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 11, 2011
Texas megachurch inspired by yesteryear’s materials, today’s design vocabulary
The third phase of The First Baptist Church of Pasadena, Texas, involves construction of a new 115,000-sf worship center addition. Currently in design by Zeigler Cooper, the project will include a 2,500-seat worship center (with circular layout and space for a 50-person orchestra and 200-person choir), a 500-seat chapel (for weddings, funerals, and special events), and a prayer room. The addition will connect to the existing church and create a Christian Commons for education, administration, music, and fellowship. The church asked for a modern design that uses traditional materials, such as stone, brick, and stained glass. Construction is scheduled to begin this summer.
| Feb 11, 2011
Apartment complex caters to University of Minnesota students
Twin Cities firm Elness Swenson Graham Architects designed the new Stadium Village Flats, in the University of Minnesota’s East Bank Campus, with students in mind. The $30 million, six-story residential/retail complex will include 120 furnished apartments with fitness rooms and lounges on each floor. More than 5,000 sf of first-floor retail space and two levels of below-ground parking will complete the complex. Opus AE Group Inc., based in Minneapolis, will provide structural engineering services.
| Feb 11, 2011
Four-story library at Salem State will hold half a million—get this—books!
Salem State University in Massachusetts broke ground on a new library and learning center in December. The new four-story library will include instructional labs, group study rooms, and a testing center. The modern, 124,000-sf design by Boston-based Shepley Bulfinch includes space for 500,000 books and study space for up to a thousand students. Sustainable features include geothermal heating and cooling, rainwater harvesting, and low-flow plumbing fixtures.
| Feb 11, 2011
Green design, white snow at Egyptian desert retail complex
The Mall of Egypt will be a 135,000-sm retail and entertainment complex in Cairo’s modern 6th of October district. The two-story center is divided into three themed zones—The City, which is arranged as a series of streets lined with retail and public spaces; The Desert Valley, which contains upscale department stores, international retailers, and a central courtyard for music and other cultural events; and The Crystal, which will include leisure and entertainment venues, including a cinema and indoor snow park. RTKL is designing the massive complex to LEED Silver standards.
| Feb 10, 2011
7 Things to Know About Impact Glazing and Fire-rated Glass
Back-to-basics answers to seven common questions about impact glazing and fire-rated glass.
| Feb 10, 2011
Medical Data Center Sets High Bar for BIM Design Team
The construction of a new data center becomes a test case for BIM’s ability to enhance project delivery across an entire medical campus.
| Feb 10, 2011
Zero Energy Buildings: When Do They Pay Off in a Hot and Humid Climate?
There’s lots of talk about zero energy as the next big milestone in green building. Realistically, how close are we to this ambitious goal? At this point, the strategies required to get to zero energy are relatively expensive. Only a few buildings, most of them 6,000 sf or less, mostly located in California and similar moderate climates, have hit the mark. What about larger buildings, commercial buildings, more problematic climates? Given the constraints of current technology and the comfort demands of building users, is zero energy a worthwhile investment for buildings in, for example, a warm, humid climate?
| Feb 9, 2011
Hospital Construction in the Age of Obamacare
The recession has hurt even the usually vibrant healthcare segment. Nearly three out of four hospital systems have put the brakes on capital projects. We asked five capital expenditure insiders for their advice on how Building Teams can still succeed in this highly competitive sector.
| Feb 9, 2011
Businesses make bigger, bolder sustainability commitments
In 2010, U.S. corporations continued to enhance their sustainable business efforts by making bigger, bolder, longer-term sustainability commitments. GreenBiz issued its 4th annual State of Green Business report, a free downloadable report that measures the progress of U.S. business and the economy from an environmental perspective, and highlights key trends in corporate culture in regard to the environment.
| Feb 8, 2011
AIA names 104 members to College of Fellows
The Fellowship program was developed to elevate those architects who have made a significant contribution to architecture and society and who have achieved a standard of excellence in the profession. Election to fellowship not only recognizes the achievements of architects as individuals, but also their significant contribution to architecture and society on a national level.
