In the United States, over 227,000 retail food stores operate their refrigeration systems around the clock to ensure proper merchandising and safety of their food products. Supermarkets and convenience stores make the largest contribution to this total (Progressive Grocer 2017). In U.S. retail food stores, refrigeration consumes about 2.3% of the total electricity consumed by all commercial buildings (EIA 2003). Refrigeration accounts for roughly 50% of the electric energy consumption of a typical supermarket (Arthur D. Little 1996). Display Refrigerators Refrigerated Storage Rooms Refrigeration Systems Condensing Methods Methods of Defrost Sustainable Retail Refrigeration Liquid Subcooling Strategies Heat Reclaim Strategies Supermarket Air-Conditioning Systems