Sustainable manufacturing and green initiatives aside, energy efficiency is a tough sell. Plentiful oil and gas supplies coupled with moderate pricing don’t make it any easier. Nonetheless, utility companies and regulators continue to prod industrial users along the efficiency path, offering carrots to complement sticks to travel that route.
Air circulation on a hot day is an obvious benefit of ceiling fans, but the big payoff in high-ceilinged spaces like McCain Foods’ plant is lower space-heating costs during winter. Photo: Big Ass Fans
More than 350 rebate programs from utility companies, government agencies and other entities are available to U.S. manufacturers who upgrade to premium efficiency motors, ballparks John Malinowski, senior industry affairs manager at Baldor Electric Co., Fort Smith, Ark.
Rebates can shave a few months off ROI calculations, but efficiency ratings on today’s electric motors make the difference between premium and standard motors negligible. A small uptick in motor efficiency is less meaningful than reliability and productivity gains, and those are the kinds of benefits OEMs are trumpeting, not energy efficiency.
Energy consumption barely registers as a consideration when fans are installed to improve worker comfort; after all, a ceiling fan is a poor man’s air conditioner, and it sips electricity compared to a compressor. Comfortable workers likely are more productive workers, although quantifying gains attributable to better air circulation is as difficult as calculating throughput improvements from better lighting.
Industrial fan manufacturers don’t even tout their units’ energy features. Instead, they focus on reductions in heating costs, particularly in the kind of high-ceilinged spaces common in food and beverage production and warehousing.
Food manufacturers “do a better job of insulating and sealing the cube off” than other industries, says Ed Quinn, a vice president at Big Ass Fan (BAF) Co., Lexington, Ky. But a tight building doesn’t trump basic physics, and the thermal stratification that occurs in a high-ceilinged building means that the air at the top is quite a bit warmer than the air at the bottom. Forcing the ceiling air back to where the humans congregate can cut winter-time heating costs up to 30 percent.
“We pay a lot of money to heat the ceiling to 80° F even if it’s 60° at the ground,” says Quinn. As an example, he cites the installation of two 24-ft. diameter fans at the Beer Store, a Mississauga, Ontario, liquor distributor. The fans shaved 18°F from the top-to-bottom temperature variation at the 125,000-sq.-ft. facility, which has a 34 ft. building height. That resulted in a 19 percent reduction in natural gas consumption during Canada’s nine-month winter, saving the firm $35,000.
Water-cooled reactors and other VFD components help boost performance and address negative side issues, such as electromagnetic interference. Photo: REO-USA
Adequate air circulation often is a quality issue in food production, whether it involves a cheese aging room or an ice cream freezer, and that’s reason enough to homogenize temperatures that otherwise would stratify. Energy reductions from an operations perspective are almost incidental.
Energy economics are a more overt driver in lighting projects, though better illumination also translates to more productive workers and less product waste. Last year, BAF hitched its star to the LED bandwagon, leveraging the talents of its 65 in-house engineers and a direct sales network to work directly with industrial clients.
A high-bay LED fixture was the first product, with washdown-ready units and other options following, including T5 and T8 fluorescents for the tradition-minded. “We thought we were late to the LED curve,” says Quinn, “but there are still a lot of people who want to lamp with fluorescents.”
Light up my life
BAF fabricates the fixtures. The LEDs are from Cree Inc., a global manufacturer that exemplifies the new wave of lighting suppliers. Legacy brands like Sylvania and Westinghouse are being passed around like wards of the state while manufacturers of televisions — the primary users of LED — invest in technical improvements. Siemens recently bailed from the lighting business and Philips is following suit. Samsung and other TV makers are replacing them as exhibitors at lighting industry trade shows.
Electronics are a big part of LED’s advantage. The electric surge and slow start-up that are destructive to fluorescents and metal halide bulbs are non-issues with LED, which are rated at 150,000 hours of service. Maintenance savings from bulb replacement alone were calculated at $129,000 for a 400,000-sq.-ft. Walmart refrigerated distribution center built in Balzac, Alberta, in 2010.
Motor manufacturers stopped banging the energy-efficiency drum years ago, relying instead on mandated improvements to drive that benefit. The payback from premium motors is real, but the timeline is longer than most manufacturers willingly will accept.
Motor efficiency ratings ratcheted up a few percentage points to the 90-95 percent range under 2010 regulations, but the regulations exempted many categories, such as gear motors and brake motors. The exemptions gradually will disappear. Beginning in June 2016, open motors down to ½ HP will have to meet standards previously considered premium efficiency.
More significant is the shift away from product efficiency and toward system efficiency. Instead of mixing and matching pumps and motors, for example, manufacturers will need to look at the interplay of the drive and motor in the application.
“System efficiency isn’t just a nice idea, it’s going to be the law,” points out Tim Albers, director of marketing and product management at Nidec Motor Corp., St. Louis. “We’re within three years of this happening.” Fans and compressors also will be affected by rules being drafted, he adds.
System efficiency should push more manufacturers toward variable frequency drives. About one third of U.S. motors currently run with variable frequency drives (VFDs), compared to 40-45 percent in Europe, Albers estimates. Pairing a premium motor with a VFD will benefit a manufacturer with 24/7 production but probably not a firm running a single shift, five days a week, he points out.
Repairing and rewinding older motors might make more sense for plants running 40 hours a week. On the other hand, repair is not an option in food production’s harshest environments. “On poultry lines, if a motor lasts two years, they’re ecstatic,” Albers says.
Service life is a concern in other food production environments, as well. Protecting the VFD investment is driving a growing number of manufacturers toward water-cooled drive components. Besides extending VFD life, water-cooled components require considerably less space than air-cooled drives. That’s a benefit when addressing undesirable side-effects of modern motor drives, such as electromagnetic interference (EMI), according to Rick Jones, senior director of engineering at Indianapolis-based REO-USA, a maker of electronic and inductive components.
Automation is bringing more electronic devices into the production environment, increasing the magnitude of the EMI problem and the need for filters. That’s almost incidental to the impact on initial purchase cost and long-term energy savings that will result from the systems approach that is coming into play, notes Baldor’s Malinowski. Too often, a 92 percent efficient motor is paired with a 50 percent efficient pump.
An inefficient pump is a false economy; he cites the example of two dealers bidding on a pump project. One offered an inefficient pump driven by an 800 HP motor, the other a more expensive, efficient pump powered by a 600 HP motor. In that case, the second bidder got the order.
“Historically, we rewarded purchasing people on the lowest first cost, but that’s not always the right thing when you have electric costs that can swing the overall cost of ownership dramatically,” Malinowski says.
“Motors don’t jump out at you” when considering energy efficiency, he muses. They account for 65-75 percent of electric consumption in food & beverage, he estimates, but they are less visible consumers than, say, lights. Out of sight, out of mind will give way to a systems approach, though, helped along by young engineers.
VFD applications used to be rare in food production, both because of cost and unfamiliarity with the technology. “People are learning how to apply them to mitigate problems like EMI filtering,” Malinowski says. “The old-school guys have been replaced by younger guys who are not scared by electronics.”
Production managers are more concerned with today’s output requirement than tomorrow’s electric bill. Motor OEMs recognize that and pour R&D money into designing more robust machines that also meet higher energy-efficiency standards. As a result, manufacturers are able to lower energy inputs per unit of production while also keeping production lines humming, demonstrating that sometimes you can have your cake and eat it, too.