4 Keys to Creating an Energy-Efficient Data Center

Electrical inefficiency in data centers results in unnecessary and substantial energy costs, and also raises wider environmental concerns.

Most of a data center’s energy is consumed not by IT equipment, but by the data center’s support infrastructure — the electric power system, the cooling system, and lighting.

In a related post, we outlined five contributors to electrical inefficiency in the data center. They are:

  • Inefficient power equipment
  • Inefficient cooling equipment
  • Power consumption by lighting
  • Over-sized power and cooling systems
  • Inefficient data center configuration

While some savings can be realized by addressing each of the above individually, a far more effective approach is to treat these contributors to inefficiency as interrelated. An integrated systems approach will yield greater overall energy savings than dealing separately with each contributor to inefficiency.

This integrated approach requires adherence to several principles, including:

  • Currently unneeded power and cooling equipment should not be energized
  • Right-sizing power and cooling equipment will increase efficiency
  • Power, cooling and lighting equipment should leverage the latest technologies to minimize energy consumption.

Focusing on that last item, let’s look at some technology, designs and techniques that can be used to make a data center more energy-efficient.

Scalable power and cooling

Enterprises typically overbuild their power and cooling systems relative to their IT loads. While it may make sense to plan ahead for a larger IT load down the road, it means your current power and cooling system is excessive for your present IT load. This matters because at lower IT loads, energy efficiency always declines.

By scaling power and cooling equipment, the IT load requirement can be met more efficiently.

Row-based cooling

Many data centers install air conditioners along the perimeter of a room, sometimes so far from IT equipment that the cool air mixes with warmer air along the way, reducing the effectiveness of the air conditioners and wasting energy.

By placing cooling units within the rows of IT equipment, the cool air will have a shorter distance to travel to do its job and won’t be compromised by warmer air in the room. In addition, row-based cooling captures hot air from the IT equipment near the source, reducing its impact on the rest of the data center.

High-efficiency UPS

New technologies are available that can substantially increase the efficiency of uninterruptible power supply systems.

Some new UPS systems can reduce wattage losses by 65%, and are particularly efficient at lighter loads.

Variable-speed drives on pumps and chillers

Great energy savings can be realized by running data center chillers and pumps more efficiently.

The pumps and chillers in a data center cooling plant typically have fixed-speed motors. These motors are configured to bear maximum possible loads. But since data center IT loads are usually well below capacity, the motors of these data center chillers and pumps are working harder than necessary, burning energy and hastening the day when they must be repaired or replaced.

Equipping data center pumps and chillers with variable-speed drives (VSDs) enables them to match the current IT load and outdoor conditions. As VSDs cost more than fixed-speed devices, they are best suited for data centers running 24/7.

To learn about more technology, designs and techniques that can be used to make a data center more energy-efficient, check out the APC by Schneider Electric white paper, An Improved Architecture for High-Efficiency, High-Density Data Centers.




  • As Paul Desmond points out, the power and cooling infrastructure offers many opportunities to reduce energy use. The good news is that organizations seem to be getting the message. A survey of facility managers by Building Operating Management magazine suggests that companies are more willing to pay a premium for energy efficient equipment than in the past. What’s more, respondents said that a variety of energy efficiency strategies are becoming more widely adopted, including the use of VFDs, adoption of new ASHRAE temperature guidelines, and control of temperature on supply air rather than return air. Go here for more details about actions facility managers are taking to increase data center efficiency.

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