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More than 30 stores will be upgraded this summer, some of which will get new natural refrigerant-based HVAC&R systems.
Sonia Saini

Aldi UK, the U.K.’s fifth largest supermarket chain, is continuing to roll out natural refrigerants across its existing stores with a series of upgrades over the summer.

According to a statement from the retailer, 33 stores will undergo refurbishments in June, July and August. Changes will vary at the store level, but a number of these sites will get upgrades to their refrigeration systems, including new natural refrigerant-based technologies to reduce carbon emissions. has contacted Aldi UK for additional information about the proposed refrigeration system upgrades.

“Finding ways to reduce any environmental impact as we continue to grow our store estate across the country is a vital part of these changes,” said Jonathan Neale, Managing Director of National Real Estate at the supermarket chain.

Other improvements include updating signage and redesigning store layouts to provide more space to shop, Aldi UK said.

Throughout 2024, Aldi UK plans to invest more than £90 million (€106.6 million/ $114.3 million) on store improvements at more than 100 locations.

“Finding ways to reduce any environmental impact as we continue to grow our store estate across the country is a vital part of these changes.”

Jonathan Neale, Aldi UK

NatRef journey

Aldi UK has been installing natural refrigerant-based systems at its new stores since the beginning of 2018, and its goal is to transition completely to natural refrigerants by the end of 2029. In the company’s existing stores, HFC-based equipment is being replaced by CO2 (R744) alternatives as stores are upgraded and when refrigeration equipment reaches its end-of-life, the retailer said in its latest sustainability report.

The retailer is also introducing heat recovery at newer stores, using waste heat from chillers to provide space heating. In new and refurbished stores, Aldi UK is installing doors on its refrigerated display cases, which it said will reduce each store’s energy use by around 20%.

In a LinkedIn post this week, U.K. HVAC&R manufacturer Clade said that it recently designed, manufactured and installed a full CO2 upgrade for an Aldi UK store in Birmingham. The system consisted of a refrigeration pack from Clade, a condenser from Coolers and Condensers, two condensing units from Panasonic and two evaporators from Rivacold.

In May 2023, German HVAC manufacturer Vaillant announced a five-year partnership agreement with Aldi UK to install its air-to-water aroTHERM plus propane (R290) heat pumps in all new store locations. Up to five of the 12kW (3.4TR)-capacity units will be installed at each location depending on store size and will provide both heating and cooling.

Additional industry commitments

Other U.K. retailers are also taking action on natural refrigerants. As of October 2022, the country’s largest supermarket chain, Tesco, had installed transcritical CO2 systems at about 1,000 stores, or about one third of its locations, with plans to be HFC-free chain-wide by 2035.

According to Sainsbury’s Sustainability Report 2024, the retailer continues to “remove refrigeration systems using HFCs, replacing them with more efficient fridges using natural refrigerant gas.”

Asda committed to “implementing lower-carbon refrigeration” in its 2022 ESG Report. However, that same year, the retailer installed R410A-based air-conditioning equipment at four of its superstores.

Morrisons has also committed to transition to CO2-based refrigeration, more efficient display cases and heat recovery systems.

From propane chillers and heat pumps to ammonia and CO2 refrigeration systems, natural refrigerants are gaining ground down under.
Sonia Saini

Held every two years in Australia, the ARBS (Air Conditioning, Refrigeration and Building Services) trade show offers perhaps the best window into the state of natural refrigerants down under. ARBS 2024 was in Sydney from May 28–30, and according to the show more than 9,000 visitors were in attendance to see new HVAC&R technology from more than 350 exhibitors.

ATMOsphere COO and Co-Founder Jan Dusek was one of the attendees, and over three days he compiled a list of highlights at the show. ATMOsphere is the publisher of

Below are a few of Dusek’s insights into the state of natural refrigerants in Australia.

Propane highlights

A handful of manufacturers were touting new propane (R290) chillers and heat pumps, with several bringing units to the show and discussing their application in commercial HVAC systems. One of those OEMs, Johnson Controls, recently received a compliance certification from the state of Queensland for its R290 heat pumps and chillers.

Residential R290 heat pumps and hot water heaters were also on full display. Dusek said that, based on conversations he had at the show, the expectation is for the market to be split between R32 and R290, with propane having the edge.

Read more: Johnson Controls Ready to Supply Commercial R290 Chillers and Heat Pumps in Australia, Says Product and Tech Manager

CO2 highlights

Transcritical CO2 (R744) refrigeration systems continue to grow in popularity in Australia as end users such as Woolworths increase their adoption of the technology. In April, the supermarket chain celebrated the opening of its 100th store equipped with a transcritical CO2 system. 

Outside of food retail, Dusek also observed that the market for CO2 heat pumps continues to grow with “hundreds” of units on the market. Back in 2022, Jonathen Hindry, owner of the South Australia-based contractor Adelaide Heat Pumps, told his company was installing between 150–200 CO2 heat pump water heaters per year.

Ammonia highlights

Ammonia continues to hold a strong position in the industrial sector, both in terms of installations and local manufacturing. Dusek spoke with Stefan Jensen, Managing Director of Scantec Refrigeration Technologies, prior to the show and was told Scantec had a “full order book” through 2025 for its low-charge ammonia refrigeration systems.

Greg Clements, Head of Sales – Compression, at GEA in Australia confirmed the popularity of low-charge ammonia systems to Dusek in an interview. “Low-charge ammonia systems are becoming more mainstream,” he said, noting that industrial refrigeration in Australia boomed during the pandemic.

The heat pump provides heating and cooling for an industrial component cleaning machine with a combined COP of 5.6.
Sonia Saini

The Fraunhofer Institute for Solar Energy Systems (ISE) has developed a propane (R290) heat pump for an industrial component cleaning machine that requires just 255g (9oz) of charge.

The machine requires both heating and cooling for its cleaning and drying processes, both of which were previously handled by electric heating and cooling components. According to ISE, the R290 heat pump achieved a combined heating and cooling COP of 5.6 relative to the electric-powered equipment previously in use. Given the size of the refrigeration circuit, ISE noted that the cleaning system would be compact enough to fit inside a room measuring just 16m2 (172.2ft2).

“As the cleaning and drying processes of the machine are carried out at both low and high temperatures, it is an ideal application for a heat pump,” said Clemens Dankwerth, Project Manager at ISE.

The power required to heat the process water for cleaning and rinsing the machine and the air for drying it were halved, and the energy needed for the heating fresh water was reduced by as much as 80%. Additionally, the condensation unit recycles the process exhaust air, recooling it in the process, which saves more than 10,000L (2,641.7gal) of fresh water annually.

ISE calculated that integrating the heat pump into the industrial component cleaning machine will bring an annual cost savings of €4,800 ($5,160) and reduction in CO2 emissions of approximately 12,600kg (27,748lbs). The figures were calculated for a facility operating two shifts per day, five days a week for 48 weeks a year.

“The use of heat pumps can make a significant contribution to the decarbonization of industrial processes,” said Dankwerth. The technology is also applicable to other processes that operate within the 50 to 70°C (122 to 158°F) temperature range, such as large dishwashers in canteens.

Previous R290 research

The refrigerant circuit for the industrial cleaning machine’s R290 heat pump came out of Fraunhofer ISE’s LC150 project, which set a goal of developing a residential heat pump that used 150g (5.3oz) or less of propane. In November 2022, the research team announced they had created a heat pump with a heating capacity of 12.8kW (3.6TR) requiring a propane charge of 124g (4.4oz).

Fraunhofer ISE subsequently launched the LCR290 project to research and develop indoor-use propane heat pumps for multi-family buildings to replace gas and oil-based heating equipment.

ISE developed the R290 heat pump in collaboration with the Bavarian Center for Applied Energy Research (ZAE Bayern) and MAFAC E. Schwarz as part of the ETA in Existing Facilities project. The project seeks to increase energy efficiency in the German industrial sector. It was launched in November 2020 and is funded by the Federal Ministry for Economic Affairs and Climate Protection (BMWK).

“The use of heat pumps can make a significant contribution to the decarbonization of industrial processes.”

Clemens Dankwerth, Project Manager at ISE

The company offers 58 models in five different equipment lines, with its first chiller installation in the country set for July.
Sonia Saini

Johnson Controls is ready to supply its commercial propane (R290) chillers and heat pumps to the Australian market, according to Rickey Du, Product and Technology Manager of Industrial Refrigeration at Johnson Controls for Australia and New Zealand. 

 Du told in an exclusive interview at the Air-Conditioning, Refrigeration and Building Services (ARBS) 2024 Expo that Johnson Controls has a total of 58 models in five different series of its YAS R290 lineup now available in the Australian market, with capacities ranging from 30 to 400kW (8.5 to 114TR). The ARBS 2024 Expo was held May 28‒30 in Sydney. 

 “Walking around [the Expo], you see quite a few smaller-scale R290 products, which indicates that the market demand is coming,” Du said. “We, however, are ready to go, and we are Queensland certified.” 

 Last month, the company received a “first-of-its-kind” compliance certification from the Queensland Resources, Safety and Health (RSH) statutory board for its York-brand YAS R290 units. “Approvals granted through this process are recognized throughout Australia, New Zealand and in some cases, internationally,” Johnson Controls said. 

 In addition, Du said that the two roughly 300kW (85TR)-capacity R290 chillers used to obtain the Queensland certification will provide air-conditioning for a commercial shopping center in the state. The propane units will replace existing HFC chillers, with the installation and commissioning of the new units set for mid-July. 

 Johnson Controls, headquartered in Cork, Ireland, also produces ammonia (R717)-based compressors, chillers and heat pumps for commercial and industrial use from various sub-brands, including Frick, Hybrid Energy and Sabroe. Last year, the company acquired U.S.-based M&M Carnot to enter the North American commercial and industrial CO2 (R744) refrigeration market. 

 In his conversation with, Du outlined the Queensland certification process, the different Johnson Controls equipment available in the Australian market and current sales of ammonia equipment in the region. 

“We are ready to go, and we are Queensland certified.” 

Rickey Du, Product and Technology Manager of Industrial Refrigeration at Johnson Controls for Australia and New Zealand.

 The interview has been edited for length and clarity. 

 What motivated Johnson Controls to bring R290 equipment to Australia? 

 Rickey Du: A year or two ago, while looking through our product portfolio, I saw we had R290 products available in the European market. Due to Australia’s carbon-neutral initiatives and sustainability goals, I saw the potential market demand for R290 equipment. To put ourselves in a better position to serve the market, I thought we should bring this product to Australia.

When a client approached me with a potential project for R290 chillers, we realized the location in Queensland presented a barrier with the state’s strict hydrocarbon requirements. We took the challenge and decided to get the certification. 

 Can you walk us through the Queensland certification process? What did it involve? 

 RD: It is a comprehensive process to ensure all standards are well met. An accredited third party comes to the factory to inspect and test the equipment. If they find something that does not meet the local standards, they allow you to fix it. For example, we had to replace several critical components compliant with European standards but not accepted in Australia. 

 Once the equipment passes the third-party inspection, they release a final report, which you submit with other engineering details to a certifier who makes the final decision. If you work with a third-party certifier, you will pass the certification. 

 Not every equipment model requires inspection and testing. Once your representative model passes the inspection and test, it applies to all your equipment, though you must guarantee that all models will use the same level of design and detail. 

 What R290 chillers and heat pumps are Johnson Controls making available in Australia? 

 RD: We have five different series lines, which include a standard chiller, producing 6 to 12°C (42.8 to 53.6°F) water for commercial building applications or −2°C (28.4°F) brine for other applications. We also have a water chiller that has an extra coil attached to the condenser to provide free cooling when the ambient air temperature is lower than the water return temperature. Then there is our low-temperature chiller, producing brine down to −14°C (6.8°F) for industrial food and beverage process cooling applications 

For heat pumps, we offer a reversible heat pump and a four-pipe multifunction unit, providing heating and cooling or simultaneous heating and cooling. 

 What type of ammonia equipment is Johnson Controls selling in Australia? 

 RD: We have been promoting ammonia heat pumps over the last few years, and that side of the business is going very strong. In the past two years, we have sold 12 heat pumps in the New Zealand market for food processing applications with temperature outputs varying from 65 to 90°C (149 to 194°F).

TFA is linked to potential health impacts, though the U.S. EPA relies on assurances from NOAA and the Montreal Protocol.
Sonia Saini

Three scientists considered the potential health and environmental risks of HFOs and their trifluoroacetic acid (TFA) degradation product during a panel discussion of PFAS (per- and polyfluoroalkyl substances) at the ATMOsphere (ATMO) America Summit 2024 in Washington, D.C.

The conference, which ran June 10–11, was organized by ATMOsphere, publisher of

The panel discussion, held on June 10, followed a keynote by Robert Bilott, the well-known environmental attorney whose lawsuits over a two-decade period first exposed the environmental and health threat of PFAS. He said that he sees “history repeating itself” in the way the chemical industry is characterizing refrigerants.

The panel agreed with Bilott that the potential hazards associated with refrigerants and TFA are being underplayed, but in a policy discussion on June 11 an Environmental Protection Agency (EPA) representative deferred to a less concerning characterization of TFA by the Montreal Protocol and the National Oceanic and Atmospheric Administration (NOAA).

Known as “forever chemicals” for their persistence in nature, PFAS encompass more than 14,000 synthetic fluorinated chemicals that have been used in a variety of applications, such as nonstick cookware and packaging, stain-resistant clothing and carpets, and firefighting foam. Bilott’s work uncovered links between a common type of PFAS called PFOA (perfluorooctanoic acid) and kidney cancer, testicular cancer, thyroid disease, high cholesterol, pre-eclampsia and ulcerative colitis.

PFOA contains eight carbon atoms, but health issues have been found for shorter chain PFAS such as GenX; concerns are now being directed at the ultra-short chain, two-carbon TFA, considered a PFAS by the scientific community. TFA, which is formed by the breakdown of HFO-1234yf in the atmosphere, is structurally the same as PFOA except with fewer carbon atoms.

TFA, formed by the 100% oxidation of HFO-1234yf in the atmosphere, is well-known to be very persistent and mobile (vPvM), and the German government has linked it to reproductive toxicity. A study of Indiana households states that TFA’s presence in human blood suggests bioaccumulative properties. TFA has been found in drinking water in Europe, also attributed to pesticide breakdown and other sources.

One of the panelists, Mindi Messmer, Senior Research Scientist for MedStar Health and former Member of the New Hampshire House of Representatives, said she saw a parallel between the health findings for PFOA and the potential health effects of TFA. “We are seeing a repeat of the PFOA and the GenX issue with respect to TFA,” she said.

Bilott’s first PFAS client, the West Virginia farmer Wilbur Earl Tennant, complained about the devastating health impact on his cows of what turned out to be PFOA. Messmer noted that  German authorities found “almost identical health effects in rabbits associated with TFA exposure: they saw fetal abnormalities. They saw the same eye defects that Mr. Tennant’s cows had. They see fertility issues, and they see reproductive and child development issues. So it’s history repeating itself again. Do we really want to continue down this road again and in another 40 years understand that we’ve made a huge mistake?”

Ultrashort-chain PFAS like TFA are often cited as not being very bioaccumulative, though in the Indiana study TFA was reported to bind to protein fractions and lipids. “I absolutely think [TFA] could be bioaccumulative,” said Messmer. “I think there’s enough information to show that your body is not going to discriminate between how many [carbon–fluorine] bonds there are, whether it’s a PFOA or a TFA. As long as it has that C–F bond, it appears that the health effects are similar.”

The EPA currently excludes f-gases and TFA from its definition and takes a piecemeal approach to regulating PFAS. Messmer was one of more than 150 PFAS scientists who recently signed a statement calling for a broader definition of PFAS that includes f-gases and TFA and for government agencies to regulate PFAS chemicals as a class rather than one by one. “There is precedent for this; we did do this in 1980s with PCBs [polychlorinated biphenyls],” she said. “So it’s not like it’s an outlandish request.”

By contrast, the chemical industry prefers to carve out certain types of PFAS so that they are not subject to regulation. When Messmer was working on getting her PFAS bills passed in the New Hampshire legislature, she said, “the American Chemistry Council came and told us that these PFAS chemicals are like berries – some are good for you, and some are bad for you – and we really need to limit that definition down, which is an absurd thing to say.” (The American Chemistry Council declined to comment for this article.)

But New Hampshire regulators are not sampling for TFA yet in any water systems, despite the state “[leading] the way in understanding how widespread PFAS was in our water systems.”

The essential-use approach

Another PFAS panelist, Richie Kaur, Non-CO2 Climate Pollution Reduction Advocate, Climate & Energy for the Natural Resources Defense Council (NRDC), recommended the “essential-use approach” to HFOs in applications like residential heat pumps and air conditioners in the U.S. The HFOs would be used only as long as it took for standards groups like ASHRAE and UL, the EPA and building codes to approve higher charge limits for propane (R290) in those applications. R290 heat pump and ACs are already being used in Europe.

“There is a need for getting to sustainable refrigerant alternatives now, and it’s more urgent now than it has ever been because the trade-off shouldn’t be that I get cooling, but then I get exposed to this toxic chemical that’s going to stay in my body forever as that science becomes clearer and clearer,” said Kaur.

However, the transition to non-PFAS refrigerants “is not easy, particularly not for air conditioners and heat pumps, and particularly not here in the U.S.,” she noted.

This is where the essential-use approach comes in, dealing with PFAS as a class and not chasing “one compound after the other until we fully elucidated all the effects over a period of 30 years because we’ll never get there with 14,000 or potentially 7 million compounds,” said Kaur. The essential-use approach would also “expedite the [standards] process and help prevent undue delays.”

The essential-use framework offers a time-limited exemptions for refrigerants that are deemed critical and essential when no other technically or economically feasible alternatives are available. “Except the burden of proof is on the industry, noted Kaur. “It’s not on the government to point out with certainty that something is causing harm. It says we have enough evidence of harm with this class of chemicals that we will put the burden of proof on industry to demonstrate that they can come up with nothing better. It flips the script.” The industry has to prove every five years or so that that exemption should still stand.

Kaur also called for more research, development and deployment of the most sustainable alternatives, “without arguing what the definition of PFAS is or why something should be forever exempted from regulations.” Also critical is training the workforce on how to safely handle flammable refrigerants like propane in heat pumps and ACs. In the U.S. “the one thing that equipment manufacturers are afraid of is the liability risk of propane,” she said.

Kaur pointed out the effort underway by the U.S. Department of Energy regarding the future of refrigerants. “It is talking about looking at the coefficient of performance, analyzing various refrigerant alternatives and figuring out where we need to update the codes and standards and how quickly we can get there,” she said.

A third PFAS panelist, Gabriel Salierno, Green Chemist for the Toxics Use Reduction Institute at the University of Massachusetts, Lowell, explained research he conducted showing that under certain conditions TFA – and another HFO degradation product called TFE (trifluoroacetaldehyde) – can degrade into HFC-23, a potent global warming gas with a 100-year GWP of 14,600 (IPCC, AR6). He also rejected the claim often made by the chemical industry that TFA is naturally occurring. “if anyone tells you that it is naturally occurring, don’t believe them,” he said.

While TFA is extremely stable, “what I found is if we start factoring in some environmental factors such as visible light and some biological process, we can produce HFC-23,” Salierno said. “Actually, if TFA degrades, the product is going to be HFC-23.” On the other hand, TFE – formed from the complete atmospheric breakdown of HFO-1234ze(Z) and HFO-1336mzz(Z) – is very reactive and short lived and can either become TFA, the most likely pathway, or through photolysis generate HFC-23.

Because of the high GWP of HFC-23, it only takes a 1.1% HFO conversion into HFC-23 for the effective GWP of the HFO to jump from around 1 to more than 150, the regulatory threshold for most applications in Europe and the U.S., said Salierno.


Cindy Newberg, EPA
Cindy Newberg, U.S. EPA

In the policy panel discussion at ATMO America on June 11, Cindy Newberg, Director of the Stratospheric Protection Division at the EPA’s Office of Atmospheric Programs, provided an update on the agency’s rollout of the U.S. AIM Act regulating HFCs.

 Asked about concerns regarding HFOs’ transformation into TFA, she said the EPA has worked closely with NOAA, which monitors the chemical for the U.S., and the Montreal Protocol to determine its stance on TFA. “And every assessment I’ve seen from them, and the most recent was the 2022 assessment report, they have basically said this is not of concern from their perspective, though we need to continue to monitor and keep a watch on TFA and bioaccumulation.”

The EPA is open to new information on TFA when it becomes available, Newberg added. “It’s not like we’ve never changed our minds about something. HFCs is a good example. Because we all know, 30 years ago, that’s where we thought everybody was going to go.”

“I think there’s enough information to show that your body is not going to discriminate between how many [carbon–fluorine] bonds there are, whether it’s a PFOA or a TFA. As long as it has that C–F bond, it appears that the health effects are similar.”

Mindi Messmer, Senior Research Scientist for MedStar Health

According to Nikolai Vodolzov, the company’s founder, the heat pump can supply water temperatures up to 90°C.
Sonia Saini

Israel-based HVAC&R contractor Nik Systems has developed a CO2 (R744) heat pump that can provide space heating and hot water simultaneously, the company’s founder, Nikolai Vodolzov, told

The unit is designed for various commercial and industrial applications, including hotels, hospitals, factories and shared buildings, he explained.

The heat pump has a heating capacity of 450kW (128TR) at an ambient temperature of 0°C (32°F) and can supply water temperatures up to 90°C (194°F). It can perform efficiently in a range of conditions, operating reliably in temperatures as low as −5°C (23°F), he added.

The unit is “currently the most economical among heat pumps,” thanks to its dual-circuit design, which consists of an open and closed circuit, he said.

“The combination of these two circuits for different needs [helps] raise the COP to a significant level,” he added.

The heat pump’s open circuit can take an inlet temperature of 10°C (50°F) and raise it to 45–50°C (113–122°F). This can then be heated further to produce hot water for domestic or commercial applications.

In the heat pump’s closed circuit, it can elevate water temperatures from 75°C (167°F) to 90°C, which is ideal for space heating applications like underfloor heating or radiators.

The heat pump includes components from numerous suppliers, including receivers from TECNAC, a heat exchanger from SWEP, Carel controls, Danfoss valves and compressors from Bock, which was acquired by Danfoss in 2023.

Economical efficiency

According to the manufacturer’s financial efficiency analysis, its CO2 heat pump is up to 14 times more economical than alternative heating systems.

It costs €0.09–0.12 ($0.10–0.13) to produce 1W of thermal energy using Nik System’s heat pump, Vodolzov explained. Comparatively, producing the same amount of thermal energy costs €1.30 ($1.41) with a diesel-based system, €0.87 ($0.94) with a gas-based system and €0.38 ($0.41) with a “normal” subcritical CO2 heat pump.

“Transcritical CO2 heat pumps are more efficient in terms of other systems of this type on the market, [with] the production of higher water temperatures [and being] more economical,” he said. “Standard subcritical heat pumps cannot answer most of the needs that exist in the market today, and [their] efficiency is very low.”

“Transcritical CO2 heat pumps are more efficient in terms of other systems of this type on the market, [with] the production of higher water temperatures [and being] more economical.”

Nikolai Vodolzov, Nik Systems

Vodolzov attributes the efficiency of the company’s heat pumps to several elements, in addition to the dual-circuit design. This includes the elimination of an expansion valve, which is traditionally placed at the entrance of the evaporator. Instead, the system uses fans and “other components” to regulate its operation based on ambient temperatures, he explained. This allows for a more dynamic response to changes in conditions, reducing energy consumption and optimizing system performance.

Growing demand

As of February 2024, the manufacturer had installed 50 of its CO2 heat pumps in Israel. The units are operating effectively and reliably in various locations, including places that experience summer and winter extremes, Vodolzov said. has contacted Nik Systems for an update on its installations and additional information about the unit. The company has not yet commented.

The company is seeing a growing demand for its systems, including interest from European companies, he added. To meet this demand, Nik Systems is working to increase production. At present, the manufacturer is able to produce up to five systems per month.

“We are constantly looking for [opportunities to collaborate] with large companies to increase exposure [and market share],” he said.

Nik Systems has been working with transcritical CO2 for around seven years, with a focus on introducing the technology to Israel’s commercial and industrial refrigeration and air-conditioning sectors.

The cascade heat pump system will also lead to an annual reduction of 621 metric tons of CO2e compared to the previous R290 boiler.
Sonia Saini

Japanese OEM Mayekawa is developing an ammonia/pentane (R717/R601) cascade system for heat pumps that will produce steam at 145°C (293°F) for Norwegian prawn producer Stella Polaris.

The new heat pump system utilizes a unique cascade setup that features ammonia and pentane heat pumps. This configuration allows for effective heat recovery from the existing cooling system, which is then used to produce steam for prawn cooking. The Stella Polaris facility, located in Finnsnes, Norway, produces around 15,000 metric tons of frozen, cooked and peeled prawns annually.

“The new heat pump technology aims to reduce the carbon footprint by nearly a quarter compared to the previous propane [R290] boiler system,” said Faraz Neakakhtar, Project Engineer at Mayekawa. “By recovering waste heat that would otherwise be lost to the environment, we can conserve energy and reduce greenhouse gas emissions by 621 metric tons of CO2e/year.”

Currently, Stella Polaris freezes prawns using a system that rejects heat into the sea. To cook them, the facility utilizes a propane boiler system, which consumes about 9,000MWh of energy annually and produces 2,600 metric tons of CO2e per year.

“In addition to the environmental benefits, the expected energy reduction is projected at 1,043MWh, increasing the energy savings of the new system,” Neakakhtar added. “Our project seeks to enhance operational efficiency and drastically reduce the carbon footprint of one of Norway’s key prawn producers.”

Neakakhtar presented Mayekawa’s heat pump project for Stella Polaris at the Norwegian Refrigeration Technical Meeting 2024 (NKM 2024), held April 10–11 in Oslo.

Mayekawa’s heat pump is being developed as part of the SPIRIT-Heat project, funded by the European Union in collaboration with the Netherlands Organization for Applied Scientific Research (TNO) and Mayekawa. The SPIRIT-Heat Project, funded by the European Commission’s Horizon Europe program, focuses on “sustainable heat-upgrade technologies” for industry.

System design

The ammonia cycle is a lower stage in the cascade system and primarily enhances heat recovery efficiency from the freezing plant. In this cycle, the system operates by boosting condenser waste heat from 18°C  to 82°C (64.4 to 179.6°F). This cycle uses a piston compressor from the HS series and a shell and plate-flooded evaporator.

The pentane cycle handles higher temperature demands between 78°C and 150°C (172.4 and 302°F). This cycle is essential for producing 715kW (203.3TR) of heating capacity and generating steam at 145°C (293°F) at 3.2bar (46.4psi), which is directly used in the prawn cookers. A MYCOM screw compressor is used to manage the thermal energy transfer.

“The ammonia/pentane heat pump system has a worst-case combined COP of 1.78 when operating at 18°C/21°C [64.4°F/69.8°F] on the ammonia cascade heat exchanger and 145°C/150°C [293/302°F] on the steam generator heat exchanger [boiler],” said Neakakhtar. “However, if the system runs at a higher source temperature of 22°C/25°C [71.6/77°F] and a lower boiler temperature of 135°C/140°C [275/284°F], the COP can be over 2.”

Next steps

The ammonia/pentane cascade system will be delivered to Stella Polaris at the end of April 2024, with commissioning scheduled between September and October. The operational team will focus on optimizing the compressor and oil systems for high-temperature operations by the end of 2025 alongside conducting testing to ensure the system’s reliability and effectiveness under part-load operations.

“Our system is not only theoretically and technically sound but also proven in operational environments, which is crucial for wider adoption in the industry,” said Neakakhtar. “We are proud to be at the forefront of this change, pushing boundaries of high-temperature lift and using pentane as a refrigerant for different heating processes.”

“Our system is not only theoretically and technically sound but also proven in operational environments, which is crucial for wider adoption in the industry.”

Faraz Neakakhtar, Project Engineer at Mayekawa

The U.S.-based discount food retailer has already specified transcritical CO2 refrigeration as standard for its new stores in California.
Sonia Saini

U.S.-based discount food retailer Grocery Outlet has said it is exploring opportunities to retrofit its existing stores with natural refrigerants and expand its use of CO2 (R744)-based refrigeration in new stores nationwide.

Having already specified transcritical CO2 as standard for its new stores in California, all of the company’s 16 R744-based systems are located in the state, explained Megan Rodriguez, Senior Manager of Refrigeration at Grocery Outlet. Four of the five Grocery Outlet stores using propane (R290) refrigeration technologies are also located in California.

The retailer’s focus on the state has been driven by California Air Resources Board (CARB) regulations that require new stationary refrigeration systems with more than 22.7kg (50lbs) of refrigerant to use refrigerants with a GWP of less than 150. According to a factsheet published by ATMOsphere, publisher of, both CO2 and R290 have a 20-year GWP of one or less.

By the end of 2025, the retailer plans to have a total of 38 stores using transcritical CO2 refrigeration systems, she added.

Rodriguez shared details of the chain’s transition to natural refrigerants during her presentation in the End Users Panel at the ATMOsphere (ATMO) America Summit 2024. The conference took place June 10–11 in Washington, D.C., and was organized by ATMOsphere.

Founded in San Francisco in 1946, Grocery Outlet now has 481 stores across the country. Having opened 81 stores since 2021, the company has been expanding rapidly over recent years. While the majority of its locations are along the west coast, the chain also has stores in Delaware, Maryland, New Jersey and Pennsylvania.

Grocery Outlet stores, which are 12,000–18,000ft2 (1,114–1,672m2) on average, are independently owned and operated. However, the chain decides on store design and purchases, installs and maintains its ownership of equipment such as refrigeration systems, explained Rodriguez.

The benefits of CO2

Grocery Outlet opened its first CO2-based store in 2020 in Sacramento, California. The system consists of a transcritical booster with adiabatic gas cooler, manufactured by OEM Hillphoenix.

For this installation, the company took advantage of financial incentives through the Sacramento Municipal Utility District (SMUD) and the North American Sustainable Refrigeration Council (NASRC). In total, Grocery Outlet received $217,000 (€202,732) in funding for the project: approximately $79,000 (€73,805) came from SMUD’s natural refrigerant incentive fund, $13,000 (€12,145) came from the utility’s energy efficiency incentive fund, and $125,000 (€116,781) came from an American Public Power Association (APPA)’s Demonstration of Energy and Efficiency Developments (DEED) grant.

According to a study conducted by Hillphoenix, the CO2 system reduced energy use by 27% compared to the R404A-based system of a similar Grocery Outlet store nearby. During her presentation, Rodriguez shared results from another Hillphoenix study that saw energy savings of 15% compared to an R448 alternative.

“Our operators pay 100% of their energy bill, so we’re always looking for ways to reduce their energy costs,” she said. To ensure the optimal performance of CO2-based refrigeration systems in warmer climates, the company is currently exploring options for boosting efficiency, she added.

Beyond energy savings and regulatory compliance, the retailer has seen multiple benefits of CO2-based refrigeration compared to traditional HFCs, including lower installation and refrigerant costs.

“Our experience with it has been pretty positive,” Rodriguez said during her presentation. “The [environmental] impact, total cost of operation, installation cost and startup cost for charging the full CO2 system is definitely lower.”

Despite these benefits, the company still has some concerns as it continues to adopt CO2, including higher equipment costs, refrigerant availability and leaks.

“Training is also a concern for us; [however,] we are feeling pretty comfortable [with] expanding our CO2 footprint with the training programs that are [currently] out there,” she explained.

“Our experience with it has been pretty positive. The [environmental] impact, total cost of operation, installation cost and startup cost for charging the full CO2 system is definitely lower.”

Megan Rodriguez, Grocery Outlet

Refrigerant leaks and efficiencies account for one-sixth of a building’s emissions, says DOE’s Deputy Director of Building Technologies.
Sonia Saini

The U.S. Department of Energy (DOE) is inviting HVAC&R industry stakeholders to participate in two working groups ‒ one focused on codes and standards and one on research and development ‒ to support the early, voluntary market introduction of ultra-low GWP refrigerants in various building sectors.

The working groups, announced in April, will set market priorities and draft documents in preparation for future U.S. building code regulations and energy efficiency standards, according to Ram Narayanamurthy, the Deputy Director of the DOE’s Building Technologies Office.

“Between leaks and energy efficiencies, we realized that refrigerants account for about one-sixth of a building’s total emissions,” said Narayanamurthy. “As part of our national blueprint to decarbonize the building sector and cut emissions by 90% by 2050 compared to the 2005 baseline, we want to advance refrigerant technology and adoption, especially for space conditioning.”

Narayanamurthy extended the DOE invitation and outlined the goals and objectives of the working groups during a presentation at the ATMOsphere America Summit 2024, held in Washington D.C. June 10‒11. ATMOsphere is the publisher of

“Between leaks and energy efficiencies, we realized that refrigerants account for about one-sixth of a building’s total emissions.”

Ram Narayanamurthy, DOE’s Deputy Director, Building Technologies Office

DOE objectives

According to Narayanamurthy, the DOE wants input and collaboration from manufacturers, trade associations, utilities, advocacy groups and other industry participants to help define the crossroads between affordable, efficient and safe HVAC, water heating and refrigeration technologies to reduce carbon emissions of buildings in conjunction with electrical grid capacities.

“We want to advance ultra-low GWP refrigeration technology across multiple sectors to reduce emissions,” Narayanamurthy explained. With regulatory efforts outside of the scope of the working groups, the focus instead will be on transforming the refrigeration market, including the technologies and the acceptance of those technologies.

By taking a “holistic approach” ‒ looking at emissions, risk management, maintenance, efficiencies, safety and life cycles of equipment, and the various refrigerant options for residential, commercial and industrial applications, the two groups will provide valuable input for future regulations, Narayanamurthy said. “It’s a voluntary effort, but we are not going to advance without these conversations,” he added.

“As we move to electrify buildings, cars and industries for decarbonization, we need to make our systems more energy efficient, but we need to do so safely and cost-effectively,” he said, noting that the DOE is paying attention to the international market, too, having just awarded $5 million (€4.7 million) to two different projects developing CO2 (R744) heat pump water heaters.

Working group examples

Narayanamurthy provided several working group examples, ranging from the advantages of CO2 (R744) residential water heaters to the development of propane (R290) heat pumps.

Using CO2 refrigerant for water heaters, according to Narayanamurthy, may reduce total installation costs, especially with thermal storage capacity. “Its heat storage potential shrinks the size needed to meet the capacity load, driving power requirements from 240V to 120V,” he said, which has a “huge impact” on installation costs.

From a prioritization standpoint, Narayanamurthy indicated that the DOE was starting with evaluating indirect A3 systems commonly used in Europe. “Basic architecture in the U.S. revolves around direct systems where the refrigerant goes into the built environment,” he said. “However, indirect hydrocarbon air-to-water systems for commercial and residential buildings bring higher efficiencies, but the EPA SNAP [U.S. Environmental Protection Agency’s Significant New Alternatives Policy] limits allowable charges.”

He acknowledged strides made by the Oak Ridge National Laboratory to produce a functioning water heater using less than 114g (4oz) of propane, which meets the SNAP limits. “We are looking for similar small charge A3 systems that fit under the current regulations to get these products in the market.”

Other focuses for the working group that Narayanamurthy mentioned included:

  • Refrigerant costs and training issues, both of which affect the serviceability of the equipment
  • Characterization of refrigerants
  • Developing new heat exchanger designs to reduce hydrocarbon charges
  • Low GWP leak detector sensors
  • Multifunction propane heat pumps
  • High-temperature CO2 heat pumps
  • Heat recovery chillers for hybrid systems for large building electrification
  • Pumped liquid systems using natural refrigerants to replace VRF (variable flow refrigerant)
  • Codes and standard issues related to ammonia (R717), CO2 and hydrocarbon refrigerants

“We are collaborating with state agencies, so we can take all these advancements in ultra-low GWP refrigerants and move the technology into the market,” Narayanamurthy said.

He said professionals in the sector should contact him if they are interested in participating in a working group or for more information. “We want to take this journey with everyone in this room,” Narayanamurthy added, inviting key stakeholders to join the working groups to help hasten this transition.

“Working together, we can increase a building’s efficiency and reduce its emissions with ultra-low GWP refrigerants to meet our decarbonization goals,” he concluded.

In past year, the DOE has announced several programs and grants to facilitate ultra-low GWP equipment production and installation in the U.S., including $63 million (€58.5 million) to accelerate domestic production of residential heat pumps and heat pump water heaters, a grant to support a $2.5 million (€2.3 million) research project by Copeland to develop propane-based HVAC systems, and a rooftop heat pump accelerator program with implementation and evaluation by commercial end users, including Amazon, IKEA and Target.

“Working together, we can increase a building’s efficiency and reduce its emissions with ultra-low GWP refrigerants.”

Ram Narayanamurthy, DOE’s Deputy Director, Building Technologies Office

“We’re hearing the same arguments – that there’s not sufficient science to say we should regulate this,” he said in his keynote.
Sonia Saini

Robert Bilott, the award-winning and widely profiled environmental attorney whose lawsuits over a two-decade period first exposed the environmental and health threat of PFAS (per- and polyfluoroalkyl substances), sees “history repeating itself” in the way the chemical industry is characterizing refrigerants.

Bilott told the story of his involvement in the PFAS issue – and provided lessons that could be applied to the refrigerants issue – in a keynote speech on June 10 at the ATMOsphere (ATMO) America Summit 2024 on natural refrigerant-based HVAC&R in Washington, D.C. He received a standing ovation at the end of his keynote from the more than 350 attendees. The conference, held June 10–11, was organized by ATMOsphere, publisher of

Known as “forever chemicals” for their persistence in nature, PFAS encompass more than 14,000 synthetic fluorinated chemicals that have been used in a variety of applications, such as non-stick cookware and packaging, stain-resistant clothing and carpets, and firefighting foam. Bilott, whose work was the basis for the 2019 film Dark Waters and the 2018 documentary The Devil We Know, revealed the carcinogenic and other health impacts of two prevalent PFAS called PFOA (perfluorooctanoic acid) and PFOS (perfluorooctanesulfonic acid), which contain eight carbon atoms (known as C8s). Moreover, he learned that DuPont and 3M, the manufacturers of the chemicals, did not disclose their internal findings that these chemicals caused harm to laboratory animals and their own employees and publicly said that they were harmless.

“I think what we’ve learned here is we’re seeing this whole story repeat itself,” said Bilott. “We’re hearing the same arguments we heard on C8s 20 to 30 years ago – that there’s not sufficient science to say we should regulate this.”

According to the scientifically supported definition developed by the Organisation for Economic Co-operation and Development (OECD), PFAS also includes many “ultrashort-chain” two- and three-carbon HFO and HFC gases, some of which degrade into another two-carbon PFAS, trifluoroacetic acid (TFA), in the atmosphere; notably, HFO-1234yf degrades completely into TFA over the course of a few weeks. TFA, which is in the same chemical family as PFOA, descends in rainwater and infiltrates the environment and has been found in human blood. (There are other sources of TFA, such as the breakdown of pesticides and pharmaceuticals, and industrial waste.)

While Europe is in the process of considering regulations of f-gases and TFA as PFAS, the U.S. Environmental Protection Agency (EPA) and some U.S. states have decided to use a definition of PFAS that excludes f-gases and TFA. In response, more than 150 scientists recently signed a statement supporting a definition (such as OECD’s) that says PFAS contains “at least one fully fluorinated carbon atom” and includes f-gases and TFA.

Bilott noted the effort to define PFAS in a way that excludes ultrashort-chain chemicals. “Things are being removed from the definition – anything that’s got less than a certain number of carbons. So the public is seeing this thinking, ‘Oh, there’s no PFAS in it.’ It’s simply a different definition.” He also cautioned to be cognizant of the detection levels that are established for various PFAS. “As we’ve all learned, those detection levels change over time. And they get a lot more sensitive.”

The chemical industry has downplayed the connection between PFAS and f-gases/TFA. For example, the Sustainable PFAS Action Network (SPAN), which represents chemical industry interests, says that low-GWP refrigerants such as HFOs “do not show the three characters of greatest concern regarding PFAS, as they are not persistent, bioaccumulative, and toxic” according to a statement on its website. However, HFO degradation product TFA is well-known to be very persistent and mobile (vPvM), and the German government has linked it to reproductive toxicity. A study of Indiana households states that TFA’s presence in human blood suggests bioaccumulative properties. (A SPAN representative did not immediately respond to a request for comment on Bilott’s remarks.)

Chuck Allgood, Technical Fellow at U.S. HFO manufacturer Chemours, called TFA a “naturally occurring substance” with 95–99% of it “found in low levels throughout the Earth that has been there for hundreds of years, well before the industrial age” on May 1 at a University of Maryland (UMD) workshop called “Ultra-Low GWP Refrigerants for Refrigeration, Water Heating, and HVAC Applications,” sponsored by UMD, Oak Ridge National Laboratory, the U.S. Department of Energy and Guidehouse. However, Canadian researchers have determined that there are “no compelling scientific arguments” to support the existence of naturally formed TFA.

The contention that TFA is naturally occurring parallels a claim made by 3M-supported studies in the 1970s when human blood data was showing evidence of organic fluorine chemicals, which contain a carbon-fluorine bond like PFAS. “3M actually published studies, or had people print published studies, to try to suggest there were natural sources, when there was no evidence of any natural source for this organic fluorine,” said Bilott.

The chemical companies continued to influence the publication of studies on this topic. In 2004, Bilott said, all of the published peer-reviewed literature “had been essentially seeded by the companies to say, ‘No harm, there’s no problem here.’”

Poisoned cows

Bilott’s journey battling PFAS began in 1998 when he was approached by West Virginia farmer Wilbur Earl Tennant, who was convinced that a creek on his property had been poisoned by runoff from a nearby DuPont landfill, causing the death of many of his cows. That landfill proved to be a dumping site for PFOA.

The farmer’s case revealed that DuPont had covered up evidence that PFAS was harmful, leading to a class-action suit and penalties from the EPA. In a 2004 settlement of the class-action suit, DuPont agreed to pay $70 million (€64.8 million), which was used as an incentive to get nearly 70,000 West Virginians to provide blood samples that scientists could use to study the health effects of PFAS.

In December 2011, the scientists began to release their findings: there was a “probable link” between PFOA and kidney cancer, testicular cancer, thyroid disease, high cholesterol, pre-eclampsia and ulcerative colitis. This sparked more than 3,500 lawsuits, and DuPont ultimately agreed to pay $750 million (€701 million) to settle those suits. (In 2015, DuPont spun off its fluorinated chemicals business to a new independent company, Chemours.)

Finally in April of this year, a quarter-century since Bilott began exposing PFAS, the EPA issued stringent drinking water regulations for six PFAS, including 4ppt limits for PFOA and PFOS. His firm is continuing to represent more than a dozen states and hundreds of water suppliers in the latest lawsuits seeking millions of dollars to remove PFAS from the water supply.

In his 2019 book, Exposure, Bilott wrote about the ongoing questions about other PFAS chemicals: “There was growing awareness that the entire class of PFAS chemicals – as many as four thousand related compounds – might be a problem, including the newer replacement chemicals (like GenX) that were being billed as less persistent than PFOA and PFOS. Their structural similarity and some evidence from animal studies suggested they could be toxic or carcinogenic but we were hearing the same familiar argument that nobody had done the extensive science required to reach a firm and actionable conclusion on the human impact of these additional PFAS chemicals.”

Bilott echoed those thoughts in his ATMO America keynote: “This campaign [has begun] in the U.S. and overseas by the [chemical] makers to say there’s no evidence that they’re harmful, there’s no evidence yet that any of these cause any problem and they should be carved out from any attempts to regulate this stuff.”

Society needs to “learn from what we already know about the C8 debacle here,” he said. “Look how long it took us to get to the point where despite all of these internal studies that had been covered up for decades, and all the public representations that there’s no evidence of any harm, we finally learned the truth.”

The chemical industry, Bilott noted, has argued that regulating PFAS as a class that includes ultrashort-chain chemicals “is going to devastate the economy since thousands of jobs depend on these new related chemicals. And they’re instrumental in the transition to the green economy.” However, he noted, studies have shown that the impact of PFAS equates to tens of billions of dollars in health care costs and six million deaths. “Staggering, right?” he said.

An alternative would be to adopt the “precautionary approach – prevent the harm before it happens, not wait till people get sick and die,” he said.

Chemical interests also argue that there are no alternatives to PFAS refrigerants, but, he likened this to the contention about PFOA and PFOS, for which “there were plenty of alternatives that were quickly found and switched to when these were phased out.” Natural refrigerants, including CO2 (R744), propane (R290), isobutane (R600a) and ammonia (R717), are widely used throughout the world in virtually every HVAC&R application.

Bilott believes “it’s critically important” to find ways to present information on the environmental growth and health impacts of ultrashort-chain PFAS to government agencies like the EPA. “The EPA was completely misled for decades, and it took a long time for them to realize that, ‘wait a minute, [chemical companies] withheld information from us.’ So it’s incredibly important to find a way to get that information to the agencies presented in a way that it can be understood.”

What’s also important is “making sure the public understands what’s happening,” said Bilott. “We can’t just assume that if we provide the science and information to the government agencies, they will take care of it all. No, there needs to be public engagement in this. And that’s what prompts the change. That’s what gets the agencies to respond and to take action.”

“This campaign [has begun] in the U.S. and overseas by the [chemical] makers to say there’s no evidence that they’re harmful, there’s no evidence yet that any of these cause any problem and they should be carved out from any attempts to regulate this stuff.”

Robert Bilott

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