I've been thinking about hacking an old 6,000 BTU AC and, I also have an old
de-humidifier that I could hack up.
But, I don't want to release any refrigerant into the air.
I've seen some affordable vacuum pumps for removing air from heatpump systems (preparation for R-410A),
but have not seen any cheap refrigerant recovery hardware.
The smaller units are in the $500 range.
That's interesting about the propane. I guess one could make his own
heat exchangers etc if he had the compressor..
I would really like to try making an HP hotwater heater for use in the summertime. (Air to water HP).