Reclaiming thermal energy is being done on a wider scale than ever before in food processing, reflecting a change in attitude toward the value of energy resources.

EPS Corp.’s Jay Zoellner (left) shimmies up a ladder to a CHP engine at Dean Foods’ Garelick Farms plant in Lynn, MA. High-profile projects like cogen installations improve a company’s image, but energy audits and ongoing usage monitoring are more fertile ground for utility efficiencies. Source: EPS Corp. 

In the long run, wasteful utility and energy management practices are neither smart nor cost effective, and recent years have seen a flurry of food company initiatives to recapture and reuse waste heat from motors, exhaust stacks and other sources to reduce energy consumption and clean up the industry’s image in terms of pollution.

Then the bottom fell out of the economy, and the wind came out of reuse’s sails. Six months ago, the plant engineer at one food company had high expectations for a $600,000 project to recapture heat in boiler-stack economizers and route it to tankless water heaters, which would resolve peak-demand shortfalls at his East Coast plant. The benefits are compelling, but as of mid-October, financial managers still were mulling it over. “If it isn’t approved,” the frustrated engineer says, “I’ll quit.”

The steady march toward sustainable manufacturing practices ran smack into the wall of capital constraints this year, putting energy initiatives on hold in many organizations. “We are doing gratis walk-throughs for food and beverage clients, identifying areas where additional study could lead to an action plan,” according to Doug Shively, director of electrical for the engineering firm Nutec Group in York, PA. Two electric utilities serving the middle of the Keystone state will be deregulated in the coming months, and the forecast is a minimum rate hike of 25%. Manufacturers recognize the need to reduce their demand from the electric grid, but getting projects off the drawing board is a challenge.

An existing boiler building houses a combined heat and power system that supplies hot water to Stahlbush Island Farms’ processing plant and generates electricity from a methane-powered 1.6 MW engine. Source: Essential Consulting Oregon.

Numerous options, if plants can act

Cogen and heat-recovery opportunities abound in food plants, Shively allows, but “people aren’t willing to spend the capital” for now. A loosening of credit next year hopefully will change action plans into projects.  

Solar is likely to be a declining factor in the mix, he fears. Wind power offers an even less attractive ROI. When PepsiCo designed its sustainability center at its Chicago headquarters, both wind and solar generation were included. Wind turbines were sourced from a local start-up company in part, PepsiCo managers explained, to help nurture the firm until it could mass produce the units (see related story on page 30). A year later, the turbine builder continues its search for a venture-capital angel.

Less exotic meat-and-potatoes projects, on the other hand, continue to come on stream. A Hormel Foods plant set to open in January in Dubuque, IA, will incorporate a heat recovery loop that theoretically will recover 100% of the electric energy consumed by compressors. The CarbonZero system from Atlas Copco is used at 20 manufacturing facilities worldwide, though the Hormel installation is a first in North America.

Dedicated to production of the company’s successful Compleats line, the $89 million project is designed to win LEED certification. Referring to Compleats as “a very cutting edge product,” company president Jeff Ettinger proclaimed at the groundbreaking ceremony, “the production facility will reflect that.”

“Compressors are sometimes seen as energy pigs,” concedes John Conover, Atlas Copco business line manager. Heat recovery can change that, and CarbonZero systems can pay for themselves within two years, depending on the energy source being replaced. Significant conservation of water also is possible: a water-cooled compressor with a 350-HP motor requires 60 gallons a minute to cool. With the heat recovery component, water consumption is 17 gallons a minute.

 Thermal recovery was incorporated into the construction plans for Summer Garden Food Manufacturing, another new facility with LEED aspirations. Waste heat from kettles is used to warm air for the HVAC system. “We’ve estimated we’ll save $40,000-$60,000 a year,” says CFO John Angelilli. The 55,000-sq.-ft. plant opened in Boardman, OH, in February.

A combination of solar and wind power on the second story roof of PepsiCo/Quaker Oats Sustainability Center showcases the leading edge of alternative energy for office space, but the payback from wind energy remains prohibitive in manufacturing. Source: Aerotecture Inc.

Closing the energy loop

For sheer ambition, few projects can match the scope of a biogas system that came on line last summer in Oregon’s Willamette Valley. The centerpieces at vertically integrated Stahlbush Island Farms are two 900,000-gallon anaerobic digesters and a 1.6 MW Caterpillar engine. The projected 12,000 MW annual electric output is double what the operation consumes.

Stahlbush Island started modestly 24 years ago as a two-crop farm. Today, Bill and Karla Chambers farm 5,000 acres and operate an IQF and canning facility that processes more than 75 million lb. of sweet corn, berries, broccoli and other produce each year. The biggest crop is pumpkin; Stahlbush is a major supplier of pumpkin puree to pie makers. Hollow pumpkin gourds are one of the better energy sources from food waste and can yield twice as much methane as cow manure. A feasibility study by Essential Consulting Oregon two years ago confirmed that a biogas project would be on solid footing, both technically and financially. Bill Chambers involved Covert Engineers to integrate the biogas system with CHP to supply jacketed steam and hot water to the plant. Air from the building housing the engine and boiler is exhausted to dry pumpkin seeds for the next harvest. “We’re using energy two or three times, in some cases,” marvels Rainer Greve, vice president-operations at Tigard, OR-based Covert. Sludge and liquid waste from the digesters are used as fertilizer, closing the loop back to field crops.

The self-mixing fermenters don’t require electricity, says Chambers, and a sophisticated controls package runs the system automatically. The 2,200-HP V-20 engine was engineered specifically to run on methane. One of the mechanics who maintains the farms’ trucks and tractors recognized the engine block as a twin to railroad locomotives he used to maintain. “At the end of the day, it’s just an internal combustion engine with a sparkplug,” Chambers shrugs.

The Austrian firm AAT Abwasser recently was honored for the design of the biogas digester used at Stahlbush. “Germany alone has close to 5,000 biogas plants,” according to Essential Consulting’s Matt Coen. “We’re decades behind (the Europeans).” The new installation is only the fourth in Oregon, and while quite a number of dairy digesters are operating in North America, most rely on obsolete technology. “Some were backyard mad-scientist projects,” Coen laments. 

The state of Oregon nurtures projects like Stahlbush with a tax credit for half the cost of renewable energy projects and a mandated kWh purchase price of 5 cents by utility companies. Even so, alternative energy is new ground for those organizations as well. Discussions with the local utility were the first step in the Stahlbush project, “and that was the last thing that got completed,” says Chambers, who holds a master’s in agricultural economics.

He expects a five-to seven-year ROI on the $10 million project. “It met all our business objectives and addresses the issues of sustainability and our desire to be energy independent,” Chambers concludes.

New-age insulation

Most businesses have less ambitious goals. The dollar savings from some projects can be too compelling to ignore, however, particularly when older equipment is involved. A Houston insulating-coatings firm has focused in recent years on thermal processing equipment in food plants, replacing mineral wool or no insulation with ceramic. “Plants may put off maintenance and other projects,” says Art Fleahmann, vice president-sales for Mascoat Products. “They never put off the opportunity to save money and energy.”

After demonstrating its insulating coating at several facilities in the ConAgra network, Mascoat applied the material to 32 carbon-steel cookers in the company’s Milton, PA, plant, where Chef Boyardee and other products are manufactured. The film, which was applied in 20-mil layers over six days, does not contain any VOCs, making it acceptable for use in cooking areas. The cookers work at 270° F, which computed to a 3.5 mm (1/7th in.) coating as the optimal thickness, Fleah-mann says. The project shaved $280,000 from the plant’s yearly natural gas costs.

Similar projects typically generate a payback in 16 months, he adds. “Fiberglass and mineral wool encapsulation will be a thing of yesterday,” says Fleahmann. “The future of insulation is in ceramic products.”

High-profile cogen installations highlighted EPS Corp.’s work for Dean Foods in recent years. Those initiatives are few and far between these days, and the Costa Mesa, CA, firm’s work has focused more on establishing baseline standards for energy use, then monitoring and controlling actual demand to trim costs. At Dean’s City of Industry dairy, for example, refrigeration (46% of electrical demand) and compressed air (13%) stood out as energy-savings targets. New controls and equipment upgrades targeting those areas quickly generated returns. Verified savings in refrigeration alone totaled $340,000, according to Shiva Subramanya, EPS cofounder.

“Continuous monitoring is the key to maintaining your savings,” Subramanya emphasizes, “and uncovering other opportunities you might not be aware of.” Even with corporate rates of returns ticking up in a harsh economic climate, energy-efficiency projects remain attractive investments, he adds.

LEED-related upgrades such as extra insulation and natural lighting, augmented with high-efficiency fluorescents, added 25% to the cost of Summer Garden’s new plant, Angelilli estimates, but it was money well spent. “People know it’s wrong to waste energy and pollute the land, and our customers believe in green practices, as well,” he explains. It’s uncertain how much of the firm’s rapid growth can be attributed to green initiatives, but Angelilli is convinced fundamental change is occurring in how manufacturers manage energy.

For more information:
John Conover, Atlas-Copco, 847-981-8995,
Rainer Greve, Covert Engineers Inc., 503-603-0995,
Matt Coen, Essential Consulting Oregon, 541-485-9095,
Shiva Subramanya, EPS Corp., 866-377-7834
Art Fleahmann, Mascoat Products, 716-572-2938,
Douglas K. Shively, Nutec Group, 717-434-1564,
Namir Habboush, Raytheon Integrated Defense Systems, 978-858-5000

Energy-efficient pasteurization with millimeter waves

The people who brought you microwave cooking are looking for a food equipment fabricator to help deliver a frequency in the electromagnetic spectrum to pasteurize foods more efficiently than any existing thermal technology.

Raytheon Co.’s Integrated Defense Systems (IDS) recently validated the effectiveness of millimeter wave energy in killing three food pathogens, including Listeria, on inoculated meat samples. Sterility was achieved within 16 seconds exposure to the light beam, according to Namir Habboosh, project lead, though commercial applications will focus on pasteurization. “A one-second exposure exceeded (meat processors’) reduction requirements for Listeria,” Habboosh reports.

Because the light penetrates only “a few millimeters,” it won’t partially cook the food with ionization, unlike an electron beam, he adds. “The initial cost is on the low end of the low end,” of irradiation, and, “recurring costs are about a tenth,” Habboosh says. The real competition, though, is steam pasteurization, and cost comparisons with those systems are underway. Intuitively, Habboosh expects millimeter waves, which operate in the W band at 75-110 GHz, to prove more energy efficient; whereas energy is scattered with steam, 95% of the energy used to generate millimeter waves is applied to a food’s surface. While the beam penetrates less than one-fifth inch, a 10-second exposure would raise surface temperature to 125

Public displays of energy-awareness

Sustainable manufacturing practices can be good for both the environment and the corporate bottom line, as PepsiCo Inc. has demonstrated with its lengthening list of LEED-certified plants. Those utility-efficient facilities tend to be in remote areas, though. To make sure the public gets the message, the company is investing in visible symbols in urban areas, including downtown Chicago, where the PepsiCo-Quaker Oats headquarters won LEED silver certification in December 2008, thanks in part to a 20% reduction in electricity consumption.

Recycling materials and cutting water use by 37% doesn’t yield dramatic visuals, nor do dimmer switches and occupancy sensors that will help cut 226 metric tons of greenhouse gas emissions attributable to PepsiCo’s offices. The four 1,000-watt vertical-axis wind turbines mounted on a second story rooftop, on the other hand, make a bold statement.

“If we’re going to be a sustainable company, we’ve got to address the footprint that buildings exert,” says Tim Carey, director or sustainability and technology in the Chicago division, noting that buildings account for 70% of electric use.