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R134a phase-out

Discussion in 'Energy, Environment, and Policy' started by nwdiver, Apr 1, 2017.

  1. nwdiver

    nwdiver Active Member

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    I was pleased but not too surprised to find Tesla on the list of automotive manufacturers that have adopted the new refrigerant.

    I've been concerned about the high GWP (Global Warming Potential) of refrigerants for a while now. While researching CO2 as a refrigerant I stumbled across another 'new' refrigerant that borders on being miraculous. CO2 has a GWP of 1 since it's the index. R134a has a 100-year GWP of 1430! The new refrigerant that has been selected to replace R134a, with the catchy name of R1234YF has a GWP of 4!

    CO2 is very difficult to use as a refrigerant due to the high pressures required but R1234YF is nearly identical to R134a... although it sadly can't be used in R134a system... I've got a slow refrigerant leak in my Heat Pump Hot Water Heater... hopefully the next generation will use more eco-friendly refrigerant.
     
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  2. TSLA Pilot

    TSLA Pilot Member

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    FWIW, our February, 2017, production Model S (US Spec) still uses R-134a.

    IF Tesla is using R-1234yf refrigerant, it may just be limited to EU or other country production, or your source page may be wrong.

    Just FYI.
     
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  3. nwdiver

    nwdiver Active Member

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    That's unfortunate :mad:
     
  4. AudubonB

    AudubonB Mild-mannered Moderator Lord Vetinari*

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    I hope the jury still is out on RF1234-yf. I have a healthy - ¿unhealthy? - fear of exposure to HF, which Daimler's engineers determined is created when the refrigerant is subjected to temperatures of, say, the engine block of an ICE.

    Now, that likely is not a realistic likelihood with a Tesla...except in the rare case of the battery module igniting, where the temperatures generated are at least as great.

    Overall, I'd be happier to have the engineering efforts focused toward designing an HVAC system capable of operating under the higher pressures that a CO2 system requires.
     
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  5. nwdiver

    nwdiver Active Member

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    I work with HF. I'm exposed to small amounts on a fairly regular basis (enough that I can smell it). Unless it's vaporized directly into the cabin of the car in fairly large quantities it's not going to cause much of a problem. It's lighter than air so the odds of it reaching significant concentrations in the open are low. Some of the other vapors emitted by burning plastics if there's a car fire are likely a greater threat than HF from the HVAC system.

    I do like the idea of using CO2 as a refrigerant... unfortunately it's hard to justify the expense. Systems that can operate at ~2000 psi aren't cheap.
     
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  6. brucet999

    brucet999 Active Member

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    I take it the the lower the GWP number the better?
     
  7. MRPLUGIN

    MRPLUGIN Member

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    Have not read much on the benefits....but it is crazy expensive. Its sold for $10 per oz. Typical cost to fill a vehicle $220-$250 (just for the 1234yf Freon)
     
  8. nwdiver

    nwdiver Active Member

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    Costs will come down as it scales. The GWP difference is enormous. Some refrigerant is recovered at the end of life but most of it leaks out over the life of the vehicle (often several times over)
     
  9. gckmac

    gckmac Supporting Member

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    I test drove an S yesterday at a Tesla event. I don't recall the production year, but after the test drive I had them open the front hood. On the passenger side, under the hood, is a refrigerant label stating that HFC-134a is used.

    Why would Tesla do that? HFC-134a, aka R-134a, has a GWP (global warming potential) of over 1,300. In other words, one molecule is like 1,300+ molecules of CO2.

    Already available and being used by other car manufacturers is HFO-1234yf, with a 100 year GWP less than one (or at most 4, depending on what source you read). It is now required for vehicles being sold in Europe. See 2,3,3,3-Tetrafluoropropene - Wikipedia
    It also is a near "drop-in" replacement for HFC-134a.

    The cost differential between HFC-134a and HFO-1234ya is, at this point, negligible, certainly in relation to a $75,000+ automobile.

    For what it is worth, if you've read Drawdown, changing refrigerants is the #1 way to reduce atmospheric warming molecules, with a 90 gigaton annual impact. The removal of all ICE cars & trucks? Just 4 gigatons. See “Drawdown” — The Definitive Guide To Combating Climate Change

    Has anyone tweeted Elon about this?

    Thanks,
    gckmac
     
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  10. SageBrush

    SageBrush Active Member

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    Let's see ...
    The MW of R-124a is about 2.5x that of CO2
    About 20 lbs of CO2 is emitted per gallon of petrol combusted
    Figuring American household petrol use at 1000 gallons a year
    that is 20,000 lbs of CO2
    If the GWP of the refrigerant is ~ 1000x, it would take 20 pounds of refrigerant to equal petrol combustion ...
    But the refrigerant is 2.5x heavier, so a household has to emit 50 pounds a year to match petrol

    Any error here ?
     
  11. nwdiver

    nwdiver Active Member

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    R-134a is ~1400x CO2.

    Irrelevant if it never leaks but a better refrigerant would be ideal.
     
  12. SageBrush

    SageBrush Active Member

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    OK -- 35 gallons a year would have to leak to match petrol combustion if my arithmetic is correct.

    Does a family ever come anywhere near that ?
    And note gckmac's assertion that refrigerant leaks are > 20x the harm of petrol emissions
    One of us has grave errors in calculation.
     
  13. Skotty

    Skotty 2014 Model S P85

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    I find the quoted Drawdown numbers to be highly suspect. Maybe the 4 gigatons for EVs assumes crappy energy mix? Maybe their numbers are just wrong. I'm no expert, but it seems a rather extreme claim to say that refrigerant leaking from a car, something that may amount to one system full on average every 5 to 10 years, can be more significant than the CO2 generated from daily gas burn. Definitely in need of some math checks and possibly clarification from experts.

    I'm also very negative towards the "have less children" argument that has been making the rounds and appears to also make an appearance in Drawdown. It's sort of a "give up" approach where you stop trying to solve the real problem and just start eliminating people. It's not a solution, it's a cop out. It's the equivalent of fixing your bad performance in a college class by dropping out. Okay, maybe in a pinch it helps, but not really the strategy to success you want to preach to the students.
     
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  14. nwdiver

    nwdiver Active Member

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    I think the point here is being missed somehow.... this isn't ICE vs EV. This is HFC-134a vs HFO-1234yf. 134a is >1400x worse than 1234yf. The point is that Tesla as a sustainability leader should be helping to push for that shift to help bring the cost down.
     
  15. Skotty

    Skotty 2014 Model S P85

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    Worth arguing to Elon, but who can get his ear?

    Also, what do home A/C units use? Whose leading that effort?

    The Drawdown numbers matter because of scale. For setting proper priority, we need a clear understanding of how small or big the problem is compared to everything else. Should this be Tesla's #1 issue, or #57? The Drawdown numbers are huge, and they need to be reviewed and either discredited or, if accurate, bought to much higher attention internationally.
     
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  16. nwdiver

    nwdiver Active Member

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    Home units are trickier... not sure why. They operate at a much higher pressure. They use R410a which is 1/3 as bad as R134. Ironically the best refrigerant is probably R-744... which is CO2.
     
  17. Skotty

    Skotty 2014 Model S P85

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    I like this thread, just because it made me think about what is used in home A/C units. I've followed what has been used in automotive for decades, but I can honestly say it never really crossed my mind for home A/C before today. It's just not something I've ever had to work on or thought about before. I was genuinely curious.
     
  18. nwdiver

    nwdiver Active Member

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    Refrigerants are the sleeper threat to climate change. A small amount can have an out-sized effect. With India becoming a wealthier country and ~1B Indians seeking refuge from the heat small AC units will become more and more common. The type of refrigerant these units use will have a tremendous impact on climate both in terms of potential release and energy consumption. OEMs can help influence this by driving down the cost of better refrigerants through economies of scale.
     
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  19. Drewflux

    Drewflux Member

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    The other issue with R1234YF is the charging equipment is ×10 $$ more than R134A. It is also not very tolerant to a mixed fill system. Recovering a system will other gas can kill the charge station. Making the change over to new equipment will always be slow on the uptake.
     
  20. SageBrush

    SageBrush Active Member

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    I agree, and thanks for bringing the chemical to my attention.

    That said, I'm now more convinced than earlier that the relative contribution of refrigerants to AGW compared to fossil fuel combustion has been wildly over-stated. Please let me know if I am wrong, but it looks to me like 1B more cars is a whole lot bigger problem than 1B more A/C units.
     
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