Last year, a coalition of scientists and policy experts at the nonprofit Drawdown ranked the top one hundred climate change solutions by level of impact. No one guessed that refrigerant management, which includes CFCs and two other classes of chemicals known as HCFCs and HFCs, would top the list. But it did.
Heh, refrigerants was once my way into all of this, it started in the early 90s when talking to a really good hvac engineer. Heat pumps was my No1 hobby for many years and I don't need assistance to take care of those I use myself. My oldest in (24/7/365) use, is now 14 years old and even though it is "leak free" it has leaked (manufacturing and installation) and will leak during/after de-installation. All domestic heat pumps will leak at some point in time.
Most during operation thanks to crappy installations...
Everyone in that business knows that CFC is still around and why it shouldn't be used, everyone.
The newer blends is a result of the refrigerant oligopoly defending patented blends.
There has been alternative refrigerants for as long as there has been heat pumps.
Still, CFC is the only real success story we have to date, levels are dropping in the atmosphere.
Edit; instead of just vomiting over these companies I will try to add some more substance. Had breakfast and then checked the main AGGI site but it still wasn't updated with numbers for 2018 so I took a graph for R32 (HFC-32), "the new blue" from the refrigerant industry. It's not new, but comes with the same nasty property like non patended refrigerants like ethane(R170), propane (R290) and propylene (R1270), namely fire hazards.
R32 is also toxic and produces hydrogen fluoride while burning. R32 has been used for a long time in blends like the popular R410a, a blend of R32 and R125.
R125 is useless as a refrigerant, it's used to lower the fire hazards of R32.
Using AR4 numbers:
R410a has a GWP of 2088, R32(675), R125(3500).
R170(6), R290(3) and R1270(2)
Aha, someone says, R410a/R32 must surely be more efficent than the hydrocarbons!?
No. Adding a modeled COP comparison with R410a as baseline, as the second image.
I've used propylene myself in a R410a heat pump, for cooling it's great but for heating it only works really well down to ~0°C, to be able to use it effectively in sub zero temps you need to add ethane to increase the pressure in/of the blend. My problem some years back was that ethane was incredibly expensive, so I shelved further tests. But it will work just fine. In a domestic heat pump there's normally ~1kg of R410a or slightly less.
The fire hazards involved with hydrocarbons are easily fixed with sensors and fans but/and I guess people have a lot more flammable stuff in their homes without thinking about it at all.
The last twist here is that when you use hydrocarbons you lower the charge of refrigerant to roughly ~0,5kg (also visible in the second image). Lastly adding a P/T-comparison made almost seven years ago, when playing with these things. A 80/20 blend would do just fine as a drop in replacement for R410a. You don't even have to change the oil...
Edit2: Forgot the real twist but it's visible if you read carefully and look at the second image. When replacing R410a with a proper HC blend, you will have a better COP on your existing machine.
Hmm, sorry for this lengthy rant of memories...