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DuctSox Case Study: A Cost-Cutting Solution to Full Cooling Build-Outs in Data Centers

Cooling build-outs are one of the highest operational costs facing data storage facilities today, however executives at San Diegobased redIT have implemented a new cost-saving measure at their data centers. The new procedure involves adding cooling drops for individual partitions inexpensively, and only as new customers come onboard.

To ensure redundant capacity, data centers construction requires a complete and expensive build-out of a space’s HVAC system, including ductwork and diffusers. Because it may take years to lease-out the entire space, this upfront cooling build-out can be a costly practice. A short-term, more cost-effective alternative is to install each sheet metal drop and diffuser only after a customer comes onboard. This approach postpones construction costs, saving data centers valuable time and resources. But, this phased sheet metal construction approach also has disadvantages. Sheet metal construction creates airborne particulates and poses other unnecessary risks to neighboring computer equipment. It also costs thousands of dollars in installation labor and material associated with each new cooling drop. Additionally, outsourced sheet metal contractors in highly restricted access control areas can potentially jeopardize security efforts.

redIT, operating multi-tenant facilities with many clients including Fortune 500 firms such as McDonald’s Corp., IBM, Costco and Bank of America, realized these challenges. Furthermore, the 13-year-old firm wasn’t satisfied with the prices, performance or flexibility of conventional computer room air conditioning (CRAC) air distribution systems.

redIT utilized this cost-saving phased cooling approach during the build-out of the first 14,800-square-foot data center phase of their 88,000-square-foot facility. Their HVAC service contractor, Countywide Mechanical Systems, Santee, Calif., introduced fabric ductwork to redIT’s design team, Mark Hopperton, chief technology officer (CTO), and Gabriel Faulkner, facility manager. Factory engineers from fabric duct manufacturer, DuctSox Corp., Peosta, Iowa, and the redIT team partnered with Gilbert Dominguez, manager of the Poway, Calif., office of air-conditioning and ventilation manufacturer’s representative Toro-Aire, Dominguez Hills, Calif, to design a custom fabricated fabric ductwork drop as an alternative to conventional sheet metal drops. The application was the first case for the manufacturer where a custom-fabricated, inverted T-shaped fabric fitting was used for data center equipment spot cooling.

The Fabric-Based Inverted T-Shaped Drops

Each fabric T connects to sheet metal trunk line supplied by several redundant 55,000-cfm units. The air handling units are supplied by multiple redundant 440-ton chillers. Each air handler has a piped-in soft water supply for humidifying San Diego’s inherent dry outdoor air. Humidifying the air helps to maintain ASHRAE standards with respect to relative humidity and potential static electricity risks within the facility. The air handlers reside in a secure, remote outdoor yard, removing the risk of water pipe leaks in the data center.

The Ts are connected via a round metal/fabric collar adaptor called a DuctBuckle. The DuctBuckle clamp is manufactured for the sole purpose of clamping tightly onto round metal connections without the use of screws or other fasteners. Each drop area can accommodate up to three Ts, which can produce higher cooling densities and greater flexibility of additional airflow than many of redIT’s competitors. The Ts drop as low as necessary to accommodate the different heights of customer cabinets within the data center. The ends of each T’s run are capped, however they can easily be removed for zippering in extra lengths in-line and extending airflow over a cage’s equipment rack reconfiguration.

The application’s unique needs necessitated a custom-designed suspension system. Typically, ceiling-hung round fabric ductwork in conventional applications, such as warehousing, retail or athletic facilities, is installed in long runs suspended by horizontal cable or cable/ track hanging systems. The T’s bullhead would have obstructed this suspension method. Instead, Faulkner used thin, undetectable aircraftstyle cable and adjustable clamps for attaining proper hanging tension. The vertical cables attach to the metal collar on one end. The Ts run on the other end where the manufacturer sewed in receiving clips.

redIT keeps an inventory of Ts, and redIT’s in-house staff can install these Ts for new clients in approximately 10 to 15 minutes without creating airborne debris or messes near existing equipment. According to Faulkner, who supervises the fabric duct installations, installing and suspending a sheet metal drop and diffuser would require an outsourced contractor, a minimum one day of construction, plus the aforementioned risks to surrounding equipment.

Presenting a Unique Appeal to New Clients

According to Audrey Veitas, redIT’s director of marketing, the bright blue Ts present a unique first impression to potential clients. The colorful Ts stand out against a monochromatic scene of black computer equipment, racks and cages, representing the innovative cooling approach to this space. Most data centers look very similar, but the bright blue fabric ductwork clearly separates redIT from the competition.

The woven polyester fabric Ts aren’t just visually appealing. They also outperform most sheet metal diffusers in air distribution. Each T provides the exact amount of air that is required for each cage environment and disperses this air through orifices that can be custom configured. The CAD-generated, precision machine-cut orifices can be placed linearly anywhere on the bottom half of the run at 4, 5, 6, 7 or 8-o’clock or a combination of those positions. redIT’s design is based on the cage layout and cold aisle cooling architecture.

Data center equipment generates significant heat where significant cooling is required to ensure trouble free operation, and may very significantly, as identified by ASHRAE TC9.9 released guidelines for data processing environments affirms. Data centers should maintain a consistent temperature without wide variances. Set point temperature is secondary as long as it rests within the desired range. Therefore, once the fabric Ts are fabricated to accommodate any client customization requests, they efficiently supply consistent temperatures and maintain cold aisle/hot aisle design parameters.

The cooler air supply descends through the equipment racks. The subsequent air displacement expedites warmer air ascension toward a centralized common return grill. The supply air, return air and slight mix of outdoor air induction is calibrated to maintain a desired zero space pressurization differential.

Future Data Centers and Build-Outs

redIT is planning a new build-out phase, possibly using the same successful cooling design strategy. Until then, redIT’s ongoing green mission includes making the current system more efficient. They recently added a building automation system to control all of the air handlers’ economizer dampers to take full advantage of outdoor air when outdoor temperature and humidity are ideal.

Current refinements to the system include a matching blue fabric based containment plenum above certain equipment to help contain cool air in and around the equipment for longer. This containment plenum creates more total energy efficiency and savings, according to Faulkner.

The fabric Ts are inherently flexible. Factory engineers can virtually accommodate any reconfiguration or special request for airflow, which has convinced many companies to become redIT customers as they weigh their data center options.

Data center clients are primarily concerned with three major services: security, power and cooling. A strategic cooling and delivery system that is carefully and economically designed (in terms of upfront capital and operational costs) has the greatest potential for reducing operational expenses. Ultimately, redIT passes the savings created by this cooling cost reduction onto its clients.