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Energy Conservation: Refrigeration
In grocery and convenience stores, refrigeration represents over 60 per cent of the energy usage. Many retailers report a substantial return on investment with energy savings from refrigeration technology.
Besides reducing energy bills, best practices for refrigeration has many positive impacts:
For most retailers, besides supermarkets and convenience stores, refrigeration is not a concern. However, an increasing number of big-box stores are selling food that requires refrigeration or freezing.
Breadth of Practice
Conservation practices range from simpler measures, such as putting night blinds on open cases, to more substantial measures, such as overhauling or replacing systems with energy-efficient technologies.
Of the 13 case studies in the Greening Retail database with refrigeration and freezing practices, two include the use of night blinds on open freezers and refrigerators; two mention the addition of doors on cases; two describe the overhauling of their refrigeration systems in some way or replacing components. In one case, the retailer bought new, more efficient refrigerators. Three case studies report on the adoption of secondary loop refrigeration technology by retailers. Finally, monitoring energy use by refrigerators and freezers is an important component of managing refrigeration energy use. One of our case studies is devoted entirely to that topic, but it is also mentioned in a number of other cases.
The following table summarizes the types of practices found in the Greening Retail best practice database that pertain to energy conservation in the area of refrigeration and includes the number of companies for which this practice is described in the database.
Night Blinds and Doors
As mentioned above, night blinds are a relatively simple measure for reducing energy use for open refrigerators and freezers. H-E-B is currently testing the use of night blinds over the open freezers and refrigeration cases. They are reflective and secured by a magnet at the bottom. Payback has been calculated at three years for this initiative.
This corresponds to a City of Amsterdam study (http://www.ecn.nl/docs/library/report/2007/e07098.pdf) that calculated the payback period for closing existing upright refrigerators at 2.9 years. As well, the research paper stated that closing refrigerator and freezer displays does not negatively affect sales, but it will help to improve the comfort of the store temperature. Wal-Mart is adding doors to refrigerated cases, which reduces refrigeration load by 70 per cent. Bestway supermarket in the US decided to reduce its energy costs by, among other measures, converting an open freezer to an enclosed case.
Recommissioning Current Systems or Replacing Components
Refrigerator Case Fans: According the ENERGY STAR building manual for supermarkets and grocery stores, electronically commutated motors use approximately one-third the energy of the typical evaporator-fan motors in walk-in coolers. (http://www.energystar.gov/ia/business/EPA_BUM_CH11_Supermarkets.pdf) Refrigerated case fans in several H-E-B stores are being modified with electronically commutated motors. H-E-B stated that the savings from the energy efficient fans amount to over 50 per cent per fan.
Recommissioning (or Retro-Commissioning): During a re-commissioning process (if commissioning has never been performed, it is called retro-commissioning), simple problems can be discovered that will save much energy and money. Because regular staff may not have the required expertise to undertake a commissioning study, it is a good idea to look for outside advisor who will be able to find maintenance and operational problems that are not obvious to regular store personnel. For example, Woolworths has planned a sophisticated refrigeration re-commissioning program where the selected service provider will re-tune then monitor and maintain system performance.
Efficient Resistor: Owner of both Cambridge (Ontario) M&M Meat Shops franchise locations, Peter Charters, recently developed a resistor for his freezer heater circuits that reduced the energy load on average by 70-75 per cent. That's an energy savings of $250-$300 per month.
Lighting on Refrigerator Cases: Another example of a refrigeration-related practices is Wal-Mart's finding that replacing fluorescent lighting with LED lighting reduces the lighting load in these cases by 50 per cent
Related to the recommissioning process, is the practice of monitoring the energy use of freezers and refrigerators. The ICA Group uses the CoolICA system, which was introduced in 276 Norwegian stores to carefully monitor energy consumption and temperatures in all refrigerated display cases and freezers. Also, Sainsbury's has installed automatic alerts to ensure that any system malfunctions can be addressed quickly.
New, More Efficient Systems
According to ENERGY STAR, manufacturers of refrigeration equipment are making much-higher efficiency equipment than was standard just a few years ago. For example, the newest medium-temperature cases have higher evaporator temperatures, more-efficient compressors, better fan motors, less-frequent defrost cycles, and more-efficient lighting. One way to be sure that new equipment is energy efficient is buy ENERGY STAR-qualified products (www.energystar.gov/purchasing).
Big G Foods upgraded their cold storage and retailing systems with new refrigerators and refrigerated cases. They also purchased new coils for walk-in freezers and coolers, high-efficiency motors, and new evaporative condensers. They saved almost $22,000 per year with these upgrades.
Secondary Loop Refrigeration Technology:
Loblaws piloted secondary loop refrigeration in a Quebec store. This technology allows heat rejected by the refrigeration system to be recovered for store heating demands while ensuring a good cold distribution to the display cases. 35 of Woolworths' Australian stores were retrofitted with these systems. Big G virtually eliminated the need for natural gas with this technology.
This synopsis was compiled from case studies in the Greening Retail Best Practice Database. Sources for the information in the case studies are cited in the database.
This database contains links to case studies of environmental best practice from retailers around the world. You can search this database by the name of the company only, or you can find case studies that match one or several specific criteria, such as the type of retailer, the type of best practice, the company's country of origin, and/or project return on investment.
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