[Archived]

If I am correct, some R12 “drop in” replacements are propane based.

[Archived]

I
don’t believe the oil or components to be a factor but I would still check them
for compatibility. The real danger as Jon pointed out is that R12 drop in
replacements are all propane based. They may get you real cool but in an
accident could get you real hot. Use in a vehicle is also not legal in most
states.

You’re thinking propane? yes is it considered a refrigerant just like many
others that have a phase change from liquid to gas. Large commercial absorption
chillers actually use water as a refrigerant. At sea level water boils at 212
degrees F. but under a deep vacuum it boils at 45 degrees F. One of the best refrigerants
ever used was ammonia and is still in use today at some large commercial ice
plants. There are a lot of studies in progress for using CO2 as the next
popular refrigerant.

[Harry]

I would like to add a little to the discussion.

All refrigerants have a “flash point”. Under the right conditions they will all burn, including Freon. Companies selling propane based drop in replacements make a big deal of this fact in trying to convince potential purchasers of their propane based product’s safety. I know of no company selling a propane based replacement for R-12 or 134A that even mentions the fact their product is propane based. They may use the term HC based or hydro carbon based to describe the product. They will compare their flash point to that of Freon to suggest their refrigerant is safer.

As a curmudgeon I try to see if claims pass the sniff test. I parse the words and phrases. I question things left unsaid. I think John has raised a very good point with his original post and as I look into the claims for propane based refrigerants I find none claim to be used for production vehicles. We all know how manufacturers are sensitive to costs and if they aren’t using a product that is cheaper and works better something is wrong. There’s a red flag for me. A big red flag.

Cars and buses and trucks just are not built using anything other than the refrigerants that were originally installed in our coaches and house systems. Even though the drop in replacements compare their performance and cost with the refrigerants we use in a very favorable light, I was unable to find a single one used as original equipment. As a fuel propane is relatively safe because it will not ignite or explode until the air fuel ratio is correct, but when it is a correct ratio as John points out it has the potential to be very dangeous. A failed seal, a broken line, or anything that can create a leak in the sealed system can relase the refrigerant and once that occurs all that is required is an ignition point and the refrigerant that kept you cool becomes a potential source of serious burns or injury.

When I look at the risk versus reward ratio I can not justify the use of a product with such potential just to save a few bucks.