Dim the lights and think about DC power

Data-center cooling expert Don Beaty shares tips for reducing data-center power consumption

Don Beaty is the founder of DLB Associates, a consulting firm specializing in mechanical, electrical and industrial engineering; and is a renowned authority on data-center cooling. He recently shared his thoughts on solving the power problems of today's data centers in an interview with Deni Connor, principal of Storage Strategies Now.

What are some ways to reduce power and cooling in the data center?

There are several ways to reduce energy consumption in a data center. Areas that need to be looked at critically include providing energy-efficient [data communications] equipment, operating this equipment efficiently, providing power to this equipment efficiently and cooling the equipment and facility efficiently. Performing an energy audit to determine how existing energy is used, and comparing this breakdown to other facilities, is a good way to identify opportunities specific to your data center.

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Don Beaty is the founder of DLB Associates, a consulting firm specializing in mechanical, electrical and industrial engineering; and is a renowned authority on data-center cooling. He recently shared his thoughts on solving the power problems of today's data centers in an interview with Deni Connor, principal of Storage Strategies Now.

What are some ways to reduce power and cooling in the data center?

There are several ways to reduce energy consumption in a data center. Areas that need to be looked at critically include providing energy-efficient [data communications] equipment, operating this equipment efficiently, providing power to this equipment efficiently and cooling the equipment and facility efficiently. Performing an energy audit to determine how existing energy is used, and comparing this breakdown to other facilities, is a good way to identify opportunities specific to your data center.

Is it practical to reduce electrical lighting in the data center?

Based on benchmarking studies by the Lawrence Berkeley National Laboratory (LBNL), lighting energy consumption averages about 4% of total energy use in a data center. Conducting a lighting audit is a worthy endeavor, and energy savings can be significant for older facilities, but there will not be a large-percentage reduction in energy from lighting systems due to [lighting's] small energy footprint to begin with.

What about retrofitting the data center with hot and cold aisles, or using cooling systems that use free cooling and variable-speed motors?

All of the ideas [you suggest] are capable of providing significant energy savings under the right circumstances. Most of the ideas, however, with the possible exception of variable-speed motors, could be difficult to retrofit into an existing and operating data center. All, however, should be considered for new facilities or major renovations. Ice storage, for instance, is a specific solution of a larger class of thermal-energy storage solutions, and the ability of these 'load-shifting' solutions to save energy is highly climate-dependent and needs careful analysis.

Many users are looking at the use of DC power in data centers. What is your opinion of that?

One method to reduce the number of conversion processes is to utilize a DC power-distribution scheme in lieu of an AC power-distribution scheme. Forty-eight-volt DC power-distribution systems are fairly common within [telecommunications] facilities, but the power cabling requirements can become burdensome for high-density [data communications] equipment. Although not common practice, a recent study, again by LBNL, highlighted the benefits of adopting a 380V DC power-distribution system for a [data communications] facility as a means to improve overall energy efficiency when compared to traditional 480V AC power-distribution systems.

Although DC power is interesting to consider, it is a topic that requires careful review. It is true that reducing the number of conversions will improve efficiency, but whether that means a DC distribution system is not an obvious decision. A facility that has AC and DC [power] in close proximity can have unexpected results on the grounding system. Also, the electrical codes have limited discussion about DC.