Ask a supermarket refrigeration technician what kind of system they will find in most stores and you will more than likely hear the term DX. Of all the various approaches to commercial refrigeration that have been tried, none has been relied upon more than conventional direct expansion systems. A multi-circuited, centralized, parallel compressor system, operating from a motor room at the back of store, is the most common kind of system in use today.
Over time, manufacturers have made significant improvements in the efficiency and operating costs of these conventional systems. Through the use of sophisticated electronics and other technologies, considerable progress has been made. But despite these advances, many problems continue to persist. The biggest among these is that refrigerants from DX systems leak. In order to address this and other deficiencies of these systems, various other approaches have found their way into the marketplace including one that provides tremendous benefits in refrigerant management.
With the overarching goal of not only reducing leaks but eliminating them entirely from the sales floor, one particular approach has been increasingly adopted by more and more customers. Medium temperature secondary refrigeration replaces the conventional refrigeration multi-circuited store piping system with a chilled fluid loop system. The only refrigerant used by the system is contained entirely within the motor room and the external condensers. Fluid-cooling heat exchangers, or chillers, in the motor room handle the entire load instead of individual evaporators at each case. There is absolutely no possibility that refrigerant leaks will occur in the sales area with this system.