Wal-Mart Stores, Inc. (Bentonville, Ark.), which operates 6,200 retail locations worldwide, has launched an internal green initiative designed to reduce greenhouse gas emissions by 20 percent in seven years, while trimming energy use by 30 percent, reducing solid waste and increasing truck fleet fuel efficiency.
Wal-Mart opened experimental “Supercenter” stores in Aurora, Colo. and McKinney, Texas to identify and assess green technology value in retail operations. The stores operate from a consumer perspective in addition to acting as living laboratories to test new technologies that may help Wal-Mart meet its green goals. Independent engineers, architects and contractors work with Wal-Mart staff to identify store operating systems and practices that save energy, conserve natural resources and reduce pollution. Any tested and proven technologies from the experimental stores will contribute to greener operations across Wal-Mart’s chain of stores and may be adopted for use in other commercial facilities.
One of the significant technology trials, hosted at Wal-Mart’s 206,000-square-foot Supercenter in Aurora, Colorado, involves a secondary loop refrigeration system containing DOWFROSTTM Inhibited Propylene Glycol-based Heat Transfer Fluid, manufactured by The Dow Chemical Company. The system—which cools the store’s meat, dairy, produce and other medium temperature chilled food display cases—is designed to reduce the use of refrigerant gas and to limit the potential for gas leaks into the environment. It also provides constant, even refrigeration at an equivalent or lower operating energy expense than a traditional direct expansion (DX) refrigeration system.
According to Aurora project consultant Steve Perkins, of The Steve Perkins Agency (Rockwall, Texas), “The number-one reason Wal-Mart chose the secondary loop system is that it is environmentally friendly. The secondary loop operates at much lower pressure using ABS plastic pipe instead of copper, and it generates significantly fewer emissions.” Perkins stated that according to nationwide studies, secondary loop systems have, on average, 50 percent lower annual maintenance costs compared to conventional DX systems. Not only do secondary loop systems provide cost savings and energy efficiency over the life of the system, installation and startup of secondary loop systems are less complicated, time-consuming, and costly because far less of the expensive, refrigerant-grade copper pipe is used, and there are fewer connections and valves to be installed, tested, and adjusted.
DOWFROST from The Dow Chemical Company will be utilized in a secondary loop refrigeration system similar to this illustration for a green-initiative test in an Aurora, Colorado Wal-Mart.