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New data center cooling systems slowly displace CRAC

As CRAC remains a top data center cooling option, cheaper and more environmentally friendly options will continue to emerge.

Data center operators will push to lower OpEex in coming years as less expensive and environmentally friendly cooling...

technologies emerge, even while CRAC use remains widespread.

Computer room air conditioning (CRAC) is still broadly used and will likely be around for many more years despite the high cost, according to Clive Longbottom, analyst with Quocirca, an IT advisory firm based in the U.K.

"I think we are really on a long tail here," Longbottom said.

That long tail may see an end by 2023, when data center managers begin to replace CRACs with a combination of free cooling, liquid cooling and chilled-water cooling, according to Faizan Akhtar, vice president of the research division of Technavio, a global technology research and advisory company. Liquid cooling will have at least 75% of the market at that time and CRAC systems will be used mainly in warmer climates such as the Middle East and Africa, Akhtar said.

One of the newest additions to the market is Emerson Network Power's suite of Liebert Custom Air Handling Units that combines an Evaporative Free-Cooling Unit, an Indirect Evaporative Free-Cooling Unit, a Chilled Water Air Handler and DX Air Handler that together provide the ability to customize the cooling system for a data center flexibly.

Liebert expects evaporative system use to be a growing trend as companies seek more sustainable ways of using evaporating water to supplement or replace mechanical cooling and compressor usage, according to Tifft Gannon, a product manager for Liebert Corp. 

The push to become environmentally friendly goes hand-in-hand with a drive to save money, Akhtar said. Data center operators looking to reduce cost and increase efficiency will also reduce the data center's environmental impact, and vice versa, he said.

Cooling vendors are developing green technologies to reduce energy consumption and minimize environmental impact, according to a report published earlier this month by Technavio Research that looked at the data center cooling market.

Chilled-water cooling has a dominant chunk of the new cooling business this year, said Rakesh Kumar Panda, the report's lead author. It uses water as the primary source of cooling at the room, row or rack level and is best for data centers of 15 kW or smaller but it has its limitations, Panda said.

It is for those that are pushing the envelope of IT; It's complexity is working against it.
Clive Longbottomanalyst from Quocirca on immersive cooling

The liquid immersion cooling market is nascent at about $30 million in the U.S., but it will see significant growth, Akhtar said.

"That is trending in the U.S.," he said. "This market will grow at an astonishing rate of 45 percent plus."

Some data center operators are looking at liquid immersion now and could still be three to four years away from installing it.

Immersive cooling has a role mainly for supercomputers, Longbottom said, in large part because of system's level of sophistication.

"It is for those that are pushing the envelope of IT," he said. "Its complexity is working against it."

Data center operators have also been able to save money, and lower the carbon footprint, as part of a decade-long trend toward warmer data centers (above 55 degrees Fahrenheit).

Indirect evaporative free-cooling is being used in many areas of the U.S. -- using outside air and recirculating the same water. These indirect systems are much smaller than a complete CRAC system. When it is hot outside, operators can turn on the pump and use 1/20th of the power it otherwise uses to maximize economizer hours, Liebert's Gannon said.

He also pointed to "next generation control" in data center as holding the possibility of decreasing OpEx by 20% to 30% by having all cooling units connected and responding synchronously.

Free air cooling will continue to get a long, hard look from data center operators because of the low cost. Even in the Middle East, for example, it can be used 200-250 days per year, Longbottom said.

Longbottom also warns of the dangers of a high-grade CRAC system because it could create whiskers, which are miniscule particles that grow in dry air and can short out a system.

One of the rarest cooling techniques -- but possibly the most exciting -- is Kyoto wheel cooling, which Longbottom estimates is being used in only a few dozen data centers worldwide. With this approach, a large wheel takes air flow from one side to the other, separating inside and outside air streams and heat is transferred to the outside air stream as the wheel rotates. It costs very little to run and the largest one can stretch 20 feet across.

The biggest roadblock to wider use?

"You can't retrofit it for an existing data center," he said.

Robert Gates covers data centers, data center strategies, server technologies, converged and hyperconverged infrastructure and open source operating systems for SearchDataCenter. Follow him @RBGatesTT.  

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