Food stores range from small convenience stores (such as 7-Eleven) to large supermarkets, and include specialty stores such as bakeries, grocery stores, meat &fish markets, health and ethnic food stores. There are new competitive trends in progressive food stores that repackage concepts for convenience of customers product- and lifestyle-oriented needs and desires, including offering prepared foods ready to heat-and-eat.
The energy costs in most food store operation are generally high. Food storage cooling and refrigeration is usually the largest single element since refrigerated display cases operate 24-hours a day.
Air conditioning is required for both customer comfort and, where used, proper operation of the refrigerated display cases. Data for calculating loads for people, lights, motors, and other energy-consuming equipment should be obtained from the store personnel, equipment manufacturers, and the ASHRAE Handbooks. The major difference in the HVAC system from other types of stores is the refrigerated display case loads and their effect on the HVAC system.
Existing stores can be retrofitted to one of the more modern systems. Other opportunities include: Older inefficient systems should be investigated for upgrading or replacement, particularly if CFC refrigerants are used. Energy conservation concepts discussed above not in use, or antiquated or inappropriate control systems all represent energy service opportunities.
Water heating is not a major energy user in most food stores with uses typically for hand washing and cleaning purposes.
Most water heating is done separately from the building heating system using direct resistance or gas heaters, and in some cases, point-of-use heaters.
If existing systems are inefficient or inadequate, replace with modern efficient equipment. Also, add better insulation on storage tanks, or timer controls. In some cases, refrigeration equipment heat reclaim can be used to preheat service hot water. The ASHRAE Applications Handbook Chapter on Service Water Heating publishes typical hot water use data as well as estimating procedures.
The trend in some food stores is to incorporate food preparation and food service functions. This requires the installation of some cooking equipment, such as ovens, broilers, fryers, griddles, ranges, steam cookers, and warmers.
Food stores may sell perishable foods that require a variety of refrigeration systems to preserve and attractively display the variety of items. The general purpose of a refrigeration system is to cool and store food, thereby preserving its shelf life.
In addition to various temperature refrigerated display cases, there are refrigerated food processing rooms and walk-in rooms. Cracked and crushed ice is used to display some products.
Refrigeration is often a significant steady use of year-round electricity since this equipment runs even when the building is unoccupied. Therefore, it is usually cost effective to install the most efficient refrigeration practical. Consequently, an energy utility's representatives should be asked to work closely with the energy customer during the early planning stages in order to help understand the options. Be alert to expansion needs and the potential replacement of old inefficient equipment with new, improved units as described above.
In the past refrigerants CFC-12, HCFC-22 and R-502 (an azeotropic mixture of HCFC-22 and CFC-115) were used in food store refrigeration. Production of CFCs has ceased and HCFCs are being phased out with a production freeze and no use in new equipment in 2010 and production ceases in 2020. One current replacement for R-22 and R-502 in low and medium temperature refrigeration applications is R-507 (an azeotropic mixture of HFC-125 and HFC-143a). As new refrigerants are developed, work with the food stores to phase-in replacement and include other steps to improve energy performance.
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