A Can-do Approach to Energy Savings

Energy cost-cutting is on everyone’s mind, but a recession isn’t conducive to large capital outlays. An energy-saving program may be even harder for smaller processors, and harder still for ones with seasonal operations.

But if a relatively small tomato canner in Toledo, Ohio, can make a dent in its energy costs, so can you. Following is a look at several ways Hirzel Canning (www.deifratelli.com) trimmed its energy bills despite the seasonality of its operations and overwhelming competition from California vegetable processors.

“Seasonality – that’s always hanging over our heads,” says Karl Hirzel, director of manufacturing at the family-owned company. “We have some pieces of equipment that only run 40 days out of the year, so traditional return-on-investment calculations and strategies don't always work for us. What works best are small, incremental ways to improve.” 

Hirzel Canning produces more than 100 tomato products for its Dei Fratelli and Star Cross brands and sauerkraut under the Silver Fleece name from three northwest Ohio locations: a year-round plant at its Toledo (actually suburban Northwood) headquarters and ones in Pemberville and Ottawa that operate from early August to mid-October. Additionally, a storage facility at Ottawa is slated for upgrades that will make it a processing operation.

California’s tomato growers, which account for more than 90 percent of the U.S. crop and roughly half the world’s supply, affect the little Ohio firm’s fortunes as much as any factor — a good crop there can put the squeeze on the Ohio firm. Those are factors certainly outside of Hirzel Canning’s control. While the fluctuations of most energy costs also seem beyond the company’s grasp, Hirzel Canning has found ways of controlling some of its energy usage.

Partnering for improvements
Hirzel Canning’s first energy-saving moves centered on common-sense projects to cut major plant energy hogs. For some of the work, the company looked to outside experts. For example, Hirzel took advantage of energy management services from the local offices of Crescent Electric, a national electrical distributor, that resulted in upgraded lighting fixtures and motion sensors to shut-off lights in low-traffic areas.

Ohio Burner & Boiler Service, Toledo, assisted in tuning and optimizing heat processing and recovery equipment. Help also came from Smith-Boughan Mechanical Services, Lima, Ohio.

There hasn’t been a formal full-site energy assessment or audit, although that may be coming as a result of Hirzel’s growing relationship with the Edison Center for Innovative Food Technology (www.eisc.org), part of a statewide network supported by universities and the U.S. Environmental Protection Agency. Hirzel Canning’s work with the Edison center led to process upgrades including new equipment installations.

Natural gas is a volatile substance, financially speaking. If there was a triggering event that drove Hirzel Canning to take energy saving seriously, 2005’s Hurricane Katrina was “the biggest single factor,” Hirzel says.

Prices spiked to 2.5 times the norm before coming back down in 2006. But “they could go right back up any time just as easily, for any number of reasons,” he warns. Like many processors, Hirzel Canning defends against this uncertainty with forward contracting.

To better gauge its natural gas demand, the company began tracking hourly usage readings after the 2005 processing season at Toledo, and the following year at the other plants. Now the company knows its usage, which is correlated with the tonnage of product produced. This helps in gas contracting but also helps reduce peak loading plant-wide and in specific areas. Hirzel says this has helped to optimize evaporator configurations and better utilize cook kettles.

The kettles use large rotary coils that rapidly heat product but also create a large load demand. “By reading that meter every day, every hour, we quickly saw the effects of turning that coil on and opening the valve to let product in,” Hirzel says. Valve control and better synchronization of process flows have helped reduce peak loading.

Throughout its three plants, Hirzel introduced “surges” or intermediate product-holding areas to synchronize production speeds or flows from one step to the next. This smoothes production flows as it flattens-out energy demand spikes because equipment can be used at optimal efficiency.

Benchmarking and tracking consumption against product tonnage, Hirzel says that “at the two plants where we do our heaviest evaporation, we’ve reduced natural gas usage 15-20 percent.”

Economizing boiler heat
It’s become a little cheaper to feed Hirzel’s gas-fired boiler in the year-round Toledo plant thanks to an economizer. This is essentially a heat exchanger that recovers exhaust gases to preheat feed-water, which is routed to re-heat the boiler, but can be used for other purposes as well. An economizer is planned for the Ottawa plant, as well. However, Hirzel and plant engineers first want to analyze the plant’s total heat balance, the level of heat supply and its cost-justification. 

Hirzel Canning installed variable-speed drives on as many machines as possible to save energy.

The company’s falling-film evaporators are another source of energy reduction. While not as intensive as the three- and four-stage evaporators used for tomato paste (which Hirzel does not produce), the company nonetheless has saved energy on its two-stage evaporators by capturing and re-routing heat from the first stage and feeding it to the second. Condensate recovered from the second stage is recycled for cooling systems and other plant water uses.

While Hirzel did not disclose costs, heat and condensate recovery systems vary widely with plant-specific retrofit and custom engineering requirements. According to industrial energy wonks at the at the U.S. Dept. of Energy, the average plant can save 20 percent on fuel costs related to steam product by using commercially available equipment and maintaining it properly.

“But food plant engineers need to consider factors of scale,” says Bill Wilson, a food plant veteran with more than 30 years at companies of all sizes (including Nestle and JR Simplot) and now senior industrial energy systems engineer at the Washington State University Extension Energy Program. “Heat recovery techniques that will work on a 1,000-hp boiler in a large plant may not work in a small plant.”

For example, a small boiler with intermittent bursts of feed water — say, 30-second bursts every five or 10 minutes — “generally cannot recover enough energy to justify an economizer,” Wilson says. He has posted energy-saving strategies for food plants of all sizes on the web at www.energyideas.org/TPFoodProcessing.aspx.

Back at Hirzel’s Ohio operations, improvements to motors, drives, compressed air systems, chillers and sub-metering of energy at the equipment level proceeds incrementally. For example, as old motors come due for replacement, Hirzel steps up to NEMA Premium standard-compliant models. (read Motors’ Next Big Act) These are being mated to variable-speed drives, which draw less energy while smoothing-out production flows.

Every day brings new challenges, says Hirzel. Due to fluctuations in agricultural supplies, “There will be days when we have to turn down our lines to two-thirds speed or shut one plant down and move production to another plant.” But the variable-speed drives adapt equipment to varying production rates, while reducing electrical requirements. At the Ottawa plant, more than one-third of all motors are controlled with variable-speed drives.

It’s the little steps Hirzel Canning takes that show what’s good for processing is also good for energy savings.