IT kit has toughened up, so data centres can turn off the coolers
The Green Grid – which promotes IT efficiency – has urged data centres to operate their servers at higher temperatures and greater humidity, to save energy.
Data centres are still operating on old-fashioned principles that waste energy by cooling servers and equipment down to temperatures far inside their operating limits, when IT kit is now resilient enough to run at higher temperatures and humidities, says the Green Grid, in a new report, Data Centre Efficiency & IT Equipment Reliability.
It’s not cool to cool
“The common perception of IT network, server and storage equipment is that it operates within very tight environmental tolerances, but this is a belief based on data centre practices from the 1950s,” said one of the report’s authors, Harkeeret Singh. “These practices are archaic, predicated as they are on maintaining constant and narrowly-defined temperature and humidity levels. In practice, modern equipment can tolerate periods of much greater heat and humidity, with no significant effect on failure rates.”
Traditional data centres use as much energy in cooling systems as they do in the IT equipment itself, because they are keeping servers at a temperature around 20C, which used to be needed when IT equipment was sensitive to heat.
Operating at higher temperatures means these air-conditioning systems can be switched off, and data centres can use “free air” cooling which essentially uses outside air temperatures for cooling.
A year ago, ASHRAE, the influential American Society of Heating, Refrigerating and Air-Conditioning Experts, updated its guidelines for data processing environments, based on input from server makers, who now allow users to run their servers at higher temperatures without breaking the warranty. Dell in particular boasted of making more tolerant hardware.
The Green Grid published maps of the world in 2012, indicating where it is now possible to run a data centre without turning on the chillers, to encourage data centre owners to turn the cooling down. Now some servers can even be run at 40C for short periods without harm, and air-conditioning units are not needed in any data centres in Europe, according to the Green Grid.
“When these periods are compensated by periods of more favourable environmental conditions, where water- and air-side economisers can be used for cooling, data centres can reduce reliance on mechanical chillers without any detriment to overall failure rates,” said Singh.
But the suggestion has apparently fallen on deaf ears, so the Grid is putting the case in a White Paper, which argues for higher temperatures, and urges data centre owners to stop living in the past.
“The conservative approach to interpreting the ASHRAE guidelines on operating temperature and humidity has presented a hurdle to the application of energy efficiency measures in the data centre in some areas.” says the paper. Most users are not able to quantify the risks, so “most data centre operators have been wary of using the full scope of the ranges”.
The report is free to members of The Green Grid, and explains allowable IT operating ranges, and techniques for better temperature and airflow management in facilities.
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