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Efficiency Without Compromise

(Compliments of Emerson Network Power)In the data center, efficiency has traditionally has been used to refer to energy. But in reality, energy is just one of the resources consumed by a data center. And energy efficiency, while important, is just one chapter in the larger data center lifecycle story. For example, is a system that offers excellent operating efficiency but can’t accommodate growth or change really that efficient? How about a system that offers small energy efficiency gains but exposes critical IT systems to greater risk? That’s why a data center efficiency equation should involve design, management, and operation. Of course, data center output is the other side of this formula. A data center that can double its capacity without increasing operating or management costs has been just as successful at improving efficiency as one that cuts costs by half. Taking advantage of the opportunities outlined in this paper enables IT organizations to more efficiently deploy and use all their resources throughout the life of the data center—including physical space, capital equipment dollars, design and management time, service costs, and, yes, energy. Areas of Focus • Density Creates Efficiency Industry estimates put the cost of building a data center (the building shell and raised floor) at $200-$400 per square foot. By building a data center with 2,500 square feet of raised floor space operating at 20kW per rack versus a data center with 10,000 square feet of raised floor space at 5 kW per rack, the capital savings could reach $1-$3 million. Operational savings are also impressive—about 35% of the cost of cooling the data center is eliminated by the highdensity cooling infrastructure. • High-density cooling: High-density cooling brings cooling closer to the source of heat through high-efficiency cooling units located near the rack to complement the base room air conditioning. These systems can reduce cooling power consumption by as much as 32% compared to traditional room-only designs. Pumped refrigerant solutions remove heat from the data center more efficiently than air-cooled systems and provide incremental energy savings between 25 and 48% based on kW of cooling capacity per kW of heat load. • Intelligent aisle containment: The well-established practice of hot/cold aisle alignments sets up another movement—containment. Aisle containment prevents the mixing of hot and cold air to improve cooling efficiency and enable higher densities. • High-density power distribution: Power distribution has evolved from single-stage to two-stage designs to enable increased density, reduced cabling, and more effective use of data center space. • Availability In the race to achieve improved energy efficiency—and, ultimately, cut costs—businesses cannot lose sight of the importance of maintaining—or improving–availability. • Uninterruptible power supply (UPS): Data center managers should consider the power topology and the availability requirements when selecting a UPS. Enterprise data centers should select double conversion UPS technology for its ability to completely condition power and isolate connected equipment from the power source. The extra protection that a double conversion UPS affords does come with a small price in terms of efficiency; however, most organizations believe the small amount of energy lost during the conversion is well worth the added protection this process delivers. In addition, newer UPS systems are now available with energy optimization controls that enable users to open and close different components of the UPS based on organizational priorities and operating conditions. Intelligent paralleling improves the efficiency of redundant UPS systems by deactivating UPS modules that are not required to support the load. In N + 1 UPS configurations, the load is typically evenly distributed across all modules. If a failure occurs, or a module is taken off line for service, the load is redistributed across the remaining modules. This feature is particularly useful for data centers that experience, extended periods of low demand, such as a corporate data center that is operating at low capacity on weekends and holidays. In this case, it ensures the UPS systems supporting the load are not operating at loads at which they cannot deliver optimum efficiency. • Economization: Economizers, which use outside air to reduce work required by the cooling system, can be an effective approach to lowering energy consumption if they are properly applied. • Service: A proactive view of service and preventive maintenance in the data center can deliver additional efficiencies. Making business decisions with the goal of minimizing service-related issues may result in additional expense up front, but it can increase lifecycle costs.