One of the common themes I’ve heard at several industry events this year is that supermarket refrigeration systems will probably look very different in the future. Now whether that’s five, 10, or even 20 years down the road, nobody knows, but industry experts seem to think big changes are coming.
Right now the trend is large, suburban supermarkets, most of which utilize centralized direct-expansion (DX) systems consisting of display cases on the floor that are connected via long runs of refrigerant piping to coils and compressors located in a remote mechanical room or on the roof. These types of systems are designed to be easy to access and service, as all the mechanical equipment is located in one area; however, the sizeable amount of piping can mean a greater chance for refrigerant leaks, which is becoming a greater environmental concern.
In fact, according to the Environmental Protection Agency (EPA), a typical supermarket’s refrigeration system holds a refrigerant charge of about 4,000 pounds and has an average annual leak rate of about 25 percent. That means, on average, leaks could cause a supermarket to emit up to 1,000 pounds of refrigerant – usually HFCs or even HCFCs -- every year. Multiply that by thousands of supermarkets across the country, and it is possible to see how this may be cause for concern.
Refrigerant regulations are another reason why change is coming, as HCFCs will be phased out by 2020, and given their high global warming potential (GWP), HFCs will likely be phased down in the near future as well. At some point, supermarkets will need to start considering low GWP alternatives such as HFO blends, as well as so-called “future-proof” refrigerants such as ammonia, CO2, or propane.
Part of the allure of propane systems, in particular, is the fact that they are self-contained, which means they are far more flexible than today’s centralized DX systems. So if a store manager decides to highlight a brand new soft drink, for example, she could potentially move a propane refrigeration case to a prominent place near the front registers without disrupting the floor plan or making costly changes to the rest of the refrigeration equipment in the store.
In addition, self-contained propane units contain only a small charge (no more than 150 grams – about 5.3 ounces -- per refrigerant circuit) and have a very low leak rate of about 2 percent. Depending on the size, a store using only self-contained refrigeration equipment could theoretically only have 110 pounds of propane.
Another factor leading to change may come down to demographics. Statistics show that young people are increasingly moving to densely populated cities where they may not need a car to get around. This means they will not have ready access to the suburban megastores, so supermarket owners will likely start opening smaller stores in urban areas in order to cater to this crowd. And, again, self-contained refrigeration cases may be a good solution, particularly if a supermarket is taking over an existing building that offers less flexibility with the layout.
Supermarket owners may have even more choices of self-contained units in the near future, because several industry groups are trying to raise the maximum charge size for flammable refrigerants such as propane in commercial self-contained cases from 150 to 500 grams. They note that while 150 grams of propane is adequate for small-to-medium-sized display cases, the larger display cases that are ubiquitous in the U.S. need more propane for cost-effective operation.
No one knows when – or if – larger self-contained propane units will become available, but supermarket owners would no doubt like to have that option. Refrigeration contractors, however, may not be as excited about the widespread adoption of self-contained units. That’s because these units typically require less maintenance than large rack systems, and since they’re virtually plug-and-play, owners may choose to buy a new unit rather than pay to have an older one repaired. Although in a world with a shrinking base of service technicians, perhaps that’s a good thing. That way experienced service techs could be used to work on the complex refrigeration systems that will likely still be used in the suburban megastores for many years to come.
So perhaps the stores of the future will turn out to be a win-win for everyone.
