Changing dynamics in the food cold chain

Thursday, 18 December, 2014

Buildings account for 40% of the total energy consumed in the United States. Yet, according to a recent U.S. Department of Agriculture report, food-related energy use has grown to nearly 16% of the country’s total energy budget.

It’s not surprising then that the same forces impacting the HVACR industry are also affecting the food cold chain. Industrial refrigerated warehouses, food processors, transportation companies and food retailers are responding to a rapidly changing world in which fluctuating energy prices, new regulations, the phase down of refrigerants with high global warming potential (GWP), technological innovation and globalization are shifting the nation’s food safety regime simultaneously and on multiple fronts. The cumulative impact of these various shifts is swift and transformation.

With the pace of change only increasing across the HVACR industry, it's imperative that refrigeration contractors and service professionals understand the impact of the following four challenges and how technology, policy and training will ultimately be the keys to industry change and adaptation.

Similar to buildings and HVAC systems, energy and the food cold chain are inextricably linked. According to a recent report by two environmental engineering professors at Carnegie Mellon University, the average American household has a climate impact related to food of about 8.1 tons of carbon dioxide (CO2) per year, a significant portion of which is associated with energy used in refrigeration. According to a USDA report, 80% of the increase of U.S. energy flow from 1997 to 2002 was attributed to growth in the food system. Typically, energy costs are the second highest operating expense for food producers and retailers, behind labor. This creates a vicious cycle: as global populations grow and food chain capacity increases, energy prices rise and food prices follow.

In addition to rapid growth, global populations are becoming increasingly urbanized. According to the United Nations, 54% of the world’s population currently lives in cities, a figure projected to increase to 66% by 2050. Even as populations coalesce in cities, however, the global food chain is becoming more decentralized, as new sources and markets emerge. For example, the World Bank estimates that aquaculture — or fish farming — will provide nearly two-thirds of global fish consumption by 2030, compared with just over 42% today. Nearly all of that growth is expected to come from small-scale fish farms in developing countries.

On one hand, this shift from local to global food sources better facilitates the accessibility of diverse foods to the world’s population. But, it also creates new challenges in refrigeration and transportation to keep food fresh and safe — no matter how long or segmented the journey from farm to consumer. 

Increasing reliance on a globalized food chain makes clear a basic reality: domestic governments alone cannot provide the level of inspection required by a global food chain to ensure safety. Thus, the Food Safety Modernization Act of 2011 (FSMA) marks the single biggest change in American food safety regulations since the inception of the FDA. The legislation effectively shifts key responsibilities for ensuring the integrity of food from the FDA to the private sector. In lieu of government inspections and enforcement, FSMA relies heavily on setting outcome standards and allowing the private sector to decide how to achieve those outcomes. 

"It is critical that installing and servicing contractors stay informed of the regulatory landscape and seek training for the newest technologies." 

Recognizing the energy-intensity of the food cold chain and anticipating its growing climate impact, governments worldwide have been trying to collaboratively control emissions and atmospherically harmful substances — and are regulating independently in the near-term. In the U.S., the Obama Administration, under its Climate Action Plan, has authorized EPA to reduce greenhouse gas emissions from HFCs using the Significant New Alternatives Policy (SNAP). In September 2014, EPA proposed new SNAP rules that would prohibit the use of certain high-GWP hydrofluorocarbon (HFC) refrigerants, and allow the use of other climate-friendly alternatives in refrigeration systems. At the same time, regulations to control harmful emissions and improve energy efficiency are important to the future of energy-intensive applications such as those in the food/cold chain and built sectors.

Recently, EPA proposed a 30% reduction in carbon pollution from power plants as part of section 111(d) of the Clean Air Act. The effects of this rule could have wide-spanning impacts on energy efficiency and, particularly, large energy consumers.

With SNAP rules dictating a transition to low-GWP refrigerants, efficiency, safety, environmental impact, chemical properties and economic factors all influence refrigerant choices in various applications. Some commercial refrigeration applications (ice makers and freezers) currently rely heavily on HFCs, such as R404A. The recent SNAP proposals would largely encourage the transition of these applications to hydrocarbon propane (R290), which can improve equipment performance. Hydrocarbons are more efficient than HFCs, but are also highly flammable and, depending on the application, may require implementing additional safety measures, including revisions to fire and building codes.

Carbon dioxide has been proven as a very effective refrigerant substitute in applications like supermarkets because it is chemically inert and environmentally benign. Furthermore, CO2 is nonflammable, toxic only in high concentrations and comparatively inexpensive. Its high pressure profile, however, makes it suitable only for certain applications. In subcritical systems in which pressures are lower, CO2 is used in concert with another refrigerant. These are typically applications in which HFCs or ammonia is used as the primary refrigerant and CO2 is used as a secondary refrigerant. In higher pressure transcritical systems, CO2 can function as a standalone refrigerant. Under SNAP, EPA lists it as an alternative for transportation, vending machines and food retail refrigeration.  

Ammonia is traditionally used in industrial applications of the cold/food chain, such as food processing and warehousing. It is also SNAP-approved for some commercial uses, including refrigeration and stationary air-conditioning applications. With higher toxicity and flammability than other refrigerants, however, installations using ammonia are nationally regulated to ensure safety and are subject to further pressure to reduce charge levels, especially for systems located in populated areas. One emerging solution is to use ammonia in combination with CO2 (for medium or high temperatures) or in cascade applications (for low temperatures), as previously mentioned.

The Future of the Food Chain
The low-GWP refrigerant transition is driving rapid changes to the food cold chain. FDA’s FSMA and EPA’s SNAP play significant roles in driving these changes, while new technologies are shaping how these regulations are implemented. At the heart of change, however, will be the convergence of policy, technology and training. It is critical that installing and servicing contractors stay informed of the regulatory landscape and seek training for the newest technologies. 

Lisa Tryson is Danfoss director of corporate communications and public relations.