ISS Technology Update, Volume 7 Number 2 - Newsletter

ISS Technology Update Volume 7, Number 2
2
The story behind the Active Cool fan design for the HP BladeSystem
As with most great innovations, the breakthrough design of the HP Active Cool fan
was the result of someone taking a fresh look at a growing problem. Over the last few
years, the emergence of high-density IT equipment has changed one of the top
priorities of IT organizations from optimizing floor space to constraining the cost of
power and cooling resources. This is because power and cooling costs can surpass
the total cost of the IT equipment and the facility space. This “new normal” is forcing IT
and facilities organizations to view the data center holistically. Now, their common
strategy is to maximize energy efficiency down to the component level in an effort to
lower the total cost of ownership (TCO) of the entire facility. This paradigm shift, along
with an epiphany by HP engineer Wade Vinson, was the inspiration behind the
creation of HP Active Cool fan technology for HP c-Class BladeSystem.
The common industry practice to cool server components has been to push large
volumes of air through the chassis—more than was required—despite the impact on the facility. Engineers basically had two
cooling options: (1) use several small fans to provide localized cooling in specific internal areas, or (2) use larger, blower-style
fans to provide cooling across the entire server enclosure. The smaller fans generate fairly low airflow (in cubic feet per minute,
or CFM) at medium backpressure. This means that a single server often requires several small fans to ensure adequate cooling.
Alternatively, very large blower-style fans generate higher CFM, but they typically require higher power input, take up more
space, and make more noise. They also must be designed for the maximum load of the enclosure since they cannot be adjusted
for individual servers. Consequently, using these traditional small or blower-style fans has a substantial negative impact on a
facility’s power and cooling costs.
The breakthrough occurred when Ron Noblett, VP of ISS Shared Engineering Services and a model airplane enthusiast,
suggested that Vinson look at the powerful air ducted fans found in radio-controlled aircraft. Voila! After Vinson cultivated the
idea and met with HP Cool Team engineers and designers, the HP Active Cool fan was born. In contrast to traditional fans, the
HP Active Cool fan has less negative impact on the data center by requiring less power, less airflow, and less space. Active
Cool fans use ducted fan technology (the fan is longer than it is wide) with a high performance motor and impeller. Its unique
shape allows for high-pressure flow with lower CFM and low noise levels, while still meeting the thermal requirements of the
rack equipment. Minimizing the air flow rates also minimizes the power needed to run the fans (Figure 2-2). Amazingly, 4 or 6
HP Active Cool fans can cool eight c-Class BladeSystem servers using less power than a 100-Watt light bulb.
Figure 2-2. The c-Class enclosure enables significant power savings while adding 50 percent more servers in the same power footprint.
Figure 2-1. HP Active Cool fan