The Food Chain North America FAST-FOOD RESTAURANTS FACTORIES & WAREHOUSES SUPERMARKETS 16 ICE CREAM FREEZERS VENDING MACHINES CENTRAL REFRIGERATION SYSTEMS DISPLAY CABINETS/ISLANDS/C<strong>OF</strong>FIN CASES COLD ROOMS GLASS-DOOR BOTTLE COOLERS
The Food Chain In the last two years, significant change has occurred in the North American cold chain with an emphasis toward improved refrigeration systems and efficiency. The required replacement of R-22 has resulted in a switch to ammonia or CO 2 , or ammonia/CO 2 cascade systems. Food Processing NH 3 : Ammonia has become one of the most commonly used refrigerants for the food processing industries and can be found in fish, meat, and poultry processing plants, confectionary and bakery facilities, fresh milk and dairy production plants, as well as wineries and breweries. It is widely used because it produces the greatest net refrigerating effect (btu/lb) and the lowest brake horsepower per ton of refrigeration (BHP/TR) of any industrial refrigerant. For example, Baltimore-based Northeast Foods is a commercial baking powerhouse, supplying McDonald’s with most of their hamburger buns. The company’s Clayton facility uses an ammonia refrigeration plant at its 103,000 sq. ft. (9,569 m2) site that includes a 13,500 sq. ft. (1,254 m 2 ) freezer at -10°F (-12°C). The ammonia system in its freezer is used to chill glycol for process equipment, mixers, and ingredient cooling, eliminating separate equipment for the process chilling. Kleinpeter Farms Dairy uses an ammonia refrigeration system and captures the heat from the refrigeration system to heat water used for cleaning and pasteurization purposes. In Oklahoma, Sigma Alimentos (Sigma) has an ammonia refrigerated food processing plant that produces a range of Mexican-style hams, hot dog sausages, sliced meat, and cold cuts at its Seminole facility. In addition to its use in refrigeration systems, ammonia heat pumps are another technology gaining ground. The Budweiser Anheuser-Busch Brewery in St. Louis, one of the first to commit to the development of mechanical refrigeration using large steam engine driven ammonia compressors, now has an ammonia refrigeration system rated at 18,000 tons of refrigeration. MillerCoors has also installed a new ammonia compressor at its Milwaukee brewery to help achieve its stated goal of reducing energy use by 15% by 2015. The ammonia refrigeration system contributes to annual energy savings of 3.3 million kilowatt hours. At MillerCoors Texas brewery, an upgraded ammonia refrigeration system has eliminated energy-wasting pressure drops and ensures that the evaporative condenser is used effectively. This has reduced annual energy use by 3.6%. As an addition to an existing ammonia refrigeration system, American multinational Kraft Foods uses an ammonia heat pump system to capture rejected heat and reuse it to provide water heating at a food processing facility in Davenport, Iowa. This has reduced Kraft’s heating energy costs by 61%, reduced site energy consumption for heating by more than 79%, reduced condenser water consumption by 15 million gallons (57 million liters) per year, and delivered a host of additional operation and maintenance savings. H 2 O: Exhaust heat from electricity generation is used to drive an absorption chiller for air-conditioning of closed loop food production facility, The Plant, in Chicago. CO 2 : Although used to a lesser extent, CO 2 heating and cooling systems are gaining ground in the food processing industries. In the world famous Napa Valley, California, Wine producer Somerston Wine Co. installed an integrated CO 2 heating and cooling system for glycol cooling and hot water heating. The first such system to be implemented in a winery, it is comprised of four elements: a CO 2 refrigerant heat pump, a hybrid adiabatic fluid cooler that replaces the traditional cooling tower, a glycol warming system for tank and barrel room heating, and a high efficiency glycol chiller for additional tank and barrel room cooling. The installed system had a 3.5- year payback. Midwestern commercial bakery Country Maid also installed a transcritical CO 2 heat pump system that simultaneously produces high temperature hot water for washing baking equipment and cool, comfortable air-conditioning for employees. It is expected that the heat pump will yield electrical energy savings of 30% compared to traditional energy consumption and a payback within 3.5 years. In Canada, CO 2 heat pumps have been integrated in a dairy/cheese plant in Québec. The Fromagerie Polyethnique / Fromagerie Fritz Kaiser dairy/cheese plant saves an estimated 28,000 gallons (105,000 liters) of propane fuel per year on account of the CO 2 heat pump. One of the main benefits of the CO 2 heat pump unit is that it can achieve the high temperatures needed during the production process (up to 194°F/90°C). The payback period for the project was estimated at 4-5 years, but thanks to the energy efficiency incentives of the Québec government the payback period was reduced to two years. Food Storage & Distribution NH 3 : Across North America, the demand for convenience foods has resulted in the construction of millions of square feet of cold storage facilities. In these facilities, the freezers and coolers, more often than not, use ammonia refrigeration systems to control temperatures to maintain product quality and freshness. Examples include the largest cold storage distribution center in the USA, the 840,000 sq. ft. (78,000 m 2 ) Black Mountain facility in North Carolina and, in Canada, Sobey’s 147,000 sq. ft. (13,650 m 2 ) refrigerated distribution center in Trois-Rivieres, Quebec. The center’s use of an ammonia central chiller and heat recovery on the condenser side of the chiller for space heating won the ASHRAE 2010 Technology Award. Other examples of ammonia using 17
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