Taming The Energy Hogs: Data Centers

Data centers are energy hogs. They can consume up to 100 times more energy than a standard office building, according to the Department of Energy’s (DOE’s) Office of Energy Efficiency and Renewable Energy (EERE). They eat so much power that their energy consumption doubled from 2000 to 2006, reaching more than 60 billion kilowatt-hours per year. The good news is that data centers’ exploding demand for power has driven much of recent innovation and has pushed energy efficiency to the top of the list of strategies for building a long-term competitive advantage.

“Trends in data center design are constantly evolving,” said Harry Handlin, director of critical power applications for GE’s Critical Power business, Dallas. He said data centers were traditionally designed for reliability, rather than for efficiency. Recently, however, data center designs are focusing on both. 

“Combining design criteria, such as power-usage effectiveness [PUE] and reliability levels based on the Uptime Institute’s tier levels, is now common,” he said.

The market’s evolving design trends demonstrate that reliability does not have to be sacrificed to build more efficient data centers. For example, data center owners are considering operating at a slightly higher ambient temperature, according to Ed Spears, technical product marketing manager for Eaton Corp., Cleveland. 

“There’s a direct correlation between each degree of operating temperature and energy savings,” Spears said. 

If operating temperatures are allowed to go as high as 85 degrees, all the equipment operating in the data center, including traditional battery-energy storage, must be able to work reliably at those higher temperatures. 

“The one condition that shortens battery life significantly is temperature,” said Frank DeLattre, president of Vycon, a Los Angeles manufacturer of flywheel energy-storage systems. “For every 10-degree rise in operating temperature in which a valve-regulated lead acid [VRLA] battery is operated, a reduction of 50 percent of normal life is seen.” 

Since data centers can use multiple megawatts of energy storage, the center designer must either incorporate the special cooling needs of the batteries or use an alternative type of energy, such as a high-speed flywheel system. 

“These systems are designed to work in operating temperatures of up to 104 degrees without affecting the performance or the life of the energy storage,” DeLattre said.

Data centers are also moving toward mixed-tier environments and choosing not to use the overpoweringly expensive power equipment required for Tier III or IV system design. 

“Rather,” Spears said, “these critical-mission data centers are migrating toward using virtualization techniques that enable them to electronically move critical work from one location to another, reducing the need for the highest tier design.” 

In addition, the industry is seeing a continued trend toward modular power, a sort of pay-as-you-go system. 

“Modular power systems help keep the data center from over-provisioning and help control scalability,” he said. 

From the electrical contractor’s perspective, the modular approach enables the company to learn how to install a module once, then repeat the process quickly and safely as the system is scaled.

According to Jim Hughes, national sales manager for Mitsubishi Electric Power Products, Warrendale, Pa., trends in data center efficiency go beyond power to include design, implementation, installation, cable and wire, and operation. For example, data centers are implementing never-before-used technologies, such as three-level isolated gate bipolar transistors and economy mode (or multimode) uninterruptible power supply (UPS) systems operation. 

“The industry is also showing interest in the development of hybrid economy mode operation, which does not shut off those portions of the UPS that are not in use and elevates both efficiency and reliability,” Hughes said.

Increasing efficiency

The heat that computers and servers generate makes data centers naturally very inefficient and causes electricity consumption to be the most expensive aspect of the operation. 

“The best place to find improved efficiencies is in the heating and cooling sphere as the majority of power loss occurs in HVAC,” Hughes said. 

This is an opportunity to devise new data center design strategies with a special focus on modular design, which enables designers to better size the necessary equipment for the space and make more efficient use of the HVAC and power systems.

According to Handlin, data centers can also use less energy if the mechanical and electrical infrastructure, the IT equipment, and the server software are all energy efficient. 

“It’s vital for the data center to have a high utilization rate of the IT equipment, including server capacity, network and storage,” he said.

It’s also vital for the data center to practice good thermal management and to not allow warm and cool air to mix. 

“It’s easy to fix with the use of blanking plates that cover up any air leaks in the facility,” Spears said. 

He also sees potential efficiencies in designing new data centers from “the computer rack out,” rather than from “the building in.” With this strategy, the electrical contractor can provide input that helps the data center owner determine the kind of rooms and electrical equipment that will be needed to house and efficiently operate the racks and computers that are envisioned, rather than constructing a building and then sizing the equipment.

Fortunately, many gains have already been made in efficiency improvements in the power chain of IT equipment and UPS systems, according to DeLattre. For example, UPS operational efficiency has grown from its level of 85–90 percent several years ago to 97–98 percent today. 

“This has been accomplished through removing the input and output transformers in the UPS and through advances in power electronics,” he said. “There is less to gain now in power chain efficiency, but cooling is an area of possible additional gains.”

One way to improve efficiency in the electrical system is through the use of a multimode UPS. 

“A multimode UPS examines the quality of the incoming power and determines how much of that power the data center’s electronics need to operate,” Spears said. 

The result is a UPS that operates efficiently when power quality is excellent, which is 99 percent of the time, according to Spears. In addition, the UPS instantaneously changes to a more protective operating mode when it senses a power quality issue.

Obstacles to efficiency

As with most things, money to invest in efficiency improvements is an obstacle. 

“For projects that are too focused on the bottom line, it becomes too easy to not purchase the greener, more efficient, and frequently expensive products,” Hughes said. 

In addition, the critical nature of data center operations and the unwillingness of owners, manufacturers and contractors to really improve efficiency is another obstacle.

“The very conservative nature of the industry can impede the acceptance of new technologies, even though they are more efficient,” he said.

Perhaps these obstacles will be overcome as municipalities and utilities offer even more incentives for facilities to use more efficient technologies. 

“As incentives reduce the data center’s financial risk, their willingness to make the investment in more efficient technologies should increase,” Hughes said.

Handlin said the compartmentalization of responsibilities in the data center is another key obstacle. For example, the person responsible for building the data center, the person operating it, and the person responsible for the utility bill are typically three different people from different parts of the organization. 

“Perhaps the best way to overcome the reluctance to improve data center efficiency is to change and standardize the performance metrics of the individuals building the data center and the individuals operating the data center so that there are incentives to change behavior,” he said.

A final barrier involves the battery systems. Through the years, lead-acid battery-based UPS systems have proven to be expensive and unreliable. One bad cell in a string of 40 batteries can result in a failure to protect the server. Also, batteries require an excessive amount of testing, monitoring and maintenance that hinder IT activities, and they contain hazardous chemicals that require stringent disposal methods. 

“Data from major UPS companies confirm that 70 percent of the service calls made on a failed UPS system are a result of battery problems,” DeLattre said. 

He advised using a kinetic-energy system or flywheels to help overcome these issues.

How the contractor fits in

Hughes said electrical contractors that invest more of themselves in their projects are better able to participate in the data center’s equipment decision-making process. 

“We’re seeing a new type of electrical contractor that is specifically focused on the needs of the data center,” he said. “Contractors that want to be involved in this market, however, need a dedicated staff that will learn the needs of data centers, repeat successes and improve performance.”

Spears said it is actually the nature of the data center market that enables contractors to go beyond just implementing the decisions made by others and to be more involved in the design process. 

“This market encourages contractors to leverage their expertise and be a true design partner,” he said, adding that contractors should become experts in Leadership in Energy and Environmental Design certification programs to better help the end-user make decisions and to help direct long-term energy-efficiency strategies.

Additionally, Handlin said coming data center energy-
efficiency and resource management regulations will affect the electrical contractor’s role in the market. 

“Other parts of the world have already enacted PUE and carbon-usage regulations,” he said. “As the U.S. develops its own efficiency mandates, contractors can play a pivotal role going forward by knowing how to properly measure data center PUE and ensure that proper metering is installed.”

About the Author

Darlene Bremer

Freelance Writer

Darlene Bremer, a freelance writer based in Solomons, Md., contributed frequently to ELECTRICAL CONTRACTOR until the end of 2015.

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