EPA is developing a voluntary partnership with the supermarket industry to facilitate the transition from ozone-depleting substances to ozone-friendly alternatives. Known as the GreenChill Advanced Refrigeration Partnership, the overall goal of this program is to promote the adoption of technologies, strategies, and practices that lower emissions of ozone-depleting substances (ODS) and greenhouse gases (GHGs) through both the reduction of refrigerant emissions and the increase of refrigeration systems' energy efficiency. Specific partnership goals are to provide supermarkets and organizations that support the supermarket industry with information and assistance to: Transition to non-ODS refrigerants; Reduce both ODS and non-ODS refrigerant emissions; Promote supermarkets' adoption of alternative refrigeration technologies that offer qualities such as: Reduced ODS/GHG emissions (e.g., through reduced refrigerant charges and leak rates); Reduce the total impact of supermarkets on ozone depletion and global warming. A key component of the GreenChill Partnership is to facilitate technological research and information-sharing to assist partners in meeting these goals. EPA, in conjunction with the Food Marketing Institute (FMI), determined that one area where information is currently limited involves assessment of the energy efficiencies and energy consumption of currently available, alternative supermarket refrigeration systems. Consequently, EPA commissioned this study to compare the energy consumption of alternative supermarket refrigeration technologies. The study is based on theoretical analyses of the energy efficiency of the three most common refrigeration technologies: Direct-expansion (DX) centralized systems; Secondary-loop, secondary-coolant, centralized systems (SC); Distributed systems (DS).