Inertech, Skanska Partner on Energy-Efficient Cooling Platform

A new coil technology helps the companies extend free cooling zone for data centers and reduces water and power consumption. Learn more about the cooling platform.

August 6, 2012

5 Min Read
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Two companies have partnered to deliver what they claim is a unique method for keeping a lid on temperatures while conserving water and electricity. Inertech and Skanska's Mission Critical Center of Excellence have developed an energy-efficient cooling platform called eOPTI-TRAX that extends a data center's "free cooling" zone.

Jakob Carnemark, senior VP, Skanska Mission Critical Center of Excellence, says the eOPTI-TRAX technology can dramatically reduce water and power consumption by replacing the traditional chiller plant and air handling unit found in a data center.

In a traditional chiller plant, free cooling occurs when the outside environment is cold enough and no compressors are required, says Carnemark. This is more energy efficient, but that free cooling mode occurs only when the outside temperature is 45 degrees or below. "Our free cooling mode occurs when it's 85 degrees or below outside," he says.

That means a data center using the Skanska technology in many parts of the world would be able to operate in free cooling mode approximately 83% of the year, compared with about 24% of the year for a traditional chiller plant. It's an impressive claim, and even Carnemark acknowledges that it has been met with skepticism. So how is it achieved?

Skanska's approach to data centers comprises an aisle containment system and the eOPTI-TRAX. The aisle containment system comes in the form of an eHive or eComb. EHive is a standalone container building that can be placed adjacent to an existing facility or placed on a rooftop; an eComb can be placed in an existing or newly constructed data center.

The eComb or eHive uses liquid refrigerant coil technology combined with the eOPTI-TRAX to expel the heat from the computer hardware to the outside environment. Instead of cooling the data center using a raised floor design, where an under-floor air distribution system pushes cold air up and into the server racks using many fans consuming a lot of energy, eOPTI-TRAX reduces energy usage by improving air circulation in the server aisle. Heat is absorbed by coils lining the inside of the rear walls of the server rack. Tests have shown it can bring hot aisle temperatures down from 160 degrees to 75 degrees.

Carnemark says the coils are able to attain significant heat transfer without mechanical cooling, and what's unique is that the refrigerant can be changed from a gas back to liquid at temperatures as high as 85 degrees and be used over and over again, meaning as much as 80% less water is consumed compared with a traditional open loop chiller. Compressors found in traditional data centers cool the air through an evaporation method and thereby consume incredible amounts of water.

There are other technologies available to bring cooling closer to the rack. IBM's Rear Door Heat eXchanger replaces the backdoor of the rack and cools air before it exits the cabinet, reducing the need for air conditioning units and thereby reducing energy consumption.

Carnemark says traditional cooling systems require 90 watts to cool a single server, but the eOPTI-TRAX requires only 0.3 watts. This in turn lowers the overall mechanical power utilization effectiveness (PUE) reading. (It's important to note that mechanical PUE differs from traditional PUE, which also takes into account how much energy is wasted through a facility's power distribution system.)

Next: Other Approaches to Lowering PUESkanska and Inertech are not the only companies tackling the high PUE problem. Both Google and HP have been successful in lowering the PUE in their data centers to below average. Google reported a PUE of just 1.14 at the end of 2011, an average of all its data centers, meaning overhead energy usage was only 14% of computing electricity consumption. HP operates a data center in Wynyard, England, that is located on the shore of the North Sea. Drawing in cool sea air gives the Wynyard data center a PUE of just 1.19.

Testing by the University of Maryland's Department of Mechanical Engineering found the cooling system achieved a 1.012 PUE reading, which is below the average of 1.4 to 1.6 for most data centers.

The problem with PUE comparisons is that tests capture only a moment in time and would be different if averaged out over weeks or a year. PUE is influenced by many factors, such as power and cooling equipment types and percentages of load utilization.

Telus, one of Canada's largest service providers, is the first commercial organization to deploy eCombs with eOPTI-TRAX. "We continue to see incredible growth in the need for compute storage and WAN/LAN connectivity in all our data centers," said Lloyd Switzer, SVP of network transformation at Telus. "It didn't matter how well we designed our data centers. We would quickly outgrow the capacity of the data centers, either on power, on cooling or footprint. We could never predict which."

Telus decided to take a step back and look at what made more sense: improving existing data centers and their TCO or building green field facilities. It ultimately turned to Skanska to devise a multi-year framework that would incorporate eComb and eOPTI-TRAX. The first phase has been constructed at a new prototype Telus facility in Rimouski, Quebec.

EComb enables Telus to add capacity as needed within the facility. The IT and mechanical systems are self-contained within the modules, so there's no need for the traditional facility-wide mechanical systems: Telus can add eCombs as required.

Switzer said the Skanska approach meets the TCO and agility requirements Telus was looking for, and is sustainable and environmentally friendly as well. Traditional data center design, he said, is not that efficient, and while power consumption does drive up cost, it's cooling that really increases mechanical PUE.

Telus's new data center in Quebec incorporating the eComb and eOPTI-TRAX is close to being switched on, with a second facility in British Columbia expected go online next year.

Switzer said he anticipates that Telus will be able to reduce its overall TCO by 40% by lowering up-front investment through the modular deployment approach as well as improving energy efficiency. Using tools provided by Skanska, Telus will be able to track how efficiently its new data center is operating, down to the aisle or rack level, to understand the ROI and how the technology can be applied to its 12 existing data centers across Canada.

Skanska's eComb or eHive can be deployed in modular increments of 250kW each and each rack is able to support as much as 60kW. Customers select their own IT equipment. It takes 16 weeks to add a module.

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