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
| Nov 25, 2013
Electronic plan review: Coming soon to a city near you?
With all the effort AEC professionals put into leveraging technology to communicate digitally on projects, it is a shame that there is often one major road block that becomes the paper in their otherwise “paperless” project: the local city planning and permitting department.
| Nov 22, 2013
Kieran Timberlake, PE International develop BIM tool for green building life cycle assessment
Kieran Timberlake and PE International have developed Tally, an analysis tool to help BIM users keep better score of their projects’ complete environmental footprints.
| Nov 20, 2013
Architecture Billings Index slows in October; project inquiries stay strong
Following three months of accelerating demand for design services, the Architecture Billings Index reflected a somewhat slower pace of growth in October. The October ABI score was 51.6, down from a mark of 54.3 in September.
| Nov 19, 2013
Pediatric design in an adult hospital setting
Freestanding pediatric facilities have operational and physical characteristics that differ from those of adult facilities.
| Nov 18, 2013
6 checkpoints when designing a pediatric healthcare unit
As more time and money is devoted to neonatal and pediatric research, evidence-based design is playing an increasingly crucial role in the development of healthcare facilities for children. Here are six important factors AEC firms should consider when designing pediatric healthcare facilities.
| Nov 18, 2013
Lord Aeck Sargent opens metro D.C. office, updates brand
Architecture, design, and planning firm unveils its sixth office, plus a new visual identity system and website
| Nov 18, 2013
How do construction professionals use social media?
LinkedIn is the social network used by most construction professionals, according to the results of a newly released national survey conducted by the Construction Marketing Association.
| Nov 17, 2013
How to spend your first 15 minutes with a prospect
Every business development person has been there. You’ve finally earned a few minutes to impress a prospect that you’ve been pursuing. This is your opportunity to shine. What do you say?
| Nov 17, 2013
Meet up with the BD+C team at Greenbuild. Drinks are on us!
To all our friends in the AEC industry, you are cordially invited to join the BD+C team at several fun events during the Greenbuild show this week. No RSVP required. Just show up and enjoy.
| Nov 15, 2013
Halls of ivy keep getting greener and greener
Academic institutions have been testing the limits of energy-conserving technologies, devising new ways to pay for sustainability extras, and extending sustainability to the whole campus.