Microsoft has patented a hermetically sealed data center full of high-pressure gas.
The problem of cooling data centers is acute. In an attempt to find the most efficient way to cope with heat transfer companies design new technologies, including leak-proof liquid cooling and liquid immersion baths. However, in some circumstances, these solutions may be quite expensive.
Microsoft has recently suggested an alternative approach to the cooling issue. The company has patented a system that introduces a hermetically sealed data center filled with high-pressure gas.
Although Microsoft has not yet shared any official comments on the new technology, the patent filing states that it is able to significantly improve data center cooling while requiring no additional expensive hardware.
The idea itself is quite simple. The data center facility is sealed and filled with a gas under high pressure. Increased pressure makes the air denser, which affects the heat capacity, increasing the amount of heat that can be removed from the equipment. According to the patent filing, “The gas might be pressurized, according to some embodiments, from at least substantially 2 times standard pressure to substantially 5 times standard pressure”.
Besides normal air, the new technology can also utilize inert gases such as nitrogen, carbon dioxide, and sulfur hexafluoride. For instance, filling a hermetically sealed data center with sulfur hexafluoride (SF6) at a pressure of 2 atmospheres increases heat transport nearly seven times compared to the use of normal air, while reducing fan power to only 25 percent of standard levels. Despite the presence of fluorine in the formula, SF6 has been proven to be safe for the electrical equipment.
Regarding the issues of human safety, associated mostly with the risk of gas leaks, Microsoft’s patent does not specifically delve into that. However, it gives a detailed description of a control system that can sense gas pressure and composition in a sealed server room and monitor the human access door. The patent also mentions that although SF6 is not toxic to humans, it is still not suitable for breathing.
Apparently, data centers filled with high-pressure gas may be intended for fully autonomous facilities with minimal human involvement. Thus, Microsoft is already running an experimental research project that involves an underwater low-maintenance data center, Project Natick. However, the project's website notes that the system is operated at one atmosphere.
In a system like that the use of sulfur hexafluoride may indeed be justified. Yet, when it comes to ground-based data centers, it is not clear whether the increased cooling efficiency of a high-pressure gas-filled data center will outweigh a number of inconveniences associated with the need to ensure the personnel’s safety.