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?
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
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…