Recycled Cars Drive Data Center Cooling

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A depiction of the server room design for the Sonoma Mountain Data Center in California, including projections on the amount of free cooling enabled by the design.

The "cash for clunkers" program has allowed thousands of Americans to help the environment by driving energy efficient cars. Now some old clunkers can help make a data center more efficient. 

The Sonoma Mountain Data Center will use metal from recycled automobiles in a sophisticated new cooling system for its server rooms, according to Tod Stebbins, the project manager for the new facility, which is part of the Sonoma Mountain Village sustainable community in Rohnert Park, Calif., about 40 miles north of San Francisco. 

The recycled light steel is manufactured at the Sonoma Mountain site, where community developer Codding Industries makes its own green building materials using technology from Genesis Worldwide. Old car parts are crushed and flattened into metal sheets that can be used in commercial building products.

Recycled Steel in Containment System 
The Sonoma data center is using the recycled metal in heat containment systems that will manage the airflow and temperature in high-density server cabinets. The facility is designed as a ”less than zero carbon” facility, combining high efficiency and on-site power generation. 

Sonoma Mountain Village is being developed as one of the world's greenest communites, with sustainable design permeating nearly every facet of the mixed-use community of offices, retail and housing. That's reflected in the 1 megawatt solar array that will help power the data center for up to 270 days a year.

Stebbins' mandate was to extend that end-to-end emphasis on sustainability into the data center, which has its mechanical and electrical infrastructure in place and is being offered as shell space. "Of the air distribution designs we looked at when benchmarking ours, we never really found a method that was load-following or that operated without any oversupply of cold air, what we refer to as 'zero waste' cooling," said Stebbins.

Custom Cooling Design
So the Sonoma team came up with its own approach. The resulting design uses industry best practices such as fresh air cooling, isolating waste heat from servers, and operating at a higher temperature in the cold aisle. 

The Sonoma server rooms feature a slab design rather than a raised floor, with computer room air handlers (CRAHs) housed in an adjacent galley. The cooling system, which Stebbins calls an "OnDemand Cooling Circuit," physically separates warm and cold air throughout the facility. 

'Smart Chimneys' Manage Airflow
The lynchpin of the cooling design is the rack-top heat containment chimneys, which contain sophisticated pressure sensor systems from Opengate Data Systems that also monitor the IT load within each rack. The chimneys, which are made of the recycled metal, move air from the cabinet into a ceiling plenum, which then returns the waste air to the CRAH units.

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But warmer temperatures can also prompt increased activity by server fans, which kick on as the temperature rises, nullifying gains from a warmer server room. The Opengate system detects fan activity and adjusts the air flow and pressure to compensate (see our video demo of Opengate's technology). 

"The Opengate system is so tight with the way it controls the air that you bring in only what the data center demands," said Stebbins.

Recirculation Within Cabinets
Fan activity isn't the only challenge presented by air flow issues within the cabinet. The ASHRAE Journal recently highlighted research by Syska Hennessy Group on the recirculation of hot air within cabinets, which found that pressure buildup behind servers can cause hot air to route around the outside or even the bottom of the cabinet, allowing it to mix with cool air at the server inlet. This problem becomes more acute as the power density of a cabinet increases.     

Stebbins said Opengate's pressure-centric approach can address this challenge, and be customized at the rack-top level, allowing cabinets with different power densities to be adjacent to one another, rather than zoning the data center by power density.

Former HP Site
The Sonoma Mountain data center is a former HP/Agilent facility with two stories featuring about 60,000 square feet of space. Developer Codding Enterprises says it can convert the current shell space into a turn-key data center pods of 3,000 to 4,000 square feet in about four months. The facility hopes to gain Platinum certification under the LEED (Leadership in Energy and Environmental Design), the rating system for energy efficient buildings overseen by the US Green Building Council.

Stebbins hopes Sonoma's use of recycled metal from old cars will help fill its data center with environmentally-conscious tenants. But once that task is complete, he believes the approach could prove appealing to other data centers. "Without trying, it could turn into a product," he said.