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The ATMO Approved label is a global gold standard highlighting best-in-class manufacturers and contractors of natural refrigerant systems and components.

Why It Matters

Sonia Saini

ATMOsphere, a global market accelerator of clean cooling and heating solutions and publisher of NaturalRefrigerants.com, has approved the ATMO Approved Natural Refrigerants Label for Equans Kältetechnik, an Austrian refrigeration contractor.

ATMOsphere (formerly shecco) launched the label in June 2022 as a global gold standard highlighting best-in-class manufacturers of natural refrigerant systems and components around the world. Labels were also approved in 2023 for SCM Frigo, M&M Carnot, Zudek, MIRAI Intex, Novum and Temprite. In 2024, GTS, Nihon Netsugen Systems, Refra and Zero-C have been approved, Fenagy has been reapproved, and Secon, Güntner, TEKO and M&M Carnot have been reapproved for the second time.

In November 2023, ATMOsphere opened label registration for 2024 with a new category for contractors and installers who accelerate the adoption of natural refrigerant-based cooling and heating solutions. In addition to Equans Kältetechnik, contractors SURE Solutions and General Refrigeration have been approved for the label.

“Since we know about the consequences of f-gases or HFO refrigerants (GWP, PFAS) we made a clear strategic decision to focus on natural refrigerants only in order to contribute to society for the next generations to come,” said Philipp Baumgartner, Managing Director for Equans Kältetechnik. “It is therefore a big honor for us to get the ATMO Approved Label as this qualifies us among the industry leaders that have real impact in the market with natural refrigerant systems and gives a clear signal to the market where we see the future of our organization. We will therefore do our best to do justice to this award and to further advance natural refrigerant technologies for the benefit of all of us.”

The ATMOsphere label is designed to help qualified manufacturers to market products to new customers and regions in the natural refrigerants marketplace, including products using CO2 (R744) and ammonia (R717). In addition, the label is meant to help end users identify best-in-class suppliers.

Once approved, companies can place the ATMOsphere Natural Refrigerant Label in a myriad of places, such as directly on products, marketing material, email signatures, company pitches and trade show booths.

“The label will be very visible in the global marketplace, and companies can take advantage of this to strengthen their brand,” noted Marc Chasserot, ATMOsphere Founder and CEO.

“By being global and multi-application, this label can help to create trust across the new applications and regions,” added Chasserot. “We want to use this multi-year label process to help move the market to cleaner solutions with natural refrigerant solutions over time.”

Based in Lauterach, Austria, Equans Kältetechnik is part of Equans (a subsidiary of the Bouygues group), which also supports customers in electric, HVAC, mechanics and robotics, digital and IT, and facility management. Equans operates in key European markets (notably Austria, France, Belgium, Luxembourg, the Netherlands and the U.K.) and is also positioned in the U.S. and Latin America.

Equans Kältetechnik offers tailor-made refrigeration for industrial or commercial applications, including energy performance contracts, predictive maintenance and carbon-capture installations. It uses natural refrigerants and complies with applicable legislation. Its work focuses on the following sectors: the food industry, retail (shopping centers), the biotechnology and pharmaceutical industry, logistics, defense/marine and petrochemicals/gas production.

While Equans Kältetechnik has changed its name several times since its beginning 77 years ago, “we have always had a strong focus on ammonia because of its outstanding efficiency and sustainability,” noted Baumgartner. “To be able to offer our customers also solutions in the smaller capacity range, we extended our portfolio with hydrocarbons and CO2.”

Three pillars

To qualify for an ATMOsphere label, manufacturers have to demonstrate excellence across three pillars:

1) company vision;

2) customer satisfaction (measured via testimonials from multiple end users confirming the reliability, performance and service of these companies and products); and

3) measurable impact.

New criteria

The 2024 label also includes training criteria for the first time for new applications and renewals. “We want to recognize a proactive approach to training customers, partners, employees and suppliers to ensure we not only have the best-in-class equipment but the best-in-class installation and maintenance of these systems,” Chasserot said.

Another 2024 label criterion centers around per- and polyfluoroalkyl substances (PFAS), such as trifluoroacetic acid (TFA).

Recent research found significant levels of TFA – formed by the atmospheric breakdown of certain HFO and HFC refrigerants – in dust, drinking water and human blood in a study of households in Indiana (U.S.). The study characterized TFA as being part of the PFAS chemical family. TFA and TFE, another PFAS linked to HFOs, have pathways to forming HFC-23, a super potent greenhouse gas (GWP 14,600).

“The 2024 label criteria around PFAS acknowledges what companies are doing to ensure they are PFAS-free,” Chasserot said.

“ATMO Approved companies have the vision and leadership required to navigate the market today and help [companies] move away from PFAS and global-warming synthetic alternatives,” an ATMOsphere YouTube video says.

Additional new benefits added to the 2024 ATMO label include:

  • an annual report for environmental, social and governance (ESG) investors;
  • end-user tours at major trade shows to meet approved companies;
  • exclusive webinar targeting end users, consultants and contractors; and
  • end-user case studies, showcasing best practices.

ATMOsphere has been active in the natural refrigerant space for nearly 20 years. During this time, the company has:

  • published dozens of natural refrigerant-related market reports on market players, technologies and solutions worldwide across multiple applications;
  • hosted over 60 international natural refrigerant conferences, bringing together thousands of experts and hundreds of speakers over nearly 15 years, covering all the latest trends and players;
  • written thousands of articles reporting on natural refrigerant companies and products in the industry; and
  • sent representatives to hundreds of trade shows around the world, meeting with natural refrigerant experts face-to-face (in addition to countless individual meetings outside official events).

“We feel that, as an independent player with a global mindset and a global presence across all natural refrigerants and multiple applications, we are very well suited to provide this level of approval for the label,” explained Chasserot.

“Since we know about the consequences of f-gases or HFO refrigerants (GWP, PFAS) we made a clear strategic decision to focus on natural refrigerants only in order to contribute to society for the next generations to come.”

Philipp Baumgartner, Managing Director for Equans Kältetechnik

Technical Manager Dimitrios Dalavouras spoke with NaturalRefrigerants.com about Greece’s booming R744 market at Climatherm Energy.

Why It Matters

Sonia Saini

Reversible propane (R290) heat pumps filled the show floor at the 2024 Climatherm Energy HVAC&R trade show in Athens, Greece. So local contractor General Refrigeration looked a bit out of place as one of the few exhibitors showcasing CO2 (R744)-based refrigeration technologies.

Of course, General Refrigeration didn’t see it that way. While there have been some CO2 installations in Greece to date, the technology has not been widely adopted across the southern Mediterranean region due to its reputation for being inefficient at higher ambient temperatures. However, according to Dimitrios Dalavouras, Technical Manager at General Refrigeration, this is no longer the case.

“There was a reputation that CO2 can’t work in warm climates, but the technology is there, [and] CO2 can work everywhere,” he told Marc Chasserot, CEO and Co-Founder of ATMOsphere, publisher of NaturalRefrigerants.com, during an interview at Climatherm.

In addition to the majority of new and retrofitted supermarkets now opting for centralized CO2 systems, R744 is also becoming more commonplace in smaller industrial applications in Greece, he explained.

“It’s taking market share,” he added.

To support the adoption of CO2 and other natural refrigerants in the Greek HVAC&R market, General Refrigeration is partnering with the Hellenic Federation of Refrigeration, the Hellenic Confederation of Professionals, Craftsmen and Merchants and the National Technical University of Athens to develop a standardized training program for technicians.

In recognition of General Refrigeration’s ongoing commitment to natural refrigerants, it became the second contractor to receive the ATMO Approved Natural Refrigerants Label in January 2024.

You can learn more about General Refrigeration, its training program and the current natural refrigerant trends in Greece in this exclusive interview from Climatherm.

The German manufacturer’s air-source Vitocal 250-A Pro unit, designed for modernization, provides 70°C flow temperatures.

Why It Matters

Sonia Saini

The Vitocal 250-A Pro air-source propane (R290) commercial heat pump, manufactured by German OEM Viessmann Climate Solutions, has won a 2024 gold iF Design Award for setting “a new aesthetic benchmark in the product category of large heat pumps.”

“Despite having an architectural quality, it is not over-designed,” said the iF Design Award jury. “By using a natural refrigerant, this heat pump reduces its environmental footprint compared to models that use synthetic refrigerants, [making it] a worthy winner!”

Viessmann released the Vitocal 250-A Pro heat pump in the spring of 2023, replacing a previous model that used F-gas refrigerants.

Established by iF Design in 1954, the annual iF Design Award recognizes concepts, products and projects in nine disciplines. The 2024 contest had a record 10,800 submissions from 72 countries, which were evaluated by a jury of 132 design experts from 23 countries. Only 75 submissions were awarded gold.

Viessmann was the sole heat pump manufacturer to win gold in the Product and Building Technology categories. Several companies were awarded gold in the Product category, including Apple, Kia and Fujifilm, while only three received gold in the Building Technology group.

Awards will be presented to the winners on April 29 at the Friedrichsstadt-Palast in Berlin.

Viessmann Climate Solutions previously won a gold iF Design Award in 2021 for its R290 Vitocal 25x-A residential heat pump.

“By using a natural refrigerant, this heat pump reduces its environmental footprint compared to models that use synthetic refrigerants, [making it] a worthy winner!”

iF Design Award JJry

For modernization projects

According to Viessmann, the Vitocal 250-A Pro system is developed for modernization projects and can use existing radiators with or without underfloor heating. According to the company, the heat pump can be installed in commercial buildings, multi-family buildings and smaller non-residential buildings.

The unit provides 70°C (158°F) flow temperatures in ambient temperatures down to −10°C (14°F), with a rated heating output from 2.6 to 13.4kW (0.8 to 3.8TR).

“[It] makes particularly efficient use of environmental energy for heating and cooling, with a COP of up to 5.3,” the manufacturer says. “The integrated management system ensures transparency in energy consumption and cost.”

The monobloc design requires 60% less space than comparable models, with the “whisper-quiet” operation allowing placement anywhere on the property, Viessmann says.

Florida-based OEM Carrier Global Corporation announced it was acquiring Viessmann Climate Solutions for €12 billion ($12.7 billion) from the Viessmann Group in April 2023. The deal was finalized in December after receiving regulatory approval from the European Commission.

“[It] makes particularly efficient use of environmental energy for heating and cooling, with a COP of up to 5.3.”


Other award-winning designs

The 2023 Red Dot Awards, an annual international design competition put on by Red Dot since 1992, featured four R290 monoblock heat pump awardees:

  • The A-series heating system, an air-source heat pump water heated manufactured by China-based GD Midea Heating & Ventilating Equipment, has “a characteristic design language” that ensures a “uniform appearance in the house,” according to the Red Dot jury.
  • The Dotels Window Blinds Design Heat Pump “harmonizes excellently with contemporary building architecture due to its functional design language,” said the Red Dot jury. China-based GZ Dotels Electric Appliances, a partner company of China-based Axen, manufactures the unit.
  • The Hellas R290 heat pump series, manufactured by China-based Guangdong Warmhouse Technology, uses a vertical grille to conceal the operating fan and other internal components. “The series impresses with its modern straightforwardness where form and function go hand in hand,” the Red Dot jury said.
  • The Volcanic Plus air-source heat pump, also manufactured by Guangdong Warmhouse Technology, “derives its appeal from the juxtaposition of textured and smooth surfaces complemented by color accents,” according to the jury.

The U.K.-based 2022 Build It Awards recognized Swedish manufacturer NIBE for its propane air-to-water S2125 heat pump, awarding it Best Heating System or Product. According to the manufacturer, the unit can supply water temperatures of up to 75°C, with up to 65°C (149°F) in ambient temperatures down to −25°C (−13°F).

The new TOS-Series operates in maximum working pressures up to 1,885psi.

Why It Matters

Sonia Saini

U.S.-based Westermeyer Industries, a designer and manufacturer of HVAC&R components, has introduced a new centrifugal oil separator, dubbed the TOS-Series, for transcritical CO2 (R744) systems with maximum working pressures up to 1,885psi (130bar).

According to the company, the “first-of-its kind” oil separator is an update to the “tried-and-true design” of stripping oil from refrigerants using centrifugal motion. Gary Westermeyer, Founder and President of Westermeyer Industries, helped develop the centrifugal oil separation technology.

The company is “wrapping up” provisional patent details on the technology, Adam Chapman, Sales Manager at Westermeyer Industries, told NaturalRefrigerants.com.

“Our TOS-series [will] help to meet [growing market] needs by providing efficient performance and cost-effective installation and service,” said Chapman.

The higher operating pressures and temperatures required by transcritical CO2 refrigeration make oil separation more challenging than synthetic systems due to the smaller density difference between the refrigerant and the compressor oil.

“[We] hope that the addition of centrifugal oil separators in the CO2 space will make way for further progress and product innovation in CO2 refrigeration,” Chapman said.

According to ATMOsphere’s 2023 Natural Refrigerants: State of the Industry report, there has been “robust growth” in commercial and industrial transcritical CO2 systems installed in Europe, Japan and North America. ATMOsphere is the publisher of NaturalRefrigerants.com.

Different design, similar idea

French HVAC&R component manufacturer Carly has a similar product on the market, its TURBOIL-R-P14 oil separator, for subcritical and transcritical CO2 applications, with working pressures up to 2,030psi (140bar). The manufacturer finalized the technical documentation of the design last November.

The patented TURBOIL system separates oil and refrigerant by simultaneously using “breaking speed, change of direction, centrifugation and coalescence,” Carly says.

Carly claims up to a 99.5% oil separation efficiency and recommends using TURBOIL-R-P14 for low-temperature CO2 applications.

During an appearance on the HVACRadio podcast in 2021, Chapman remarked that coalescence separators are “bulletproof with regard to oil separation” as long as they are sized correctly to the system cooling load. He added that the coalescence separator has a higher pressure drop than a centrifugal one and requires a filter.

Founded in 2001, Westermeyer Industries manufactures refrigeration system components in its 100,000ft2 (9,290m2) facility in Bluffs, Illinois, with products installed globally.

The Tequs heat pump is available in eight different models and can provide domestic hot water and space heating and cooling.

Why It Matters

Sonia Saini

Norwegian heat pump manufacturer Tequs has launched a CO2 (R744) plug-and-play water-to-water heat pump for the European market that can provide domestic hot water, space heating and cooling for a variety of applications.

The TCHP heat pump is available in eight models and offers a heating capacity ranging from 17.4–268kW (4.9–76.2TR) and a cooling capacity of 13.5–210kW (3.8–59.7TR). It can provide hot water temperatures up to 90°C (194°F) and has a heating COP of 2.5–5.5 and a cooling COP of 2–5, with the COP level varying depending on the model chosen. 

Tequs says its CO2 heat pump can serve multiple applications, including heating swimming pools, cooling servers in data centers and providing space heating and cooling in multi-family residential buildings. The company has said its heat pump can be installed by “all competent professionals,” including plumbers, ventilation specialists and refrigeration installers.

Tequs says CO2 was chosen because it is an “ideal refrigerant for heat pumps where high temperatures are needed.” While CO2 heat pumps can heat water to higher temperatures more efficiently than propane (R290) heat pumps, they lose efficiency when the return water temperature exceeds 30°C (86°F). Tequs says it has engineered its heat pump to be able to accept return temperatures up to 50°C (122°F).

Tequs originally announced its CO2 heat pump in 2022.

Scaling plans

NaturalRefrigerants.com spoke with Tequs CEO Joakim Søgård, CTO Marius Hugo Sandem and CIO Kenneth Grande about the new heat pump during the Norwegian Refrigeration Meeting 2024, held April 10 and 11 in Oslo.

Søgård told NaturalRefrigerants.com that Tequs is preparing to enter a massive growth phase, which will be powered by new partnerships. 

“We recently formed a consortium with five strategic partners [Hafslund, Eviny,  Kongsberg Innovation, Startuplab, Venture Momentum Partners] that have significantly contributed to our equity and resources, enabling us to integrate the units into our production line and take a hands-on approach during the initial delivery phase,” said Søgård. “This proactive involvement allows us to tailor our strategies to meet project demands and customer needs effectively, ensuring high-quality outcomes as we prepare for broader scaling.”

Søgård, Sandem and Grande spoke with NaturalRefrigerants.com about their scaling plan along with the unique design of the Tequs TCHP series. This interview has been edited for length and clarity.

The TCHP series provides domestic hot water and space heating and cooling. What challenges did you face in designing a heat pump with all three capabilities?

Marius Hugo Sandem: One of the primary challenges in developing our heat pump has been achieving a compact design while ensuring stable operation. This is crucial as the system needs to adapt to various applications. Careful selection of components, particularly heat exchangers, is essential. Finding suitable controllers has also been a significant hurdle as standard options do not meet our specific requirements.

How does the Tequs CO2 heat pump achieve such high COPs?

M.S.: Our CO2 plug-and-play heat pump achieves high energy efficiency through advanced components and precise engineering calculations. An essential feature is the ejector, which increases the suction pressure to enhance the system’s thermodynamic efficiency. This reduces energy consumption while maintaining adequate performance.

With plans to expand beyond Norway into the European market, what steps are you taking to ensure the heat pump meets diverse regional standards and demands?

Joakim Søgård: For each new market we enter, we initiate pilot projects and consult with experts to ensure compliance with all local standards. We prioritize closely monitoring the initial installations, effectively “sleeping next to the machine,” to ensure that everything from commissioning to the default installation processes meets the highest quality standards. We are focused on delivering high-quality projects rather than immediate profit in these early stages.

Italian OEM Rivacold is your manufacturing partner. What were the key factors in choosing Rivacold to build the TCHP series, and how has this partnership influenced the design and production process?

J.S.: We recognized the need for a partner capable of high-quality production and large-scale output to meet market demand and sought a manufacturer that could deliver large volumes and maintain exceptionally high standards. After extensive research, Rivacold offered the best combination of robust production capabilities and stringent quality control procedures.

What does your scaling plan look like?

J.S.: We are focused on successfully delivering our initial projects this year, with some scheduled before summer, across various applications. We aim to evaluate how these projects perform within Europe, especially as we introduce a few units for retrofit gas projects in the European market. We plan to scale up our operations gradually, and are cautious about expanding too quickly. We aim to maintain control over every aspect, from performance to long-term reliability. To ensure quality, we have partnered exclusively with highly reputable and skilled contractors.

What training or support does Tequs provide for installers and end users to ensure successful deployment and operation?

Kenneth Grande: We support new customers by inviting them to join us during commissioning. Additionally, we are developing a training program where customers can visit our Oslo, Norway, facilities to receive training on commissioning and service. We commit to assisting with or directly handling the first commissioning for the Norwegian and broader European markets to guarantee a successful start.

“We are focused on delivering high-quality projects rather than immediate profit in these early stages.”

Joakim Søgård, Tequs CEO

Why It Matters

Sonia Saini

Tesco, the U.K.’s largest supermarket chain, has taken delivery of two refrigerated trucks that use propylene (R1270)/CO2 (R744) refrigeration units from German manufacturer ECOOLTEC, becoming the first company in the country to adopt the technology.

According to a statement from ECOOLTEC, its electric TM182 unit is “unique” in the heavy-duty commercial transportation sector and offers zero-emission refrigeration when operated in battery mode.

“While the phase out of f-gases within the EU is a given fact, we also notice outside the EU that industries are increasingly looking for ways to reduce their carbon footprint,” ECOOLTEC CEO Henning Altebäumer told NaturalRefrigerants.com. “We offer a solution for the missing link of the F-gas-free cold chain: Our ECOOLTEC TM182 is perfect to meet these sustainability goals.”

“As we look to decarbonize our transport, using lower-impact refrigeration will play an important role in our efforts to become net zero by 2035,” said Cliff Smith, Fleet Engineering Manager at Tesco.

“We offer a solution for the missing link of the F-gas-free cold chain.”

Henning Altebäumer, CEO of ECOOLTEC

The bodywork of the two new 18-ton trucks was designed by ECOOLTEC in partnership with Gray & Adams, a British manufacturer of specialist temperature-controlled vehicles. The multi-temperature box body can be divided into two compartments with a moveable transverse bulkhead system. This allows for the simultaneous transportation of chilled and frozen products between Tesco’s cold storage warehouse in Peterborough and its surrounding stores.

“Gray & Adams is delighted to be able to once again support Tesco in their mission to reduce the carbon footprint across their distribution fleet,” said Ryan Mazgaj, Sales Manager at Gray & Adams.

Installed on the roof, ECOOLTEC’s TM182 unit houses the low-charge propylene circuit, which is hermetically sealed to maximize operational safety. This connects to the secondary CO2 refrigeration circuit that serves the system’s evaporators via a brazed plate heat exchanger.

Cold air from the TM182 unit is distributed by a single ECOOLTEC E1221 evaporator in the truck’s front compartment and a double ECOOLTEC E1312 evaporator in the second compartment.

Henning Altebäumer, ECOOLTEC (left), and Cliff Smith, Tesco. (Source: ECOOLTEC)
Henning Altebäumer, ECOOLTEC (left), and Cliff Smith, Tesco. (Source: ECOOLTEC)

Reduced direct emissions

ECOOLTEC’s TM182 transportation refrigeration unit is fully electric and can be powered via the manufacturer’s G30 alternator, which is mounted to the truck engine, or charged via a wall outlet.

In battery mode, the unit does not produce any direct emissions, and when powered by the alternator, it produces 98% fewer emissions than a diesel-powered refrigeration system, according to the manufacturer. These emissions savings are due, in part, to the unit’s efficiency, which requires 60–80% less energy than conventional diesel powered systems of the same capacity.

With negligible GWPs compared to the HFCs commonly used in transport refrigeration, the TM182’s refrigerants – CO2 and propylene – also have a minimal climate impact in the event of a leak. Per ECOOLTEC, the refrigerant leakage rate for transport refrigeration systems can be as high as 30% due to many not having fully hermetic refrigerant circuits.

As HFCs can have a GWP hundreds or thousands of times higher than CO2, a leak can result in the emission of multiple tons of CO2 equivalent per year per unit.

“The total refrigerant charge in typical systems for heavy-duty commercial vehicles is up to 14kg [30.9lbs], depending on the exact specification,” explained ECOOLTEC. “In this case, an average of around 4.2kg [9.3lbs] of f-gases per vehicle is released into the atmosphere every year. Depending on the refrigerant, this corresponds to a CO2 equivalent of around 9 tons per year and per unit.”

In contrast, if 1kg (2.2lbs) of propylene leaks, less than 1kg of CO2 equivalent is released into the atmosphere.

“Furthermore, HFC-based refrigerants belong to so-called perpetual chemicals,” the manufacturer added. “When they are released into the atmosphere, they are also responsible for the formation of environmentally harmful substances such as [per- and polyfluorinated Substances](PFAS).”

ECOOLTEC first launched its TM182 unit in August 2022 and began rolling out the product in April 2023. The TM182 was named Innovation of the Year/Refrigeration at the European ATMO Awards 2023.

An ongoing transition

As noted in its “Climate Change and Energy Factsheet,” Tesco is gradually transitioning to natural refrigerant-based systems as its existing equipment reaches its end-of-life, with a plan to phase out all HFCs by 2035. During the 2022/23 financial year, Tesco invested £60 million (€70.1 million/$74.6 million) into decarbonizing its refrigeration systems – with a focus on CO2-based technologies – as well as electrifying its online delivery fleet.

Beyond its refrigerated transport, Tesco has installed transcritical CO2 systems at around 1,000 of its stores – roughly one-third of its locations – as of October 2022. Beginning in the early 2000s, the company worked with Scottish OEM Star Refrigeration to transition its four R22-based distribution centers to ammonia (R717).

Atmospheric HFO degradation products TFA and TFE, the study says, have pathways to generating HFC-23, which has a GWP of 14,600.

Why It Matters

Sonia Saini

A new study points to a link between the long-term fate of HFO degradation products in the atmosphere and the formation of HFC-23, a potent global warming gas with a 100-year GWP of 14,600 (IPCC, AR6).

The study – “On the Chemical Pathways Influencing the Effective Global Warming Potential of Commercial Hydrofluoroolefin Gases” – was published April 4 in the journal ChemSusChem. Its author is Gabriel Salierno, a Green Chemist at the Toxics Use Reduction Institute at the University of Massachusetts/Lowell.

Widely used HFOs such as HFO-1234yf and HFO-1234ze(E) have a very low GWP (less than 1), and HFO-1336mzz(Z) has a GWP of 2; but if their atmospheric degradation products ultimately produce HFC-23, their effective GWP would be much higher, the study explains. These degradation products include trifluoroacetic acid (TFA), trifluoroacetaldehyde (TFE) and trifluoroacetyl fluoride (TFF), all considered per- and polyfluoroalkyl substances (PFAS), or “forever chemicals,” under a generally accepted definition set by the Organisation for Economic Co-operation and Development (OECD).

TFA results from the total atmospheric decomposition of HFO-1234yf and other f-gases and is known to be captured in the atmosphere by rainwater, which distributes it throughout the environment with possible health impacts. TFE is formed from the complete atmospheric breakdown of HFO-1234ze(Z) and HFO-1336mzz(Z). (TFF is rapidly transformed into TFA via hydrolysis.) “Although the atmospheric reaction networks of TFE, TFF, and TFA have a fair level of complexity, the relevant atmospheric chemical pathways are well characterized in the literature, enabling a comprehensive hazard assessment of HFC-23 formation as a secondary HFO breakdown product in diverse scenarios,” the study said.

Given the link to HFC-23 formation, a “lower bound” of the “effective [100-year] GWP” of HFOs would be above regulatory thresholds, which in Europe and the U.S. is 150. “While further research is crucial to refine climate risk assessments, the existing evidence suggests a non-negligible climate hazard associated with HFOs,” the study said.

The definition of GWP considers the average atmospheric lifetime of a gas but only includes the GWP of degradation products “after high confidence confirmation,” the study said. But “if there is at least a 2% chance of HFC-23 formation over the course of 100 years, that would be sufficient for HFO gases to have an effective GWP over regulatory thresholds.”

HFC-23 has historically been primarily generated during the production of HCFC-22, an ozone-depleting gas that has been prohibited globally. HFC-23 destruction is mandatory for parties to the Kigali Amendment to the Montreal Protocol, the 2016 global agreement to phase down HFCs.

Current atmospheric levels of HFC-23 have experienced a significant increase, and 55% of the excess “is not explained” by the failure of countries to meet reduction targets of HFC-23 emissions and HCFC-22 production, the study said. “There is a gap in the understanding of current atmospheric HFC-23 concentration trends that motivates the present review as a comprehensive global warming hazard assessment of HFOs.”

Since TFA is the one of the most likely breakdown products of HFOs with three or four carbon atoms and many other PFAS, conversion to HFC-23 “is a hazard that cannot be overlooked and might explain unexpected but certain atmospheric HFC-23 surges,” the study said.

The study recommended a reevaluation of the low-GWP designation of commonly used HFOs. “While these substances do have a relatively short atmospheric lifespan, their tendency to break down into HFC-23 can have significant, yet often overlooked, implications for the global efforts to address climate change.”

Leading to HFC-23

While HFOs are acknowledged to degrade in the atmosphere primarily to TFE and TFA, many secondary breakdown pathways “are notably leading to HFC-23” within 100 years, the study concluded.

For example, it was recently found that HFC-23 and carbon monoxide are the primary product of the fast, spontaneous and unimolecular ultraviolet (UV) B-facilitated decarbonylation of TFE. Thus, sunlight operating about half the day can lead to an effective 100-year GWP of 1,920 ± 900 for HFOs like HFO-1234ze(E) and HFO-1336mzz(Z) that break into TFE, according to the study. The study described decarbonylation of TFE by UVB radiation as having “medium environmental likelihood,” adding, “This pathway alone suggests that these HFOs could be significant global warming agents.”

The study noted that research funded by fluorocarbon gas manufacturers suggests that TFE would not produce HFC-23. However, the study found that “the methods employed to disprove the formation of HFC-23 from TFE via photolytic decarbonylation” to be insufficient. The American Chemistry Council did not immediately respond to a request for comment on the study.

For TFA, the study points to several “decarboxylation pathways” that produce HFC-23 and CO2, both in the atmosphere and on or near Earth.

For example, visible sunlight offers a decarboxylation route for TFA with “high environmental likelihood” and a 3,500–14,800 effective 100-year GWP contribution. In particular, TFA present in water aerosol is “susceptible to reacting with widely available visible sunlight,” and “HFC-23 production is thermodynamically favored.” Moreover, the increase of TFA in surface waters seen in a number of studies “exacerbate the concentration of TFA in re-evaporated water aerosols.”

Another pathway to HFC-23 from TFA, hydrothermal decarboxylation from ocean heat, is unlikely considering typical ocean temperature ranges – though it may become more likely as ocean heat content increases to record-breaking levels, the study said. This process has “medium-to-low environmental likelihood” but would be “substantial” at temperatures exceeding 35°C (95°F), with a 111–800 effective 100-year GWP contribution.

In addition, certain aerobic soil microorganisms and fungi – such as mycorrhizal fungi, particularly Pisolithus tinctorius – are able to convert TFA into HFC-23 via decarboxylation, with “medium- to-low environmental likelihood,” the study said.

Finally the study noted that hydroxyl (OH) radicals – which are the catalyst for converting HFO-1234yf into TFA – can convert up to 20% of gaseous TFA into HFC-23. But given that this competes with rainwater for the attention of TFA (wet deposition), the study said the formation of HFC-23 in this case has “low environmental likelihood” with a 0–3,000 effective 100-year GWP contribution.

The Office of Air and Radiation at the U.S. Environmental Protection Agency (EPA) has calculated the net benefit of $265–$270 billion from phasing down HFCs, considering both climate benefits and compliance costs. However, the study noted that models estimating the social costs of greenhouse gases (SC-GHG) do not incorporate “environmental fate reactions” and are limited to describing climate impact using GWP based on gases’ atmospheric lifetimes.

Thus, incorporating secondary HFC-23 generation into the analysis of HFOs “reveals the possibility of a substantially higher SC-GHG relative to their market price and expected profits,” the study said. “This signifies that the environmental impact of HFOs may exceed their economic feasibility, thereby warranting careful consideration of the trade-offs between commercial interests and climate change mitigation efforts.”

Other studies

Another recent study has determined that three HFOs react with ozone when they are released into the atmosphere to produce HFC-23. The study, “Ozonolysis can produce long-lived greenhouse gases from commercial refrigerants,” was published on December 11, 2023, in the Proceedings of the National Academy of Sciences (PNAS).

The study found in experiments that three HFOsHFO-1234ze(E), HFO-1336mzz(Z) and HFO-1243zf – generated HFC-23 by reacting with ozone (ozonolysis), with HFO-1234ze(E) producing more than eight times as much R23 as the other two. But two other HFOs – HFO-1234yf and HCFO-1233xf – did not produce R23 from ozone in the experiments.

In addition, a 2021 study by researchers at the University of New South Wales (UNSW) in Sydney, Australia, linked production of HFC-23 in the atmosphere to HFO-1234ze(E) as a result of oxidation by OH radicals and photolysis (action of light) of degradation product TFE.

“While these substances do have a relatively short atmospheric lifespan, their tendency to break down into HFC-23 can have significant, yet often overlooked, implications for the global efforts to address climate change.”

– Gabriel Salierno, author of “On the Chemical Pathways Influencing the Effective Global Warming Potential of Commercial Hydrofluoroolefin Gases”

The fact sheet provides a high-level overview of when bans on F-gases will affect the refrigeration sector.

Why It Matters

Sonia Saini

ATMOsphere, publisher of NaturalRefrigerants.com, has released a new fact sheet detailing the impact of the European Union’s recently revised F-gas Regulation on the refrigeration sector.

The regulation, which became law on March 11, mandates a complete phase out of HFCs across the EU by 2050. This will occur in stages, with the first bans affecting the refrigeration industry beginning on January 1, 2025. 

The new ATMOsphere fact sheet, “EU F-gas Version 3.0 – What Does It Mean for the Refrigeration Sector,” provides an overview of when these bans will come into effect and the equipment and F-gases they target.

In addition to providing an overview of the upcoming F-gas bans, the new fact sheet details the impact of four additional key measures contained in the revised EU F-gas Regulation. These are:

    • The 2050 consumption ban and the measures put in place to prevent the illegal HFC trade
    • A requirement to provide the 20-year GWP of HFCs and HFOs alongside the 100-year GWP
    • The establishment of a link between F-gases and PFAS (per- and polyfluorinated substances)
    • A mandate for the establishment of training and certification programs for alternative refrigerants, including natural refrigerants

The fact sheet also shows the clear relationship between HFCs and emissions, with a graph showing the estimated decrease in megatons of CO2e across the EU thanks to the revised EU F-gas Regulation.

The fact sheet can be viewed and downloaded below.

The application deadline is May 31, 2024, and the awards will be announced on June 30, 2024.

Why It Matters

Sonia Saini

The Natural Refrigeration Foundation (NRF), a nonprofit education, research and training association that is part of the U.S.-based International Institute of All-Natural Refrigeration (IIAR), is seeking applications from incoming junior and senior undergraduate engineering students for its NRF Founder’s Scholarship awards.

The scholarship is awarded each year to students exhibiting “exceptional character and pursuing an engineering or related technical degree leading to a career in the refrigeration field,” says IIAR. It is open to undergraduate students attending a four-year accredited college or university.

Scholarship funds are applicable to tuition only and are paid directly to the recipient’s college or university. The scholarship also provides additional funds for registration, travel, lodging and meals associated with attending IIAR’s Annual Natural Refrigeration Conference & Expo during the spring of their junior year.

Scholarship requirements and a link to the online application form can be found here. Application deadline is May 31, 2024. The awards will be announced on June 30, 2024.

For junior-year students, the scholarship consists of $4,000 to be paid in two equal installments of $2,000. Juniors must attend the IIAR conference and maintain the minimum grade-point average (GPA) in order to trigger a disbursement increase in their senior year.

For senior-year students, the scholarship includes $9,000 to be paid in two equal installments of $4,500 for recipients who attended IIAR conference during the spring of their junior year. For those who did not attend the conference, the amount is $4,000 to be paid in two equal installments of $2,000

Addressing climate change

 To qualify for the scholarship, students must be enrolled in an engineering field such as mechanical, electrical, civil, environmental, industrial, manufacturing, agricultural and chemical, or computer science, automation and mechatronics. “Applicants must be pursuing a degree in one of these fields and have a proven interest in applying their skills in the commercial and industrial refrigeration industry using natural refrigerants,” says IIAR.

“Engineers working in the industrial refrigeration industry have the opportunity to help address the urgent issue of climate change and reducing greenhouse gas emissions by applying environmentally friendly natural refrigerants in energy efficient refrigeration and heat pump systems,” adds IIAR.

In addition, students must have completed 45 semester credit hours (or equivalent) or 90 quarter credits at the time of application, and must hold a minimum 3.0 GPA on a 4.0 scale (3.75 on a 5.0 scale) towards an engineering degree. Two letters of recommendation are also required.

Known since its founding in 1971 as the International Institute of Ammonia Refrigeration, the IIAR is now “doing business as” the International Institute of All-Natural Refrigeration, reflecting its expanded focus on all natural refrigerants, including CO2 (R744) and hydrocarbons as well as ammonia (R717), in both industrial and commercial refrigeration.

In 2022, IIAR implemented a similar change to the name of its nonprofit  education, research and training foundation from the Ammonia Refrigeration Foundation (ARF) to the Natural Refrigeration Foundation. The NRF “promotes the climate-positive, safe, reliable, and efficient use of the most earth-friendly natural refrigerants through research and scholarships to develop industry talent, academic alliances, and outreach.”

“Engineers working in the industrial refrigeration industry have the opportunity to help address the urgent issue of climate change and reducing greenhouse gas emissions by applying environmentally friendly natural refrigerants in energy efficient refrigeration and heat pump systems.”


Using waste heat as its heat source, the HoegTemp high-temperature heat pump can produce steam at up to 200°C.

Why It Matters

Sonia Saini

A recent study has found that a helium (R704) high-temperature industrial heat pump developed by Norwegian OEM Enerin and installed at a biogas facility near Stavanger, Norway, can convert waste heat into useful high-temperature steam heat at up to 200°C (392°F). 

The study, “Performance of a High-Temperature Industrial Heat Pump, Using Helium as Refrigerant,” was authored by Arne Høeg, Kristian Løver and Gunnar Vartdal from Enerin. The study was presented at the High-Temperature Heat Pump Symposium 2024, held in Copenhagen from January 23–24.

“This type of heat pump is very well suited for high-temperature lift applications where it will deliver competitive COP and second-law efficiency,” the study wrote. “The HoegTemp heat pump is suited for applications where the source and sink temperatures vary according to the production profile of a factory and the availability of high-quality waste heat.”

The HoegTemp high-temperature heat pump (HTHP) in the study has been installed at the IVAR Central Treatment Plant Nord-Jæren since the summer of 2023. The raw biogas at the IVAR facility contains CO2 (R744), which must be removed before it can be sold. IVAR employs an amine process, using chemicals to capture and absorb the CO2. This requires steam heat at up to 200°C and cooling, both of which the HoegTemp HTHP provides.

According to the study, the HoegTemp heat pump has a capacity of 400kW (113.7TR). In simulations it was able to achieve a COP of 1.4 from a heat source averaging 21°C (69.8°F) and produce 202kW (57.4TR) of heating capacity. The study said the heat pump’s performance has not yet been mapped across its temperature range for its max output of 400kW.

Unique design

Enerin’s heat pump operates on the Stirling cycle, which is not dependent on the boiling and condensation of refrigerants. This thermodynamic cycle describes the operation of a type of reciprocating heat engine or heat pump with external heat transfer. It is ideal for high-temperature applications largely because it operates in a closed-loop system that moves the same gas back and forth rather than relying on the phase change of a refrigerant.

Helium is inert and non-toxic with zero ODP or GWP. Noble gases like helium can handle temperature from near absolute zero (−273.15°C/−460°F) to about 250 to 350°C (482 to 662°F), to cover heating and cooling needs.

Future plans

An Enerin spokesperson told NaturalRefrigerants.com that the company is planning to nearly double the capacity of the HoegTemp HTHP.

“The current design of our heat pump has a capacity of 400kW [113.7TR], but we are aiming to expand this, offering modules that can deliver up to 1MW [284.3TR] of heating capacity,” the spokesperson said.

The spokesperson also shared insights from the ongoing SUSHEAT project. SUSHEAT is a project focused on developing and testing new technologies for hybrid renewable industrial heat systems. These systems are designed to provide heat for industrial processes as needed, helping to reduce the industrial sector’s dependency on fossil fuels and decrease emissions.

“We are actively mapping the heat pump’s performance across a wide operating range, with source temperatures up to 130°C [266°F] and sink temperatures up to 250°C [482°F].”

Enerin has begun sales of the HoegTemp HTHP, selling one unit to pharmaceutical company GE Healthcare and another to fish and feed company Pelagia. Both have purchased the HoegTemp HTHP for their facilities in Norway, with the two sales reportedly fetching a combined €3.5 million ($3.7 million).

“We are actively mapping the heat pump’s performance across a wide operating range, with source temperatures up to 130°C [266°F] and sink temperatures up to 250°C [482°F]”

CEO of Enerin As


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