Using propane as AC refrigerant?

Discussion in 'The Garage' started by Shawn, Apr 6, 2008.

  1. Shawn

    Shawn Lifer

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    I have heard of people using propane in refrigerators and such but they aren't subject to high speed collisions. I wonder if there is any real risk of explosion using it in a car. There are a few companies now selling 60/40 propane/isobutane blends as R12/R134a alternatives so I figure it has to be relatively safe. They claim that the concentrations are low enough that it isn't dangerous.

    I was thinking about putting straight propane in my sister's 1989 honda accord because it's cheap and I already have a tank at home. Plus moisture in the system wouldn't be as big a deal because propane doesn't create an acid when it comes in contact with moisture like R12 does.

    I've heard that straight propane may cause problems though because it could get too cold and freeze the evaporator. That is supposedly why the blends contain isobutane. If that is the case then I guess I'll just pay a little more and get the blend. Just wondering if anyone here has experience with this stuff. I may try straight propane first just to see if the AC system even works at all.
     
  2. boomerang

    boomerang Lifer

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    It's your sisters car, so no real danger to you.

    Pics please, especially if it's an open casket funeral. Of course with the fire and all, the chances are unlikely,

    Oh well, a buck is a buck. Gotta save 'em where we can!
     
  3. dug777

    dug777 Lifer

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    I did find this comment on one site:

    Hydrocarbon refrigerants (100% hydrocarbons) can be blended to replace R-134a, and these blends are compatible with PAG or POE oils (POE may thin out too much). A typical blend would be 60/40 by weight of propane/isobutane. These blends are highly flammable and are banned in about 18 states at the present time.

    As far as I can see, there's got to be a very good reason why cheap and highly flammable hydrocarbons aren't used by the automotive industry.

    I just can't see what it might be...
     
  4. drnickriviera

    drnickriviera Platinum Member

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    It's called R-290. It's used in refrigerators as well. I used it at one time. Yes it is true that if you use 100% propane, your system will freeze up. The only time I would consider using it again would be for a R-12 system. They just don't work well with 134 since it is less efficient.

    As far as flamability, i'm not sure. Flip a coin. I think that conditions would have to be perfect to start a fire, and if it did catch fire there's not that much in the system. Why it's not used more? Dupont and the rest are making good money off their refrigerants.
     
  5. crosshairs

    crosshairs Golden Member

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    propane refrigerators DO NOT use the propane for a refrigerant..if you feel the need to use it in your car, please put a decal under the hood so if anyone ever had to work on it they have the information needed to service it properly.

    Or better yet, remove it when you sell the car so some dummy doesn't kill himself..:)
     
  6. zixxer

    zixxer Diamond Member

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    wtf are you kidding me?



    Don't do that to your sister's car.
     
  7. thedarkwolf

    thedarkwolf Diamond Member

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    I guess gasoline isn't flammable? Not to mention all the other crap that could catch on fire if in a wreck it got splashed on the exhaust manifolds or some other really hot engine part.
     
  8. getbush

    getbush Golden Member

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    Did you guys see the James Bond mythbusters where they were shooting holes in a large (50? 100? gallon) tank of propane trying to get it to explode like in the beginning of Casino Royale?

    First, they couldn't puncture the tank with a handgun round, it would just dent it. They had to use a 12 gauge slug and then a .30-06 to penetrate. After that, it wouldn't ignite, it would just throw a huge cloud of propane.

    http://youtube.com/watch?v=_FHTXwpVMvs

    I'm not making an argument here, it was just interesting and mostly off-topic :)
     
  9. sonoma1993

    sonoma1993 Diamond Member

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    i remember seeing that episode, that was awesome
     
  10. mwmorph

    mwmorph Diamond Member

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    Gasoline is a flammable liquid and gas do when it is in a car, the correct safety systems are in place to increase safety, the fuel lines are installed in such a way as to decrease the likelihood of it bending and breaking, as well as away from anything that gets too hot under operation and the fuel tank is put in front of the rear axle, below the safety cage, away from crumple zones and etcera.

    Your AC system was not designed with those safety design parameters in mind because it's designed to use R134 or R12 and thus isn't as much of a fire hazard initially. Adding a highly flammable solution in that will have a higher likelihood to do damage than gasoline to a system not designed for ti can cause problems. If decompression occurs and it the gas gets near the exhaust manifold or something else suitably heated, then yes a fire can occur.

    I would just get a can of R134 refrigerant, (they sell those $35 kits at autozone that can recharge the system as a DIY) or a R12 to R134 conversion kit so you can use R134 if it hasn't been done already. They arent particularly expensive.
     
  11. drnickriviera

    drnickriviera Platinum Member

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    Yes, some do use it as the refrigerant. I'm not talking about propane fired refrigerators that are used in RV's and such.

    The American Society of Heating, Refrigerating and Air-Conditioning Engineers even recognizes it as an alternative to R-22.
     
  12. Shawn

    Shawn Lifer

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    The compressor on this car is not compatible with R134a at all. It's a shit compressor. The higher pressures will cause it to fail quickly, or so I've heard. A compressor replacement is required to convert to R134a.
     
  13. Zenmervolt

    Zenmervolt Supermoderator<br>The Garage<br>Elite member

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    I run Duracool in my 951. Have for several years. It is very effective and perfectly safe. The car carries 21 gallons of gasoline in it, why would I worry about 14 ounces of butane? Besides, R-134a ignites at a lower temperature than Duracool and R-134a will sustain ignition. Go ahead with Duracool. It works fine.

    ZV
     
  14. Shawn

    Shawn Lifer

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    Thanks for the info! I was also looking at Freeze 12, which is legal, but I've heard that it doesn't cool as well as R12, whereas Duracool cools even better than R12. Thoughts?
     
  15. Zenmervolt

    Zenmervolt Supermoderator<br>The Garage<br>Elite member

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    Freeze-12 has R-22 in it. R-22 would be an excellent choice if the hoses could handle it. However, most cars that used R-12 did not have barrier type hoses and R-22 will seep out through the rubber lines.

    EDIT: Just read that you were contemplating commercial-grade propane. Do not use that. Look at the difference in autoignition points for that and for Duracool; there's a large difference.

    ZV
     
  16. SuperjetMatt

    SuperjetMatt Senior member

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    If, however, you shoot at it with said rifle, and then get your buddy to fire a tracer round at it a split second later, it will result in a spectacular fireball.

    Ask me how I know.
     
  17. DivideBYZero

    DivideBYZero Lifer

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    If you like driving a four wheeled bomb, go for it.