A quick google search did not show any propane fired A/C units.
My first job after my extremely short stint at the University of Science, Music and Culture was at a laundromat and car wash. The first thing I had to do everyday was to go up on the roof and add water to the gas fired A/C unit coil. It had a small leak and the guy from the Gas Co said it would most likely take all day to fix it. So he soldered on a fitting to allow us to refill the coil till fall came and he could take the unit down for a day.
Regards
alfa6 ;>}
Most of this technology has been around for a very long time
LOL.