When it comes to talking about emerging refrigeration system architectures for supermarkets, it’s good to start by taking a deep breath.

The days of centralized direct-expansion (DX) systems aren’t necessarily over, but those systems have been joined by a host of new technologies, including distributed systems in which smaller refrigeration units are located near the cases they serve; primary/secondary systems in which a small charge of refrigerant cools another heat transfer fluid (such as glycol) that is pumped out to the cases; subcritical and transcritical carbon dioxide (CO2) systems; microdistributed systems, which are similar to distributed systems that can be designed to send chilled water rather than refrigerant to the cases; and stand-alone cases. And, don’t forget the changing refrigerants: hydrofluorocarbons (HFCs) are on their way out, and naturals, hydrocarbons (HCs), and hydrofluoroolefins (HFOs) are on their way in. Finally, just to keep things interesting, keep in mind that more than one of these system architecture types can be used within the same supermarket.