Will spraying fresh water over my AC condenser make it save energy?

Spraying water onto the condensor coils will make them operate at slightly lower pressures and therefore require slightly less energy. But the unit will not run with substantially more efficiency. A unit made 20+ years ago is working on borrowed time. Most units have a life expectancy of 7 to 12 years. Today's units are much more efficient than yesterday's. The increase in efficiency is due to the coils being constructed larger and offering greater heat transfer rates because of the greater surface area of the coils. Your unit operates with R-22, but new systems use R-410a. R-410a operates at higher pressures than R-22 so the coils have to be stronger. You will need to replace both the indoor coil and the outdoor unit and the refrigerant line set at some point. You should also consider replacing the furnace with a higher efficiency one at the same time.