The rising cost of power paired with larger servers can lead to a combustive effect on the bottom line. The data center is typically a company's largest electricity consumer, not only in computing, but also in cooling racks of blades and servers. However, with green initiatives in data center cooling, relief may be just an oil bath away.
Last year, Dan Stanzione, deputy director of the Texas Advanced Computing Center, implemented a fluid submersion technology developed by Green Revolution Cooling (GRC). In submersion technology, servers -- with fans removed and disk drives encapsulated -- are immersed in a nonconductive liquid such as mineral oil. Since the oil is not conductive, it can safely store servers at much higher temperatures than traditional air-flow cooling methods, significantly reducing data center cooling costs. Similar technologies are offered by 3M Co. and Hardcore Computer Inc.
The upside of green data center cooling
"There's a lot of competing advanced cooling technologies out there right now; there's in-rack cooling, there's rack-top coolers … a lot of it involves a lot of custom engineering. One of the things I love about this [immersion] technology is that we can put any manufacturers' equipment into the oil," said Stanzione. "We can convert a server in about 15 minutes to run in this [environment]."
Liquid submersion is only one of many green data center cooling technologies. Schneider Electric SA's Uniflair system pumps chilled water to cooling coils through which fans draw newly chilled air for the data center. The Uniflair's electronically commutated fans are regulated by the heat load, reducing power consumption. Schneider also released a close-coupled air conditioner, which promises to increase efficiency by placing the cooling system closer to the heat source, replacing water with pumped refrigerant. Similarly, Emerson Electric Co.’s Liebert DSE saves energy by using a refrigerant pumping system instead of intake and exhaust fans. Like the Uniflair system, Liebert DSE relies on electronically commutated fans to reduce energy use.
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Another old-but-new development in the data center cooling arena is an indirect evaporative system. Water is sprayed on the interior wall of a heat exchanger, and the resulting evaporation cools the outer wall. These systems can also be equipped with heat recovery, which captures excess heat and uses it for other parts of the data center, saving energy and money.
After introducing liquid submersion in its data center, Austin, Texas-based Midas Networks Inc. reduced its power usage effectiveness (PUE) from 2.0 to 1.01. With the cost of installation around the same price as other cooling technologies, "we'll have payback in less than two years," said Jim Koen, CEO of Midas, which provides IT solutions to growing companies. Koen said he considers an average PUE to be 1.5, while data centers with more advanced technology like in-row coolers could get a PUE of around 1.3.
Unexpected perks to the oil bath
Although cost reduction and energy savings are the obvious benefits to green data center cooling, there are other advantages. For example, Koen discovered that fire suppression is no longer a concern in the data center. With fluid submersion technology installed, the servers are placed in a vat and topped off with a lid, allowing them to be separated and protected from sprayed fire retardant. Midas Networks also saved money by not having to raise the data center floors, "which is a huge cost concern for a lot of people," Koen said.
We'll have payback in less than
Jim Koen, CEO, Midas Networks Inc.
There are nontangible benefits to the liquid cooling, as well. For instance, since the fans are stripped from the servers, the noise level is also drastically reduced. "You can stand in the data center and have a normal-tone conversation … it's absolutely quiet in there," he said.
Stanzione only made minor modifications using the liquid cooling technique, mainly removing the fans and making sure the server didn't identify the missing fan as a failure. Likewise, Koen experienced only a small snag on a server motherboard when taking the server out of the oil.
Koen said he envisions the technology being used beyond his own company, citing the Federal Emergency Management Agency (FEMA) as an example. When FEMA goes to a disaster site, "they take huge trucks with mobile cooling systems in them to run their data centers. They don't need those anymore," he said. It would save FEMA space, time and costs, according to Koen.
Stanzione said that, as with many new technologies, the oil bath will require an introductory period to gain acceptance. He explained that once he takes the time to allow confidence to build, he plans to add liquid cooling to more server racks.
"We're expanding our data center, and we've made some accommodations to handle this new kind of rack in our data center … so we fully intend to make full use of this technology going forward," Stanzione said.
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