GREEN Dialing


Agrowing number of supermarkets are moving to replace hydrofluorocarbons with climate-friendly alternatives, such as propane, ammonia and carbon dioxide, ahead of the planned phase out of R-22 in the United States, but grocers are moving forward cautiously.

“Some supermarket chains have been very progressive, choosing natural refrigerants for all new systems. Others are still installing new stores using R-404a, which as of Jan. 1, 2017, can’t be used for new or retrofit equipment but can still be used in alreadyinstalled equipment,” said Liz Whiteley, executive director of the North American Sustainable Refrigeration Council. “Most are somewhere between those two extremes with respect to their transition,” she said adding that it is impossible to generalize about what supermarkets are doing.

Whiteley said that grocers are weary of change. “The retail food industry has been through more refrigerant transitions than perhaps any other industry that historically used CFCs and other ozone-depleting substances.” She said that one of the benefits of natural refrigerants is that they’re phase-out proof. “Whether you’re talking about ammonia, carbon dioxide or any of the hydrocarbons, all natural refrigerants have such small global warming potential that they will never be subject to a phase out.”

Andre Patenaude, director of CO2 business development for Emerson Climate Technologies, said natural refrigerants are being aggressively worked on right now. “We have to look at ammonia, CO2 and propane more seriously, but although CO2 appears to be the most dominant at this time, ammonia and propane seem to be carving out their own space.”

There are 118 CO2 systems in the U.S., but most U.S. retailers are still in the trial stage, Patenaude said. Companies have also tried small propane systems called micro-distributed architecture as well as ammonia chillers on the roof of their stores that circulate CO2 as a secondary refrigerant. “There are all kinds of architectures being trialed in North America. Retailers are really not sure what to do,” he said.

In 2015, the Piggly Wiggly store in Columbus, Georgia, launched a refrigeration system that uses a hybrid ammoniacarbon dioxide cascade refrigeration system. The system’s manufacturer, Kysor/ Warren, reduced the amount of ammonia refrigerant to 3/4 pound per ton of refrigeration totaling 53 lbs., which is confined to the roof of the supermarket.

Whole Foods Market has implemented several systems. In August, Whole Foods opened a 49,000-square-foot store in Santa Clara, California, that uses a propane-CO2 cascade refrigeration system. The system uses about 265 lbs. of propane, which is spread across seven chiller units on the roof, to condense CO2 . In November, Whole Foods opened a location in Walnut Creek, California with a CO2 transcritical system, this time utilizing parallel compression technology to help with efficiency in the warmer climate.

“My goal now is to analyze real-time data on these systems to understand what our path forward looks like. The intent was to get the systems out there so we could compare
them side-by-side. We’d like to have two years of run time on all of the systems before making any programmatic decisions.”

Tristam Coffin, director of sustainability and facilities for Whole Foods Market

Whole Foods has also implemented an ammonia/CO2 cascade system at its store in Dublin, California, and another CO2 transcritical system that uses subcooling off of the CHP at a store in San Jose, California, said Tristam Coffin, director of sustainability and facilities for Whole Foods Market.

“My goal now is to analyze real-time data on these systems to understand what our path forward looks like. The intent was to get the systems out there so we could compare them sideby-side,” Coffin said. “We’d like to have two years of run time on all of the systems before making any programmatic decisions.”

However, Coffin said he doesn’t think the company will settle on just one system as it is difficult to find a one-type-fitsall solution. “It is a matter of building type and climate-specific design,” he said, adding that he will be evaluating the total cost of ownership as well as the environmental impact of the systems. “One system might be better than another depending on how you evaluate them.”

Keilly Witman, owner of KW Refrigerant Management Strategy LLC, said self-contained hydrocarbon systems are promising. “Up until now everyone just assumed supermarket refrigeration was going to be some type of rack system. Now all of a sudden, because propane is such a good, energy-efficient refrigerant, supermarkets have an option that uses propane selfcontained cases for all the store’s refrigeration needs,” she said.

Target was the first company to make the commitment that every new self-contained unit will use propane, R-290, which Witman said is very important symbolically.

Target, which operates about 1,800 stores in the United States, also plans to use self-contained “rackless” refrigeration systems in its small-format stores, which should decrease refrigeration energy use compared with traditional technology.

The rackless systems will also keep grocery aisles warm during cold months with the heat that is rejected from self-contained cases, which will save additional energy. “Others talk about the need to do something with the heat that is rejected by selfcontained units to carry it out of the store. But Target looks at that heat as a resource that can save energy and money,” Witman said.


Trader Joe’s Co. was recently cited for failing to repair leaks of R-22, but Witman said she doesn’t believe enforcement settlements or fines are motivating anyone to move to natural refrigerants. “The phaseout is spurring more action toward naturals than the risk of enforcement action,” she said.

Although R-22 is on its way out, there is still a tremendous number of supermarkets that are using it, Patenaude said. As supermarkets renovate, shifting to naturals or low-GWP options and moving away from R-22, they can redeploy the R-22 quantities to other stores. “That keeps the cost down and the availability of refrigerant there,” he said.’

However, NASRC’s Whiteley said the general trend is that R-22 prices will increase. Beginning in 2020 the only R-22 for sale will either be stockpiled product that was produced prior to 2020, or reclaimed R-22. “Consequently, you see a growing focus within supermarkets on getting out of R-22,” she said.

An EPA spokeswoman told Condenser that the steady decrease in availability and increase in the price of R-22 over the past years probably is encouraging some companies to consider whether to install a new refrigeration system or retrofit an old one. “In addition, domestic and international policies and regulatory changes, combined with concerns about greenhouse gas emissions, are driving equipment owners and operators to choose climate-friendly refrigerants when installing new or retrofitting old commercial refrigeration systems,” EPA said.

The EPA said it doesn’t have data indicating that leaks increase as R-22 systems age, and Patenaude said equipment can last 20 years or more if it is maintained properly. However, efficiency will decrease. “The efficiencies on compressors start to wear. Evaporator efficiency goes. Condenser efficiency goes. You start spending so much on maintenance that the cost of ownership goes through the roof,” Patenaude said, adding that it gets to a point where it doesn’t make sense to keep the store operating on the old system.


Coffin said there are challenges when it comes to installing systems that use natural refrigerants, particularly with educating the local municipalities and the communities. When Whole Foods put in its first transcritical system in Brooklyn, New York, in 2013, the grocer worked to educate the building and fire departments and made some tweaks to the system to appease the jurisdiction.

Witman of KW Refrigerant Management said one problem is that codes and standards haven’t necessarily caught up with the latest natural refrigerant technology. For example, codes and standards don’t exist for the use of more than 150 grams of propane in supermarkets. “Any supermarket that wants to move into hydrocarbon use as a whole-store-solution has to fight the codes, standards, and permitting battles on a local level each and every time they want to build a new store in a new location. That is an enormous time and cost burden to put on a supermarket,” she said. “You start over every time.”

Currently EPA limits the amount of propane that can be used in a stand-alone unit to 150 grams. “We have submitted an application to the EPA to raise the limit to one kilogram,” Witman said, adding that it can take over a year for an application to be approved.

NASRC is working to collect resources in its online library, and to create new documents to help supermarkets looking to use natural refrigerants navigate the process. “Even for companies like Whole Foods, each situation is unique enough that there seem to be a lot of challenges and complexities at start up that contribute to that upfront cost. Part of what will drive transition to natural refrigerants is when we have enough collective experience under our belts. The more we can share that experience with other end-users, the faster the market will move,” Whiteley said.

When it comes to effectively communicating safety, Witman said she believes the Department of Defense project at the Lackland Air Force Base in Texas, which used natural refrigerants in the base’s supermarket, is a good example. “They really went all-out in terms of communicating with the community about the system,” she said.

As part of the project, the engineering and design company did an ammonia-plume study, which examined the way leaked ammonia would travel away from the ammonia units on the roof. The test showed that, even under the worst weather conditions and the most extreme leak conditions, the ammonia would disperse into the atmosphere rather than travel to any area where it might affect people, Witman said. “That is significant because it proves that ammonia is not only a fantastic option for supermarkets, but also it is a fantastic option for supermarkets anywhere in the country, including cities with large populations, where buildings are very close together.”

Witman said she feels that ammonia is lagging behind carbon dioxide transcritical systems and hydrocarbons mainly because of a lack of a champion. “There isn’t anyone out there singing the praises of ammonia in terms of an equipment manufacturer or end user,” she said, adding that ammonia is one of the best natural refrigerants available and it is efficient in any climate. “You can’t beat the energy efficiency and cooling capacity of ammonia.”


Overall, natural refrigerant systems are not at cost parity with 404a type of systems, and incentives could help spur use. Patenaude said utility companies are willing to offer incentives if retailers can prove their natural refrigerant solution is more efficient than their R-22 system. “The capital expenditure will be higher, but they may be able to reduce that by getting X amount of money from the utilities,” he said.

That strategy worked in Quebec, Canada, when utilities offered large incentives. “That caused independent owners to take a chance on CO2 ,” Patenaude said. “They don’t have those incentives anymore, but it caused a shift.”

NASRC brought together endusers and utility representatives for a workshop this summer to discuss some of the challenges that end-users face when it comes to choosing natural refrigerants, such as cost, and how utility incentives could help advance the market for naturals.

“Between the enormous climate benefits of choosing a natural refrigerant over a midor high-GWP HFC, and the improved energy performance, there are benefits to both endusers and utilities in incentivizing the use of natural refrigerants,” Whiteley said.

However, utilities face some hurdles in creating these incentive programs. “For example, if a retailer decides to install a state-of the-art transcritical CO2 system, in most cases that system is going into a new store,” Whiteley said. “So how do you choose a baseline to compare your new system to?”


Whole Foods has focused on natural refrigerants in new construction. “It is more economically feasible in terms of installation and space constraints to build new,” Coffin said, adding that he is looking closely at how to retrofit older stores. “We are currently looking at what opportunities exist for transcritical CO2 retrofits or even going to a subcritical system with perhaps a lower GWP HFO on the high side.”

Witman said there really is not a good way to move to natural refrigerants in existing systems. “If you want to move in an existing store from R-22 to a CO2 transcritical system, you have to basically remove the existing system and build a new system,” she said.

One challenge is that most machine rooms are not large enough to allow a company to build a new unit next to an existing unit. “Nobody is going to shut down a store for a month to swap out the existing refrigeration system and put in a new one,” Witman said.


Despite the hurdles that exist, Whiteley said she expects the use of natural refrigerants to increase. “The market continues to get better and better for transcritical CO2 , especially with the variety of add-on technologies that help transcritical systems operate more efficiently in warm climates. There is also a lot of interest from supermarkets and utilities in hydrocarbon selfcontained equipment,” Whiteley said. “When you look at natural refrigerants, they’re phase-out proof. Natural refrigerants are the end game. That is exciting, and is certainly a motivating factor.”