If your organization is facing tough economic times, take heart: Some of the best things in life aren't just free; they can even save you money. One such example is the air we breathe. Not only does it have laudable health benefits; outside air can be used to cool datacenters for a fraction of the cost of power-guzzling CRAC units -- and perhaps with fewer drawbacks than you might imagine.
Intel has released a report detailing a recent, impressive experiment in "free cooling" using air-side economization. An air-side economizer can draw on outside air to cool the inside a datacenter, then push the hot air that exits the machines back outdoors.
In conducting its proof-of-concept experiment, Intel sought not only to test the limits of air-side economization by allowing machines to be cooled by air temperatures as high as 90 degrees Fahrenheit; the company also aimed to challenge the perceptions that using outside air can be harmful to servers in that it subjects them to excessive humidity and contaminants.
Can this approach save money over using traditional chillers? Intel says yes: By using air economizers 91 percent of the time (accounting for times when outside air might not be adequate), the company says it could enjoy an estimated 67 percent in power savings at a 10MW datacenter, which would total a very cool $2.87 million.
Intel orchestrated its proof of concept at a datacenter location in New Mexico thusly: It set up about 900 heavily utilized production servers in a 1,000 square foot trailer, which was split into two 500 foot compartments. One compartment was cooled 24-7 by a relatively low-cost, warehouse-grade DX (direct expansion) air-conditioning unit; the other was cooled almost exclusively by outside air, though it was also equipped to be cooled by the DX chiller if the need arose.
As explained by Intel's report on the proof of concept test, "We designed the system to use only the economizer until the supply air exceeded the 90 degree maximum, at which point we began using the chiller to cool the air to 90 degrees . If the temperature dropped below 65 degrees , we warmed the supply air by mixing it with hot return air from the servers."
