Wheeler On HVACR: The Refrigerant Problem - Part 2
Until now, we have all assumed we will never have to worry about the phaseout of R-22, because science will eventually come up with a solution. However, that just won't be the case here. For, as one DuPont scientist explained it, “If we want a new and better refrigerant, we will have to look for it in another galaxy. We already know of all the gases on earth and what properties we can combine. And all these potential refrigerants (other than HFCs) are toxic, flammable, or they don't have the other necessary properties for air conditioners.”
Some have suggested ammonia gas as a replacement for R-22, but it isn't considered viable for residential use because of its toxicity and flammability. Propane works well, but...duh! And then there is CO2, which has some desirable characteristics. I know that Tecumseh (the compressor manufacturer) is doing some research on this, but I understand that its critical temperature is too low for standard air conditioners.
What does that leave us with? Just HFCs (hydrofluorocarbons) such as R-134A and HFC blends, such as R-410A.
The problem with HFCs is that they don't mix with the mineral oils in any R-22 residential/light-commercial HVAC systems, so they can't be retrofitted into any of the thousands of such systems that we are currently selling. So what will our customers do when R-22 is phased out in 10 years?
HFCs are made of carbon atoms, hydrogen atoms and fluorine, so they break down rather easily in the atmosphere and they contain no ozone-layer-damaging chlorine. But no straight HFC refrigerants have all the properties that are needed for current residential/light-commercial air-conditioners.
That leaves us with just some HFC/hydrocarbon blends that have been formulated to replace R-22 once it's gone - but there is nothing else and there are no hopes of anything else in the future.
I admit to having been guilty of spreading bad rumors about these R-22 drop-in replacements, for I once wrote that such refrigerants have oil-return problems. This prompted the president of a company that manufactures an R-22 drop-in replacement to contact me, and he pointed out that other major refrigerant manufacturers were spreading such stories, and that they weren't necessarily true.
So, I recommend that everyone who sells HVAC equipment contact their suppliers and demand guidelines from them on the proper use of such replacement refrigerants on all the millions of pieces of R-22 equipment they are currently selling that will either be obsolete in 10 years or have to be serviced with some of these new alternative refrigerants. And if they don't have any recommendations, at least they should have to own up to it.