Many refrigeration systems in the food retail environment (walk-in coolers, walk-in freezers, and reach-in cooler cases) comprise older equipment, and many businesses are unable to absorb the cost of replacing the equipment with newer, more expensive components. But there are options out there to retrofit the systems with energy efficiency measures that will reduce their energy usage and catch them up somewhat to brand new systems.
If you walk into just about any supermarket or food retail chain you’re likely to see some technological upgrades designed to make your interaction with them more efficient and pleasurable. Voice-activated product finders; credit card readers with a tap sensor; targeted customer data through information gathering and analytics.
One area of their business that has been slow to adopt innovation is their commercial refrigeration systems. Dairy walk-in coolers, frozen foods walk-in freezers, and reach-in aisle display cases are often older equipment operating at full capacity 24/7/365. For many food retail businesses it is simply not cost feasible to replace their systems with brand new equipment.
So some are looking at efficiency retrofits to bridge the performance gap. In reality, with how simple and effective it is to retrofit the systems, most, if not all, should take a hard look at incorporating efficiency measures.
“After all, the commercial refrigeration system is the biggest energy user within supermarkets, accounting for about 40 to 60 percent of electricity consumption, according to the Environmental Protection Agency (EPA). Buying new, higher-efficiency refrigeration equipment can be cost prohibitive, which is why making targeted retrofits or upgrades to existing systems may make the most sense for many food retailers,” says Joanna Turpin for The News.
The beauty of these refrigeration retrofits is that there are measures for every budget level. From replacing the insulation on suction lines up to large-scale controls, there is likely a solution for everyone.
Adding Glass Doors: A quick install and an instant energy saver
That’s the amount of money saved in a year from adding glass doors to a refrigerated case.
At the FMI 2018 Energy & Store Development Conference in Atlanta, results were shared from a lab experiment involving an 8-foot refrigerated case with electricity costs of $0.12 per kWh. Prior to any kind of retrofit upgrade, this particular case cost $1459 to operate. Post upgrades, which also included raising the evaporator temperature and limiting the number of defrosts to twice a day, the operating cost was only $420. This was a 71% reduction in the case’s energy usage.
There are some great ancillary benefits to adding glass doors, too, noted J.R. Cochran, Dover Food Retail, at the conference.
For starters, the glass doors made the aisles more comfortable for shoppers by retaining the cold air that previously spilled out of the cases. In a field test, aisle temperatures rose from 54 degrees all the way up to 70 degrees. This will likely encourage shoppers to shop longer, and it will also decrease how much the store’s heating system will have to work in this section of a store.
On top of customer comfort, glass doors also extended the shelf life of hamburger up to two days, a lab study showed. Other meats saw an increase in their shelf life by four or five days!
“Balanced temperatures, fewer defrost cycles, and lower standard deviation from set point are all benefits,” said Cochran. “If you can keep the temperature constant, you’re going to have a better looking product. And it’s not really cold beer until you put it behind doors.”
EXTRA READ: DOE Guide on Proper Refrigerated Case Retrofit
Smart Controls: Your system doesn’t have to run 100%, 100% of the time
While a larger undertaking than adding glass doors to a refrigerated case, to be sure, intelligent automated controls also offer huge opportunities for energy savings and performance improvements. Reserved more for a business’ walk-in coolers and freezers (though refrigerated cases can often be controlled, as well), this solution can reduce the entire footprint of a store’s refrigeration system by 30-60%.
The controls will take over the operation of the system, based on preset temperature set-points and cooling schedules. Some controls solutions incorporate anti-sweat door heater controls, and defrost cycles into their management.
And depending on the state, and the utility provider, these controls often qualify for energy efficiency incentives or rebates. This will decrease the upfront capital cost along with ensuring energy savings quickly.
During the 2018 Emerson E360 Forum in Houston, Andre Patenaude, director of food retail marketing and growth strategy, cold chain at Emerson, noted a handful of other retrofit upgrades that could provide savings.
He mentioned how the most frequent questions and concerns he hears are about older refrigeration systems. So a lot of times, there are measures that can be taken on a micro level.
“For example, older systems may have suction lines that are uninsulated or the insulation is cracked,” he said. “Or they may have a lot more flash gas in the liquid lines, which causes inefficiencies at all the expansion valves. Condensing pressure swings can also result in a lot of waste because, as the condensing pressures swing up and down, the liquid quality changes, the expansion valves are hunting, and everything is off balance. Lack of maintenance can also be a problem.”
Business owners or site managers should also consider the following:
- Conduct a baseline energy audit. It’s difficult to make actual improvements without knowing exactly what needs improved.
- Recommission the system to factory specs. Depending on the age of the system, temperature setpoints may need to be reset, superheat or suction pressure may need adjusted, and some components may be broken and need replaced.
- Install VFDs on condenser fan motors. This along with upgrading discus compressors to digital compressors can achieve a 16-20% reduction in energy usage.
“When upgrading a refrigeration system, it is important to know the difference between two simple words — effective versus efficient,” said Patenaude. “A lot of us think that just because there are no alarms and everything is at temperature, the system is working great. But a store might be running 15 or 20 percent more energy, so it’s not efficient, but it’s effective. How do you take both of those and combine them together? You want the system to be effective for food quality and food safety, but you also need it to be efficient in order to remain profitable.”