Fix what you have first: The Ultimate Green Move is improving your Legacy Data center.
Tenzing Corp (www.tenzing-corp.com) Aug. 12th, 2009
In response to soaring energy costs and the immediate demands to reduce carbon emissions the Skanska Mission Critical team recently developed and deployed a Data Center Optimization (DCO) program focusing on a "low tech" approach which is providing immediate improvement of DC efficiency and reduced operational cost.
The "Fix First" concept is based on the needs of current legacy data centers to make immediate and necessary improvements in their operational efficiency without costly retrofit, redesign or timely rebuilding options.
"The fastest way to needed improvement is often apparent and can usually be fixed with minimum cost," says Bellantoni. "We conduct a physical audit of the as built state of their current cabinets and rack installation. Most legacy data centers are in a -DEG.mid-life crisis' mode as a result of an aging design that may have been the bestof- breed at the time, but did not take critical efficiency and rising operating costs into consideration when creating the original design model."
Documented studies by the Uptime Institute.org™ indicate that 63 percent of cold air produced never actually reaches the servers. The problem: significant bypass air in cabinets, poor deployment of air distribution tiles causing classic "short cycling" effects and extensive physical obstructions such as fire suppression piping, I.T. fiber and high voltage cabling under the raised floor.
A major computer cabinet manufacturer, estimates that the gaps located at the side mounting rails in most standard cabinet design is responsible for approximately a 19 percent loss of bypass air. These side gaps alone can account for up to 24.5 square feet of bypass air in a seven foot cabinet with 1.75 inch rail spacing.
As an observer for the past 10 years and as a researcher, Bellantoni discovered that past cabinet racking and stacking installation, as deployed by most Information Technology (IT) departments, has often been conducted without a proper airflow "cooling" efficiency design discipline. Gaps and spaces are prominent between IT devices, servers are often not fully seated after installation preventing efficient laminar air flow and improper cable management adds to the cooling deficiency. IT installers are on record as saying that they believed component spacing aids cooling of the devices and in many cases servers are not fully seated or secured to allow easy access for maintenance and debugging for routine procedures. Sadly, often switches and routers, that were temporally set facing forward for easy cable access during testing, are not returned to their proper factory recommended installation position. Thus, the fans in these devices actually pull air from the back, or hot exhaust side, of the rack to mix with the cold inlet air.
The IT assumption that spaces between devices aids cooling is actually what creates many of the initial cooling problems in most cabinets. That is, air seeks the path of least resistance and in fact flows around the devices without providing cooling air to the inlet fans that are designed to optimize the internal cooling of these components as per the manufacturers' engineered design.
To better address the overall legacy-deficient design and installation, the Skanska Mission Critical Center of Excellency team is employing this new "Low tech, Low Cost" DCO. Bellantoni commonly refers to it as "Tricking out the Cabinets" with a seven point check list.
Then low cost blanking panels are installed in the cabinet's unpopulated unit spaces to maximize the cabinet's cool inlet air to the server's intake fans providing optimum cooling as per the manufacturer's intended design. The fi nal cabinet "trick" is to eliminate the racks vertical spacing by-pass air gaps with fl exible foam inserts to achieve an additional 19 percent increase in overall air cooling efficiency.
Cabinet Optimization Results:
Improvement of static pressure and accurate delivery of conditioned cooled air to the target devices was documented by infrared photography and revealed:
In Phase II we will go under the floor and control air to isolate the cold aisles with the installation of a plenum rated flexible fabric wall. This ducting will further optimize cooling and eliminate white space (unused or unpopulated areas) and even eliminate the hot aisle. And we'll go over the cabinets to prevent the unnecessary mix of supply and exhaust airflow.
The cumulative effect of both phases can significantly reduce the data center's total carbon footprint.
