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By identifying PFAS components and coatings, the research team’s goal is to make it easier for OEMs to switch to PFAS-free alternatives.
Sonia Saini

The European Chemicals Agency (ECHA) is considering a proposal submitted by Denmark, Germany, the Netherlands, Norway and Sweden to restrict PFAS (per- and polyfluoroalkyl substances), also known as forever chemicals. Chemical companies, refrigeration component manufacturers and heat pump trade organizations have argued that PFAS refrigerants and components are essential to the wide-scale roll out of heat pumps and thus the EU’s climate goals.

While the rise in natural refrigerant heat pumps proves f-gases aren’t essential, the component-centered argument is harder to refute as it’s not known how many non-refrigerant PFAS are in a modern heat pump.

Until now.

Researchers from Germany’s Karlsruhe University of Applied Sciences and the Eastern Switzerland University of Applied Sciences have found that in a commercial reversible heat pump using R410A refrigerant, the amount of PFAS components by weight was less than 1% (0.0056%). The researchers analyzed an 800-kilogram (1,763lbs) and air-to-water heat pump manufactured by Swiss OEM Heim AG Heizsysteme with a capacity of 30kW (8.5TR) designed for use in multi-family buildings.

The research team consisted of Professor Michael Kauffeld from the Karlsruhe University of Applied Sciences Institute of Refrigeration, Air-Conditioning and Environmental Engineering; Dr. Mihaela Dudiţa-Kauffeld and Kanchan Bohara from the Eastern Switzerland University of Applied Sciences SPF Institute for Solar Technology; and Raphael Gerber, System Development Engineer at Heim. 

Kauffeld presented the team’s findings at the recent Karlsruhe Heat Pump Symposium 2024 where he was interviewed by Marc Chasserot, CEO and Founder of ATMOsphere. ATMOsphere is the publisher of

“The total amount by weight by PFAS in this heat pump is 2.8%, and if you take this 2.8%, about 98% of that is the refrigerant, which is easy to replace as this heat pump is designed to be installed outside,” said Kauffeld. “We still have PFAS in the O-rings, the seal of the expansion valve and in the electronics, though.”

Identifying PFAS components

Unlike f-gas refrigerants, which leak from equipment into the atmosphere and earth, Kauffeld said that certain PFAS components do not pose health and environmental risks as long as they are recycled or disposed of properly.

“An O-ring made of PFAS material is no problem if, at the end of the lifecycle of the heat pump, you recycle it or burn it at a high enough temperature so that the PFAS is not going into the environment,” noted Kauffeld.

The Latest PFAS News
In Follow-Up Study, European NGO Finds TFA in Drinking Water Throughout Europe

Kauffeld said that, in addition to individual components, the heat pump his team examined also contained PFAS components that were used in the electronics to prevent sparks, and a PFAS was used to coat the evaporator to prevent de-icing. Despite the pervasiveness of PFAS, Kauffeld said manufacturers can analyze their products to pinpoint which components contain the forever chemicals.

“[The manufacturers] can go to different laboratories that can make infrared spectroscopy measurements that tell you exactly what type of PFAS you have in the material,” said Kauffeld, with Chasserot noting that both Karlsruhe University of Applied Sciences and the Eastern Switzerland University of Applied Sciences have such laboratories.

“There is a rough measurement that can be done quickly and then a more detailed one,” added Kauffeld. “It’s easy.”

Looking back

Chasserot was quick to point out that testing a product in a lab may be easy, but replacing its PFAS components with those that don’t contain forever chemicals is a much larger challenge. Indeed, the Association of European Refrigeration Component Manufacturers (ASERCOM) said its members “are collaboratively exploring alternative substances with their supply partners, though viable solutions achieving equal performance are not yet identified.”

Based on what Chasserot said he’s seen, though, the issue is solvable by companies with the will and resources to tackle it.

“I personally have talked to quite a few companies in the last few months that are already working on this that know it’ll be solvable – not in 10 years but well before then,” said Chasserot. “It’s not rocket science to solve this problem for the small percentage of the issue we’re talking about.”

In his presentation, Kauffeld showed how companies in other industries have gone PFAS-free, such as German outdoor apparel and equipment company Vaude. The company began moving away from using PFAS to make its products water repellent in 2010, and by 2025 it plans for all of its offerings to be PFAS-free.

Vaude provides an example of how moving away from PFAS is possible in today’s PFAS-dominated supply chain. Kauffeld says the HVAC&R industry may only need to look to its past to understand how to design systems completely free of PFAS components.

“All we have to do is go back 90 years before the invention of PFAS,” said Kauffeld. “There were refrigeration systems and heat pumps, and they worked without PFAS. If the people back then could do it, then we can do it today.”

“[The manufacturers] can go to different laboratories that can make infrared spectroscopy measurements that tell you exactly what type of PFAS you have in the material.”

Professor Michael Kauffeld, Karlsruhe University of Applied Sciences

Why It Matters: Curated News With Commentary
Source: Business Day

The Energy Game Changer: Why Nigerian Businesses Must Embrace Transcritical Efficiency Technology

Why It Matters: An op-ed in Business Day, a Nigerian financial publication, has called transcritical CO2 (R744) a “game-changer” for the country’s HVAC&R-dependent businesses like supermarkets, food processors, hotels and hospitals. Chiemeka Okeke, the op-ed’s writer and the Co-Founder and CFO of solar financing company Powerfull, said “transcritical efficiency technology” has the potential to “revolutionize Nigerian businesses” by reducing energy consumption, electricity bills and operational costs. The technology can also reduce a business’s direct greenhouse gas emissions and environmental footprint, as well as help them stay ahead of global and national regulations targeting synthetic refrigerants, Okeke adds.

While not yet widely used in Nigeria, successful installations of transcritical CO2 systems in other countries with similar climates and economies like Jordan, Malaysia and the Philippines highlight the technology’s potential benefits. With the Nigerian cold chain market projected to grow by 10% annually over the coming years, the widespread adoption of transcritical CO2 refrigeration could have a sizable impact on the country’s energy demand and transition to natural refrigerants.

Why It Matters: Curated News With Commentary
Source: The Verge

Biden Gives States Billions of Dollars for EV Chargers, Heat Pumps and Other Green Tech

Why It Matters: With the U.S. facing the prospect of another four years of former President Donald Trump rolling back environmental protections at the federal level, the Biden administration announced $4.3 billion in Climate Pollution Reduction Grants (CPRG) funding on July 22 for 25 different initiatives led by state, municipal, and tribal governments as well as coalitions of local governments. The money can be used to deploy a wide array of clean energy technologies — from solar and wind farms to EV chargers and heat pumps. These awards are made possible by Biden’s Inflation Reduction Act (IRA).
Meanwhile, the U.S. Climate Alliance, a bipartisan coalition of 24 governors representing approximately 60% of the U.S. economy and 55% of the U.S. population, announced that 14 of its members have collectively secured approximately $2.6 billion in CPRG funding. Eleven Alliance members also have programs to reduce f-gas emissions. Those states should be motivated to use natural refrigerants instead of f-gases in their heat pump initiatives.
The detailed analysis shows energy-saving strategies using low superheat technologies, dual-suction systems and optimal coil selection.
Sonia Saini

Lowering evaporator superheat (SH) can improve the efficiency of CO2(R744) refrigeration systems by up to 11.5%, according to Kurt Knapke, Vice President of Solutions Strategy for Cold Chain at Copeland, and Wynand Groenewald, Founder of CO2 refrigeration engineering consultant firm Future Green Now.

Knapke and Groenewald presented this finding during a presentation at the ATMOsphere (ATMO) America Summit 2024. ATMOsphere is the publisher of, and the ATMO America Summit 2024 was held June 10–11 in Washington, D.C.

The study, which lasted several months, involved analyzing 214 DOE/AHRI1200 certified display cases and 51 DOE/AWEF certified unit coolers under various coil temperature difference (TD) conditions. The display cases were analyzed with medium-temperature (MT) superheats of  6–8°F (-14.4 to -13.3°C)  and low-temperature (LT) superheats of  3–5°F (-16.1 to -15°C), while the unit coolers were analyzed with a consistent superheat of  6.5°F (-14.2°C).  The study’s goal was to evaluate different technologies and design approaches to optimize evaporator superheat levels and overall system performance.

“Our research shows that these methods can significantly improve system efficiency,” Knapke said. 

The strategies

The study highlighted three primary strategies to enhance energy efficiency in CO2 refrigeration systems. These strategies were compared to a baseline system, which was designed using coil design superheat setpoints with an average coil TD. The three strategies involved using the highest coil TD, average TD and lowest TD. The annualized saving potential for these strategies was evaluated with MT conditions at 400MBH (117.2 kW/33.3TR) and LT conditions at 100MBH (29.3kW/8.3TR).

The three strategies consisted of:

  • Energy modeled using no superheat with liquid ejector: Implementing liquid ejectors to maintain no superheat in the evaporators proved effective in increasing the saturated suction temperature and showed energy savings of 10.9% at a TD of 10°F (-12.2°C), 4.4% at a TD of 7°F (-13.9°C) and 3.2% at a TD of 4°F (-15.6°C).
  • No superheat with liquid to low LT: Using liquid to maintain no superheat in low-temperature evaporators demonstrated increased saturated suction temperature and showed energy savings of 11.5% at a TD of 10°F, 5.1% at a TD of 7°F and 3.9% at a TD of 4°F.
  • Dual suction with standard operating SH: The concept of dual suction lines, catering to different temperature requirements, presented energy savings of 7.2% at a TD of 10°F, 6.1% at a TD of 7°F and 6.3% at a TD of 4°F.

The research demonstrated that considerable energy savings could be achieved by selecting appropriate equipment and optimizing the system design. Using coils with the lowest TD for lowest-temperature load in the suction group resulted in energy savings without the need of advanced low-superheat technologies. Additionally, incorporating internal heat exchangers improved system performance by enabling operation based on design coil superheat rating points.

The implementation of liquid ejectors to maintain no superheat in evaporators increased the saturated suction temperature, leading to energy savings. Dual suction lines, which cater to different temperature requirements, also showed significant energy savings.

Practical implications 

The study underscored the importance of selecting the right equipment and incorporating design elements to maximize efficiency.

“If you can reduce the superheat or get rid of your superheat, you can move the pinch point of your air temperature through your coil versus your refrigerant temperature, moving your pinch point to the most efficient location,” Groenewald explained. “That allows it to increase your saturated suction temperature, leading to energy efficiency.”

The findings suggest that integrating the study’s strategies with existing high-ambient climate solutions can further increase energy efficiency. By combining low SH technologies, dual-suction systems and optimal coil selection with other energy-saving measures, CO2  systems can achieve higher efficiency.

“We need to keep pushing the boundaries and exploring new solutions,” Knapke said.

“We need to keep pushing the boundaries and exploring new solutions.”

Kurt Knapke, Vice President of Solutions Strategy for Cold Chain at Copeland

Why It Matters: Curated News With Commentary
Source: Bloomberg Law

EPA’s ‘Forever Chemicals’ Rule at Risk Without Chevron Deference

Why It Matters: The U.S. Supreme Court’s June 28 Loper Bright decision to end judicial deference to federal agencies’ reasonable interpretations of ambiguity in laws under the “Chevron doctrine” comes at a pivotal time for new regulations related to “forever chemicals”—per- and polyfluoroalkyl substances known as PFAS. Following Loper Bright, courts must now exercise their independent judgment in deciding whether an agency acted within its statutory authority. This is expected to trigger new legal challenges to regulations enacted by the U.S. Environmental Protection Agency (EPA) and other agencies.
The EPA is already facing judicial challenge in the U.S. Court of Appeals for the DC Circuit after designating two PFAS – perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) – as hazardous substances under the Superfund law, or CERCLA. In regard to the HVAC&R industry, the EPA’s definition of PFAS excludes ultrashort-chain substances such as f-gases and trifluoroacetic acid (TFA), an atmospheric degradation product of HFO-1234yf and other f-gases; that definition has been widely criticized by scientists and is contrary to the more expansive definition used in the EU and some U.S. states. The Loper Bright decision would seem to be another roadblock preventing the EPA from adopting a broader approach to PFAS that includes f-gases and TFA. It also raises the possibility that the EPA’s f-gas restrictions under the U.S. AIM Act could be challenged, though those regulations are clearly defined by the Act and not reliant on interpretation of ambiguity.
The store and its R744-based system is fully powered by an extensive installation of roof- and facade-mounted PV panels.
Sonia Saini

Supermarket chain Migros Ticino, one of Swiss retailer Migros Group’s 10 regional cooperatives, has installed an integrated CO2 (R744) HVAC&R system from local OEM Biaggini Frigoriferi at its newest store in Bellinzona, Switzerland.

The TotalGreEnergy system will meet all of the supermarket’s refrigeration, heating, air-conditioning and hot water needs as well as serving the office space located in the same building.

To further boost the green credentials of the facility, more than 1,274 photovoltaic (PV) modules have been installed on the roof and one facade of the building, the retailer explained in a LinkedIn post. Covering a total area of 2,298m2 (24,735ft2), the PV system is expected to produce over 301,000 kWh of electricity annually, providing enough energy to power the store and its HVAC&R system, Luca Rossi, Engineer Project Manager at Biaggini Frigoriferi, told It will save roughly 39 metric tons of CO2 per year.

According to a statement from engineering firm Greenkey, installing PV panels on the side of the building in addition to the roof will help meet the store’s electricity demand in the winter months when energy production is lower and consumption is higher.

In total, Migros Ticino invested more than 12 million Swiss francs (€12.4 million/$13.56 million) in its new supermarket.

High efficiency

The Bellinzona Nord store consists of a sales area of around 809m2 (8,708ft2) with 50m (164ft) of refrigerated cabinets. It also includes two medium-temperature (MT) cold rooms, one low-temperature (LT) cold room and two electrical rooms that require cooling.

Biaggini’s TotalGreEnergy system provides 65kW (18.5TR) for MT refrigeration, 20kW (5.7TR) for LT refrigeration, 80kW (22.7TR) for space heating, 90kW (25.6TR) for air-conditioning and 40kW (11.4TR) for hot water production.

The system comprises three MT compressors, three LT compressors and two auxiliary compressors, all from Italian manufacturer Dorin. To boost system efficiency, the compressors are fitted with permanent magnetic motors, producing less heat compared to traditional motors to minimize energy loss during operation.

The TotalGreEnergy rack includes eight Dorin compressors. (Source: Biaggini Frigoriferi)
The TotalGreEnergy rack includes eight Dorin compressors. (Source: Biaggini Frigoriferi)

To further improve system performance, the rack is cooled by ground water during summer months to enable subcritical operation.

“The energy efficiency will be very high,” Rossi told Marc Chasserot, Co-Founder and CEO of ATMOsphere, in an interview and site visit in January. ATMOsphere is the publisher of

With the store’s PV panels and energy-efficient natural refrigerant-based HVAC&R system, among other features, Migros Ticino is hoping to receive the Minergie label – the highest building certification in Switzerland – Rossi added.

100% CO2 refrigeration

With the opening of this store, as well as other refurbishment projects over the last year, Migros Ticino is close to achieving its goal of converting all of its supermarkets to CO2-based refrigeration by 2025, with just one of its existing stores yet to be upgraded.

Of the chain’s 34 supermarkets, 21 have installed CO2-based refrigeration systems, while a further 12 have all of their HVAC&R needs met by R744-based technologies. According to Rossi, Migros Ticino plans to install two more integrated CO2 systems by the end of 2024.

Migros Ticino and Biaggini have been working together since 2009, when the chain installed its first transcritical CO2 refrigeration system, which was designed and manufactured by Biaggini. The retailer then installed its first integrated CO2 system, also designed and manufactured by Biaggini.

On its current trajectory, Migros Ticino is set to achieve its 100% CO2 target 15 years ahead of the wider Migros Group, which has a total of 630 stores across the country and aims to use 100% natural refrigerants by 2040, according to its net-zero goals.

Sonia Saini

Three of the seven finalist companies for the Empire Technology Prize, an initiative of the New York State Energy Research and Development Authority (NYSERDA) that seeks to advance low-carbon heating system retrofit technology for high-rise buildings, are natural refrigerant heat pumps.

The Empire Technology Prize was launched in October 2023 and challenged companies to develop prototype heating or distribution systems that could be installed without displacing occupants in buildings seven stories or higher. The Clean Fight, a non-profit climate tech accelerator and administrator of the Empire Technology Prize, will match finalists with New York-based real estate companies for pilot projects.

“New York is advancing the latest technology and innovations to reduce emissions and build cleaner, greener buildings,” said Governor Kathy Hochul.

The big three: Of the three natural refrigerant heat pumps, two use CO2 (R744) as a refrigerant and one uses helium (R704).

  • Minnesota-based OEM Flow Environmental Systems and New York-based HVAC design and implementation firm Ambient Enterprises and contractor Gil-Bar were named finalists for Flow’s CO2 high-temperature heat pump (HTHP). The company’s CO2 HTHP is capable of heating water to 180°F (82°C), can also provide domestic hot water (DHW) and cooling and can use air or water as a heat source.
  • Pittsburgh-based Clean Heat Technologies, a division of Thar Energy, was recognized as a finalist for its water-source CO2 heat pump that generates steam. Up to 80% of New York City’s multifamily buildings are still heated by steam, with the vast majority produced by fossil fuel-powered boilers. According to NYSERDA, Clean Heat Technologies has developed six prototypes of its CO2 heat pump.
  • Enerin, based in Lysaker, Norway, was named a finalist for its helium HTHP, which can produce both steam and DHW using air or water as a heat source. The company recently conducted a successful test of its HTHP at a biogas facility in Norway that saw it produce steam at 392°F (200°C).

Honorable mention: Hydronic Shell Technologies of Queens and multifamily retrofit company Cycle Retrotech of Brooklyn were also named finalists for the former’s Hydronic Shell HVAC distribution system.

  • The Hydronic Shell system is made up of modular panels containing water-filled pipes that connect to a rooftop-based heating/cooling system. The system is designed to enable older buildings to install new heating/cooling systems without the need for an extensive retrofit of the existing distribution apparatus. 
  • has reached out to the other three finalists – Johnson Controls, AtmosZero and Miller Proctor Nickolas – to confirm the refrigerant their entries use and will update this article as new information becomes available.

The prize: Each finalist will receive $250,000 (€229,043) and will have the potential to be awarded up to $750,000 (€687,131) “as they achieve milestones in progressing their solutions over the next year.”

  • An additional $2 million (€1.8 million) is available to offset pilot project installation costs.
  • The project deemed to have the greatest potential to reduce building carbon emissions will be awarded $1 million (€916,650), with the winner to be announced in June 2025.

What it means for NatRefs: The Empire Technology Prize presents an opportunity for natural refrigerant heat pumps to play a major role in decarbonizing New York’s building stock. NYSERDA’s goal is for 85% of the state’s 6 million buildings, which account for one third of its greenhouse gas emissions, to use clean heating and cooling technologies by 2050.

  • The city of New York has a more aggressive goal: net-zero emissions from the city’s largest buildings, those exceeding 25,000ft2 (2,322m2), by 2050.
  • New York State’s Department of Environmental Conversation (DEC) is also considering a revision to its HFC regulations that would see a GWP limit of 10 set for many new HVAC&R systems by 2034.

Quotable: “The scoring criteria for evaluating Empire Technology Prize proposals included a focus on the global warming potential of the proposed refrigerant,” NYSERDA told “NYSERDA is excited to see a diverse set of finalists with proposals to develop and commercialize high-temperature heat pump solutions with low GWP refrigerants, including several solutions with natural refrigerants. ”

Sonia Saini

Auburn, Washington-based manufacturer Pro Refrigeration has obtained funding for an independent evaluation of two California installations of its PROGreen CO2 (R744) Hybrid Series chiller to directly compare the operating efficiency of the CO2-only part versus the R448A-based part, following its own tests showing “significant” energy savings from the CO2 side.

Funding comes from CalNEXT, an emerging electric-technologies program for California designed and implemented by Energy Solutions.

In 2021, Pro Refrigeration introduced its standard 100HP CO2-only PROGreen packaged chiller, equipped with Alfa Laval heat exchangers, targeting its traditional customer base of dairy farms, breweries and wineries. That was followed in 2022 with the two-part PROGreen Hybrid, which combines the CO2 Chiller with PRO’s R448A V Piston system, which serves as a backup to the CO2 system; each part has its own electrical power supplies and control centers, but the overall system operates on a single chassis with a shared 2,000gal (7,571L)-capacity chilled propylene glycol tank.

“The PROGreen R744 Hybrid Series offers dairy farms the advantages of a CO2‑based system, including heat recovery and reduced power consumption,” said Pro Refrigeration. “It heralds a new era for dairy farms, delivering unprecedented performance in milk cooling and water heating efficiency, cost-effectiveness and sustainability gains.”

The hybrid design has given Pro Refrigeration the opportunity to do long-term energy comparisons of the CO2 and R448A components. “We are logging kW usage individually on each refrigerant,” said Jim VanderGiessen, CEO and Co-Founder of Pro Refrigeration. “Based on our data we see significant kW savings on the R744 system versus the synthetic-based system.”

The first site that will undergo independent evaluation of its hybrid system is Costa View Farms in Madera, California, with a report on the results published in January 2025. “We look forward to sharing this report,” said VanderGiessen.

Pro Refrigeration developed the hybrid model because its customers wanted to see a hybrid option in addition to the CO2-only and R448A-only options, he said. (R449A is also available as an f-gas refrigerant.) Dairy farms typically oversize their chiller systems, requesting 100% redundancy to provide backup in the event of a system fault or alarm, the company noted.

Both parts of the hybrid system are kept active, with the CO2 part the primary system and the R448A part the backup. According to VanderGiessen, the R448A part is used less than 1% of the time: when there is a fault in the CO2 part, or there is an ambient temperature issue. “It is normal to see both sides running during high cooling loads and during high ambient,” he said.

Pro Refrigeration credited Swedish manufacturer Alfa Laval with helping in the chiller’s company’s transition to CO2-based units. “We were fortunate to have Alfa Laval as a key supply partner on our PROGreen team,” said VanderGiessen.

In particular, Alfa Laval helped Pro Refrigeration to deal with higher CO2 pressures, which called for adjustments in infrastructure and technician training, and to achieve “a threefold increase in the heat recovery, enabling the reuse of nearly all the waste heat,” said Damon Reed, Pro Refrigeration’s Chief Operating Officer.

The PROGreen CO2 chiller, both the stand-alone unit and the system in the hybrid chiller, incorporates Alfa Laval’s AXP and CBXP brazed heat exchangers for different functions, including heat recovery, sub-cooling and evaporation.

Robust heat recovery

Waste heat recovery has proven to be one of the most significant benefits of the PROGreen CO2 chiller. For example:

  • William & John Jongsma Dairy in California slashed its annual propane usage by 75%, saving over 45gal (170L) per day, or about $4,500 (€4,114) a month based on an average price of $3 (€2.74) per gallon.
  • Another California farm, South Creek Dairy, saved over $1,400 (€1,280) per month using PROGreen to generate hot water above 150°F (65.5°C) from waste heat, eliminating the need for their natural gas water heater.

Waste heat recovery from the CO2 system raises water temperatures from 70°F (21°C) to over 180°F (82°C), exceeding the limitations of f-gas-based systems, which typically heat water only to 125°F (52°C), said Pro Refrigeration. Both the hybrid system and the standard CO2 chiller system are equipped with the same heat-recovery capabilities.

VanderGiessen sees a role for propane (R290) in chillers as well as CO2. “Our business strategy hinges on shifting focus from synthetic-based refrigerants towards natural alternatives such as CO2 and propane. Both are needed to replace synthetics,” he said. “This paradigm shift is already underway in Europe, where diverse solutions are the norm. There is no one-refrigerant-fits-all solution.”

“Today, CO2 is emerging as the frontrunner for PRO customers who want to replace synthetic-based systems, especially those with high demand for hot water at drastically reduced or no cost,” he added. “The emergence of propane-based systems in the U.S. also signals a promising future.”

“Our business strategy hinges on shifting focus from synthetic-based refrigerants towards natural alternatives such as CO2 and propane.”

Jim VanderGiessen, CEO of Pro RefrigerationCalNEXT


The Italian company said its MAC unit can provide heating, cooling and hot water using a fraction of the electricity of traditional systems.
Sonia Saini

MT Innovation, an Italian company specializing in product research and development, has created a prototype mobile air-conditioning (MAC) unit for camper vans that uses ammonia-water (R717-R718) absorption technology.

The unit offers a cooling and heating capacity of 3kW (0.85TR) and 6kW (1.7TR), respectively, and MT Innovation said it uses only 5% of the electricity required by traditional camper van MAC systems. It can provide space heating and cooling and domestic hot water. MT Innovation did not specify the charge size of its prototype MAC unit.

“A car typically consumes around 2L [0.52gal] of fuel every hour to cool the passenger compartment,” Luca Barin, Research and Development Specialist at MT Innovation, told “Our system, however, uses between 0.1 to 0.6L [0.02 to 0.15gal] of fuel per hour. It uses 0L when the cooling heat is fully recovered from the engine and up to 0.6L when the vehicle is off or parked.”

Designed to be scalable and adaptable, the system is built in blocks with the fluid supply circuit separated from the refrigeration section. The company notes its modular design ensures compatibility with a variety of vehicles outside of camper vans and even boats. The prototype measures 60 × 40 × 35cm (23.6 × 15.7 × 13.8in) – those dimensions are expected to shrink by 30% in the production version according to Barin – and weighs less than 30kg (66lbs).

The ammonia-water absorption cycle requires heat, which can be provided by waste heat in gas-powered vehicles or by a small burner that can use gasoline from the vehicle’s tank, hydrogen from a fuel cell or natural gas as its fuel source. MT Innovation has not disclosed the charge size of the unit.

MT Innovation said it patented its ammonia-water absorption MAC unit in 2020 and that it received financing for the project from the Italian Ministry of Economic Development (MISE) at the end of 2021. The company told that a working prototype will be presented to “interested companies” in September 2024. 

The technology

MT Innovation’s prototype MAC system operates by leveraging the absorption properties of ammonia and water. Ammonia acts as the refrigerant, while water serves as the absorbent. The cycle begins in the evaporator, where ammonia absorbs heat and evaporates. The gaseous ammonia is absorbed by water in the absorber, creating an ammonia-water solution. This solution is then pumped to the generator where heat is applied, causing the ammonia to vaporize and separate from the water.

The ammonia vapor proceeds to the condenser, where it releases heat and condenses back into a liquid. Before returning to the evaporator, the ammonia passes through an expansion valve, lowering its pressure and temperature and allowing it to absorb heat once more in the evaporator.

Throughout the process, the regenerative heat exchanger helps to improve efficiency by transferring heat between the solutions entering and leaving the generator. The dephlegmator is involved in removing any remaining water vapor from the ammonia vapor, ensuring pure ammonia enters the condenser.

From left, Simone Barin, Maria Reginella and Luca Barin, inventors and coordinators of the ammonia-absorption MAC unit project at MT Innovation. Photo credit: MT Innovation.

NatRefs in MAC

While ammonia-water absorption technology has not been seen before in the MAC sector, the use of natural refrigerants is on the rise.

According to a recent white paper from consulting firm Ducker Carlisle, manufacturers of plug-in-hybrid electric vehicles and electric vehicles are “high likely” to opt for natural refrigerants like CO2 (R744) or propane (R290) in place of HFO 1234yf in mobile air-conditioning systems over the next five years. The consulting firm notes that this shift is driven by stricter environmental legislation and an anticipated EU regulation that could ban R1234yf by 2030. 

The transition is also influenced by government subsidies favoring low-GWP refrigerants and the need to improve vehicle performance, particularly battery range and lifespan. CO2 heat pumps, for example, have shown higher efficiency in EVs due to increased suction vapor density and the elimination of auxiliary heaters.

This trend is further evidenced by Volkswagen’s commitment to using R744 heat pumps in all its EVs by 2030, a strategy the Ducker Carlisle white paper said is likely to be followed by other automakers.

“A car typically consumes around 2L [0.52gal] of fuel every hour to cool the passenger compartment. Our system, however, uses between 0.1 to 0.6L [0.02 to 0.15gal] of fuel per hour. .”

Luca Barin, Research and Development Specialist at MT Innovation

The Denver-based facility stores more than 82,020 feet of ice cores at temperatures as low as −32.8°F.
Sonia Saini

The U.S. National Science Foundation Ice Core Facility (NSF-ICF) in Denver, Colorado, has announced that it is replacing its hydrochlorofluorocarbon (HCFC)-based refrigeration system with a transcritical CO2 (R744) unit.

The Denver facility stores 82,020 feet (25,000 meters) of ice cores harvested from North America, Antarctica and Greenland. In addition to storage, the facility is also used by scientists and academics to cut ice cores for further studies back at their laboratories or universities.

The NSF-ICF is the world’s largest ice core storage facility. Its main storage room measures 55,000ft3 (1,557m3) and is kept at −32.8°F (−36°C). The facility’s examination room, where ice cores are cut, is 12,000ft3 (339m3) and is kept at −11.2°F (−24°C). 

Michael Jackson, Program Director for Antarctic Earth Sciences at the NSF and the manager of the refrigeration system update, told Nature the NSF decided to replace its existing HCFC refrigeration system due to its age and poor performance. He said the move to CO2 was driven by a desire for an efficient and future-proof refrigerant.

“[It] is more efficient at low operating temperatures,” said Jackson. “It is difficult to quantify, but CO2 appears to be the most future-proof low-temperature refrigerant.”

The ice cores stored at the NSF-ICF present a window into past climatic conditions, with one of the cores dating back more than 4 million years and some drilled from depths exceeding 2 miles (3.2km). Scientists study the cores, which are formed as layers of snow are compressed one on top of another, to understand everything from past temperatures to atmospheric concentrations of CO2.

The NSF-ICF did not provide Nature with technical details of its new transcritical CO2 refrigeration system. has reached out to the facility seeking more information and will update this story with new information if it becomes available.

Moving to NatRefs

The Environmental Protection Agency (EPA) has established a GWP limit of 150 for many new types of refrigeration equipment under authority granted to it by the American Innovation and Manufacturing (AIM) Act. Compliance dates begin in 2025, and with a GWP of 1, CO2-based equipment is not subject to any restrictions.

Curt La Bombard, Curator of NSF-ICF, said his team has offered assistance to other ice core storage facilities interested in moving to transcritical CO2 refrigeration. Per Nature, a handful of universities are paying close attention to the Denver facility’s refrigeration system upgrade as they consider replacements for their own equipment. “We’re in the same boat,” Ellen Mosley-Thompson, a Paleoclimatologist at Ohio State University in Columbus, told Nature.

The NSF-ICF is not the first large ice core storage facility to opt for natural refrigerants, with Japan’s National Institute of Polar Research using an ammonia (R717) refrigeration system. Two other comparable facilities, one at the University of Alberta in Edmonton and another at the Alfred Wegener Institute in Bremerhaven, Germany, both use HFC-based refrigeration systems.

“It is difficult to quantify, but CO2 appears to be the most future-proof low-temperature refrigerant.”

Michael Jackson, Program Director for Antarctic Earth Sciences at the NSF

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