Will propane take over from CO2 in supermarkets? Stay tuned.
QBD Cooling Deck 3.0 R290 cassette system
In the competition among natural refrigerants in the food retail sector, CO2 was the first to gain widespread acceptance, starting in Europe and then moving around the world.
But lately, self-contained display cases using hydrocarbons – propane (R290) and isobutane (R600a), in particular – have been moving aggressively into food retail and foodservice outlets in major industrial countries, including the U.S., Canada and Mexico. In the U.S., higher energy-efficiency requirements imposed last year by the Department of Energy greatly increased interest in efficient hydrocarbon cases.
Many supermarkets have started using these self-contained cases – such as glass-door beverage coolers or bunker displays – for spot assignments around the store, particularly at the front end, while continuing to rely primarily on central systems. Some stores are beginning to employ more and more of these “microdistributed” modular cases, with some even exploring full-store lineups.
The growth of hydrocarbon cabinets suggests the possibility that, if the charge limits applied to hydrocarbons due to their flammability are raised – and that is expected to begin happening over the next year – then microdistributed propane cases could challenge remote systems as the go-to architecture in supermarkets. This, of course, would be transformational.
The potential for self-contained propane cases in small supermarkets was recently highlighted by German discounter Lidl, which began opening stores in the U.S. last year. Lidl US confirmed that it recently received platinum certification from the U.S. Environmental Protection Agency’s GreenChill Partnership for achieving certain refrigeration goals at a store in Kinston, N.C.
Platinum is the highest certification level that the GreenChill Partnership grants a supermarket. GreenChill has often awarded platinum certification to stores that use natural refrigerant systems like transcritical CO2 that bring refrigerant GWP levels under 150.
Neither Lidl US nor the EPA would confirm what type of refrigeration system the chain is using at the Kinston store. However, public information points to Lidl US using self-contained cases with propane.
In the GreenChill Partnership Group on LindedIn, Gabrielle Jette, associate in Greenhouse Gas Mitigation & sustainability at consulting firm ICF, wrote last month that the store “is the first to achieve GreenChill certification using self-contained cases as a primary refrigeration system.”
Lidl said in 2016 that it was committed to using propane for all new self-contained refrigerated units at its German stores, and planned to roll out R290 in all future installations across Europe.
In an email response to a query from Hydrocarbons21.comabout the GreenChill certification and the refrigeration system used at the Kinston store, Chandler Ebeier, public relations specialist for Lidl US replied, "Our teams work with a variety of technologies and processes that help us increase efficiency. This is an important part of our business that allows us to reduce waste and deliver our customers better prices. Although we do not comment on each individual process or technology we have in our stores, we can confirm that we have received a GreenChill platinum certification related to those."
Another sign that hydrocarbon cases are catching on in North America is that last year two OEMs, AHT Cooling Systems USA and MTL Cool built plants in the U.S. and Canada, respectively, to manufacture these units.
AHT and True Manufacturing have led the movement by OEMs to hydrocarbon cabinets, with numerous other companies coming out with hydrocarbon units in North America over the past few years, including QBD Cooling Systems (Quality By Design), Welbilt, Beverage-Air, Traulsen, Liebherr USA, Turbo Coil, Montague, Fogel, Minus-Forty Technologies, Imbera, SandenVendo and Turbo Air.
Compressor makers Embraco and Tecumseh have also stepped up to meet the growing demand for hydrocarbon components in North America while designing more energy efficient, variable-speed compression systems.
On the end user side, many retailers have been equipping their stores with multiple hydrocarbon display cases, notably national operators Whole Foods Market (100-plus stores), Target (more than 900 stores in 2017) and ALDI US (about 200 stores last year), as well as regional players like Hannaford Supermarkets and Lowe’s Markets, and many others that are installing hydrocarbon coolers at the checkout. In addition, foodservice outlets like Starbucks and McDonald’s, convenience store chains like Circle K and USA To Go, dollar discount stores, and specialty chains like Freshpet have begun installing hydrocarbon equipment, and brands like Red Bull, Coca-Cola, PepsiCo, Nestlé, General Mills, and Unilever have rolled out hydrocarbon equipment in retail locations.
“Self-contained is an easy add-on."
Drew Tombs, AHT Cooling Systems USA
Why are self-contained hydrocarbon cabinets causing such a buzz in the retail sector? For one, it's their simplified design, which typically includes hermetic, factory-charged condensing units, either air-cooled or water-cooled by means of an external loop.
Compared with traditional centrally cooled cases, this design offers lower installation and maintenance costs and very low leak rates, with no need for a machine room, large rooftop condensers or extensive piping to cases.
In addition, their plug-and-play flexibility allows self-contained cases to be moved at will around the store for whatever marketing purpose.
AHT’s self-contained propane cases – including multidecks and deep freezers – are designed to offer a simpler alternative to remote systems, one that provides retailers in urban environments “with more flexible spaces,” said Drew Tombs, president of AHT Cooling Systems USA, who spoke during a recent Emerson E360 webinar.
That flexibility also enables retailers to convert centralized R22 or HFC systems to a self-contained all-natural scenario in a stepwise fashion without disrupting store operations. “Self-contained is an easy add-on,” said Tombs.
AHT began serial production of propane cases in Europe in 2002 in response to global ice cream customers “who were looking for ways to reduce energy consumption of their cases,” said Tombs. Since then the company has supplied over one million propane cabinets globally, with both R290 and R600a, including more than 20,000 in North American supermarkets and convenience stores, said Tombs.
Last year, AHT opened its first production plant in the U.S., near Charleston, S.C., the company’s fourth global plant. The new plant was built “on the assumption that this market was ready for our solutions, particularly multi-deck propane plug-in units,” said Tombs.
The benefits of self-contained cases have captured the attention of Whole Foods Markets, one of the leading users of R290 units in the North American food retail market, with installations in more than 100 stores, mostly under-counter cases and bunker displays on the sales floor.
In general, Whole Foods has taken a “silver buckshot” approach to natural refrigerants, testing several different system types, said Tristam Coffin, director of sustainability and facilities for the chain’s Northern California region in the Emerson E360 webinar. But he has grown increasingly impressed with the potential of self-contained cases. “In regard to serviceability as well as mobility, especially in urban environments, the self-contained option presents a level of flexibility that I think is unmatched in many respects,” he said.
Whole Foods is also testing the first propane/CO2cascade centralized system at a store in Santa Clara, Calif.
From an energy perspective, hydrocarbon cases have an exceptional track record. Target, for example, has found that an R290 cooler can consume 53% less power than a comparable R134a unit. According to Coffin, self-contained hydrocarbon systems offer energy savings of between 30% to 50% over traditional self-contained cases or DX racks. (In some instances, a portion of the efficiency gain may be due to ECM motors, LED lights or other improvements not used in baseline units.)
Moreover, hydrocarbons deliver cooling capacity with minimal charge sizes, and are compatible with copper, standard mineral oils and other common system components.
And, of course, hydrocarbons propane and isobutane feature a negligible GWP of about three, making it a “future-proof” refrigerant when it comes to environmental regulations. The low GWP combined with energy efficiency results in a very competitive total equivalent warming impact (TEWI).
In comparison to low-GWP HFOs like R1234YF, propane has an expected cost advantage, noted André Patenaude, director of food retail marketing and growth strategy, Cold Chain, Emerson, in the E360 webinar. The larger compressor displacement used by R1234YF requires bigger compressors, valves and heat exchangers, which can drive up cost. “R290 systems are much smaller and more cost efficient,” he said.
ACHILLES’ HEEL
Hydrocarbons’ Achilles’ heel is its flammability. Because of this, hydrocarbons must adhere to strict charge limits imposed by regulators around the world. On the domestic level, isobutane-based refrigerators, with a maximum charge of 150 g (what’s contained in a cigarette lighter) have been widespread in Europe and other countries outside of the U.S. for many years, thanks to the pioneering efforts of Greenpeace. However, in the U.S., manufacturers have not been able to market these fridges due to the charge restriction of 57 g.
But there is a growing movement to raise the charge limit for domestic fridges in North America to 150 g, and the U.S. home appliances market is preparing the take advantage of that increase when it occurs
The hydrocarbon charge limitation of 150 g, while acceptable for domestic fridges, is still considered insufficient for larger commercial units, prompting industry-wide interest in raising that charge limit to 500 g. The current 150 g limit “creates challenges for end users, OEMs and engineers of record to design systems that are applicable for the grocery industry,” said Coffin.
AHT’s larger units, such as some of its multi-decks, are designed with multiple propane circuits (each still under 150 g) to accommodate the bigger loads, Tombs noted. With a higher charge limit, one circuit would be sufficient, reducing the cost of the cases.
“We have invested in how to do microdistributed systems with multiple circuits that can still meet current regulations and bring propane into the market while legislation continues to look at [charge] increases,” said Tombs.
In 2015, AHT showed in Europe that, with bigger circuit charges, it was possible to use only propane self-contained cases in a store. The OEM gained special permission to use up to 700 g of propane in a single circuit. Today, more than 50 stores supplied by AHT use propane in more than half of their refrigeration and “we’re starting to establish full-store systems,” Tombs said.
Mark Bedard, president and CEO of MTL Cool, Chambly, Quebec said he is also “anxious to get the charge limit up to 500 g.”
After opening a manufacturing plant last year for four lines of glass-door hydrocarbon beverage coolers (three with propane and one with isobutane) and an open freezer case, MTL Cool began selling them, mostly in the U.S. “In six months, we expect to have thousands installed,” he said, adding that in a year these cases will account for 55% to 60% of MTL Cool’s business,. Many of MTL Cool’s retail and brand customers have asked for hydrocarbon technology because “they want to be green and fly that flag.”
But until the charge limit goes up, MTL is unable to cost effectively make some open cases with hydrocarbons. With a charge of 500 g, “we could shift 100% to hydrocarbons,” Bedard said.
MTL Cool is trying to differentiate itself in the marketplace with specially designed cabinet doors. For example, its Vista hydrocarbon unit features insulated glass doors with clear frames that have “no visual impairment,” said Bedard.
Another difference in MTL Cool’s hydrocarbon units is that they mostly use MicroGroove 5 mm tubes in heat exchangers. “That lets us put less refrigerant in the system and keeps us under 150 g,” said Bedard. “We can also absorb more heat with less material,” though the cost of MicroGroove tubes is higher than conventional tubes.
MTL Cool obtains its MicroGroove coils from Super Radiator Coils, one of the few providers of these coils.
Another Canadian OEM, which started shipping hydrocarbon glass-door merchandisers in 2016 as a result of changing regulations and requests from customers, is QBD Cooling Systems (Quality By Design), Toronto. R290 units now represent about 70% of its business and growing.
QBD’s hydrocarbon cabinets were recognized in 2017 and 2018 by Natural Resources Canada with ENERGY STAR Manufacturer of the Year in Commercial Products awards.
“I see people waking up to the fact that this is something they need to get on board with and get a comfort level with,” said Safder Jaffer, VP and general manager at QBD.
QBD’s key customers include global beverage brands and global foodservice and retail chain stores. “Because our customer base is ahead and have their own sustainability mandates, they keep us ahead,” said Jaffer. QBD has also started supplying hydrocarbon cases to food retailers, and provides units with advanced cooling controls to retail pharmacies for storing medication and vaccines.
About 70% of QBD’s hydrocarbon coolers contain removable refrigeration decks (cassette systems) called Cooling Deck 3.0, according to QBD. “You can remove them in two minutes,” said Jaffer, saving on maintenance and achieving lower total lifecycle costs. “It’s a better system in the long run because of flexibility.” Fogel is another OEM that offers removable cassettes.
The rest of QBD’s units use traditional split systems. QBD has also started developing open-air hydrocarbon units.
QBD’s Cooling Deck 3.0 uses “lint-tolerant” condensers designed with larger openings to allow debris to pass through and not clog up the coil. “It’s easier to clean and tolerates more build-up,” said Jaffer.
SAFETY FIRST
Given the flammable nature of hydrocarbons – and concerns about the knowledge base of technicians – OEMs and industry groups have taken pains to train technicians in the safe servicing of the equipment. Training expert Arthur Miller, principal at KAM Associates, has been delivering morning-long training sessions at the AHR Expo RSES offers online hydrocarbon training.
QBD is in the habit of listening to technicians “to understand what their challenges are,” said Jaffer. “Many good ideas will come from the field.”
As technicians get more experience with hydrocarbon equipment, “their fear will diminish,” Jaffer added. “There is still some sense of, ‘This is kind of new,' but that will improve with time and experience.”
MTL Cool’s Bedard see service improving for R290 but still problematic for R600a. “There’s still not a lot out there with R600a and it’s a smaller system,” he said. Hydrocarbons are not always carried in technicians’ trucks, though that too is changing, he added.
Bedard does not believe there is anything “sinister or dangerous” about hydrocarbons, as long as basic precautions are taken. “Anybody who has ever charged up a barbecue knows that,” he said.
