Peer 1 Saves With Evaporative Data Centre Cooling

International web hosting provider Peer 1 has saved 85 percent of the  data centre cooling bill for its Portsmouth facility by using an evaporative system from the UK’s ExCool.

The units use water evaporation to keep the new data centre cool even when the outside air temperature is as high as 34C, so Peer 1 does not need to use more wasteful mechanical chillers. The data centre has been open since February, and results so far suggest the company could get down to a record PUE efficiency score of 1.035. It’s ExCool’s first data centre installation in Europe.

Reducing the energy needs for cooling cuts a data centre’s bills, but also makes it more resilient, as Peer 1 found in New York, when its data centre needed gallons of diesel fuel to keep going after Superstorm Sandy took out Manhattan’s electricity supply.

They’ll talk for eight hours straight about cooling

“We wanted a data centre closer to our business,”  Dom Monkhouse, UK director of PEER 1 Hosting told TechweekEurope. “Peer 1 had built one in Toronto with a PUE of 1.35 [the emerging power usage effectiveness or PUE standard is the ratio of energy supplied to the building divided by the energy that reaches the IT equipment]. We felt we could build one over here, cheaper than buying one in.”

The planned data centre at Havant near Portsmouth used the same mechanical engineering design as Peer 1’s Toronto site, but during the process of building it, Monkhouse met ExCool, a UK firm based in Worcestershire, that Monkhouse says is “super-passionate about their niche… which is cooling.”

ExCool’s Mark Collins convinced Monkhouse with the force of his argument for ExCool’s indirect evaporative cooling system. “If you let him, he will talk to you for eight hours straight about cooling,” said Monkhouse.

Three 250kW ExCool units were retrofitted into the Havant data centre as it neared completion. “We opened in October 2011, and put in the ExCool units in January,” said Monkhouse. They had to be lifted by crane onto a specially strengthened metal frame on the roof of the data centre – the evaporative units were added later.

Now with nine months of energy use data, Monkhouse hopes to achieve a PUE of 1.035 – though this is a “cooling only” PUE which may not include all the overheads built into other PUE measures.

Using the outside air for cooling is efficient, but if that air is pumped directly into the data centre, it can introduce impurities even if it is filtered – so many cooling units use heat exchangers, keeping the outside air on a separate system. The problem with this is that the heat exchanger reduces the efficiency with which the heat can be taken away from the system.

Evaporative cooling uses a mist of water that takes away heat when it evaporates – a process all known as “adiabatic cooling”, and ExCool’s system combines the heat exchanger with the evaporator very effectively, says ExCool’s Collins, who is every bit as enthusiastic as Monkhouse says: “There is no manufacturer who manages to get the entering air fully saturated as we do – and equally important nobody who has a heat exchanger system anywhere near as efficient as ours,” he enthuses. “Our efficiency has been independently verified at 94.5 percent when tested to the relevant  standard. The next nearest on the market achieves a claimed but non-independent 65 percent.”

ExCool competitors include U=-based EcoCooling, which makes smaller units that use outside air directly, designed to be fitted to older data centres, and APC, which makes giant evaporative cooling units under the name EcoBreeze. Others include Munters and GEA Denco. “The APC system is nearly four times the physical size, about three times the cost and uses 20-50 times more water,” said Collins.

The three units at Havant are keeping some 5000 servers cool in the first part “pod 1” of Peer 1’s site, and have reduced the energy needs so much that the firm thinks it has saved nearly three million tonnes of CO2 emissions, thanks to 8000 hours of “free cooling”.

The reduced power bill means that Peer 1 may be able to expand further than it expected in the Havant site. It has five pods planned, but could use storage space for a sixth unit on the site, which can have up to 11MVA of power, said Monkhouse. That expansion isn’t going to happen all at once though: filling up Havant would double the size of Peer 1.

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