CISL Annual Report 2005 > Computing facility accomplishments

Chilled water system upgrade

In FY2005, SCD completed the third phase of a massive upgrade of the NCAR Mesa Laboratory computer room: a redesign of the chilled water system that cools the air in the computer room. The upgrade makes it possible for the computing facility — designed 40 years ago for machines that needed minimal power and cooling by today's standards — to support today's supercomputers. These supercomputers contain thousands of processors that run fast and hot.

From planning to completion, the upgrade of the computer room infrastructure was a three-phase process that started in 1997. The first two phases saw the installation of new uninterruptible power supply (UPS) units (2001) and standby generators (2004), which provide power to NCAR supercomputers in the event of electrical outages. The final phase in FY2005 involved an extensive redesign and rebuilding of the computer room's chilled-water cooling system.

The old chilled water system was more complex than it needed to be. Facility managers wanted to increase its capacity and decrease its complexity to arrive at a more reliable system. After specifications and designs were approved, both of the computer room's two chillers were replaced with higher-capacity units. Water pipes were torn out and replaced, new pump motors and transmissions were installed, and the cooling-tower fans were improved.

Much of this work had to be done while the computer room was online. With careful planning, monitoring, and execution, the project was completed without a problem. The new system is rated at 450 tons of cooling capacity. (One ton is the equivalent of 12,000 British Thermal Units worth of heat removed per hour.) An added benefit of the new system is that it will divert waste heat from the computer room to warm the Mesa Lab in colder months.

Welders install new chilled-water pipes during the upgrade of the NCAR Mesa Lab's computer room.