replacing HFCs with natural refrigerants worldwide today

Dick,

You seem to have some background in these matters, so certainly you must realise the serious error in your suggestion/implication that R134a could be considered as dangerous as HFO1234yf.

Not even the fluorocarbon propagandists agree with you on that point. HFO1234yf is obviously more dangerous than R134a because HFO1234yf is much more flammable than R134a. So on top of the shared risks of toxic products of heating and combustion, HFO has the additional risks of developing a self-propagating fire and the hazards that naturally result from that. Compare the MSDS sheets for the two and it should be obvious to you. If you need more evidence, take a look at the storage and transportation hazard classifications for HFO1234yf vs R134a - unlike the refrigerant safety classifications which the fluoro-lobbyists are desperately trying to reshape to keep a safe marketing distance between HFO and hydrocarbons, they have no such control over most storage and handling classifications. Look there and you will find that HFO is in the same or similar safety class as hydrocarbons. In short, the fact that HFO1234yf presents more risk factors than R134a is well beyond doubt.

Now, the follow-up question "what is a 'safe' refrigerant?" is the next obvious question.

The short answer is "none of them". By that I mean to point out that all refrigerants are potentially very dangerous. The slightly longer answer is "all of them, with appropriate risk mitigation measures in place".

The real answer to that question has been clouded by decades of black, grey and white propaganda campaigns by the fluorocarbon industry agaiinst hydrocarbons - most memorably in numerous "exploding car" stunts which are obviously very emotionally persuasive on the hearts and minds of policymakers and top level OEM's. The result of this has been decades of misconceptions throughout the industry (and government) about flammable refrigerants generally.

After 20 years of widespread use of hydrocarbons as an automotive aftermarket refrigerant (>20 million car-user-years as per the most current peer reviewed research) in otherwise unmodified vehicle AC systems without the much-prophesied "exploding cars" ever occurring, it is obvious to any objective analyst that the risks were grossly overstated (surprise, surprise).

So the answer to the question of "what refrigerants are safe" is staring right back at us already in the real-world data which shows us that hydrocarbons are already proven to be safe.

Depending on who you believe, HFO1234yf is ever so marginally less dangerous than hydrocarbons, or it may be considerably more dangerous.

If the former, then purely from a safety point of view then it should be obvious that HFO1234yf would then also be suitably safe. If the latter, then doubts about the suitability of HFO1234yf are warranted.

But seeking the answer to this last question seems to be a waste of time to me, because my research indicates that HFO1234yf, on a realistic assessment of risk, is AT LEAST as dangerous as hydrocarbons (although HFO has a narrower flammability range, it has massively more serious toxicity risks). Add into this mix that HFO is terribly complex (and therefore expensive) to produce, has more material incompatibilities and is less efficient than hydrocarbons, and the obvious question that should be left in an independent thinker's mind is "why should a motor vehicle OEM even consider HFO1234yf over hydrocarbons?"

It is only industry politics and the ghosts-of-scare-campaigns-past that hold them back from this obvious conclusion right now.

Finally, I'm glad you brought up the issue of "combustion energies". I can do little but applaud the fluorocarbon marketers and lobbyists for having done such a good job of painting lipstick on this particular pig. I ask all who read this to consider two critical issues in a little more depth:

1. Combustion energies are only an issue if those energies produce combustion that is 'explosive' - in the true meaning of the term - that is, where ballistic and heat forces are at a level which creates a whole new strata of risk factors. Although the media continually misuse the term 'explosive' and 'explosion' when referring to hydrocarbons, neither hydrocarbons nor HFO1234yf are explosives. When they ignite, they cause a 'flash fire' which quickly self-extinguishes. There is no "bang". The flame front is so slow a standard video camera can capture the moving flame front. A human being in a hydrocarbon flash fire will be very much alive after the fire self-extinguishes. In a HFO1234yf flash fire, however, they will remain in grave danger after the fire extinguishes due to the toxic HF released during the fire.

2. Lower combustion energies (and therefore lower flame front velocities) are NOT necessarily better. This is where the fluorocarbon spin machine really needs to be applauded for their skill at painting black as white. Tell me, readers, would you rather your skin be exposed to a faster or slower moving flame front? The answer should be obvious, yet the fluorocarbon propagandists have convinced most people that exactly the opposite is true.

Finally, I think it's good that such reports on HFO1234yf come out, because it brings some balance to the propaganda from the fluorocarbon manufacturers. I suspect that the German authorities behind this release also have some vested interest in promoting CO2, but it's our job as readers to think critically and extract the truth from the various published info. It's not that difficult.

Full disclosure: I work for a hydrocarbon refrigerant manufacturer. But you can check and verify these facts for yourself, if the reasoning itself eludes you.

HFC-134a, molecule for molecule, contains the same quantity of fluorine as HFO1234yf and slightly more on a mass basis. If R134a was ejected into flames during a vehicle fire I would expect about the same amount of HF to be generated.

This can be taken in two ways:

1) R134a may be considered as dangerous as R1234yf. Should 134a therefore be removed from all cars, if necessary by governement regulation, and we do without a/c?

2) If R134a has not caused any injuries or fatalities by generating HF in a vehicle fire over the past 15 years for which it has been used, then maybe the actual HF hazard associated with 1234yf is at best minor?

Hydrocarbons work efficiently in a/c units. Dimethylether, which also low has a low GWP, looks potentially more efficient than R134a or R12 and has similar properties. But HCs and DME have higher combustion energies than R1234yf, which is being described as "explosive".

We need to take care that in trying argue against R1234yf we do not also damn acceptable fluids by implication.

I don't work for any of the companies trying to introduce HFO1234yf. My interest is in using natural refrigerants more efficiently and safely.