By Patricia Provot, President of the America, Armstrong International
From rising supply chain constraints and elevated inflation to evolving consumer preferences, the food industry is facing many challenges. But perhaps the single biggest concern among global food manufacturers is how they’re continuing to balance growth and productivity with environmental emissions and reliance on fossil fuels.
A new report led by the World Meteorological Organization (WMO) highlighted record-breaking climate change indicators in 2023, bringing to light the effects that extreme weather events are going to have on food security, agriculture, and the wider socio-economic implications. These findings and others like it underscore the importance of finding new and innovative ways to decarbonize food processing without hindering production output and putting further strain on food supplies.
While many are quick to look to electricity, like solar and wind, as a silver bullet solution, it may not be the answer just yet. Renewable energy is still quite intermittent, and the energy grid is already stressed. An industry-wide switch to electricity would only burden the grid even further, causing energy prices to climb higher and food prices to soar. There is a better way to decarbonize and ultimately achieve net-zero emissions without hurting a company’s bottom line or disrupting current food production.
The U.S. Department of Energy (DOE) released its “Industrial Decarbonization Roadmap,” identifying four key pathways for reducing industrial emissions in manufacturing. Within that report, the DOE highlights energy efficiency as “the most cost-effective option for near-term reductions of greenhouse gas emissions.” This is absolutely true. But it’s important to understand that this concept of “energy-efficiency” goes far beyond improving the efficiencies of existing utilities and extends to process efficiencies, like waste heat recovery.
This is significant for many of today’s food manufacturing plants, which were built more than 50 years ago, before energy efficiency was a contributing factor to design. While many of these buildings have been largely retrofitted over time, most are not updated with efficient technology and therefore leave a lot of energy on the table.
In addition, safe food production requires significant amounts of energy 24/7 for heating and cooling processes – including sterilization and cold storage – leading to a lot of waste heat in the process. Why? I am sure I’m speaking to the choir when I say this, but cooling something requires the removal of heat, which typically leaves the plant in the form of hot exhaust gasses and radiating heat from hot equipment surfaces and heated products. What is not widely known is that between 50 and 80% of the primary energy input used in food manufacturing leaves a plant as waste heat. Interestingly, the thing about energy is that it cannot be destroyed; the first law of thermodynamics tells us this simple fact. Therefore, in theory, that waste heat or energy should be usable if it could be captured and rerouted back into the plant to power processes. This would not only significantly reduce a plant’s energy needs, thereby lowering its Co2 emissions, but also equate to substantial annual savings in energy and production costs and shield the grid from wasteful use.
Fortunately, this is not just theory.
Circular thermal
Manufacturers across the globe are beginning to apply a process known as circular thermal. By implementing an internal process heat exchanger network, along with industrial high-temperature heat pumps, manufacturers can recover low-grade heat from cooling systems and process stacks and upgrade it to valuable high-grade heat, which can be used to power a number of plant processes. High-temperature heat pumps become invaluable in this process because of their efficiency. In fact, these heat pumps produce two to three times more heat output than they consume in electricity input, allowing them to upgrade energy into a higher-grade heat for a specific need at a very low energy cost.
Plants that apply this approach can achieve up to 80% total carbon reduction, especially food processing plants, which eject a significant amount of heat when cooling products like ice cream or frozen foods. Simultaneously, plants need heat at relatively low temperatures to operate effectively – making that waste heat a valuable resource. Moreover, many factories have such an excess of waste heat from cooling that they can power neighboring facilities, even after their own heating needs are fulfilled.
Pinch
Prior to any major decarbonization efforts, manufacturers must understand the energy life cycle within their plant. Where is the energy going? How much is wasted versus the amount going into the product itself? The answers to these questions are vital to developing a roadmap to decarbonization, and a common method for defining the flow of energy within a plant is called pinch. Also known as process integration, it is a tool that allows engineers to transform a theoretical resolution into a practical solution that works for their specific plant and its processes. Broadly speaking, it consists of mapping and overlapping heat sources and heat sinks in a plant with the goal of optimizing heat recovery.
After an initial walkthrough of a plant, a thermal energy expert can evaluate the overall performance of the operation and establish a baseline of the thermal utilities. This includes following the raw materials from when they enter the facility until they are shipped to identify the pain points within the utility infrastructure and create a thermal map of areas where there is heat demand and heat sources. The team can then develop a strategy for integrating all heat sources within the facility to achieve the lowest possible amount of energy consumption.
So, what’s the catch? Why isn’t everyone in the food industry doing this? There is no catch. Until recently, energy efficiency wasn’t a priority, not just within food processing but industry as a whole. This was due in large part to the affordability and abundance of fossil fuels and the lack of concern for CO2 emissions. Now that energy waste is a significant business risk, the value proposition has changed. Recovering waste heat is not only the fastest and most economical method for achieving net-zero emissions, but vital for healthy profit margins, and companies are recognizing this reality. Optimizing facilities with waste heat recovery is what we like to call a no-regret, first step toward net-zero emissions because it is one of the very few decarbonization strategies with a positive return on investment.
Patricia joined Armstrong in 2000 as an energy auditor. She has since served clients and assisted teams across the U.S., Belgium, India, China, the Philippines and more. Patricia is heavily involved in product innovations, growing the next generation of energy auditors, standardizing Armstrong’s methodology and pursuing the company’s carbon-cutting initiatives.
