At least five new refrigerants under consideration for automotive applications
- PostedPublished 16 September 2022
“By somewhere between 2025 and 2028, there will be a new refrigerant on the market dedicated to EVs from the factory.”
This was the bombshell dropped by Mobile Air Climate Systems Association (MACS) president Peter Coll at Wire & Gas 2022.
“Five new refrigerants are proposed – YF is also under consideration – and all of them except for YF will be multi-component blends,” he said.
On the topic of multi-component blends, momentum is gathering behind the adoption of R456 as a retrofit refrigerant for R134a systems, especially in Europe.
This non-flammable blend of 49 per cent R1234ze(E), 45 per cent R134a and six per cent R32 has a global warming potential rating of 626, less than half that of R134a.
Although many VASA members already use a suite of separate pieces of equipment for refrigerant recovery and recharge, these proposed blends will make it impossible to use existing all-in-one recover/recycle/recharge (RRR) equipment technology.
“You’ll recover the refrigerant, store it in the container and that container that gets sent off to somebody for reclamation,” said Peter. “And you’ll charge it with virgin or reclaimed refrigerant that’s already been processed; that’s really a downside to these refrigerants”.
Peter described the ability for workshops to use RRR machines with R1234yf as “one saving grace” for what is currently the most widely adopted low-GWP automotive refrigerant.
“Everybody else is currently not looking at reprocessing on site, or recycling on site,” he said.
The race to identify a new EV-specific refrigerant stems from the need for a product that can perform triple duties.
Peter said a “thermal management refrigerant cooperative research program” had been established by the Society of Automotive Engineers (SAE) with the goal of “improving the efficiency of heating and cooling in electric vehicles”.
The aim is to “create a system which is likely to be a heat pump that can operate in very cold conditions, very warm conditions, and operate in a heating mode for the cold conditions and a cooling mode for the warm conditions,” said Peter.
The result will likely be a heat pump with glycol-based secondary loop that can heat or cool the passenger compartment for occupant comfort while also managing battery and driveline temperatures.
Although such systems already exist using R134a, R1234yf and R744 (CO2), none can effectively and efficiently perform all tasks in all climates.
Peter said R744 – popular among German EV manufacturers – would not be adopted in North America.
He explained that like any refrigerant, for it to be approved by the Environmental Protection Agency, there must be equipment available to service systems that use it.
“Those equipment standards, such as SAE J2773 are suspended and we suspended them because we didn’t get any cooperation from our European partners, the Daimlers and the BMWs,” he said.
“And we said, we’re not using it here, nobody’s really interested at Ford, or Toyota or Chrysler to use it. So if you guys aren’t going to help us, we’re not going to reinvent the wheel. So we’ll just let it sit here. So until such time as they want to cooperate, and we develop the standards, the EPA is unable to approve the use of CO2 in the US.
“So we’ll have to kind of wait and see how that all plays out … Volkswagen is trying to send the ID [electric car range] with CO2; they’ve been told they can’t send it with CO2, it’s got to be YF.”
MAC Partners Europe president Michael Ingvardsen, joining the event via video link from his office in Copenhagen, Denmark, added that the VW ID’s R744 systems are notoriously leaky.
“Be very careful of the ID if you’re buying a CO2 unit simply because it does leak. And it does leak very quickly,” he said.
“In general, all of the German car manufacturers, Mercedes, Audi, BMW, Volkswagen and so forth, really like the CO2 option.”
Michael explained that R744 is rarely seen on internal combustion engine vehicles but that its efficiency in heat pump applications meant it was becoming prevalent on hybrid and electric vehicles in Europe, to provide cabin comfort in cold climates, cooling in milder summer conditions and thermal management for electric drive systems and battery packs.
However, the relatively high failure rate and complexity of these R744 systems, which combined with tight operating tolerances and high working pressures juxtaposed by a total lack of regular preventative maintenance schedules from car manufacturers had led to a lot of work for those who know their way around an automotive heat pump running R744.
“They have got more tubes and pipes and hoses, but also up to six to seven, solenoid valves that need to open and close independently of each other,” said Michael.
“And once you have a breakdown of a system, you need to make sure that system is clean, you need to make sure that the solenoid valves are free of any dirt or residue and so forth.
“As it is right now, there really isn’t any maintenance schedule for the systems; I actually just had a conversation with the Volkswagen importer in Denmark and they said, no, we don’t have any basic maintenance schedule for the heat pump system or the AC system in general; we will service it if you want us to, but you more or less have to ask us to do it.”
Just as VASA has been highlighting to the repair sector since electric vehicles with refrigerant-based thermal management systems emerged, if the AC goes wrong, the whole car will shut down or – best case scenario – enter limp home mode.
“Unfortunately, with these vehicles, if your heat pump system does not work, and if the CO2 is causing some issues the car simply will not run,” he said.
“It’s not going to go anywhere until you fix that heat pump system.”
People with the technical skills required to diagnose and repair automotive R744 systems are scarce – although training does exist – and replacement parts of requisite quality are expensive, with cheaper alternatives likely to quickly fail and cost consumers more in the long run.
It is, then, looking like R744 may be a flash in the pan for automotive. Which brings us back to the half-dozen or so refrigerants now under evaluation for electric vehicle heat pump applications.
Michael said R456a is already “very much welcomed into the European society” to retrofit R134a systems as strict F-Gas quotas on high global warming potential HFCs cause supplies of R134a simply dry up part way through the year.
In the United States, Peter said R456a, nor any of the mooted YF and R744 alternatives have yet made it onto the US Environmental Protection Agency’s (EPA) Significant New Alternatives Policy (SNAP) list of approved refrigerants.
“The manufacturer of R456a is meeting routinely, weekly, with the EPA to identify what the next steps are to get it on the SNAP list,” said Peter.
“A vehicle that’s made today with R134a may well still be on the road in 2034 and may need air-conditioning service. But what refrigerant will be available?”
Peter expected R456a to be approved as a service refrigerant for R134a systems.
R744 is absent from the six candidates vying to be the refrigerant of choice for electric vehicle heat pumps, but YF is there.
Peter said a product called Enhanced CO2 is also among the six, along with products from Chemours (formerly DuPont), Daikin, AGC Chemicals, and Koura (formerly Mexichem).
Whatever the outcome, Peter said the product that ends up on the SNAP list for electric vehicle heat pumps “is likely going to be an A2L mildly flammable refrigerant”.
- CategoriesIn SightGlass
- Tagsheat pump, R1234yf, r744, refrigerant, refrigerants, SightGlass News Issue 27, Wire & Gas 2022, YF