In the rush to slash energy consumption in power-hungry data centers, design teams, equipment manufacturers, and tech companies have been developing clever, low-energy cooling solutions—from Facebook’s open-rack server setup with exposed motherboards, to Skanska’s eOPTI-TRAX liquid refrigerant coil system, to Google’s evaporative cooling schemes.
Solutions like these have helped data center facility operators achieve unprecedented energy performance levels, with power utilization effectiveness (PUE) ratios dipping below 1.10 in some instances. This means that less than 10% of the total energy consumption in a facility is attributed to noncomputing functions, such as air-conditioning and lighting.
Now, a new technology promises to push the limits of data center energy efficiency even further. Called immersive cooling, it uses a liquid instead of air to cool the servers. LiquidCool Solutions, Green Revolution, and 3M are among the pioneers of this technology. Each system works a bit differently, but the basic idea is to submerge the motherboards in tanks filled with nonconductive fluid, which absorbs the heat generated by the processors.
LiquidCool Solutions, for example, uses an enclosed server module and pumps dielectric fluid through the server enclosure. Green Revolution uses a tub full of dielectric oil and circulates the liquid through the tubs. 3M also uses the tub approach, but the fluid boils and then is condensed to reject the heat.
By using liquid-based cooling at the server level, the need for air-conditioning is greatly reduced, or even eliminated in some climates. The same goes for traditional HVAC equipment and systems—chillers, fan units, raised floors, and so on.
The Allied Control 500 kW immersion-cooled data center in Hong Kong is capable of delivering a PUE of just 1.02. The standard, 19-inch server racks use 3M Novec Engineered Fluids to enable tight component packaging for greater computing power in less space, according to Allied. Its open-bath design permits easy access to hardware and eliminates the need for pressure vessel enclosures and charging/recovery systems. PHOTO: COURTESY ALLIED CONTROL
“In most parts of the world, compressorized cooling would not be required with immersive cooling, since the liquid temperatures can be at a level where direct heat rejection using outdoor condensers or cooling towers would be sufficient,” says Thomas Squillo, PE, LEED AP, Vice President with Environmental Systems Design, who is currently researching the technology for the firm’s data center clients. “The fan energy is also eliminated, both in the HVAC system and in the server itself. Fluid pumping energy is very low.”
Other advantages of the cooling technology, according to Squillo:
• Increased performance and service life of the computer chips by eliminating heat buildup and problems related to contaminated air and dust.
• Ability to deploy data centers in extremely harsh environments without greatly impacting energy performance.
• Potential construction cost savings by downsizing or eliminating traditional HVAC systems.
Other than a few pilot projects, including a Bitcoin mining data center in Hong Kong and a Lawrence Berkeley National Laboratory-led installation in Chippewa Falls, Wis., immersive cooling technology is largely untested. A year into the Bitcoin pilot, the data center operator reported a 95% reduction in cooling costs.
AEC professionals are starting to realize the potential for immersive cooling, especially for high-performance computing centers and consolidated, high-density data centers.
“Large data centers that have many homogenous machines at high density—like those operated by Internet and cloud providers—are a good application,” says Squillo. “Small footprint and minimal energy use are very important due to the volume of servers. These can be deployed in remote areas where space and energy are cheap, but where air quality may be a concern, without having to worry about the data center air.”
TRICKY DESIGN CONSIDERATIONS
Before the technology can be implemented, says Squillo, several nettlesome design factors specific to immersive cooling have to be addressed:
• Piping distribution to the racks and cooling units requires redundancy and valving to accommodate equipment maintenance without disrupting server performance.
• Additional equipment and space are needed to drain fluid from the tanks for server maintenance.
• Local code requirements may limit the amount of fluid that can be stored in a single room.
• For the foreseeable future, it’s unlikely that a large data center would be 100% liquid-immersion cooled. This means provisions will have to be made for both air- and liquid-cooling systems, which will require additional space in the data hall and mechanical room.
“I think that some form of this technology will definitely be the direction the data center market will take in the future,” says Squillo. “The market just needs to mature enough for owners to trust the technology and demand servers that are designed for a particular type of liquid cooling. In the short term, I see large companies and server manufacturers doing small-scale installations to test the concept, before wanting to implement it at a large scale.”
Related Stories
| Feb 10, 2012
Atlanta Housing Authority taps Johnson Controls to improve public housing efficiency
Energy-efficiency program to improve 13 senior residential care facilities and save nearly $18 million.
| Feb 10, 2012
Besculides joins New York Office of Perkins Eastman as associate principal
Besculides joins with more than 17 years’ experience in design, business development, and account management for the government, healthcare, and corporate practice areas with a particular focus on the financial and media sectors.
| Feb 10, 2012
Mortenson Construction research identifies healthcare industry and facility design trends
The 2012 Mortenson Construction Healthcare Industry Study includes insights and perspectives regarding government program concerns, the importance of lean operations, flexible facility design, project delivery trends, improving patient experience, and evidence-based design.
| Feb 10, 2012
LAX Central Utility Plant project tops out
Construction workers placed the final structural steel beam atop the Plant, which was designed with strict seismic criteria to help protect the facility and airport utilities during an earthquake.
| Feb 8, 2012
Nauset completes addition and renovation for Winchester senior living community
Theater, library, fitness center, and bistro enhance facility.
| Feb 8, 2012
Mega-malls expanding internationally
Historically, malls have always been the icons of America – the first mall ever was built in Minneapolis in 1956.
| Feb 8, 2012
World’s tallest solar PV-installation
The solar array is at the elevation of 737 feet, making the building the tallest in the world with a solar PV-installation on its roof.
| Feb 7, 2012
AIA introduces seven new contract documents to Documents-On-Demand service??
AIA Contract Documents are widely-used standard form contracts among the building industry to support construction and design projects.
| Feb 7, 2012
Data center construction boom driven by healthcare and technology
The study includes insight and perspective regarding current investment plans of stakeholders, potential challenges to the data center boom, data center efficiency levels, the impact of new designs and technologies, and delivery methods.
| Feb 7, 2012
Kawneer and Traco combine portfolios
Portfolio includes curtain wall systems, windows, entrances and framing systems.