Saw this on an earlier topic.

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...

This is my problem exactly. On the hot days, even here in Sydney. The extremely hot days last summer had our system tripping out regularly. Has anyone had any experience on this type of pre-cooling? Mine is bigger than the one mentioned above as it is a small commercial system and has to keep a small office based team working during the hotter months.

I saw these ones and they seem to that you need to evaporate the mist in the air before the coils to get the air cooled and the water completely gone before it gets to the unit. mistafog.com.au/air-conditioner-pre-cooling/ That would certainly solve the concerns of some people on the earlier post.
Heres a video from the same site - mistafog.com.au/coilcool-air-conditioner-pre-cooling-videos/

They are a lot bigger air conditioner than mine but the concept is the same.

Anyone got any experience with this, or any other advice. Thanks.

Just harden up and deal with the heat

I like your thinking Adrian.

?re you hoping the cost of setting up/running the pre-cooling equipment will offset the cost of running the AC?

Or are you trying to make the AC last longer?

Either way, interested in opinions.

It works very well, but the problem is with the minerals that are deposited on the aluminium condenser by the evaporating water. There is potential to ruin it. Do a google and read about how people address the issue, then make up your mind if you think you can manage the risk in your situation.

Could you overcome that issue with distilled water?

I tried it. Had a cheap mist kit that I initially used to cool down the patio area. The mist droplets are too big and just get everything wet, so put it on the ac to try.
Yes it works for cooling the ac, it cycles less, but the calciumcarb build up on vanes is noticeable.
Vinegar or similar would clean it... but also damage the alloy.

The proper misters require a pump to create the fine 'dry' mist and they weren't cheap to buy or run.

My ac unit is outside and gets wet anyway... so....?

I have created shade (trees) for the system so it doesnt get direct sunlight and hotter than neccesary and spray the trees and area with water... this also works.

Theres no free lunch in thermo dynamics though.

If the unit is tripping it sounds like you do not have sufficient air flow around the condenser (outdoor) unit, fix this first and you may find the unit works a whole lot better.

The unit shouldn't trip on hot days if installed properly but just struggle to keep up. Most units are rated for a "design" day of 35c at temperatures above this they will start to struggle to maintain conditions.

Mist kit with 100% methanol

No rust, no deposits.

Don't tell anyone though...