– Peter A. Panfil, Vice President Global Power at EmersonNetwork Power, says:
It is an ongoing undertaking; data centers must become more efficient, reliable and agile to support future business growth. Yet the problems of the past—low utilization, lack of visibility and inefficient equipment and processes—are holding many organizations back from achieving the required transformation.
The data center infrastructure—power and cooling systems that ensure safe and continuous operation— often represents the least agile and scalable component of the data center. If improperly designed and maintained, it can constrain growth and contribute to downtime. Conversely, the right infrastructure creates a foundation for continuous availability, increased return on capital and cost-effective growth.
Approaches for Infrastructure Scalability
Heat density has been a top concern identified by the Data Center Users Group (DCUG) in eight of the last nine years. Yet, according to DCUG survey data, average rack power density in the data center was about the same in 2013 as in 2006.This is the result of more efficient servers and greater virtualization and indicates an opportunity to add capacity by increasing rack density.
Perimeter cooling systems now operate at higher levels of efficiency and have built-in intelligence that allows them to communicate and collaborate. Cooling has also steadily migrated closer to the heat source, increasing efficiency and the ability to cool higher density racks. With the proper power and cooling infrastructure in place, most data centers can double or triple their capacity without increasing data center space.
If additional capacity is required, an aisle-based or container-based expansion strategy can be employed in which initial capacity is met by the required number of aisles or containers but space and power capacity are reserved for the addition of future “modules.” When capacity is needed, additional aisles or containers—with integrated cooling, monitoring and power protection and distribution—can be added, enabling an easy-to-implement modular growth strategy.
This approach has been popular with organizations that need to expand quickly to react to market demands or opportunity, such as colocation providers, or those delivering cloud services. With proper planning, significant blocks of new capacity can be added in a fraction of the time it would take to conduct a traditional build-out or build a new data center. Because they have the ability to respond quickly, these organizations can reduce upfront capital costs and increase operating efficiency by using a higher percentage of their operating capacity at startup.
Alternately, capacity can be added through cloud or colocation providers, but even in this case, infrastructure remains an important consideration. The in-house data center infrastructure has to adapt to varying loads without compromising efficiency. The infrastructure of the cloud or colocation provider should be evaluated to ensure it uses technologies and configurations proven to support high availability.
While difficult to predict exactly what will be expected from the data center of the future, it is hard to imagine a scenario in which downtime isn’t a serious issue. Data centers attempting to completely eliminate power-related downtime generally use dual-bus architecture to eliminate single points of failure across the entire power distribution system. This approach includes two or more independent UPS systems each capable of carrying the entire load with N capacity after any single failure within the electrical infrastructure. This is a proven approach for delivering Tier IV availability, but does require custom switchgear and limits power equipment utilization to 50 percent, impacting initial costs and operating costs.
Alternate configurations in recent years support high availability while increasing power equipment utilization, including distributed reserve dual-bus architecture. Static transfer switches (STS) are used to provide redundancy across multiple UPS systems as well as the transfer switch itself (Figure 1).
The reserve-catcher dual bus approach is extremely attractive to organizations seeking dual-bus availability with lower initial costs and greater efficiency. Like the distributed-reverse dual bus, it uses STS as the power tie; however, instead of creating redundancy through distributed primary UPS systems, it uses a secondary or reserve system to provide dual-bus protection across multiple primary UPS systems. The result is lower initial costs than other dual bus approaches with increased power equipment utilization. Less critical facilities may consider a parallel redundant configuration, such as the N + 1 architecture—in which “N” is the number of UPS units required to support the load and “+1” is an additional unit for redundancy. This architecture provides cost-effective scalability.
For organizations seeking to optimize data center efficiency, technology strategies that comprise a holistic approach to improving data center energy efficiency with a comprehensive, vendor-neutral approach to achieving meaningful reductions in data center energy costs is needed.
Power and cooling systems can be configured to increase efficiency. Double conversion UPS topologies deliver better protection than other types of UPS because they completely isolate sensitive electronics from the incoming power source, remove a wider range of disturbances and provide a seamless transition to backup power sources. With the combination of improved operating efficiencies and the smart use of an active inverter eco-mode that provides reliable power protection and enhanced flexibility, these robust power systems can achieve efficiencies in excess of 98 percent. In addition, intelligent paralleling can improve the efficiency of redundant UPS systems in a parallel configuration by deactivating UPS modules that are not required to support the load and taking advantage of the inherent efficiency improvement available at higher loads. Additional efficiencies can also be achieved in the distribution system by bringing higher voltage power closer to the point of use, minimizing step down losses.
No single technology can remove all of the constraints that prevent organizations from optimizing data center performance and efficiency. But when technology is addressed through a systematic review and evolution of data center management technologies each of those constraints can be effectively overcome.