LED Lighting for Supermarket Freezer Display Cases
Supermarkets use lighted refrigerator and freezer cases to display a variety of foods and beverages. These cases account for nearly half of a supermarket’s annual electricity costs, with interior lighting systems using a quarter of the electricity required to operate the case.
Until recently, nearly all commercial freezers used linear fluorescent lamps. Although fluorescent lamps provide superior energy efficiency in many lighting applications, their use in commercial refrigeration is not ideal. Fluorescent lamps in this application exhibit a reduced light output of up to 25% and uneven lighting on the products. These problems are a result of ineffective lamp operation at cold temperatures, the lack of optics to direct the light, and poor configuration and mounting location within the freezers.
LEDs can provide a better solution. LEDs do not suffer the same drop in light output under cold temperatures. LEDs also can be customized to provide several distributions of light to provide more even lighting across freezer shelves. These differences mean that LEDs potentially can provide more efficient lighting.
Today, this application is mostly transformed, with new freezers employing LEDs in many supermarkets, and retrofit LED lighting kits available for existing fluorescent-lighted freezers.
The LRC began studying LED lighting for supermarket freezers in 2002 with a laboratory study. In 2005, LRC researchers followed up with an in-store demonstration project and shoppers’ survey. Finally, in 2008, ASSIST published a recommended test method to evaluate the performance and efficacy of luminaires designed for freezer display cases. This method considers the luminaire’s efficacy under the cold application environment and is suitable for all lighting technologies.
Technical Reports and Publications
Narendran, N., J.P. Freyssinier, J. Taylor, T. Dong, and R. Capó. 2010. Application efficacy for comparing energy demand in lighting applications. Tenth International Conference on Solid State Lighting, August 1- 5, 2010, San Diego, CA, Proceedings of SPIE 7784: 77840L.
ASSIST. 2008. ASSIST recommends...Recommendations for Testing and Evaluating Luminaires for Refrigerated and Freezer Display Cases. Vol. 5, Issue 1. Troy, N.Y.: Lighting Research Center.
Narendran, N., J. Brons, and J. Taylor. 2006. Energy-efficient Alternative for Commercial Refrigeration. Project report prepared for the New York State Energy Research and Development Authority.
Narendran, N. 2006. Field Test DELTA Snapshots: LED Lighting In Freezer Cases. Troy, N.Y.: Lighting Research Center.
Raghavan, R., and N. Narendran. 2002. Refrigerated display case lighting with LEDs. Solid State Lighting II: Proceedings of SPIE 4776: 74-81.
Project Summary Sheets
ASSIST recommends… Efficiency Testing for Freezer Case Lighting (2010)
Energy-Efficient Lighting Alternative for Commercial Refrigeration (2006)
LED Lighting Gives Appeal to Frozen Foods – LRC Newsletter, February 2007
Lighting Research Center studies LED technology for supermarkets – Press Release, October 2004
Foster Miller (2002)
New York State Energy Research and Development Authority (NYSERDA) (2006)
Price Chopper (2006)
Tyler Refrigeration (2006)
U.S. Department of Energy, Oak Ridge National Laboratories (2002)