Quote Originally Posted by Goober View Post
The cynic in me would say this is misinformation spread by the coporates to bump up the price of R290 etc. As there is enough anecdotal evidence on this site and elswhere that standard LPG works just fine.
It actually depends where you live. In most of the US, and in the Eastern States of Australia, LPG (the stuff you get in 9KG BBQ bottles) can contain a variable mix of Propane and Butane (not ISO-Butane), plus (in the US anyway) a healthy dose of Methanol. This can be hard to separate out to get just the Propane. On the other hand, in Western Australia BBQ LPG is 100% Propane.

I decanted about 5KG into a recovery cylinder and hooked it up to small refrigeration unit as a liquid receiver, with a honking great drier and sporlan sight glass in the liquid line and let it run for a couple of days. I did before and after weighs to determine how much gunk the drier took out of the Propane. The answer (for my specific LPG source anyway) was not a lot. It took out *all* the Ethyl Mercaptan. According to the sight glass, the Propane was pretty dry to begin with. It matches the R290 PT chart perfectly.

The guys over at the ecorenovator forum (in the Geothermal section) have done quite a lot of work on a foolproof way to distil the US LPG to get just the Propane out of it. It's a lot of work, but it can be done.

I priced the Australian HC refrigerants recently, and they wanted over $50 a kilo. My dried and filtered Propane came in at about $8.60 a Kilo (the drier cost twice what the Propane did). Now this is for my own experimentation and use. I'd never dream of putting it into someone elses system.

60% Propane & 40% Iso-Butane (now readily available in camping stores) comes very close to matching R-12 pt characteristics and works a treat in a Car A/C.