The University of Arizona’s ongoing commitment to energy efficiency campus-wide includes several major buildings cooled with a chilled water system instead of the massive air conditioning units one would expect to find in the desert heat. That commitment now extends to computational resources as well.

Among supercomputing facilities worldwide -- including corporations, private research centers and universities -- the SGI Altix ICE system operated by the University of Arizona's University Information Technology Services (UITS) is the 237th most powerful computer in the world and the 50th greenest in the world in electrical usage. The June 2008 rankings are by Top500 and Green500.

The Altix ICE system’s water-chilled racks conserve energy and greatly reduce electrical costs associated with the data center’s cooling. The UITS has three air-conditioning systems: one 30-ton and two 20-ton units. They were running the 30-ton and the 20-ton continuously to keep the room cool with previous systems; the third was the backup unit.

UITS currently provides processing power to 97 research groups in 29 different departments at the University. In April 2007, UITS' supercomputers were replaced with an SGI Altix 4700 shared memory system. Earlier this year, the SGI Altix ICE with 1,392 Intel Xeon processors and 2.8TB of memory was added to provide additional resources and optimize the performance of applications best suited to cluster computing. Together the two computers provide 30 times the power in half the space of the previous machines.

With both systems, instead of 29 tons of air conditioning they will need only 1.7 tons, even with 2,020 processors. According to Dr. Michael Bruck, Assistant Director of Research Computing at UITS, "We're getting 30 times the processing power and less than one-tenth of the A/C cooling requirement. The computers are generating as much heat as the old one we had, but now, the chilled water in the doors is absorbing all the heat. Our data center has turned off the 20-ton unit, saving 40 percent on the air conditioning bill, right from day one."

The two computers use the university's chilled water system to cool the air coming off the processors, meaning that the machines provide cold air to the entire computer room while they run. The UITS now has two fully functioning A/C units as back up. This reduction in cooling requirements will also extend the expected lifetime of the air conditioners. Dr. Bruck estimates they would normally have a 5 to 7 year life expectancy but they will last a lot longer functioning only as backup.

Some of the projects the University of Arizona’s UITS supports are worldwide climate modeling for Geosciences and modeling space shuttle re-entry at Mach 8 for Aerospace and Mechanical Engineering. Researchers using the system range in specialization from BIO5, to Steward Observatory, Arizona Research Labs, and Ecology and Evolutionary Biology. Other research on the Altix ICE includes astronomy, life sciences, engineering, business, social sciences and psychology.

Deepak Thakkar, Ph.D. is the higher education and research segment manager at SGI.