So, you may be surprised to hear that this is not always the case. In fact, sometimes scientists submerge electronics as a go-to solution designed to protect them.
“Whoa! Wouldn’t there be sparks flying?” exclaims Dale Sartor, staff scientist at the Lawrence Berkeley National Laboratory.
That is the same reaction scientists get when they show people 3M™ Novec™ Fluid demonstrations. They see that sparks don’t fly, and your photos still appear on your phone or camera even after submersion into the fluid.
The chemical makeup of this fluid is what excites Dale the most, especially when it comes to cooling data centers. “The liquid that we are using is a non-conductive fluid, and therefore it can touch the IT equipment and cool it directly,” explains Dale.
That is because the liquid immersion cooling fluids are dielectric fluids – unlike water, which is a very good conductor of electricity.
As fascinating as this may sound, why is it important? Servers housed in data centers rely on being cooled in order to function efficiently – especially since operating the server equipment generates a great amount of heat.
But, the cooling process is also energy intensive.
“About 38 percent of the electricity needed to run the operation is just to cool the electronics,” explains Laura Nereng, sustainability and business development leader for the Electronics and Energy Business Group at 3M.
For data center operators, liquid immersion cooling can be a solution.
3M scientists utilize both single-phase and two-phase immersion cooling techniques. In single-phase immersion cooling, the fluid has a higher boiling point and remains in its liquid phase throughout the process. Electronic components are submerged in a non-conductive bath filled with a liquid. The heat from the components is transferred to the fluid and the heated fluid is then pumped to a heat exchanger, where it is cooled and cycled back into the bath.
The scientists at 3M also utilize a passive two-phase immersion cooling process, where component racks are submerged in a bath of 3M™ Novec™ Engineered Fluid. Phil Tuma, who works with the application of this technology at 3M, explains how it works. “Novec fluids remove heat through direct contact with the chip or other heat source, which causes the fluid to boil and capture the heat as vapor,” he says. “The vapor generated rises from the liquid to a condenser coil and then falls back into the bath. No energy is required to move the vapor, and no chiller is needed for the condenser, which is cooled by facility water supplied by a dry cooler.”
Being able to submerge the electronics directly into a liquid without damaging the electronic components isn’t the only benefit to liquid immersion cooling. Another advantage is that less space is required.
“Instead of spreading out the electronics so that you can air cool them, you just pack them together, because they will be cooled by this engineered fluid much more efficiently,” says Laura. “You take what was going to take 100 percent of the space and put it in 10 percent of the space.” This can result in a significantly smaller environmental footprint for the facility.
The ability to house data centers in less floor space sparked the interest of Allied Control, a pioneer in specializing in two-phase immersion cooling using Novec Engineered Fluids.
“This allows us to shrink down the data center size to only a fraction of what it would be if you were to run a data center with traditional air cooling,” says Kar-Wing Lau, CEO at Allied Control.
Phil of 3M explains that a smaller data center is particularly beneficial in certain types of environments. “If you are required to put a data center in Tokyo, for example, you have to use high-rise buildings, and you have noise ordinances and seismic regulations that come into play for earthquakes,” he says. “So, shrinking the footprint of the data center and making it more economical to build is very important.”
Another benefit is a lower Power Usage Effectiveness (PUE) – which is expressed as the ratio of total facility electricity required, including cooling the electronics, to the electricity needed just to enable the function of the servers.
“PUE is really about, ‘How efficiently can I get energy from the utility to a piece of IT equipment in my data center?’” explains Zahl Limbuwala, founder of Romonet, a company that provides predictive analytics software services to data centers.
“It basically measures how much electricity is being used for the actual IT electronics itself – for instance, measuring the servers versus the entire data center facility electricity,” adds Kar-Wing. “This gives you a ratio to evaluate how efficiently your data center is running.”
The most ideal PUE value would be 1.0, where the entire data center electricity would only be consumed by your server electronics.
This is important because when it comes to data center operations, the cooling of the electronics is the largest part of data center energy costs. “Cooling is the biggest chunk of the electricity needed in the operation,” explains Laura.
Novec fluids are taking it a step forward in providing a solution. They cool while maintaining a thermal PUE under 1.02 (PDF, 3.15 MB), meaning that less than 2 percent of the electrical power used by the IT equipment is needed to cool it – well below the government standard of a PUE of less than 1.5.
In total, the most efficient liquid immersion cooling methods can help improve data center energy efficiency by up to 97 percent, because they eliminate the need for the chillers and air conditioning units that correlate to high energy costs.
Data center operators also measure the water consumption of data centers with Water Usage Effectiveness (WUE).
Many air-cooled data centers use water chillers and evaporative cooling. “Evaporative cooling basically means that you are evaporating tap water to cool the air,” explains Phil. This can use massive amounts of water in the cooling process.
With passive two-phase immersion cooling, the use of water in this way can be eliminated. “[It] allows the possibility to have close-loop cooling where we have water pumped through the entire system to the dry coolers without ever leaving the system,” says Phil. “With that, we can achieve a very low Water Usage Effectiveness.”
Finally, liquid immersion cooling is designed to be a simple process. “You can simply open a tank, remove the server within it while the others are still operational and perform maintenance,” says Phil.
In many ways, liquid immersion cooling is an ideal technology. “You have best in class power density, coupled with best in class energy efficiency, and dramatically simplified design,” says Phil.
“There is an increased desire, particularly on the very large-scale data centers, to find the ways to use liquid cooling,” says Bruce Taylor, executive vice president of Data Center Dynamics, North America. One of these areas may be in high-density applications supporting hyperscale data centers, explains Lucas Beran, senior research analyst with IHS Markit.
“Immersion cooling is seen as an acceptable solution by operators of hyperscale data centers,” he says. “As they start to deploy it, I think this will start to drive further adoption of immersion cooling more widespread, specifically for high-density applications.”
Learn more about immersion cooing from the experts.
3M scientists and engineers are working with some of the leading tech firms and innovators to develop solutions to help make data centers more efficient. 3M’s new documentary, ‘Data Driven,’ explores the importance of the data center industry and also the challenges it faces as it scales into the future.
Note: The views and opinions expressed do not necessarily state or reflect those of The Regents of the University of California or the Lawrence Berkeley National Laboratory, and shall not be used for advertising or product endorsement purposes.