Don’s Corner: “Is Perimeter Cooling Dead?”

Posted by on March 6, 2012

Don Melchert, Critical Facility Specialist

“IS PERIMETER COOLING DEAD?”

Traditional data center “room” cooling is unable to accommodate the latest generation of high and variable density IT equipment resulting in cooling systems that are inefficient, unpredictable, and low in power density.  To address these problems row-oriented and rack-oriented cooling architectures have been developed.  Our presentation, “Is Perimeter Cooling Dead” examines and contrasts the 3 basic cooling approaches: room, row, and rack architectures. Each approach has an appropriate application but row-orientated cooling is emerging as the solution of choice for most next generation data centers. Next generation data centers demand the flexibility, predicability, scalability, reduced electrical power consumption, reduced TCO, and optimum availability that row and rack-oriented cooling architectures can provide. Additionally, the factors that gave rise to the establishment and use of the raised floor in the data center environment are presented.  For many applications the use of the raised floor is no longer justified or desirable. To learn more about this topic, “Is Perimeter Cooling Dead” is available for your organization via our unique “Breakfast and Learn” Educational Series For Data Center Professionals.  This series provides the education that will lay the critical found for your organization to run an efficient data center.  Please feel free to contact me for further information at d.melchert@apcdistributors.com or 918-760-8236.

The Advantages of Row and Rack-Oriented Cooling Architectures for Data Centers (White Paper #30) Overview:

Executive Summary:

Latest generation high density and variable density IT equipment create conditions that traditional data center room cooling was never intended to address, resulting in cooling systems that are inefficient, unpredictable, and low in power density. Row-oriented and rack-oriented cooling architectures have been developed to address these problems. This paper contrasts room, row, and rack architectures and shows why row- oriented cooling will emerge as the preferred solution for most next generation data centers.

Highlights:

  • Discuss the following cooling approaches:  room, row and rack-based cooling architectures.
  • Benefit comparison of cooling architectures:  challenges in agility, availability, lifecycle costs, serviceability, and manageability
  • Special issues:  capacity utilization, humidification, electrical efficiency, water near IT equipment, location and redundancy.
  • Elements of the raised floor and problems associated with using a raised floor.
  • Hurdles to eliminating the raised floor
  • Designing without a raised floor.

Conclusion:

The conventional legacy approach to data center cooling using room-oriented architecture has technical and practical limitations in next generation data centers. The need of next generation data centers to adapt to changing requirements, to reliably support high and variable power density, and to reduce electrical power consumption and other operating costs have directly led to the development of row and rack-oriented cooling architectures. These two architectures are more successful at addressing these needs, particularly at operating densities of 3 kW per rack or greater. The legacy room-oriented approach has served the industry well, and remains an effective and practical alternative for lower density installations and those applications where IT technology changes are minimal.

Row and rack-oriented cooling architecture provides the flexibility, predictability, scalability, reduced electrical power consumption, reduced TCO, and optimum availability that next- generations data centers require. Users should expect that many new product offerings from suppliers will utilize these approaches.

It is expected that many data centers will utilize a mixture of the three cooling architectures. Rack-oriented cooling will find application in situations where extreme densities, high granularity of deployment, or unstructured layout are the key drivers. Room-oriented cooling will remain an effective approach for low density applications and applications where change is infrequent. For most users with newer high density server technologies, row-oriented cooling will provide the best balance of high predictability, high power density, and adaptability, at the best overall TCO.

References:

Avoidable Mistakes that Compromise Cooling Performance in Data Centers and Network Rooms (White Paper#49) Overview:

Executive Summary:

Avoidable mistakes that are routinely made when installing cooling systems and racks in data centers or network rooms compromise availability and increase costs. These unintentional flaws create hot-spots, decrease fault tolerance, decrease efficiency, and reduce cooling capacity. Although facilities operators are often held accountable for cooling problems, many problems are actually caused by improper deployment of IT equipment outside of their control. This paper examines these typical mistakes, explains their principles, quantifies their impacts, and describes simple remedies.

Conclusion:

The air distribution system is a part of the data center that is not well understood, and facility operators and IT personnel often take actions involving airflow that have unintentional and adverse consequences to both availability and cost.

Flawed airflow implementation has not been a serious problem in the past, due to low power density in the data center. However, recent increases in power density are beginning to test the capacity of cooling systems and give rise to hot-spots and unexpected limitations of cooling capacity

Decisions such as facing all racks in the same direction are often made for cosmetic reasons to project image; but as users and customers become more educated they will conclude that people who do not implement airflow correctly are inexperienced, which is the opposite of the original intent.

Adopting a number of simple policies and providing a simple justification for them can achieve alignment between IT and Facilities staff resulting in maximum availability and optimized TCO.

References:

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