11 Best Practices to Save on Data Centre Power

Implement cold-aisle or hot-aisle containment: Once a data centre has been organised around hot aisles and cold aisles, dramatically improved separation of cold supply air and hot exhaust air through containment becomes an option. For most users, hot-aisle containment or cold-aisle containment will have the single largest payback of any of these energy efficiency best practices.

Raise the temperature in the data centre: Many data centres are run colder than an efficient standard. ASHRAE (the American Society of Heating, Refrigerating, and Air-Conditioning Engineers) has increased the top end of allowable supply-side air temperatures from 77 to 80 degrees Fahrenheit (25-27 degrees Celsius). Not all data centres should be run at the top end of this temperature range, but a step-by-step increase, even to the 75 to 76 F (24ºC) range, would have a beneficial effect on data centre electrical use.

Install variable-speed fans and pumps: Traditional CRAC and CRAH (computer room air handler) units contain fans that run at a single speed. Emerging best practices suggest that variable-speed fans be used whenever possible. A reduction of 10 percent in fan speed yields an approximately 27 percent reduction in the fan’s electrical use, and a 20 percent reduction in speed yields electrical savings of approximately 49 percent.

Exploit “free cooling”: Free cooling is the general term for any technique that cools air without the use of chillers or refrigeration units. The two most common forms of free cooling are air-side economization and water-side economization. The amount of free cooling available depends on the local climate, and ranges from approximately 100 hours per year to more than 8,000 hours per year.

Design new data centres using modular cooling: Traditional raised-floor-perimeter air distribution systems have long been the method used to cool data centre’s. However, mounting evidence strongly points to the use of modular cooling (in-row or in-rack) as a more energy-efficient data centre cooling strategy.

The entire report (priced at £131) can be found on the Gartner Web site: “How to Save a Million Kilowatt Hours in Your Data Centre.”