A data center owned and operated by Citi, the large global financial-services company, has become the fourth data center to receive an Energy Star label from the US Environmental Protection Agency under its new energy efficiency benchmarking program designed specifically for data centers.

Citi's data center near Columbus, Ohio, which measures more than 300,000 sq ft, received a score of 84 on the agency's 0-100 energy efficiency scale. This means the facility is more energy efficient than 84 percent of facilities the EPA used to develop the benchmarking system. A data center qualifies to receive the Energy Star label if it falls within the top 25 percent of facilities used to benchmark efficiency. 

John Killey, Global Head of Sustainability at Citi Realty Services, said the EPA's rating system was helpful for the company in its efforts to reduce the amount of resources it consumes. "The use of Energy Star is integral to energy management at Citi, being a simple but effective global benchmarking tool that enables us to focus on areas of opportunity." 

For Citi, the primary area of focus in making the data center more energy efficient was its cooling system. The engineers raised space and supply-air temperatures beyond their previous set-points. The facility's air-side economizer allows it to use free cooling 35 percent of the year. 

The team also put high- and low-density IT gear in separate sections of the data center to reduce fan speeds in the less-energy-intensive areas and created an energy management system, which measures equipment efficiency and shows peak-performance targets in real time. A formal process was put in place for routine analysis of the data collected by the EMS and incorporating results of the analysis in operating procedures. 

Citi's first data center to earn Energy Star under the new rating system. It is, however, one of 54 Citi facilities that have the label under the EPA's older rating program for energy efficient commercial buildings. 

The agency launched Energy Star for data centers in June. The program uses data center Power Usage Effectiveness ration to judge its energy efficiency. Other data centers to receive the label included NetApp's facility in North Carolina and a Consonus data center in Utah.