REI hits the roof to put a ceiling on data center cooling

Practical Magic

REI hits the roof to put a ceiling on data center cooling

REI store image by functoruser via Flickr

A recent data center retrofit undertaken by outdoor products retailer REI offers a vivid illustration of how an unplanned data center can exacerbate a company's power consumption.

The brains of the company's e-commerce site and point-of-sale servers for 132 retail stores slowly crept from a small computer room into a 6,000-square-feet space sprawling across nearly an entire floor at its main headquarters outside Seattle. REI knew the design was inefficient but didn't realize just how much energy it guzzled until the company submetered and measured power consumption, with help from CLEAResult, an energy efficiency firm from Austin, Texas.

"We aren't big enough to have energy engineers on staff," said Kirk Myers, REI's corporate social responsibility manager. "We are thoughtful about our environmental impact, and we needed this initial accounting to understand where things stood."

Armed with that information, CLEAResult offered multiple recommendations, all intended to reduce power consumption without any detrimental effect on uptime. "We were worried that it would impact redundancy, and that was unacceptable," Myers said.

One of CLEAResult's main objectives is to find the simplest options available for each data center, said Michael Stachowiak, the company's senior energy engineer. "There is no clear solution for every client," he said.

CLEAResult offers 225 energy efficiency programs, with more than 1,200 specialists in more than 30 U.S. states and Canadian provinces. It works directly with large industrial customers and on behalf of local utilities. So far, it has managed programs for more than 100 clients, according to the company's corporate overview.

Payback in less than one year

The solution that REI embraced didn't require it to pay for "the craziest cutting-edge technology," Myers said.

But it did require a retrofit in the form of a rooftop evaporative cooling tower (pictured below) that enables the data center to use "free cooling" techniques to keep its servers at an optimal temperature. As part of the multiphase effort, REI also upgraded its backup battery banks, replaced its old power distribution units, reconfigured the data center to include more distinct hot and cold aisles, and rewired the subfloor cabling to improve air flow under the raised floor.

This will enable REI to increase its IT load without requiring more electricity. "We aspire to grow the company without using more energy, and this will support that goal," Myers said.

Considered together, the technology reduced the number of hours that REI needed to run mechanical chillers by about 8,672 hours annually. Overall, that translates to a 93 percent reduction in electricity needed for cooling, or about 1.8 million kilowatt-hours annually. That's enough power to operate six REI stores for an entire year. The electricity load for the IT equipment is an average of 150 kilowatts, Myers estimated.

REI and CLEAResult declined to comment specifically on the cost. The initiative paid for itself within one year, with the help of incentives from the local utility, Puget Sound Energy, Myers said.

"Even without the incentive, this is one of the best projects we have done," he said. "It was the last obvious low-hanging fruit we could address."

Top image of REI store by functoruser via Flickr