Work continues on an ISO standard (ISO 20854) that would allow flammable refrigerants to be used in reefer containers. The ISO/TC 104/ SC02/ WG01 working group has been working on this since 2015, and the finish line is now in sight.
Reefer machinery manufacturers expect the measure will provide safety standards for the design and operation of refrigeration systems using different levels of flammable refrigerants. The details are important. Maersk Container Industry (MCI) points out: “ISO 20854 is a product safety standard that covers all flammable and non-toxic refrigerants (A2L, A2, A3) and is limited to container refrigerating systems operated in conjunction with the carriage of refrigerated cargo as operating reefer or when used as non-operating reefer or when empty for positioning – while in intermodal transit. Static land-based continuous operations are excluded”.
The standard is currently in the Final Draft International Standard (FDIS) approval stage, and the ballot for this is open until 24 September 2019. A positive two-thirds majority approval vote means the DIS is circulated to national bodies and an ISO standard can be issued. The expected publication date, based on the current timeline, is 8 December 2019. “As the previous DIS voting of the standard has received 100% positive votes, it is expected that the standard will also pass the FDIS ballot,” added MCI.
Daikin and MCI are both enthusiastic about this move. As previously reported, Daikin has stated that it is investigating the refrigerant R1234yf as a replacement for R134a. R1234yf has a GWP of four and an A2L rating, meaning it is a “mildly” flammable substance. It is also compatible with existing R134a machinery.
In an update to WorldCargo News, Daikin said it continues to study several alternative refrigerants to find the best fit for reefer containers. This work, continued Daikin, shows that R1234yf has the same energy efficiency as R134a and is, therefore “one candidate” for reefer applications. Daikin is now analysing the potential hazards from its flammability class in different scenarios, including misuse.
MCI is also working on a reefer using R1234yf, now that it is no longer pursuing propane as a next-generation refrigerant. Anders Holm, global head of sales and marketing at MCI, said the need to be pragmatic while considering the environmental aspects led MCI to identify R1234yf as an energy-smart flexible solution that will be for the industry to adapt to on a global scale, considering how M&R work is performed around the globe.
“MCI is working on maturing and improving the design and, together with DNV GL, to en sure compliance of the R1234yf Ready design to ISO 20854,” said Holm. He noted that using R1234yf in a system that is “very close” to what MCI offers today with Star Cool will give reefer owners three alternatives – R134a, R513A and R1234yf – on the one platform.
One of the reasons MCI was previously perusing propane was its strong performance on the TEWI (total equivalent warming impact) scale, but Holm said R1234yf also performs well in this regard. “The energyefficiency will be very close to the same as R134a and R513A, which we offer today. TEWI is the combination of both indirect and direct emissions. On the direct emissions, the GWP of R1234yf is lower than the others, so overall, the TEWI will be lower,” said Holm. MCI plans to field test R1234yf in a reefer in 2020, and have a “triple refrigerant” Star Cool reefer on the market by 2021.
It is not just Daikin and MCI that are supporting the ISO 20854 initiative. Jessica Poliner, vice president and general manager, Global Marine, Rail and Air at Thermo King, said it too has been working closely with major refrigeration equipment OEMs and the shipping lines on the standard.
Thermo King has long used R-404A in its reefer machinery. In 2015, the company introduced R-452A as a drop-in alternative with a lower GWP. Poliner said this helps protect the residual value of R-404A designed equipment, but Thermo King is also looking for alternatives in different market segments. “Specific to the marine industry, Thermo King is analysing additional lowpressure refrigerants for our reefer fleet,” she said.
However, Thermo King is not giving up on R-452A. “We still need to remember,” said Poliner, “that using R-452A, the Thermo King Magnum Plus unit is the only one in the industry capable of reaching -40 degC temperature and maintaining the reefer container performance, even when the box is ageing. With Thermo King, the cargo is always protected.”
Thermo King also uses R134a in its Super Freezer reefer, which actually has two refrigeration circuits, one containing R134a and the other using R23, to achieve a temperature of below -60 degC. “This ultra-low set point halts enzyme activity in special cargoes, reducing spoilage,” said Bruno Fusciani, commercial leader, Global Marine, Thermo King. “This feature means that cargoes that might otherwise have to be shipped by air can now be more environmentally transported, and at reduced cost. Along with certain foodstuffs, our Super freezers are regularly called upon for medicine, blood and blood plasma transport and protection. The recent Ebola outbreak in Africa had the vaccine transported and stored locally in one of our super freezers.