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Sep 29 2016

FUJITSU Cool-safe® ATD Extended: Refreshing PRIMERGY Temperature Control

Today's almost proverbial data tsunami entails a number of consequences that often escape professional and public scrutiny. One is that it drives massive power consumption and energy costs – not only because servers, storage and network equipment suck lots of electricity from the grid, but also because standard technologies used in server and data center cooling add their own fair amount on top of that. This article explains how Fujitsu's sophisticated cooling technology can help solve the latter problem.

As people and organizations increasingly rely on powerful IT services to help them do business and organize their lives, they drive a phenomenon that can best be described as data center sprawl. Service providers as well as multinational companies set up new infrastructures in every key region or expand and modernize those that already exist. The constant increase in facilities and ongoing renovations have led to a boost in server density: today, thousands of data centers are literally housing millions of servers. As an unwelcome side effect, power consumption has also grown beyond rational limits: two years ago, a report by the Natural Resources Defense Council, a U.S.-based environmental advocacy group, alleged that all of the country's data centers combined ate up as much as 17 gigawatts per year - equivalent to the annual output of 34 coal-fired, 500 megawatt power plants and "enough to power all the [3.1 million, N.B.] households in New York City for two years."

Until a few years ago, these high environmental costs hardly played a major role in companies' financial reports. That only changed after experts pointed out that wasting energy had negative effects on their bottom lines, for instance that their power bills accounted for 20% of their total IT costs. Even worse was the possibility that this share could soon rise to 50% if data center growth and expansion continue at the current rates. These sample calculations convinced managers and IT departments that building 'greener' infrastructures was not only a moral, but also a financial imperative. And fortunately for them, they don't have to stick with old equipment to achieve this goal – instead they can buy new, more eco- and revenue-friendly hardware today, in the form of Fujitsu's PRIMERGY server family.


Fig. 1: Servers are almost like people. They will suffer when temperatures in their workplace get too hot...

Cool-safe®, the Original
For nearly three decades, Fujitsu has been doing lots of pioneering work in the field of "green IT"; examples of successful technologies are legion. One of our biggest hits in this context was the original Cool-safe® Design, introduced in 2004. Cool-safe® stood for a holistic approach to building servers that involved EPA-compliant power supplies, a special use of airflow channels and a mostly cable-less design to ensure that PRIMERGY servers generated less heat than competing systems and thus used 20% less power on average.

Cool-safe® Advanced Thermal Design
Nine years later, we developed Cool-safe® ATD, an extension of the predecessor that served two main purposes, namely enabling servers to run under "extreme conditions" and facilitating even higher cost savings. Cool-safe® ATD enhanced the ambient temperature range within which PRIMERGY servers remained functional. Older rack and tower models tolerated between 10 and 35 °C (50 and 95 °F); the new systems could handle between 5 and 40 °C (41 and 104 °F). Hence they hit the alert threshold at a later point in time, and turning on the data center air-conditioning system was postponed. This helped cut air-conditioning expenses by 5 to 6% per additional degree. Better still, when combined with additional features such as maximum efficiency PSUs etc., Cool-safe® ATD allowed for a 50% increase in server performance per watt – so these configurations not only saved money, but operated faster and thus saved time as well.

Cool-safe® ATD Extended
As of the PRIMERGY M2 model generation, Fujitsu again raised the bar and further extended Cool-safe® ATD: select tower and rack systems are now capable of operating within an even higher temperature range of up to 45 °C (113 °F), offering more headroom for chiller-less data center or server room setups. The advantages are clear and unmistakable:

  • Servers can be put into hotter rooms without a need to specifically cool these rooms in advance.
  • Customers now can choose whether their servers shall run within a temperature range of 5 to 40 °C or 5 to 45 °C and reap exactly the benefits they require.
  • Potential savings on energy and cooling costs turn out to be even more significant than before. Our calculations show that increasing the temperature in a server room by 5 °C can save up to 20% power needed to run the cooling system.

Over the years, we've also learned that the Cool-safe® concept blends well with various new models for data center cooling, especially those demanding a constant influx of fresh outside air. This prompted us to rework what may be called our "Cool-safe philosophy": since we wanted to offer a truly comprehensive solution, it was necessary to not only apply the concept to select servers, but also to a number of ETERNUS storage systems and networking components (switches etc.). With Cool-safe® ATD Extended as an umbrella, customers can now build complete infrastructures that will fit varying climate and operational conditions as needed. Let's look at a few examples in the next section.


Fig. 2: ... and tend to freeze when temperatures drop below a certain limit.

Usage Scenarios
Possible implementation options for FUJITSU Cool-safe® ATD/ATD Extended include:

  • Free air cooling: as noted above, our Cool-safe® technology plays particularly well with so-called alternative server and data center cooling concepts that diverge from the traditional model, which uses compressors and 100% air conditioning. These alternative models may either rely on liquid cooling, like Fujitsu's Cool-Central® LCT, or they feed filtered outside air into a data center or server room. Both approaches help to minimize the pressure on classic air conditioning, so the compressors have less work to do and require less energy, which in turn leads to a reduced power bill. However, the success of fresh air cooling depends on the target temperature customers have in mind and on whether the outside temperature is low enough to produce meaningful cooling effects. For more details, please see our white paper on FUJITSU Cool-safe® ATD.
  • Container data centers: in recent years, many organizations have at least temporarily relied on IT infrastructures that are housed inside containers, for instance if regular data centers underwent reconstruction or if a branch office at a new site was not yet fully equipped. In all of these cases, container data centers serve as substitutes for their regular counterparts. Since they're only used on an interim basis, container data centers can be fitted with a "lighter," yet equally efficient cooling solution. Moreover, container data centers are much more exposed to changing weather conditions and extreme climates than stationary ones – so it only helps if the hardware inside can cope with these changes and extremes.
  • SMB data centers: Small and medium businesses with a few hundred employees often can't afford to build dedicated data centers – they will house their servers, storage and networking equipment in a secluded section of their office building or probably inside a server room at the far end of the floor. Given these restrictions, it's no surprise that air conditioning and air cooling are often achieved by leaving a window half open. Needless to say, this is a less than ideal solution, for various reasons. One is that an open window also lets in considerable amounts of humidity, which is detrimental to the proper functioning of the hardware. Another is that open windows may suggest lax security measures and policies and thus attract hardware thieves and other miscreants. By contrast, PRIMERGY servers with Cool-safe® ATD/ATD Extended enabled will work well even under IT-adverse conditions, so there's no need for open windows and the risks they entail. Plus, the potential cost savings will certainly be more than welcome in an SMB context. More information is available from our SMB microsite.


Fig. 3: Cool-safe® ATD/ATD Extended will keep them alive and well.

Fujitsu's Cool-safe® technology offers a comprehensive solution for many 'climate problems' that regularly occur in server rooms and data centers of any size. It ensures that servers and other equipment are robust enough to work within an extended temperature range of 5 to 40 or even 45 °C (between 41 and 104 or 113 °F). At the same time, Cool-safe® substantially minimizes the workload traditional cooling has to deal with – air conditioning sets in later and will run for a shorter time, which in turn helps to cut companies' power bills. In other words, the technology is highly recommendable for organizations of all sizes. The infographic linked below neatly sums it all up.

Icon Cool-safe® ATD infographic

Marcel Schuster


About the Author:

Marcel Schuster

Senior Specialist Marketing Manager – Data Center Systems / Server


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