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		Energy Services Bulletin home page
		Marshall, Schwan lighting project puts custom in customer service
		Mor-Gran-Sou partners with Boy Scouts to change lights and the world
		Western's IR cameras help utilities, customers maintain efficiency
		Technology Spotlight: Energy efficiency in new and existing computer data centers
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Marshall, Schwan lighting project puts custom in customer service

Above, Schwan's freezer before the installation of high-efficiency T5 fixtures. Below, the new lights improve lighting quality as well as energy consumption. (Photos by The Schwan Food Company)

Improving a large industrial customer's energy efficiency is not a one-size-fits-all proposition. When The Schwan Food Company asked Marshall, Minn., Municipal Utilities for help upgrading its freezer lighting, it took tenacity and creativity to reach the right solution.

Usual options ruled out

During a compressed-air study MMU Energy Services Coordinator Mark Antony assisted with for the frozen-food company in 2004, Senior Project Manager David Bero asked about other potential energy saving measures. "Lighting was an area of particular interest because of the opportunity for dual savings," said Bero. "For every watt of light, the cooling system has to pull out 3.414 Btus. When lights are on 24/7/365 as our freezer lights are, that really adds up."

There is more than one option for companies looking to save on lighting in cold storage areas, but none of them suited Schwan's case. Light-emitting diode fixtures are now becoming popular for this application because they use about 50 percent less energy than traditional fluorescent lamps, can be turned off and on and last about as long as the refrigerator cases. However, at the time, LEDs were not widely available commercially. 

Occupancy sensors are a good energy-saving strategy for relatively small walk-in units, but Schwan's freezer resembles a warehouse rather than a room, complete with warehouse-style traffic.  The ballast on a high intensity discharge lamp takes time to cool before it can restart. "The long restrike time meant that a person going into the freezer would have to wait up to 15 minutes before the light came on," Antony explained.

"We tested the sensors in our dry warehouses," Bero added. "The way lights pop on right in front of the occupant is hard on the eyes, and it creates safety issues for forklift drivers."

Vendor joins search for creative solution

Determined to find a solution that met Schwan's needs, Antony turned to the Internet to do a little research. "Mark was very, very helpful throughout the project," Bero commented. "He really stuck with it."

Antony finally came across 1st Source Lighting, a company in Auburn, Calif., that offered a product that seemed close to what Schwan was looking for. "They at least had fixtures that operated in freezer applications," Antony said. "Other manufacturers indicated that their T5 fixtures wouldn't perform in those conditions."

Unfortunately, the lowest recommended temperature for 1st Source's T5HO lamp was minus18 degrees, not low enough for Schwan's freezers. The lighting manufacturer did have ultra-induction fixtures that worked down to minus 40 degrees. Like occupancy sensors, though, UI fixtures are better suited to walk-in freezers than a warehouse-scale environment. "Our freezer ceilings are 25 to 35 feet high," said Bero. "Also, the fixtures didn't give us the return on investment we needed to make the project feasible."
 
The designers at 1st Source were not about to give up, however, so they applied the cold-resistant construction features used on UI fixtures to some four-lamp T5 fixtures. "We've been building freezer fixtures for some time, and we knew we could come up with a solution that worked for Schwan," said Sales Manager Greg Cooper. "We sent the plant a few of the modified T5 fixtures to test."

Determination rewarded with savings

Bero tried out the lamps and recommended a few additional changes that resulted in a T5 lamp that worked flawlessly at temperatures down to 32 below zero. The new fixtures saved Schwan $113,000 on electricity last year. Lighting was about $66,000 of the savings, "And the rest came from reduced cooling demand, because the ballasts put out less heat than HID ballasts," said Bero. 

Unlike HIDs, the new lights can be turned off on the weekends when the plant is closed. "They turn right back on at full output, and they have a much lower fire rate—they don't burn out as easily as HIDs do in freezer conditions," Bero pointed out. "So the savings are better than we initially calculated."

The project also gave 1st Source a new product. "We now have a standard T5 fixture rated to minus18 degrees that is sufficient for most businesses," said Cooper. "There is less demand for the VTF32 series Schwan uses, so we offer it as a custom fixture."

The Marshall plant replaced almost all its HID fixtures with the T5s, and Bero is encouraging other Schwan facilities around the country to install the technology. He estimates the payback on the Marshall plant retrofit to be between one and two years. "It depends on the fixture space," he noted.

Schwan received MMU's commercial customer rebate of $0.20 per nameplate watt saved through the installation of the fixtures. The program specifies that the lighting must be in operation during peak hours and provide a net reduction in kW use from the previous system without affecting lumen output.

More commercial customer rebates

The lighting rebate is one of several energy efficiency incentives available to MMU commercial customers. MMU offers a variety of energy-efficient HVAC programs, including geothermal and air source heat pump rebates and Energy Star-qualified air conditioners. The utility has also created a custom rebate plan to assist customers in developing innovative, energy-efficiency measures not covered under other rebate programs.

Antony said lighting is MMU's most popular incentive, adding that the Schwan project has been a very successful retrofit. "There is another facility in Marshall—a turkey processing plant—that could also benefit from this particular lighting measure," he observed.

New challenges expected from diverse customers

Marshall's significant—and diverse—commercial load may well offer other opportunities for creative energy-efficiency strategies, however. Archer Daniels Midland Company has a corn wet-milling facility in town which accounts for half the utility's load. Other major employers include Southwest Minnesota State University, Avera Marshall Regional Medical Center, US Bank Corporation, Wal-Mart Supercenter, Hy-Vee Foods and Independent School District #413.

MMU recently worked with the school district on the construction of an energy efficient new high school. "Interest in energy efficiency among our large customers is perking up again as energy costs rise," said Antony.

Luckily for those businesses, their utility is a match for their unique challenges. As the Schwan retrofit proved, Marshall Municipal Utilities has improving energy efficiency down cold.