familyman;59711 wroteNot that I put a lot of weight on that, but it's the guys that have actually used it I'd want to hear from.
I've used it for years, and in the last 5 or so I now blend it myself.
Lots of hyperbole in your post but not a lot of fact, so here let me lay some out.
Let's start with the worst possible case from a safety perspective :
Fact : Your average Volvo 2/7/9 A/C holds a little over 300g of hydrocarbon refrigerant. That's the same amount as held in a can of Butane from your local Bunnings. If you dump it all in one place at one time and can get it to light up it will make quite a big fireball and you will lose eyebrows. You need a confined space and catastrophic failure to allow this to happen. So put the windows up and put an axe through the evaporator and you're in for some fun.
Hydrocarbons have quite a narrow flammability limit and an even narrower explosivity limit. If you puncture your condenser and spray liquid onto your exhaust manifold it won't burst into flames. If you puncture the condenser (or burst a hose) and try and light it with a lighter or blow-torch 99% of the time it'll blow out the flame. Not hyperbole or third party regurgitation, but personally tried and tested. Turn a propane bottle upside down and spray some liquid around and try it yourself. I have.
Your wife's hair care products all have hydrocarbon propellants and she uses those around heating devices that run red hot elements.
Fact : When hydrocarbons burn, they generate CO2 & H2O and a lot of heat.
Fact : When sprayed from a catastrophic failure such as a burst hose or ruptured evap/condenser r134a comes out as a mist of vapor and oil and is *as* flammable as hydrocarbons.
Fact : When r134a burns it generates hydrofluoric acid. Not nice.
Now, from an operational perspective r134a has a lower coefficient of heat transfer (than either R12 or Hychill) as a vapor. The impact of this is the condenser needs a much greater refrigerant side surface area to condense the vapor, so your standard serpentine condenser works very poorly with r134a. An upgrade to a parallel flow condenser mitigates this to a degree. Hydrocarbons have a very high coefficient of heat transfer, better than R12 in fact. The upshot is they work well with the standard serpentine condenser, and they work even better with a parallel flow condenser. The more efficient the condenser the lower the condensation temperature. This has a couple of positives :
A) You lose less potential cooling in bringing the refrigerant temperature down from the hot liquid to the boiling liquid so you get more cooling per volume of refrigerant.
B) You have a lower head pressure. This means your compressor does not have to work as hard, so it takes less horsepower to turn, but it also means it moves more refrigerant per revolution. So you *increase* the capacity of your compressor by having a lower condensation temperature.
r134a has higher pressures than either R12 or the Hydrocarbons at comparable temperatures, so the combination of a standard condenser and r134a means a much higher head pressure, and therefore a reduced system capacity (less mass flow per revolution). Leakage is not such an issue if the right seals and compatible o-rings are in place, but it can be another point of handwaving hysteria if you want to whip up a frenzy.
As to the flammability of new refrigerants, it's true. The r134a replacement HFO-1234yf is "mildly flammable" by itself and suffers from the same problem as r134a when mixed with lubricant. It also suffers from the problem of generating HF when burned.
Mechanics and A/C shops generally like to push r134a because they have a license to use it and it helps keep the hacks out of the market. In addition, over the years Dupont have used many means to scare up hysteria against the Hydrocarbons and no matter how much teflon you wear, sometimes mud sticks.
The upshot is use what you want to use and believe what you want to believe, but there are some actual facts that can be backed up with testing and evidence.
