As the latest holiday shopping season ends, American retailers are gearing up for the next big event. Their brightly lit buildings will feature the latest sales and the energy needed to power eye-catching displays will be readily available.
By Heather Lammers/NREL
Together, residential and commercial buildings account for a staggering 40 percent of energy use in the United States.
Although the power is always “on” for use in our country’s buildings, the U.S. Department of Energy (DOE) and its National Renewable Energy Laboratory (NREL) are
working with the nation’s commercial building owners — from retailers to offices and warehouses — to discover
new and innovative ways to reduce commercial building energy use.
DOE’s Commercial Building Partnerships (CBP) program is a public/private, cost-shared program that pairs selected commercial building owners with DOE’s national laboratories and private-sector technical experts. The goal is challenging, yet simple: new commercial construction is designed to consume at least 50 percent less energy than today’s code allows (ANSI/ASHRAE/IES Standard 90.1-2004), and retrofits are designed to consume at least 30 percent less energy.
Teams representing NREL, three other DOE national laboratories and private sector experts provide technical know-how throughout the project. Working with companies and their design teams, laboratory staff identify energy efficiency technologies across building systems — including building envelope, HVAC, lighting, and miscellaneous electrical loads — all while using advanced energy modeling to achieve optimum whole-building performance.
The potential energy savings means a financial benefit for companies and consumers alike.
GOOD FOR THE EARTH AND THE BOTTOM LINE
“An underlying idea with CBP is to demonstrate that energy efficiency makes good business sense,” NREL Senior Engineer Greg Stark said. “We are helping the companies develop better stores that use significantly less energy than their current prototypes — and for roughly the same cost as their current buildings.”
Consumers also could see a benefit from the work NREL is doing under the CBP program. According to researchers, a typical retailer needs to make upwards of $50 in sales to cover every dollar it spends on energy costs. Saving energy means savings for customers.
NREL researchers are taking a whole-building approach when looking at energy saving solutions for CBP members. “We are not just looking at individual technologies,” NREL Senior Mechanical Engineer Adam Hirsch said. “In order to hit these levels of energy savings, companies have to take a multi-pronged approach.”
“We work very closely with their design and engineering teams to brainstorm new efficiency measures,” added NREL Project Lead Michael Deru. “Due to our enhanced analysis capabilities, we are able to provide better energy analysis — especially when it comes to analyzing those measures all across the country.”
Coming up with energy saving solutions that can be repeated throughout the U.S. is a key CBP goal.
“It’s important for us to work with these large companies because they can replicate the lessons learned across their building portfolios,” Deru said. “Walmart is the largest private consumer of electricity in the U.S. And, because they are so big, they can make a large impact that ripples out into the industry by creating a marketplace for new energy efficient technologies.”
Other opportunities abound to expand the program’s reach. Current CBP projects represent more than 8 million square feet of commercial real estate. These same partners have committed to reproducing low-energy technologies and strategies throughout their building portfolios, which represent nearly 4 billion square feet of commercial real estate.
“These retailers are cooperating and sharing information across industry,” Deru said. “This effort can motivate manufacturers to make higher efficiency equipment, especially if they know these big companies are waiting
to buy it.”
SUPERTARGET RETROFIT SAVES 2 MILLION KWH OF ELECTRICITY
One retailer working with NREL is Target, the United States’ second largest general merchandise retailer. “We worked with the engineering and design teams at Target to come up with a list of measures that would help them save energy at an existing Colorado store,” Deru said. “In the end, we came up with solutions that exceeded the 30 percent energy savings goal for a retrofit project. “
If the actual savings in the Thornton, Colo., SuperTarget match the modeling results, each year the store will save more than 2 million kilowatt hours (kWh) of electricity and 3,300 therms of natural gas. But, coming up with such significant energy savings was a challenge for the NREL team.
Pictured at left, NREL Engineers Michael Deru, left, and Ian Doebber examine rooftop units at the Thornton SuperTarget. Through its CBP partnership with NREL, the store could potentially save more than 2 million kilowatt-hours of electricity. Credit: Dennis Schroeder
“Target is very advanced on their own, which made this a tough project,” Deru said. “As an existing building approaches 30 percent savings, it gets harder to find options that make economic sense. Target already is aggressive with their lighting systems. However, we were able to include incremental lighting improvements such as LED lights in their walk-in coolers, daylighting in the front of the store, and removal of additional lights.
“On the HVAC and refrigeration systems, we studied several options, ultimately recommending exhaust energy recovery units, evaporative condensers, variable speed fan control, and high efficiency replacement units. We also took a close look at plug loads and helped to implement turning off the drink coolers at night and putting their cash registers in standby mode when not in use. Ultimately, we were able to add another 7 to 8 percent savings on their overall savings.”
WALMART BALANCES HEAT, HUMIDITY AND COOLING
When the CBP program began a few years ago, it was mostly DOE and lab employees doing the work. Now, in an effort to share knowledge with industry, the teams are bringing in third-party design and engineering firms to help with projects. In this case, NREL, Stantec, and CTA Architects Engineers are working with Walmart to design a new store outside of Dallas.
“As part of CBP we are testing ideas that have been part of the NREL’s Buildings work for a long time,” Hirsch said. “We put out design guides with recommendations for hitting these advanced energy savings levels. Now, working with industry, we can test those out and see how they match up with the needs of companies’ business models.”
According to Stark, one difference with the Walmart project is the team is looking at balancing HVAC (heating ventilation and air conditioning)and refrigeration energy. This can be very important in a place like Dallas where the humidity is high. “Keeping humidity low helps reduce refrigeration energy — for example, it lessens the number of times you have to defrost the freezer case doors. However, reducing the humidity level takes HVAC energy. NREL, Stantec, and CTA worked closely with Walmart to find the humidity level that reduces the combined HVAC and refrigeration energy use and minimizes the overall energy use in the store.”
“NREL clearly has done a lot of work on big retail projects, including looking at commercial refrigeration energy savings, which is a big part of one of the facilities we are currently looking at,” added Stantec Associate David Okada.
According to Okada, other solutions on the table for the Walmart project include putting doors on as many of the refrigeration cases as possible and reducing lighting energy.
“It’s been an enjoyable process to work with people who have pushed the envelope very far when it comes to energy savings,” Okada said. “It’s also great to be involved with pushing the savings to the next step.”
Learn more about DOE’s Commercial Building Partnerships and NREL’s Buildings work.