3 Opportunities for Improving Energy Efficiency in Food Processing
In the food processing industry, loss points can be found in many areas: time, energy, water, ingredients, packaging, scaling, scrap, and trash. In a food processing facility the proofer, oven, cooler and associated steam systems typically account for between 50 and 60 percent of the energy consumed, with the oven using the most energy. Improving energy efficiency in food processing not only reduces costs but also translates into reduced emissions—a huge plus as emissions regulations continue to get stricter.
The Carbon Trust, a UK organization, identified several significant loss points, both in terms of carbon emissions and in terms of energy efficiency in the baking industry, in its guide to the industrial sector, “Industrial Energy Efficiency Accelerator.” What follows are three of the ripest opportunities for improving energy efficiency in food processing.
Efficient oven burners are at the crux of improving energy efficiency in food processing. You can optimize your burners by analyzing the combustion stack gases and then adjusting the controls accordingly. Enhancing combustion efficiency through improved controls such as oxygen trim and burner operations is a standard practice in other sectors (e.g., boiler plant operation). While still an emerging practice in baking, developing appropriate strategies for determining the ideal combustion air/fuel ratio has a big payoff. According to the Carbon Trust’s guide, an estimated gas saving of up to 10 percent can be made for an indirect oven by reducing the levels of excess air during combustion.
Waste Heat Recovery
Taking advantage of waste heat can prove to be a huge boon for food processing. Although in the past attempts to recover wasted heat had somewhat meager returns, new technologies—such as heat pipes and self-cleaning heat exchangers—and the changing economics of saving energy mean that this is now a much more viable efficiency strategy. Installing air-to-air heat exchangers in the exhaust stack, which lowers fuel consumption, may cost roughly $8,000, but it has a typical payback period of only two to four years.
Hot water and steam are significant energy users in U.S. baking plants—and can be major sources of energy loss. The good news? Efficiency improvements in steam generation, distribution and end-use are possible, regardless of your steam system’s primary purpose. According to the U.S. Department of Energy, a typical industrial steam system assessment can identify potential energy use and cost savings of 10 to 15 percent per year. One of the most typical challenges baking plants face is that steam is often generated at higher pressures or in larger volumes than needed, creating unnecessary waste. The key to addressing this issue is determining appropriate pressure levels to match production schedules.
If the steam generation pressure can’t be scaled back, another strategy is to recover the energy through a turbo expander or back-pressure steam turbine, which allows for the efficient cogeneration of power and heat. Improved process integration and management of steam flows are other ways of making the entire steam system more efficient.
Even if the savings associated with each of these strategies is relatively small, cumulatively each improvement, combined with internal cultural shifts, adds up to create an undeniable impact. With the volatility of energy costs in mind and our uncertain energy future, these strategies to reduce energy consumption in the baking industry will become increasingly valuable.