Walk-In Coolers and Freezers

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THE PRODUCT:

Walk-in coolers and freezers (walk-ins) are large, insulated refrigerated spaces with access door(s) large enough for people to enter. Walk-ins are used to temporarily store refrigerated or frozen food or other perishable items. The equipment is composed of an envelope and refrigeration system, and there are three different refrigeration designs: (1) a packaged system where the evaporator and condensing unit are integrated into a single piece of equipment; (2) a dedicated remote condensing system where the condensing unit (which only serves the walk-in) is located remotely from the evaporator; and (3) a remote system where the evaporator is connected to a multiplex condensing system (a "rack" unit) that serves multiple pieces of refrigeration equipment. Walk-ins are primarily used in supermarkets, convenience stores, and food service establishments.

POTENTIAL STANDARD:

In 2004, California set the first standards for walk-ins, reducing average walk-in energy use by over 40% through prescriptive requirements for insulation levels, motors, and use of automatic door-closers. Connecticut, DC, Maryland, Oregon, and Rhode Island later adopted the California standards. In 2007, ACEEE reached an agreement with walk-in cooler and freezer manufacturers on national standards for walk-ins that built upon the California standards but added some provisions and modified others. This agreement was incorporated into the Energy Independence and Security Act (EISA) of 2007 and includes prescriptive requirements for the thermal enclosure, motors, and lights. The EISA standards went into effect January 1, 2009. EISA also directed DOE to publish a final rule establishing performance-based standards for walk-ins by 2012. DOE issued the preliminary technical support document for the current walk-ins rulemaking in April 2010 and the final rule for test procedures in April 2011.

The ASAP/ACEEE report, The Efficiency Boom, analyzed standards based on a set of efficiency measures for walk-in cooler and freezer refrigeration systems including floating head pressure control, evaporator fan control, and high-efficiency compressors, fan blades, and fan motors. The specific measures applicable to a given type of walk-in depend on whether the walk-in is located indoors or outdoors and whether it has a dedicated condensing unit or is connected to a remote rack system. On average, the standards represent energy savings of about 20% relative to the current standards. The average incremental cost of $725 results in a 20 month payback period. The report estimates annual savings of 15 TWh in 2035 and net present value savings of $9.1 billion on purchases through 2035.

The statutory deadline for the final rule was January 1, 2012. DOE missed the deadline.

KEY FACTS:

Walk-in coolers and freezers are generally assembled on-site from pre-fabricated wall, ceiling, and floor panels; doors; a refrigerator system; and electrical components. Annual shipments are approximately 340,000.