Page 33 - OHS, October 2020

ALTERNATIVE IMPLEMENTATION OF FABRIC DUCTWORK
Controlling server temperatures is a critical challenge for any data center. After exploring standard air dispersion and air flow- based solutions to this problem, international data center provider Liquid Web decided to use a more innovative approach when retrofitting its multi-server 75,000-square-foot Michigan location. Rather than using traditional metal ductwork, Liquid Web opted for an air-distribution system for rack cooling, using fabric ductwork with directional diffusers.
Liquid Web’s data centers had long deployed an open-air area strategy for controlling server temperatures. Multiple server rows were spread throughout the facility and collectively cooled by a network of traditional metal ducts with air diffusers placed several feet apart. However, this set-up created hot and cold spots between the spaced diffusers.
The team converted the open-air facility to a series of directed-air areas with eight sections of 12 server rows, each using clear curtain walls. These dedicated sections created focused micro-climates, which allowed for the targeted, controlled cooling of server racks. Better yet, each of the original 39 air conditioning (A/C) units, which ranged from 64KW-90KW, were able to
be replaced by 22 A/C units each operating at 165 KW of cooling capacity. Improving on the outdated loosely balanced A/C system, the retrofitted design operates as an N+1 redundancy environment, covering the 8 server sections seamlessly.
As part of the new layout, a raised plenum surface was built at the end of each row. Fitted with a customized adapter, the fabric ducts extend vertically towards the ceiling. At that point, a 90-degree turn extends the duct horizontally across the length of each narrow server row. In addition to a porous strip of material on the underside of each fabric duct that distributes air throughout the server space, adjustable nozzles force air in targeted directions at the server racks. Each directional diffuser can be adjusted or shutoff depending on the evolving needs of a given row.
Mounting of the duct was another key consideration in this project. Unlike heavy metal ductwork options, the light- weight fabric makeup made ceiling suspension possible. Using a custom hanging system, the fabric ducts are connected to the ceiling grid and positioned above the cold aisles in each server section, allowing for air distribution as close to the load as possible.
“As our server demands continue to grow,” said Aaron Reif, data center project manager at Liquid Web. “We’re confident that this air distribution layout can adapt and expand with us.”
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OCTOBER 2020 | Occupational Health2&/13S/2a0fet1y2:59 P2M9
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