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
| Sep 27, 2013
ASHRAE/IES publish first standard focused on commissioning process
ANSI/ASHRAE/IES Standard 202, Commissioning Process for Buildings and Systems, identifies the minimum acceptable commissioning process for buildings and systems as described in ASHRAE’s Guideline 0-2005, The Commissioning Process. Standard 202 is ASHRAE’s first standard focused on the commissioning process.
| Sep 26, 2013
6 ways to maximize home-field advantage in sports venue design
Home-field advantage can play a significant role in game outcomes. Here are ways AEC firms can help create the conditions that draw big crowds, energize the home team to perform better, and disrupt visiting players.
| Sep 26, 2013
Literature review affirms benefits of daylighting, architectural glazing
The use of glass as a building material positively impacts learning, healing, productivity and well-being, according to a white paper published by Guardian Industries and the University of Michigan Taubman College of Architecture and Urban Planning. The findings highlight the significant influence daylighting and outside views have on employees, workers, students, consumers and patients.
| Sep 26, 2013
Mobilizing your job site to achieve a paperless project: fact or fiction?
True mobility in the field has rapidly evolved from lock-box kiosks on each floor to laptops on rolling carts to tablets and iPads loaded with drawings sets stored in the cloud. And WiFi-ready job sites have gone from “nice to have” to “must have” status in just a little over a year.
| Sep 26, 2013
Leading in the face of change
As AEC firms navigate toward an uncertain future, the most effective leaders are those who eagerly adapt to change. Here are three attitudes that drive leaders who are of most value to their firms.
| Sep 23, 2013
The art of rewarding employees
What’s the best way to reward those employees who go the extra mile, particularly when it’s not always feasible to give large financial bonuses? According to author and “recognition expert” Dr. Bob Nelson, the most effective employee rewards are also the least expensive.
| Sep 23, 2013
Six-acre Essex Crossing development set to transform vacant New York property
A six-acre parcel on the Lower East Side of New York City, vacant since tenements were torn down in 1967, will be the site of the new Essex Crossing mixed-use development. The product of a compromise between Mayor Michael Bloomberg and various interested community groups, the complex will include ~1,000 apartments.
| Sep 20, 2013
August housing starts reveal multifamily still healthy but single-family stagnating
Peter Muoio, Ph.D., senior principal and economist with Auction.com Research, says the Census Bureau's August Housing Starts data released yesterday hints at improvements in the single-family sector with multifamily slowing down.
| Sep 19, 2013
What we can learn from the world’s greenest buildings
Renowned green building author, Jerry Yudelson, offers five valuable lessons for designers, contractors, and building owners, based on a study of 55 high-performance projects from around the world.
| Sep 19, 2013
6 emerging energy-management glazing technologies
Phase-change materials, electrochromic glass, and building-integrated PVs are among the breakthrough glazing technologies that are taking energy performance to a new level.