This is someone's ingenious water heater system.
Why use your propane when you can get the sun to do the heating for you?
Don't laugh, that black plastic tubing can get real hot sitting in the sun.
Although it will not work on a day like today. There's no sun, its cold, the wind is blowing and there is supposed to be rain later today. I've learned the winter season here in the desert is unusually cooler this year due to El Nino or La Nina, one of those. Still it is better than back at home right now.