The U.S. Department of Energy (DOE) estimates that the energy consumption of a data center can be as much as 100 times greater than a standard office building. Because almost all organizations rely on information technology equipment (ITE), most office buildings have one or more data centers. More energy is typically provided to the support equipment (e.g., chiller, humidifier, air-conditioning, and power supply) than to the IT equipment itself, as shown in this figure.
Critical Power Infrastructure
24/7 operation is typical for most data centers. In order to achieve or approach zero down time, redundant power distribution paths are the norm. Levels of redundancy are ranked by the Building Industry Consulting Service International (BICSI) as levels F0 through F4, with F4 being the highest, even including dual utility feeds into the building. That means that critical power infrastructure, such as uninterruptible power supply (UPS) systems, power distribution units/transformers, and switchboards are often operating between 20-50% of rated capacity. Older equipment would often run at efficiency levels in the low 80% range at such loading, but today’s equipment is designed for operation in the high 90% range. To maximize the energy efficiency of your data center, you should look for:
- ENERGY STAR-certified and labeled equipment;
- Multi-mode operation: energy saving operating modes when higher operation is not needed;
- High-efficiency transformers, or elimination of transformers wherever possible; and
- Pre-configured, scalable modules or performance-optimized datacenters (PODs).
Cooling and Environmental Control
Temperature and air quality management represent the greatest area of energy consumption, and therefore the greatest potential for energy efficiency improvement. It starts with a few simple concepts:
- Align equipment to create hot aisles and cold aisles;
- Keep hot and cold aisles contained;
- Use blanking panels in cabinets to prevent mixing of hot and cold air;
- Use point of use cooling systems (e.g., in-row, ceiling mount) rather than whole-room cooling systems; and
- Use economizer mode (“free cooling”) when outdoor air temperature and quality are suitable.
Data Center Infrastructure Management (DCIM)
Software to manage everything in a data center requires a holistic approach, because all elements of the data center (power, cooling, lighting, IT equipment, etc.) are interconnected. A change in one element can cause a change in another element. Intelligent management prevents “fighting” between different equipment. DCIM should integrate easily with a building information management system. The common metric for defining data center efficiency, developed by the Green Grid, is Power Utilization Efficiency (PUE). While very effective for tracking trends in a data center, PUE is not easily used for comparison with similar data centers. The method of calculation must be identified.
Information Technology Equipment (ITE)
Because the ITE is the single largest consumer of energy in a data center, it should be a primary target for energy savings. Owners of data centers should:
- Use ITE with multiple operating modes – cease power draw when not needed;
- Use ITE with high efficiency power supplies; and
- Discontinue use of “stranded capacity” (i.e., decommission or consolidate servers and other devices that are under-utilized).
As recommended in Step 1 and Step 2 of this Toolkit, the first thing you should do is conduct an energy audit to find out where and how energy is being used and wasted. Consider engaging an organization that specializes in vendor-neutral data center infrastructure management services including:
- Data center life cycle services;
- Project management services;
- Vendor management services;
- Maintenance management services; and
- Facility operations management services.
The following companies can help you get started with your project: