Proposed R-134a Replacement Refrigerant

I was looking at refrigerants and ran into a discussion of the proposed mandated replacement for R-134a. The notion being that various refrigerants do damage to the ozone layer and / or cause “global warming”. Now I bought into the whole “ozone hole” thing when it first hit, but the more I looked at it, the less real it was.

For a “well mixed gas”, the “depletion” spots tended to dynamically move and change a LOT. Seems things ought to be well mixed in the depletion as well… Further watching showed they moved much as a Birkeland Current landing zone on the poles would move and changed much as such an electrical flow would change. Then there was the problem of folks “declaring victory” that the ban on R-12 has eliminated the Ozone Hole problem when they had just been screaming that it had a 50 year atmospheric residency time. Well things with a 50 year residency don’t just go away in 5 years (and especially not when still being made, used, and vented in other countries…)

But “whatever”… You can now buy R-134a for about $5 / can and it works about as well.

So of course now there is a push to ban it, too. Guess another patent ran out and they need to get profit margins back up… But “with what” is the question. Well, European car makers are not decided yet. One group wants to use CO2, but the compressor pressures are very high and mechanical stresses will be higher too. Another group is advocating for a particular molecule that has the most “endorsement” (meaning “green push” near as I can tell, mixed with some Crony Profit motives).

What’s that gas?,3,3,3-Tetrafluoropropene

This stuff does not impress me as a decent choice. It “has issues”. (Not the least of which is that there is no need to change whatsoever…)


Preferred IUPAC name
Other names
HFO-1234yf; R1234yf; R-1234yf; 2,3,3,3-Tetrafluoropropylene

405 °C (761 °F; 678 K)
Explosive limits 6.2 %(v); 12.3 %(v)

2,3,3,3-Tetrafluoropropene, or HFO-1234yf, is a hydrofluoroolefin (HFO) with the formula CH2=CFCF3. This colorless gas has been proposed as a replacement for R-134a as a refrigerant in automobile air conditioners.

HFO-1234yf is the first in a new class of refrigerants acquiring a global warming potential (GWP) rating  1⁄335 that of R-134a and only 4 times higher than carbon dioxide.

You got it… a FLAMMABLE gas to be used only due to ‘global warming potential’… In other words, bull shit.


Although the product is classified slightly flammable by ASHRAE, several years of testing by SAE proved that the product could not be ignited under conditions normally experienced by a vehicle. In addition several independent authorities evaluated the safety of the product in vehicles and some of them concluded that it was as safe to use as R-134a, the product in use in cars today.

Now I’m not squeamish about a quart of flammable gas in a vehicle full of gallons of gasoline. Ive run a iso-Butane / Propane mix in my own R-12 cars before, for several years, without any problems. However, I don’t smoke and I’m pretty sure my cabin is drafty enough that a leak would not accumulate…

But what happens in case of an engine fire or accident?

In the atmosphere, HFO-1234yf degrades to trifluoroacetic acid, which is a mildly phytotoxic strong organic acid with no known biodegradation mechanism in water. In case of fire it releases highly corrosive and toxic hydrogen fluoride and the highly toxic gas carbonyl fluoride.

Um, hydrogen fluoride is nasty nasty stuff…

And just what happens to that “no known biodegradation” product over time as millions of pounds of it get vented / degraded?

But about that “doesn’t burn – much…” claim: We have the chemical company saying “No Problem” – in effect. While a car maker I trust has said “Um, woopsy! Not interested”…

In July 2008, Honeywell/Du-Pont published a report claiming “HFO-1234yf is very difficult to ignite with electric spark” detailing the tests they did passing the gas over a hot plate heated to various temperatures in the range of 500°C – 900°C. Ignition was only seen when HFO-1234yf was mixed with PAG oil and passed over a plate that was > 900°C.

How about when it is sprayed into an engine compartment during an engine fire? How about when the oil / gas mix gets misted over the ignition system and onto the exhaust manifold?

In December 2012, Mercedes-Benz showed that the substance ignited when researchers sprayed it and A/C compressor oil onto a car’s hot engine. A senior Daimler engineer who ran the tests, stated “We were frozen in shock, I am not going to deny it. We needed a day to comprehend what we had just seen.” Combustion occurred in more than two thirds of simulated head-on collisions. The engineers also noticed etching on the windshield caused by the corrosive gases.
BMW, and VW-Audi agreed with Mercedes and left the SAE R-1234yf CRP Team, stating that the performed tests are not sufficient to fully judge the safety of their vehicles. The German automakers have been leaning towards carbon dioxide refrigerant, which may be safer for both passengers and the environment.

“etching on the windshield” does not bode well for the lungs of occupants nor first responders…

Following Mercedes claims that the new refrigerant could be ignited, Germany’s Kraftfahrt-Bundesamt (Federal Motor Transport Authority) conducted its own tests. The Authority concluded that while the substance was potentially more hazardous than previously used R-134a, it did not comprise a serious danger. However the German automakers disagree with their findings, and test procedures. Following other independent and in house testing, General Motors still plans to transition all new models to the new refrigerant by 2018. Chrysler announced that they would continue the transition to R1234yf as well. Japanese automakers are also making the transition to R1234yf, Honda and Subaru have begun to introduce the new refrigerant already with the 2017 models.

Well, I wasn’t going to be buying any GM cars anyway… Looks like Chrysler, Honda and Subaru are on the list too.

Adoption by automotive industry

HFO-1234yf was developed to meet the European directive 2006/40/EC that went into effect in 2011 requiring that all new car platforms for sale in Europe use a refrigerant in its AC system with a GWP below 150.

HFO-1234yf, which has a 100-year GWP lower than 1, could be used as a “near drop-in replacement” for R-134a, the current product used in automobile AC systems, which has a 100-year GWP of 1430. This means that automakers would not have to make significant modifications in assembly lines or in vehicle system designs to accommodate the product. HFO-1234yf has the lowest switching cost for automakers among the currently proposed alternatives, although the initial cost of the product is much higher than that of R-134a. The product could be handled in repair shops in the same way as R-134a, although it would require different, specialized equipment to perform the service. One of the reasons for that is the mild flammability of HFO-1234yf. Another issue affecting the compatibility between HFO-1234yf and R-134a-based systems is the choice of lubricating oil. The current lubricating oil is showing signs of damage to plastic and aluminium, and issues with health, including mouth dryness, rashes, and sore throat, among other effects.

So car repair shops need to buy new gear, raise prices, and watch out for increased damage to plastics and aluminum. Oh Joy. Oh, and being sickened by the stuff…

So why oh why bother to make such a shift for a fantasy gain in a non-problem?

Shortly after confirmation from automakers that HFO-1234yf would be adopted as a replacement of R-134a automotive air-conditioning refrigerant, Honeywell and DuPont announced jointly built a manufacturing facility in Changshu, Jiangsu Province, China to produce HFO-1234yf. In addition, Honeywell is building a new plant in Geismar, Louisiana, USA to produce the new refrigerant as well. Although others claim to be able to make and sell HFO-1234yf, Honeywell and DuPont hold most or all of the patents registered for HFO-1234yf.

Oh… That explains it…

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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12 Responses to Proposed R-134a Replacement Refrigerant

  1. philjourdan says:

    Yea, I think we will hold onto our cars for a few years. Give it 3 or 4 tops. Before the lawsuits bankrupt everyone.

    That sh*t is a lawsuit looking for a lawyer!

  2. D. J. Hawkins says:

    I worked for Matheson Gas Products for a number of years, designing ultra-high purity gas delivery systems for semiconductor fabs. I worked with silane, arsine, boron trifluoride, and any number of others that used 99% H2 as a carrier gas. The only one that terrified me was HF.

  3. jim2 says:

    R-134a degrades a bit in the AC system, resulting in some HF. That’s why it’s important that the drier works well.

    Also, from the article:
    Contact of 1,1,1,2-tetrafluoroethane with flames or hot surfaces in excess of 250 °C (482 °F) may cause vapor decomposition and the emission of toxic gases including hydrogen fluoride and carbonyl halides.,1,1,2-Tetrafluoroethane

    That said, this new stuff looks more dangerous than what we have. When is someone going to stuff a shirt into the green movement??

  4. dougleach says:

    Yes but. 134a will also burn. And upon combustion or thermal decomposition, what do you suppose two of the principal products are? Hydrogen fluoride and carbonyl fluoride. If you performed the Daimler test with 134a, it would burn too.

    Remember some 25 years ago NBC ran a report on Dateline claiming the gas tanks on GM pickups were a bomb waiting to explode? Turns out the test was setup to make them explode. Daimler’s test was no different.

  5. gallopingcamel says:

    The Montreal protocol is a sacred cow that gets very little attention even though there are plenty of reasons to doubt the validity of the underlying “Science” as you show in this post.

    The Montreal Protocol essentially banned the production of Freon and similar compounds based on the prediction that this would reduce the size of the polar “Ozone Holes”. After the ban went into effect the size of the ozone holes diminished. This may mean that the science presented by McElroy and his cohorts was “Robust” or it may be dumb luck. Either way, McElroy has credibility and “Skeptics” are ridiculed.

  6. jim2 says:

    Also, molecules with a double bond are feedstocks for polymers (plastics). I’m wondering if this stuff, under heat and pressure, will make a solid residue over time.

  7. cdquarles says:

    Hydrogen fluoride should frighten you. I have worked with it, very cautiously. Nasty stuff. I’ve worked with nastier stuff than that, too; still, I’d not want anything that could produce more than a trace of HF gas. Carbonyl fluoride? Never worked with that. Sounds like something that would decompose into HF and carbon monoxide.

    The nice things about full fluorocarbons was how very inert they were under normal conditions and how hard it was to get conditions that would decompose them and get hydrogen fluoride from it. One of the reasons why they went to chloro-fluorocarbons was that for a slight decrease in decomposition difficulty you got a lot less HF generation potential.

  8. cdquarles says:

    I misread the chemical name. Prop-ene. A double bond (unsaturated) containing hydrofluorocarbon.
    Well, yes, it is going to be flammable, since oxygen can and will attack at that double bond point. On the other hand, that double bond gives it a potential spot for biochemical degradation, since there are lots of enzymes that operate on that kind of a chemical. It also gives it a spot where water can attack it.

  9. Jeff says:

    There’s a fellow at Purdue, in the EE department, who is an inventor (and subject of a Dave Barry column) in his spare time. He has created substitutes for various refrigerants which are safer, and has a number of patents to his name. Wiki has a small article on him: .

    The Dave Barry article is about him and his barbecue buddies lighting up a grill in 3 (!) seconds. LOX helped substantially (and then some).

    The refrigerant that sounds interesting is R406a (AutoFrost).

    I have a freezer here with “EuroSafe” refrigerant R600a. Seems it is HIGHLY flammable, to the extent that they specify that the freezer must be in a space with free air access of 9 M³. Oh joy, my cellar won’t do it, although it’s the only place I can fit said freezer.

    Never had these problems before the Fake Ozone Hole appeared. I’ve seen articles which attribute the size of the “hole” to cosmic ray activity (or lack thereof), upper atmosphere weather patterns, or the vagaries of the electric universe. I remember the good old days when I could go to Grand Auto and get cans of Freon to recharge my cars’ air conditioners. Could have been exciting, I suppose, if had accidentally connected the jig to the high side of the system. Then again, R600a and the new refrigerant (which Mercedes has vehemently refused) are disasters waiting to happen.

    Here’s the Dave Barry column about the BBQ experiment:

    YouTube vid of said “BBQ”

    And a “how-to” article/interview:

  10. Larry Ledwick says:

    I assume he knows that they use LOX and charcoal as a binary explosive?

    I have heard several horror stories about incidents with LOX during the early days of the rocket program that would cause me to take off at a dead run if someone wanted to do that.

    In one case I believe it was in the X-15 program a person who had been involved with LOX fueling of the rocket plane stepped well clear of the plane for a smoke break. His cloths were saturated with LOX vapor and he had not allowed enough time for the oxygen enriched clothing to “breath” when he lit the match, his cloths exploded with terminal results.

  11. gallopingcamel says:

    Thanks for finding that video (I had lost my link to it).
    That is the kind of thing that makes one proud to be a scientist!

  12. John F. Hultquist says:

    We still have a 1980 Chevy PU with saddlebag gas tanks. It still runs but has various unrelated issues.
    We have Subarus (2014 & 2016) — perhaps we will never need to buy another auto.
    I see a “community” in our future where we zip around on gliding walkways and electric carts.
    Maybe the atmosphere will be controlled ! We are downwind to 2 large forest fires — 30 miles to Jolly Mountain, and 40 miles to Norse Peak [Washington State]. Should mention the temp is about 95°F.
    Full-house air filtering is a wonderful invention — with cooling as necessary. At 4 PM the hallway is at 77°F but the cooling has not yet kicked in.
    At 2200 feet elevation we can get the whole house naturally cool during the night.
    We do need to do some maintenance/addition on the attic insulation and then even do better.

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