Information technology is one of the fastest growing uses of energy in the country, but facilities teams may have limited authority over IT infrastructure, hampering energy efficiency gains.
ENERGY STAR’s Low Carbon IT Program aims to bring FM and IT together to cut costs and slash energy use. The agency recently spotlighted a handful of Low Carbon IT Champions whose efficiency measures led to big gains for their organizations.
Target, for example, recently conducted efficiency upgrades on two 45,000-square-foot data centers in Minnesota – a Brooklyn Park facility built in 2001 and an Elk River building from 2007. The upgrades were part of an ongoing effort to increase Target’s percentage of ENERGY STAR-certified buildings from 9% in 2009 to 75% by 2016.
The two data centers house 3.4 MW of IT load between them and could support a combined total of 9.7 MW. Cooling for the two comes from a dozen chillers with 650- to 675-ton capacity feeding 102 computer room air handlers (CRAHs) in 20- to 30-ton sizes.
After an efficiency audit, Target embarked on a series of initiatives with short payback periods:
- Variable frequency drives were installed on CRAHs, air handling units, and exhaust fans. Fan speed was lowered by as much as 78% on some units and led to a 99% reduction in power use. The VFD installation accounts for about 79% of the total savings from the upgrades.
- Temperature adjustments on 16 standby generator heaters were lowered from 140 to 110 degrees F. after consulting with the manufacturer, creating a 4 kW decrease for each heater.
- Timers were installed to turn lights on at 6 a.m. and off at 4:30 p.m., eliminating off-hour waste.
- A lighting retrofit replaced inefficient lamps throughout the building with more efficient sources. This included swapping out T12s for T8s and high-beam metal halides for high-output T8s.
- Unloaded transformers, each 300 kVA, were taken offline at the Elk River data center, where the computing load was not fully built out yet.
Target’s retrofits saved more than 5.8 million kWh annually, with annual avoided emissions equal to taking 800 cars of the road. The Brooklyn Park data center earned an ENERGY STAR rating of 91 in 2012; the Elk River facility, which was not completely built out during the scoring period, received a 77.