This is not what most people think when somebody says propane
I felt this might be a good place to add a little known fact. Propane
is an excellent refrigerant. I have used propane as a refrigerant instead of R12 for years in cars. It's actually too cold and on a humid day you freeze the coils and have to turn it off every once in a while to melt the ice that has formed. It's illegal here in the states to use it in cars I think mostly because refrigerant manufacturers have lobbied for it to be illegal. People are worried about the flamability. In a car this is absolutely crazy in my book, they are worried about one pound of propane in a sealed system when they have a 140 pound tank of gasoline in a rather flimsy container they don't worry about. Almost all refineries use propane in their air conditioning
systems. It's even got R numbers so you can design a system using it. R-290.
I tend to get by without refrigeration on my boat but the last two boats I bought and still have, have it installed, but I haven't used it yet. I still haven't really started my big trip though so I may change and start using it. My first boat and years of backpacking have taught me to live without it. If I ever need to replace the refrigerant in my system I'm going to use propane, it's cheaper and much less damaging to the environment
if it leaks. Any leak would most likely be slow and dissipate to be no fire danger
. Also propane is not hard on the materials used in the seals
of the systems. The operating pressures might need slight adjusting but probably not, it's very close to R-12 and R-22 which is used in many freezers and AC units. It's just a little colder at the same pressures.
As for car systems I just wish the regulating people the is the US would pull their head
out and realize that freon which is terrible for the environment
could be replaced with propane instead of using very high dollar new stuff that is ozone friendly. It normally requires slightly less pounds of propane to fill the system then freon. It is widely and cheaply available. They also skim over the fact that many common refrigerants are also flammable.
also see Homemade Refrigeration System With Propane Refrigerant.