Business is reducing its reliance on air conditioning to cool IT equipment with Internet giants such as Facebook, eBay and Google leading the move to free air. Keeping computer systems cool accounts for 70 per cent of a data centre’s non-IT energy consumption. Sandra Van Dijk profiles the free cooling pioneers.
One of the first IT firms to make the move from mechanical cooling to outside air cooling for temperature control was eBay.
The company has established a new data centre in Phoenix, Arizona, with 100 per cent free cooling all year round even on days that top 46°C.
Meanwhile, Facebook claims its data centre in Washington was specifically built to only use free cooling.
More companies are set to follow in the wake of a Green Grid conference earlier this year which provided attendees with free cooling maps.
These maps, based on guidelines provided by the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE), show where in the world and for how many hours per year, outside air can be used in place of air conditioners and other cooling devices.
With these new maps in hand, companies are hoping to achieve big savings.
According to the Green Grid, a non-profit consortium committed to achieving data centre efficiency, there are plenty of free cooling locations across the globe.
By eliminating air conditioners and chillers, the Green Grid said organisations can expect energy and cost savings of at least 20 per cent.
The maps show free cooling is available all year round in more than 75 per cent of North America and 97 per cent of Europe.
In other countries such as Japan there is a sharp drop in these figures.
While there is no specific map for Australia, there are technology providers taking steps to encourage free cooling locally.
For example, Dell is selling its servers in Australia with warranties that guarantee its “fresh air cooling solutions” are capable of running at 40°C for up to 900 hours per year and 45°C for 90 hours per year.
Dell claims it is the highest temperature warranty for servers in the industry today and is ideally suited for warmer climates like Australia.
The standard server warranty is generally for about 35°C.
One company that runs huge server farms around the world and has relied heavily on chillers in the past is Google.
The company has its own fresh air cooling facility in Belgium but is also trialling thermal energy storage and other techniques in different parts of the world.
This may be because the Belgium centre, which relies exclusively on fresh air cooling, has reached temperatures above 35°C.
The typical temperature range for a data centre is between 20 and 22°C.
The thermal option the company plans to use at its Taiwan facility involves running the air conditioning at night when electricity rates are lower, cooling insulated tanks filled with ice or liquid coolant that can then be used to dissipate heat in the data centre when temperatures rise during the day.
The technique could be described as a kind of thermal battery, where cold is stored for later use.
The unit freezes 1700 litres of water overnight creating a giant ice block.
This ice can then be used in place of a conventional compressor for at least six hours the following day.
Google plans to have the data centre operational in 2013 and says the thermal storage system will reduce its reliance on the electricity grid, which is notoriously unreliable in Asia during the summer months.
In its Georgia-based data centre in the US, Google is using recycled sewerage water for cooling to reduce the strain on the area’s potable water system.
In Finland, Google has converted an abandoned paper mill into a data centre utilising water from the Baltic Sea to cool its servers.
With so many natural cooling options, companies will increasingly look to mechanical cooling alternatives.
What will it mean for the air conditioning industry?