Barbara Gengler | June 17, 2008
THE use of economisers that take advantage of nature to help cool data centres is gaining traction in the US.
Microsoft, for instance, is planning to use cooling systems that take advantage of the weather to cool its new 46,000sqm Chicago data centre.There are two kinds of economiser: airside, which use outside air to cool data centres, and waterside, which take water from a natural source such as a stream, pond or river and bring it in contact with pipes carrying heated water out of the data centre. Both reduce energy bills.
Because of Chicago's climate Microsoft can use both approaches at its data centre.
Another supporter of these technologies is data centre operator Equinix, which says it saves up to 80 per cent in annual cooling costs by using economisers in eight of its 19 US facilities.
United Parcel Service, which installed waterside economising, says it gets about five months of free cooling each year in its Atlanta data centre.
At the site, a thermal storage tank provides ride-through during warm afternoons and is then recharged during cool evenings. Airside economisers work best in mild conditions, such as those in northern California, but not in places such as Miami.
Waterside economisers work best in climates with a cool autumn and spring and cold winter, such as New York or Chicago.
Recently, a team of researchers from the Lawrence Berkeley National Laboratory and the Environmental Protection Agency studied the measurements of server energy performance and found data centres' power and cooling infrastructure accounted for about half of the electricity consumption, while IT equipment accounted for the other half.
It is estimated servers and data centres consumed about 61 billion kilowatt-hours (kWh) in 2006, costing $4.5 billion.
If the status quo continues, by 2011, data centres will consume 100 billion kWh of energy at an annual cost of $7.4 billion. The study emphasises that "IT equipment reliability degradation due to outdoor contamination appears to be a poor justification for not using economisers in data centres".
The study says there are three energy-efficient rating systems that data centres could use as guidelines: improved, best practice and state of the art.
The state of the art system, (which includes consolidation of servers and storage and using direct liquid cooling), could reduce electricity use by up to 55 per cent, while the best practice scenario, (which includes adopting energy efficient servers and adopting free cooling), could reduce electricity use by up to 45 per cent compared with current trends.
The improved system offers potential electricity savings of more than 20 per cent.