Phase Immersion Cooling in Hong Kong

Kar-Wing Lau and his partners had decided to tackle one of the toughest engineering challenges in the world: Ending the computing industry’s reliance on air cooling for everything from computers to data centers.

Air cooling is inherently inefficient. Bulky heat sinks, thousands of fans, and raised floors take up a lot of space. Computer room A/C and A/C compressors consume a lot of electricity. And worst of all, the cooling performance is poor: With an average Power Usage Effectiveness (PUE) of 2.0 in Hong Kong, air cooling wastes 50% of the energy it uses.

As it turns out, there is a more efficient way to transfer heat out of a system: Harnessing the physics of phase change. A phase change happens, for example, when water boils and produces steam. In this situation, the water stays the same temperature (100°C) and all the excess heat drives the transition from liquid to gas.

This insight led to a true innovation: 2-Phase Immersion Cooling.

When one places hardware in an open bath and surrounds it with a liquid that has a very low boiling point – Lau chose 3M’s Novec™ 7000 that boils at 34°C (93°F) – heat generating components make the fluid boil and take the heat away. That’s phase 1. The rising steam then condenses (phase 2) and falls back into the tank passively without the use of any pumps, and the cycle continues.

Using this technology, Lau built a 500kW data center in the hot and humid climate of Hong Kong. It achieved a PUE of 1.02. The data center, despite being housed in Hong Kong’s sticky climate, saved more than 95 percent of its cooling electricity energy. This represented a staggering $64,000 savings per month. Additionally, the IT equipment in the data center uses 10 times less space than traditional data centers, requiring less than 160 square feet (15 square meters). The system is located in one of Hong Kong’s high rise buildings and fits into the size of a standard shipping container.

As Lau put it at the time, “This new data center project demonstrates the elegance of immersion cooling and showcases that it has what it takes to be the new gold standard in the industry.”

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