Lowering the GWP

In the US, The Environmental Protection Agency (EPA) is limiting the use of HFCs including R-404A in new (manufactured or imported) refrigerated transport-road equipment and imposing a Global Warming Potential (GWP) limit of 700 on refrigerants used in intermodal containers from 1 January 2025.

In Europe, the proposed ban and phase-out of equipment containing PFAS (per- and polyfluoroalkyl substances – so-called ‘Forever Chemicals’) currently captures refrigerants used in reefer containers.

US limits

On January 1, 2025, intermodal containers manufactured or imported for sale in the United States must comply with new regulations mandating the use of refrigerants with a GWP of less than 700 for refrigerated transport. The regulation covers intermodal containers with the temperature of the refrigerant entering the evaporator (for direct heat exchange systems) or the temperature of the fluid exiting (for chillers) of -50°C (-58°F).

Domestic trailer refrigeration units that contain an integrated motor (i.e., those that do not require a separate electrical power system or separate generator set to operate), that are transported as part of a truck, on truck trailers, and on railway flat cars, are not included in the 700 GWP limit.  Instead, the EPA has banned the use of certain blends, including R-404A, for this purpose.

The EPA has approved R-452A for this use under its Significant New Alternatives Policy (SNAP) program. Taking intermodal containers produced to ISO 668 first, the regulatory change is expected to significantly impact the intermodal container industry, which imports several thousand reefers annually into the US.

“While most machines use R-134a as refrigerant, the GWP of 1430 makes it non-compliant to the regulation,” Maersk Container Industry (MCI) said in its newsletter.

Time for R-513A?

For some time now reefer suppliers have been offering new reefer containers with R-513A, which has a GWP of 630. R-513A can also be used as a replacement for R-134a, but not all R-134a machinery will perform to the same capacity as R-513A.

As MCI explains: “Since mid-2017, all reefers from MCI are optimised for R513A, delivering full capacity in all operating conditions, this accounts to approx. 1/3 of all Star Cools ever produced. Approx. 2/3 of Star Cools can operate with R513A, but at 8-10% lower capacity. This may be sufficient for many stationary applications. If more capacity is needed, these units can be optimised with a conversion kit, delivering full capacity. Only a small number of Star Cool reefers, equivalent to 6%, are not capable to operate with R513A and have seen 15+ years in operation until today.”

With regard to 53ft containers, MCI says Star Cool machinery has the refrigeration capacity to be used in this application.

Daikin’s approach

Asked how it will meet the new US requirement for refrigerants to be below 700 GWP from 2025, Japanese refrigeration supplier Daikin said: “First and foremost, all Daikin reefer units currently use R134a, and R-513A is a suitable alternative refrigerant to R134a, which meets this regulation among refrigerants and is currently widely used in the industry. It is important to stress that all our reefer units produced after 2008 are ready for R-513A refrigerant, in case customers decide to replace with/drop-in R513A.”

For existing Daikin units manufactured from 2008, replacing R-134a with R-513A requires an additive, a small kit and a software upgrade. For new units, Daikin can deliver ZeSTIA machinery charged with R-513A from the factory or charged with R-134a and ready for R-513A as a drop-in replacement.

As to whether other markets will follow the US, Daikin says it is not aware of any similar regulatory GWP limits in other jurisdictions other than EU F-gas regulations. While the US move may help drive a wider change to lower GWP refrigerants, Daikin says more widespread adoption of these across the industry more likely depends on other factors including refrigerant prices, availability, and the operation of existing equipment. “R513A is still a more expensive option in the short term,” Daikin noted.

More complex problem

For Thermo King, part of Trane Technologies, refrigerant choices are more customised. Thermo King has the broadest portfolio of marine refrigeration units with the greatest variety of refrigerants in the industry to serve different segments and commodities.

Thermo King offers units with temperature set-points ranging from -70°C to +40°C. These include the SuperFreezer for cargo requiring ultra-low setpoints down to -70°C such as pharmaceuticals and seafood below its eutectic point. The SuperFreezer uses a cascade system charged with R-23 and R-134a. The Magnum Plus units offer a -40°C setpoint charged with R-404A or R-452A. The newer CFF for ISO1496-2 containers, which provides a setpoint between -30°C and +30°C, is charged with R-134a or R-513A refrigerants.

In the US, Thermo King also supplies different refrigeration machinery for domestic 53ft rail cargo containers. In 2023, for example, Canadian Pacific Kansas City took delivery of 1,500 new reefer containers fitted with Thermo King SLXi DRC machinery, which has an integrated power pack and is charged with either R-404A or R-452A.

Design factors

In an interview with WorldCargo News Peter Hansen, Senior Product Manager Thermo King Marine, Rail and Bus, said the choice of refrigerant is a key consideration when designing and selecting intermodal refrigeration units.

“We evaluate the lifecycle impact for the solution, where 90% comes from energy, 8% from refrigerant and 2% from materials/processes. The energy efficiency of the solution is our top priority when considering Total Equivalent Warming Impact (TEWI), cargo protection by controls and overall system, and the Global Warming Potential (GWP) of the refrigerant used. Factors such as charged volume, GWP per kg, potential leak rate, and end-of-life processes for reclaiming and recycling are all critical. Therefore, designing for leak prevention, ensuring refrigerant safety during handling and operation, evaluating performance (range/envelope), global availability, and price trends, all influence our selection of current and future refrigerants.”

The Magnum Plus machinery uses R-404A or R-452A to offer a -40°C setpoint. Hansen said a -40°C setpoint is used for shipping cargo including life sciences products such as blood plasma and pharmaceuticals.

“This refrigerant offers higher cooling capacity than lower-pressure refrigerants and provides quicker pull-down after an intermodal move, such as from vessel to rail, or if cargo is loaded warm. If used for temporary storage of products where door openings can be more frequent, this system protects the cargo, and is more energy efficient, compared to using lower-pressure refrigerants. The benefit is also evident when the heat leakage of containers increases with age, as the Magnum Plus provides the essential extra cooling capacity,” Hansen said.

Thermo King is prepared to meet the USA EPA ruling. As noted, it offers the CFF which uses R-513A with a GWP of 631, but Thermo King is not recommending the CFF for all applications.

“Intermodal reefer containers designed per ISO1496-2 standards are used mainly for international trade and temporary storage. The availability of Thermo King’s CFF model ensures compliance for users who place these units into the domestic market or need a low-GWP solution for temperature-sensitive cargo,” Hansen said.

Big and leaky

US 53ft reefer containers require additional considerations. The Thermo King CFF model with R-513A can be used.

“However, these containers often experience heat leakage above 70w/k, making it challenging to achieve and maintain temperatures as low as -30°C. This is an issue for rail operators using 53ft containers, which is why units with refrigerants like R-404A, R-452A, and R-454A are preferred due to their efficiency in maintaining such low temperatures. R-454A is a good candidate for a future lower GWP (238), though it is an A2L class mildly flammable refrigerant, once safety standards and federal and local authorities consider and allow its use,” Hansen said.

The EPA granted a petition from Thermo King to reconsider the regulation regarding the nuanced language around temperature limits. In Thermo King’s view, critical life sciences products such as blood plasma and pharmaceuticals are shipped below -35°C, which technically, requires access to additional refrigerants.

Regulations and the national phase-downs under the Kigali Amendment to the Montreal Protocol will impact the supply of R-404A globally. Chemours stopped selling R-404A in the US in May 2024, but Hansen said there is no supply issue at the moment, and in future “there will be a good supply/volume of reclaimed and recycled refrigerants, including R-404A”.

There is no drop-in replacement for R-404A. Chemours is offering Opteon XL 40 (R-454A with a GWP of 238) as a replacement for both R-404A and R-452A. Thermo King agrees that R-454A works well and is a “good candidate” as a replacement, but not the only one. It is a lower flammability A2L refrigerant, which means upgrades to controls, leak detection and compressor temperature cut-out are needed. In addition, a full Operational Mode Risk Assessment and acceptance in the Intermodal Cold Chain operation are required to ensure safe operation.

Thermo King offers the CFF, which can be supplied with R-134a or R-513A as a refrigerant / Credit: Thermo King

Currently, reefer containers only use A1 non-flammable refrigerants. Industry consensus safety standards and acceptance by authorities are also required to enable new refrigerants. Chemours is also offering XP40 (R-449A – GWP 1282) as a replacement for R-507 and for R-404A in low- and medium-temperature applications.

Hansen notes that the operating envelope for R-449A does not meet the requirements for ISO 1496-2 intermodal reefer containers, where the setpoint range is a minimum of -30°C to +30°C in ambient temperatures between -30°C and +50°C. “If an end-user can narrow requirements and make dedicated temperature settings, then it could be an alternative,” he said.

Towards natural refrigerants

Carrier’s view on how the US regulation will impact the industry is shaped by its decision to develop the NaturaLINE machine with CO2 as a refrigerant, which is still unique in the reefer container industry. While NaturaLINE has been on the market for some time now, Carrier’s most popular reefer machine remains its PrimeLINE system that uses R-134a and is R-513A ready.

Carrier notes that PrimeLINE and the more recently launched OptimaLINE also have the R-1234yf option available to allow customers greater flexibility as the regulatory landscape evolves and continues to move towards lower GWP options. “That said, shipping lines would be wise to begin investing now in natural refrigerant solutions as a hedge against potential synthetic refrigerant price increases or availability issues,” Carrier said.

R-1234yf has a GWP of 1, but as noted it is a mildly flammable A2 refrigerant. When it comes to natural refrigerants Carrier says CO2 “is the baseline with a GWP of one, as compared with 1,300 for R-134a and 573 for R-513A, and remains the only natural refrigerant in use in the industry, while also being non-flammable.” With regard to the US market and 53ft reefer containers, Carrier says its machinery with R-513A is an option.

“Despite it having a slightly lower (5 – 10%) cooling capacity than R-134a at perishable cargo setpoints, R-513A can be used on a 53ft intermodal container if the box UA1 is not very high,” Carrier said, referring to the measure of the heat transmission across the area of the container.

Similarly, NaturaLINE can be used in 53ft reefers if the box UA “is not high”. Carrier notes that NaturaLINE has been used by DFDS in 45ft reefers for several years now, but it has yet to receive a request on 53ft containers.

“Interim solution”

While the new US regulation has created impetus to nudge the reefer industry towards replacing R-134a with R-513A, Carrier believes R513A can only be an “interim refrigerant” because it is a blend containing 44% R-134a, which is now being restricted by the US EPA.CO2 on the other hand, is “the natural refrigerant of choice in some of our most environmentally sustainable refrigeration solutions. By choosing refrigeration systems that use the natural refrigerant CO2, shipping lines can have a non-ozone depleting, GWP-neutral, non-flammable, non-toxic, and relatively inexpensive refrigerant, driving a highly efficient refrigeration system,” Carrier stressed.

While Carrier has chosen its course with CO2, other players in the industry are continuing to evaluate other natural refrigerant options, including mildly flammable and flammable refrigerants, along with other measures to improve the energy efficiency of reefer containers.

Carrier is “actively engaged” in discussions and continues to monitor the regulatory landscape, but has not changed its view that flammable refrigerants are not suitable for the industry due to the safety risk during operations and servicing.

Refrigerant costs

As well as the regulation, an increase in the cost of R-134a is expected to be a factor that will drive more container operators to R-513A. Hansen from Thermo King noted that the price of R-134a has increased by around 10% in China, but surged by 50% in Europe, due to regional quotas and market conditions.

At this point, however, the initial cost of R-513A is still more expensive, when compared to R-134a. Taking the total lifecycle cost over approximately 13 years the two become comparable, Hansen said. “As customers are considering long-term operational and environmental benefits, this long-term cost parity encourages transition to R-513A, despite its higher upfront cost.”

Carrier has a different view. It noted that the price of R-134a “has been increasing steadily throughout 2024” and availability is decreasing. However, Carrier believes reefer operators are still taking a “wait and see” approach when it comes to switching to R-513A. Some are saying that they do not intend to move to R-513A just for an interim solution, Carrier said.

Fösel from MCI added that there is no reported global shortage of R-134a, but production in China is limited because China has frozen its F-gas quantitates as of January 2024, which will put upward pressure on price. Overall, however, R-143a remains cheaper and more easily available than R-513A at this point.

PFAS regulation

There is currently a lack of clarity around regulatory changes to the use of refrigerants and the phase-out of those containing PFAS. (per- and polyfluoroalkyl substances – so-called ‘Forever Chemicals’). Administrations in the US, Europe and Asia are all moving to regulated PFAS, but not all the proposed regulations capture refrigerants in their definition of PFAS.

At the Federal level, the US has not included refrigerants and their degradation product, trifluoroacetic acid (TFA), with proposed legislation that excludes fluorinated refrigerants. China has not included refrigerants in the scope of its PFAS regulation at this point.

The EU published its revised Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) proposal in 2021. This was amended by the European Parliament in March 2023. It would ban the use of PFAS in refrigerants used on new equipment sold into Europe from 2025 and in servicing and repairing existing reefer equipment by 2035.

Europe proposes to ban all products using at least one fluorinated methyl or methylene carbon atom. This includes practically all existing low GWP hydrofluorocarbon (HFC) refrigerants, such as R-125, R-134a, R-143a, R-513a and HFO alternatives, including R-1234yf and R-1234ze(E).

Will refrigerants be included?

It is currently unclear if this proposal will go through in its current form. Georg Fösel Refrigeration Specialist, Reefer R&D – Tinglev, Denmark noted that Europe’s PFAS proposal will be evaluated by the European Chemical Agency (ECHA), which will take up the review process for fluorinated gases in the fall of 2024.

“It is therefore not expected that any regulation will enter into force in 2025, also as a minimum transition period of 18 months follows the date of entry into force of the regulation,” he said.

It is not certain that any ban will include refrigerants falling under the definition of PFAS at this point. The EU may opt to align the scope of PFAS restrictions to the US legislation, as advocated by the US EPA and Senate. There could be an extended derogation period as proposed by the Container Owners Association (COA) (20 years for refrigerants, unlimited for solid fluoropolymers), Fösel notes.

Staying the course

Carrier, as noted, stands ready with its NaturaLINE machinery with CO2 refrigerant. Carrier believes that “regulations coupled with customer ESG goals are likely to drive increased adoption”. In the wider refrigeration industry the use CO2 continues to increase in cool stores and retail refrigeration applications, especially in Europe.

Aside from Carrier, the other reefer machinery manufacturers are staying the course with their current direction with regard to refrigerants. Fösel said MCI is following closely, but given the uncertainty around the regulatory outcome, “has no plans to work with other refrigerants than R-134a, R-513A and R-1234yf.”

Hansen said Thermo King is also looking for clarity, but its approach to refrigerant selection has not changed at this point. “As always, we aim to select the best available refrigerant for the application based on the balance of safety, environmental impact, performance, energy efficiency, capacity and other considerations.”

Daikin is also watching the regulatory landscape, and in particular how the ECHA responds to the COA’s request for an extended phase-in period of any PFAS ban that affects refrigerants. “Daikin’s direction has always been the refrigerant choices R-134a, R-513A followed by R-1234yf,” the company reiterated. “At the same time, considering a sustainable solution to further reduce environmental impact and in response to the expectation that environmental regulations will be strengthened, Daikin is continuously looking at other refrigerant options for reefer containers, including CO2.”

“From our in-house knowledge and experience with our air conditioning products that use natural refrigerants, we see CO2 as a possible ‘PFAS free’ solution for reefer containers, in the event that the PFAS ban will include all existing low GWP hydrofluorocarbons (HFCs).

“The environmental performance of a reefer covers not only natural refrigerant itself, but also power consumption of the equipment and the ability to service the equipment globally. Daikin is therefore considering all the steps to provide our customers with a timely solution meeting the legislative changes and regulatory requirements,” Daikin concluded.