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4 Commercial refrigeration 4.1 Introduction Commercial refrigeration is characterised by storing and displaying food and beverages at different levels of temperature within commercial stores with sales areas varying in size from approximately 10 m2 to 20,000 m2. The refrigerating capacities of equipment vary from hundreds of watts to as high as around 1.5 MW. Two main levels of temperatures are generated by refrigeration systems from around 0°C to 8°C for the conservation of fresh food and beverages, commonly referred to as medium temperature, and around -18°C for frozen food and ice cream, commonly referred to as low temperature. Globally, HCFC-22 continues to represent the largest refrigerant bank within commercial refrigeration and is used at all temperature levels. The most used HFCs are HFC-134a for medium temperature and R-404A (blend) for all temperature levels. Traditionally, commercial refrigeration applications are prone to significant refrigerant leakage due to the fact that most of the large systems are field installed. In recent years, some progress has been made to improve leak tightness, especially for centralised systems, and the effort continues for better refrigerant management during the life of the equipment. The progressing phase-out of HCFC-22 in developing countries, and the phase-down of high GWP HFCs in many countries, requires making informed choices on the best replacement options. AHRI launched a Low GWP Alternative Refrigerant Evaluation Program (AREP) in 2010 (AHRI, 2013). A number of new blends based on HFO-1234yf and HFO-1234ze(E) as well as HFC-32 have been formulated to replace HFC-134a, HCFC-22, and R-404A. So, for the three groups of commercial refrigeration equipment, comparisons were made in order to select amongst the most energy efficient options with the smallest environmental impact due to both refrigerant emissions and energy consumption. Additional studies have also been carried out or ongoing, with cooperation between AHRI, ASHRAE and the U.S. Department of Energy to study the effects of flammable (A2L, A2 and A3) refrigerants in various applications (ASHRAE, 2016). In parallel there has been a significant development of technology and concepts for using R-744 as refrigerant, especially for larger capacity systems (Hafner, 2018), and HC-290, especially for smaller capacity systems. In commercial refrigeration, as in air-conditioning, high ambient applications require special consideration in selecting and designing components and equipment. However, designers of commercial refrigeration equipment choose components to design systems based on delivering the cooling required at the highest ambient condition. For moderate and cold climate regions recovering heat from the refrigeration system for heating purposes in the cold season increases system efficiency. Considering the supermarket as an energy system, including the building HVAC, water use, lighting and the commercial refrigeration as a single “system” for which energy use should be minimised, may give considerable total energy savings. 4.2 Types of equipment and applications Stand-alone equipment are self-contained refrigeration systems and comprise a wide variety of appliances: ice-cream freezers, ice machines, vending machines, and display cases. These systems are found not only in large commercial stores but also in restaurants, convenience stores, mini supermarkets and gas stations. In developing countries, domestic refrigerators and freezers can be 2018 TOC Refrigeration, A/C and Heat Pumps Assessment Report 77PDF Image | Heat Pumps Technical Options
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