Question for any A/C tech regarding pre-cooling outdoor A/C unit. I have 7.2 kW Panasonic Inverter split system and the recent heat wave in Perth got me thinking that I could use a simple evaporative cooler to cool down the outdoor unit.

Did a quick search on the net and sure enough there are misting systems on the market that do just that.
Most of them look like something I could cobble together by using some PVC lines and misting sprinklers from Bunnings.
I also found some reviews on discussion forums that indicate that the water droplets will cause corrosion inside the head unit.

Does anybody have any experience with this?
Does pre-cooling make any difference?
Will the mist / water droplets cause any damage? The A/C is less than year old so I would not want to damage it.

Another option I thought of is to buy a small portable evap cooler (Big W sell them for $78) and let it blow cool air on the main unit.
This shouldn't cause any dramas with water as it will blow only moist air but will this make any difference? Theoretically on a (very) hot dry day I should get temperature drop around 10 – 12 C assuming I'll get within 75% of Delta-T. But for 78 it sounds too good to be true...

Thanks for any info...