Recharging AC with propane

As the summer heats up an air conditioning system is a necessity in many climates. [Grayson's] system suffered some damage over the winter that caused it to vent its refrigerant, avoiding an explosive situation. Before he can chill out inside he’ll need to recharge it and he’s chosen to use propane in his cooling system. According to our friend Google this is not his original idea, but has been done many times before. [Grayson] makes the point that although propane is flammable it’s not necessarily any more dangerous in a fire than Chlorodiflouromethane, or R22, which is the nasty little gas that fled his system for its new home in the upper atmosphere.

The video above includes a brief explanation of recharging the system and the tools needed. We’d need to mill this over for quite a while before working up the gumption to give it a try. For now we’ll stick to [Grayson's] more pedestrian hacks like making some servo motors sing or easing our yard work woes.

Comments

  1. cliff says:

    lots of industrial places use propane as a refrigerant, you don’t need special licenses to work on it and its waaaaaay cheaper.

  2. SS says:

    I disagree. Propane is highly flammable (NFPA704 rate 4 = highest flammability), while the R22 and R134a has flammability 0 and 1, respectively. Cheap doesn’t mean safe.

    • william says:

      Well, there is no O2 in the refrigerant circuit, so it can’t burn inside the circuit. If it leaks, it will leak slowly, not causing much of a hazard. Even if something weird happens, and it leaks all at once, it won’t be any more dangerous than a propane leak from a stove, dryer, water heater, or furnace, which are kept and operated inside. The highest pressure parts of the AC are outside. So if it’s so dangerous, why do people use propane appliances inside? Methinks you are a R-12 salesman.

    • bill says:

      what is more dangerous than having 20 gal of gasoline under your back seat and fuel lines running all over a hot engine.

  3. hmburgers says:

    Propane is far more dangerous then R22.

    I think this is no more of a hack then some other inappropriate substitution–is it a hack if I use parallel pieces of lamp cord to wire up some 15A circuits in my house? Sure maybe they have the same current carrying capability, but it’s just not a smart or safe thing to do.

    Good luck w/ the propane… at least the knuckle head isn’t using it to replace the R12 in his old car.

    • william says:

      Is it any more dangerous than the gasoline in your car? I’d say not, since the propane won’t stay on your skin, and clothes and keep burning you, even if you get away from the car. You know there is a 10 or 20 gallon tank of it under your back seat.

  4. @SS agreed. Also buying quality equipment needed to do a DIY repair (vacuum pump, refill gauges/hose set, torch, solder, pipe, insulation) will far outstrip the cost of having the local pro do it correctly. The only way this is cost effective is if you have to refill multiple times, in which case you’ve got bigger problems…Not to mention the AC compressors are not designed to work with propane (even though it may happen to work)…Personally that’s not a warranty I’m willing to void (and it would probably screw you’re home insurance too).

  5. Tim says:

    Now my air conditioner is both clean burning and efficient.

  6. Pedro says:

    Hank Hill would be proud, I tell you what.

  7. fartface says:

    I have seen idiots do this in a car. Only ragingly stupid people use propane in a car AC system.

    Ragingly stupid.. as in go get a L tattooed on your forehead.

  8. cgmark says:

    3 year old system ? I would have contacted the manufacturer. There is no reason a 3 year old system should need more refrigerant unless physically damaged . The lines have to be pressure tested, vacuumed out , refilled with oil, refrigerant replaced and if it wasn’t done in a timely manner when the leak occurred you got bigger problems.

    When refrigerant leaks out that also means moisture is getting in. Adding propane removed any chance of having the manufacturer replace the compressor on failure, which it will , especially on a system that has a leak. The refrigerant will leak out and take the oil with it, moisture will convert the compressor into a rusted block of metal inside.

  9. HW says:

    I am a retired professional car mechanic and am certified in AC. Using propane will work, it will also make your car a giant freaking BOMB.
    Let’s say you do this and then you have an accident, the fireman has no clue you’ve made your car a rolling bomb and cuts the wrong thing…BOOM, fireman is now dead and it’s all YOUR fault cause your a tightwad who won’t fix things properly.
    There are countless bad scenarios that can come from this. Who ever wrote this should not be allowed to handle a spoon, much less work on a car.
    Anyone who argues this is not certified as I am and therefore your comments are ignorance based, highly UNSAFE drivel and should be ignored.

    • lummox says:

      I had a dodge caravan AC system high pressure switch stick on me after doing a recharge. It blew the relief valve and filled half the shop with a fog of r134a. If that was a propane blended fuel, I would not be making this post right now. I watched it engulf the heater near the roof as we ran out the door. That would’ve leveled our shop and the neighbor’s building.

    • Nate says:

      Propane is used in many parts of the world as a mobile refrigerant and you haven’t heard and stories or European or Japanese cars erupting in fireballs have you?

  10. steeve says:

    Oh, this is a neat hack. I would like to post my hack of inappropriatly repairing fuses with aluminium foil tomorrow, please?!

  11. Awesomenesser says:

    I prefer to replace my multimeter fuses with drive bits.

  12. Larry says:

    With that kind of duct tape to fix it knowledge he had better have some really good health insurance and a prepaid funeral plan!

  13. angryScientist says:

    Density of Chlorodifluoromethane is 3.66 kg/m3 at 15°C. The density of air at sea level is about 1.2 kg/m3.
    My question is; How the hell does one believe that R22 is going to rise into the upper atmosphere? Who cares if ozone gets destroyed? That is what is does. The UV will make more. Duh!

    I’m may be pretty stupid in my own way but seeing the people around me paying for something that is so obviously erroneous just makes me angry.

    I guess there is a sucker born every minute and they must pay for their stupidity. It’s just not right all the profit taking. People’s stupidity hurts me deeply. I feel like I’m living in the dark ages.

    • stevebb says:

      Rocks are also considerably heavier than air, and yet small rocks ie sand has been found high up- and before you try saying that must have come down from space they’ve found plant spores/bacteria etc from ground level along with it.

      I think I see your main point- you’re under the impression that less ozone would mean more UV absorption as there’d then be more oxygen for the UV to convert into ozone? That’s half true. Far more UV gets captured when UV encounters ozone, and breaks it down. It’s a reversible reaction catalysed in *both* directions by UV. Free radicals from CFCs/FCs catalyse towards oxygen.

    • Tim says:

      Maybe you should read the wiki article on ozone degradation before you make ignorant posts

    • educator says:

      @Angry S. We can tell you’re angry, we can tell you’re no scientist. We can also tell you subscribe to the ostrich theory of education and knowledge in general.

  14. stevecrozz says:

    @hmburgers Since when does a hack necessarily have to be safe? You could certainly wire your home with lamp cord and call it a hack, but it wouldn’t be very interesting.

    And on another note, when did the hackaday community become concerned with voiding warranties? I don’t recall that ever being a big concern around here.

  15. NatureTM says:

    So from the posts it sounds like propane is much more flammable. cgmark also pointed out that after the leak, the innards were exposed to the air, and the oil which kept the compressor from getting rusty also may have leaked out. So now we have rust and corrosion which could lead to a spark, we have a flammable refrigerant, and we have a diy recharge where it’s possible some air got in. Even if no air got in, what happens when it leaks again, and he’s grilling out or if the machine clicks on and sparks?
    I just hope he knows what he’s doing for his own safety and the safety of any loved ones.

  16. Life2Death says:

    Why not use glycol or something?

  17. McNoob says:

    This is why I won’t work on aircraft that have been serviced south of the border.

  18. Bob says:

    To those that are complaining about this hack, figure out a better way to fix an AC system yourself. Not everyone lives in an industrialized country. Look at William Kamkwamba and his third world fuse design. Probably not safe enough by our standards, but it gets the job done with limited resources.

  19. Hackineer says:

    While I probably won’t try this myself, I don’t see how it is significantly more dangerous than a system designed to use R290.

    Propane is only explosive in the presence of oxygen and I believe only over a fairly small range of concentration that isn’t likely to exist inside the system, even if there is a leak.

    Since the system wasn’t designed for propane, I can see how efficiency and reliability of the system might be compromised, but what do you expect for a hack?

  20. Rick says:

    Did you people even WATCH the video?
    1: His system was damaged by a gigantic chunk of ice freezing it up until it vented the charge. That’s probably voided any warranty right there.
    2: He uses a vacuum pump to evacuate the system to boil off any moisture which leaked in when the system vented, and remove air (and thus O2)
    3: He’s not putting propane (R290 aka R22a) into a CAR, he’s putting it in his HOME heat pump
    4: Propane sold commercially has an added odorant to help locate leaks safely.
    I would NEVER mess with CFC-based refrigerants myself; they’re just outside my comfort zone. But propane, flammable though it is, is well within my capabilities to handle safely. And rather than convert my existing R22 systems to R134a, I will now stronngly consider recharging them with propane instead.

  21. Jim says:

    He says that he used vacuum pump prior to re-gassing. This should get rid of moisture.

  22. Rick says:

    “Propane as R22-Replacement in Commercial Appliances” http://ec.europa.eu/environment/ozone/pdf/danfoss_r290.pdf

  23. Don says:

    Granted this does work. But there are reasons
    we have licenced trades in North America. If
    his house burns down, his insurance maybe wont pay.
    This the kind of hack you should not have posted..

  24. Toolboy says:

    @angryScientist:
    Not sure where to begin. Denser gasses will stay lower in the atmosphere but diffusion, weather, and other real world effects will ensure some % of it gets to the upper atmosphere. Halogenated alkanes cause CATALYTIC breakdown of ozone. This means it will continue to destroy ozone as long as it is around. So the same mechanism that has always made ozone (UV) will continue but now concentrations of CFCs have increased the rate of breakdown shifting the equilibrium toward killing us all. Let me know if you want a conversation about evolution being real or climate change not being a conspiracy by scientists…

  25. Rick says:

    And by the way, for you AirSoft players: “Green Gas” is and always has been propane with a different odorant added.

  26. Hackineer says:

    Why do people think this would be so much more dangerous in a car? I seems to me that the 100+ pounds of gasoline in a car’s fuel tank might be a bigger safety hazard than a couple pounds of propane.

    • Andrew says:

      Gas tanks are in the back and protected,(Unless you’re driving a Pinto) and the fuel is in a liquid state – a lot less volatile than gaseous fuel. The condensor in an AC system is in the front of the car, in front of the radiator with little in front of it but plastic. One minor fender bender and you have the potential for a nasty fireball.

      As for using propane in an AC system, most industrial refrigeration units (that don’t use ammonia) use propane, including the diesel powered reefer units that chill semi trailers. (Mainly talking about refrigeration though, not air conditioning)

  27. Bergo says:

    While it’s not the safest thing in the world, it works incredibly well. As with anything dangerous, just be careful and respect that what you are working with could potentially harm you. About 6 years ago I built a refrigeration system using a 1/4HP compressor and some spare HVAC parts to cool my computer, used propane as the refrigerant, it still works great. loud, but works great.

  28. stormdog says:

    Certain articles sure seem to provoke near-hysteria on this site.
    AC’s used to use ammonia, and many refrigerators still do. I don’t know that I’d worry about propane any more than I would ammonia.

  29. Rick says:

    @Hackineer I agree that charging an automotive A/C system with propane is a bad idea. The trouble is, as @HW pointed out, that, while rescue personnel know that the fuel system of a vehicle is filled with volatile, flammable liquid, they have no reason to expect the A/C system to be charged with a flammable gas.
    Whereas one can vent an R12 system in an emergency without risking a fire, a rescue worker with the jaws-of-life or chop-saw might cut into the system and cause a very intense fire or explosion without any warning.

  30. >But there are reasons we have licenced (sic) trades in North America..

    Which of course have nothing at all to do with unions and trade groups guaranteeing work for themselves by buying themselves a poly-tick or three ;)

    >I am a retired professional car mechanic and am certified in AC. Using propane will work, it will also make your car a giant freaking BOMB.

    Wow, maybe I shouldn’t drive around in my car with 15 gallons of HIGHLY EXPLOSIVE gasoline. Damn, sometimes I even park it inside the house!

    >Anyone who argues this is not certified as I am and therefore your comments are ignorance based, highly UNSAFE drivel and should be ignored.

    Did you take the same open-book, online, 15 minute test that I did to get your chit to work on car AC systems?

    >I disagree. Propane is highly flammable…

    That’s why the only fuel that can be used indoors in forklifts and floor buffers is propane. There’s only a narrow ratio mix with oxygen where the stuff will burn. Propane is wildly popular with the RV crowd for the exact same reason.

    Guys, just wait until they get CO2 refrigeration working half-assed reliability. When that happens, everyone will suddenly realize the awful global warming potential that exists with 1,1,1,2-Tetrafluoroethan (the same stuff used in dust-off and air-horns) and everyone will be forced to upgrade their refrigeration equipment yet again to save the planet as the older gear is phased out. Meanwhile, hydrocarbon based refrigerants will continue to be used in the rest of the world with a reasonable trade off of safety (think a refrigerator with only a few ounces of refrigerant inside)

    BTW, is Snow Peak Giga Power considered fuel, or stealth drop-in blended hydrocarbon R12 replacement?

  31. ejonesss says:

    using propane is not safe if the compressor should fail and the windings short you could have a fire or explosion.

    if you are that tight of a wad that you cant afford the service costs you can.

    1. get your self a bunch of old window air conditioners that are junkers ( hope they still have the charge in them and even run)

    then get the required charge tap to put on the high side of the window air conditioner.

    then with the charge hose you can blow the freon from the junker to the house air conditioner.

    risky because unless you are a licensed refrigeration handler you could be busted for illegal handling although i have heard that the laws seem not to bother with amounts under 50 pounds.

    2. you can charge with r134a also used in dusters and air horns .

    r134a does work but may not as economical you may not get as good of a cost per btu from it.

  32. Lobo says:

    @Don – spoken like a true licensed tradesman…

  33. >a rescue worker with the jaws-of-life or chop-saw might cut into the system and cause a very intense fire or explosion without any warning.

    Hydrocarbon based R-12 refrigerants are (finally) legal for auto AC systems with the proper fittings and labels.

    Piercing an old R-12 system can vent a mist of light oil that can be highly flammable and dangerous in itself.

    Hybrid cars can have high voltages present when turned off. This could be very bad for the untrained rescuers. Should we ban hybrids too?

    It’s all about the balance of risk/rewards. I’m willing to bet the chest x-ray worth of radiation you would have gotten if spread-eagled against the fence on March 1979 in Harrisburg, PA looks a bit less risky than drilling in the gulf nowadays with the benefit of hindsight. Unfortunately, you’ll get the benefits of nether now.

    And we’ll continue to make crappy gasoline substitute at a net energy loss AND crappy sugar substitute out of home-grown subsidized corn while refusing to allow cheaper ethanol imports in the country from overseas, Free Trade and NAFTA and the starving in Africa be dammed.

  34. Bob says:

    Gasoline as a liquid doesn’t burn. Neither does propane as a liquid, but it happens to have a very low boiling point. Even if you threw a match in your gas tank, not much would happen. The gasoline vapors above the liquid gasoline would burn if there was sufficient oxygen, but it would quickly suffocate itself. Even if there were enough energy released to sustain a flow of gasoline vapors out the filling portal, it would be anything but an explosion, just a slow burn. In a system containing propane in thin metal pipes, a rupture would quickly lead to a drop in pressure and the boiling of any liquid propane in the system. This also wouldn’t explode, but the sudden release of all of the propane in gas form would create an immediately dangerous situation that could cause a large fireball if there was an ignition source nearby.

  35. aztraph says:

    ok.
    1st GO BACK TO SCHOOL YOU DUMBASS!!
    2nd you have a heat pump, it has a suction line accumulator to store the excess refrigerant in the winter to prevent it from getting to the compressor, so, go nuts with the feeding it liquid.
    3rd r290, as you refer to propane, is compatible with most oils (miscibility is important, you have internal moving parts like reversing valve and the piston metering device at the inside coil) but not POE oil and has a compatibility problem with certain plastics (piston gasket) and rubber (the hoses you use need to be certified compatible with propane).
    4th clean up around your system, damn.
    5th Anyone who thinks that man can affect anything as massively complex as the earths’ climate, has got to belong to the most conceited group of people on the face of the planet.

    sorry for the rant, but when i see stupid, i have to call it for what it is. i guess a lot of people have a problem with it too. and FYI, a few years ago there was a product called maxx fridge, will have to look up the paper i have on it, it’s essentially propane but a different formula suitable as a drop in replacement for any refrigerant, i will post again when i find it.

    otherwise, kudos for making the darwin award wanabe list

  36. localroger says:

    My main problem with this hack is that if the leak is inside the house, the propane that escapes could be trapped in a space like the attic awaiting a source of ignition. If the leak is outside it’s not a problem. Does he know where the leak is? Wait, I guess if he did he could just like fix the leak and do it right. OK.

    I’ve seen several articles over the years about charging refrigerators and AC’s with propane instead of Freon, it’s one of those things that comes up every once in awhile especially since the R12 restrictions.

    It’s not an inherently bad idea; as noted upthread some commercial systems use ammonia and I can tell you from personal experience you don’t want to be around when they spring a leak. Thing is, this system is leaky, that’s why he doesn’t want to spring for the Freon to fix it right. This is not a good combination of factors.

  37. Bob says:

    I’m so with you aztraph. I have no idea why man thinks it can change the world in any significant way. There’s no floating garbage island the size of Texas in the middle of the Pacific ocean. We haven’t leeched so much birth control hormones into the environment that fish are starting to change sexes spontaneously. The oil leak in the Gulf of Mexico, 35 years of nuclear testing (making Cs 137 dating possible), 1 billion cars, 1 million dams, acid rain, mass extinction of animals worldwide due to hunting and habitat loss, the brown cloud floating over most industrialized cities….ect. These are all just ridiculous. These have no effect on the world as a whole. We can kill every animal and plant on earth, and we will still be just fine.

    By the way, when you want to question one’s intelligence, you may not want to type like a retard in the process.

  38. rd7575 says:

    For the love of FSM, this guy’s system is practically new and he’s not indicated in any way that it leaks! It’s low on charge because the condenser fan was seized with ice and the pressure shot up enough to trigger the release valve… which immediately closes again. I’m not ready to go do this to my system just yet, but I do recognize that propane is not explosive until it’s mixed with the right amount of oxygen. Even with a bad leak, the worst that’s likely to happen is that the leak point turns into a pilot light or small torch. Yeah, it might start a fire… burn his house down, even. But that’s a far cry from a freaking explosion. Far more likely is that the propane slowly leaks out until the system stops cooling efficiently, just like the original R22. No drama.

  39. Mark says:

    Couple this with a propane detector in your house and you have a sweet hack. By the way what is up with all of the crap about if the compessor shorts out it can explode and stuff? Get real, you must have a concentration of propane in air that is between the LEL and UEL. Yes there is risk and he accepted it. In most cases of rapid expulsion of the propane will extinguish any spark or cool any ember before it mixes with enough air to ignite so there would be no ignition. Like there is no risk hacking into someones computer? Give me a break! Next thing people will be posting is you shouldn’t post how to hack computers because someone else may actually do it!

  40. cliff says:

    lmao this is an epic thread, I suppose that the refrigerator that is in my RV is a bomb too as it came from the factory charged with propane. holy crap people are stupid. Zomg I don’t know anything about it but it sounds dangerous! Think of the Children!

    /literally laughing out loud

  41. jh says:

    Anyone remember freeze12? Propane is just another alternative to some of the expensive refrigerants. As long as the system stays sealed after installing propane, there is no real danger of explosion due to propane’s flammable properties. even if there is a leak, the leak will work like a pilot light if it’s near a spark or a torch if the pressure is high enough. Propane rarely explodes when a leak point in present. If you want a non-flammable replacement for R-12, upgrade to R134a or use freeze12. For R-22, use R417a. If you are fine with propane… use this hack.

  42. aztraph says:

    focus bob, i said the climate was too big, everything else you mentioned i can’t comment on, but the energies moving our climate system around are far too vast to affect short of man unleashing a nuclear holocaust.

  43. Jehu says:

    Humm, my car runs on LPG (Propane/Butane mix). Does that mean I’m driving a massive bomb considering I have 60L of LPG in the boot? Oh and I also fill it up myself! Yup, I have a filling port right next to my petrol filler cap that screws on to the bowser hose. Oooh, look! I’m driving around with 130L of explosive fuels!

  44. Patrick says:

    I have a very old gas stove in my apartment; the pilot lights to out almost every day. I just relight them. I’ve never been blown up. Sometimes they go out while I’m gone for the weekend. When I get back, I relight them. Still haven’t blown up.

    Granted, that’s natural gas instead of propane, but the reason I haven’t blown up is the same: the concentration of the fuel gas with oxygen is not right, and chances are it will never be right.

    We can go round and round about safety and environment all day, but the reality is that you take a big risk every time you get out of bed, and if you really care about the environment, there are a LOT of MUCH BIGGER things you can do to save it. Quit living your lives in fear and misguided indignation.

    • stevebb says:

      When you are relighting the pilot I expect you have to press a button down to relight (pressing often sparks a piezoelectric igniter) , and you need to keep that button pressed down for a short down after lighting otherwise the flame will go out again? If so ever thought why? It’s got a thermostatically controlled valve that shuts the gas off when the thermal sensor get’s cold, as it does very quickly without a flame to heat it. If it’s an old stove it wont be using electrical control to do that, but something more like a bimetallic strip, or a capsule of special wax that expands when it gets warm. Holding the “start” button down just bypasses the thermostatically controlled part of the valve, until the valve sensor gets warm enough to keep the valve open.

  45. ADPoliak says:

    @Bob (comment #comment-150520 on this) post:

    Only way to improve your post would have been to sign it “Summer Glau” (as in http://www.xkcd.com/406/ )

  46. jeditalian says:

    i know somebody that’s done that. no reason it would explode. at the very worst, if a leak ignited you get a little blowtorch action under the hood, which either hits metal, melts plastic, or burns through the fuel lines, THEN you have a problem.

  47. gyro_john says:

    OK, what about you keep the entire propane-refrigerant circuit outside. Use it to refrigerate a water/antifreeze mix, pump that through the wall into the house, blow a fan at a radiator and you’ve got a second heat-exchanger circuit which keeps the heavy, flammable refrigerant all outside in case it leaks.

    Gentlemen, we can rebuild him.

  48. Paradox says:

    Not all hack’s are safe, but it seems trolling is prevalent on these forums.

    You can make rail guns, high voltage capacitors
    all have the potential to kill you but are good hacks to learn from.

    What happened to the pursuit of knowledge and not the trolling/flaming of forums. There is no need to call people stupid, they are merely misinformed.
    So pass on your knowledge and let them learn.
    Lumen accipe et imperti

  49. nubie says:

    Well, fancy that, I was thinking of doing this myself earlier this week.

    and 2nd, has mythbusters looked into this at all?

    Awesome.

    I have a deep freezer, 2 fridges and a window A/C unit, what can I do to overclock my Celeron 440 :)

  50. Peter says:

    Excuse me, but *what the H3LL* makes anyone think that replacing a non-flammable working medium with a flammable, nay, EXPLOSIVE gas would ever be a good idea?

    Just because you *can* do something, doesn’t mean you *should* do it.

    I’d suggest skipping this experiment if a long and healthy life is part of your long term plans.

    Save the propane for spud guns and barbecues.

    • Robert Galloway says:

      My opinion i think was succinct. The total amount of flammable in an automotive air conditioner would be trivial compared with the amount of gasoline in the machine.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s