Misting the home a/c condenser

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Misting is great for cooling the hot condenser - it will help for sure.
I overdid this and puked an AC fan motor and controller, though!
Big difference from misting to water spray!
 
Originally Posted By: Kestas
I'm confident my a/c unit is in decent shape. I just had a spark of an idea to boost the output because I use the same technique when servicing automotive a/c in the driveway, and when my car overheated in Death Valley. Also, thermal transfer is some 13 times greater with water than with air.

Nighttime cooling is not a problem.

As far as mineral buildup, thanks for the heads up. But my imperfect system also washes away the excess water and probably any mineral buildup.

Is your evaporator coil clean? If not, your unit will run longer than necessary due to the fact that a dirty/clogged evap will not efficiently absorb heat.

I experimented with misting my condensor coils years ago and it was interesting. I have a water softener so I wasn't worried about mineral build-up. I tied an electric sprinkler valve into the 18vac line so the valve opened allowing water to flow when the relay tripped. Made it all automatic. You have to carefully watch for any mineral build-up. Use a foaming acid based detergent condensor coil cleaner, not soap. Don't use this type of cleaner indoors as it'll generate fumes.

That said, if its a temporary heat load during the day due to the excessive temps in your area, you can also ease the load on your A/C by watering your roof. No kidding. Direct the stream so it arcs up and hits the roof at the ridge and let it run down to the eave. This works due to waters high specific heat. You can do it during the day, but it will eventually heat back up; best to do it after the sun is low in the west or has set. Water it down good.

This will cool your attic and lower the delta-T between your living space and attic.

I did this regularly last year when the big heat wave was here in Tx. 70+ days of over 100°. My attic temp would drop 12° in an hour when I did this at sunset.
 
We still have one of the few "original" condensers in our whole subdivision. It may not be the most "green", but it keeps working. I clean it every Spring, and we keep our thermostat at 80 in summer (thermostat is on 2nd floor). Our condenser is rusty, and nasty looking on the outside, but it will be there as long as it keeps us cool. It's 17 yrs old.
 
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I have a friend that owns a rental condo. Still has the original condenser unit outside. Built in 1972. 40 years old. He has the coils cleaned every few years. It has had several capacitor and contactors replaced. Still cools well.
 
When I was growing up, we used to do this to the A/C unit we had in the window. It wasn't one of the ones that would splash anything with the water - instead it would drip out.

I seem to remember it making a difference. Of course we used to do it on those REALLY humid days where it would ice itself solid.

The A/C unit I have now doesn't drain anything anywhere so I'm assuming it's misting itself?
 
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This thread gets me thinking about building a mister to spray the condensed water over the coil to cool it. I would imagine I can build it with some tubes, a small pump, and a nozzle for less than $50.
 
Problem with that is pickingup all the other junk that ends up in the water that is sitting in there. Despite filters and whatnot, the coils (evaporator) always seem dirty.

Of course if you could put a filter in the discharge of the condensate pump, and then store that clean water in a closed tank that contains the high pressure pump at the condenser, it would be OK...

Until biological growth starts... then the mist nozzle clogs.
 
My two AC condensers were in the hot sun most of the day. I planted heat loving Crepe Myrtle trees about 8-10 feet away. Now the units are shaded from the hot sun. Made a small difference.
 
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I will help markedly.

My prev FL home had a 3 ton unit, and the roof was black, attic had poor insulation. The result was uncomfortable inside temps in the summer. 100 degree days resulted in 90 degrees inside. The roof radiated that much heat inside!

I manually sprayed water on the condenser. It drove the house temps down immediately! And the duct discharge temps went from 70F to 45F in a matter of a couple minutes.

Just a quick note, my new home (twice the size) costs less to cool. My roof is bright white concrete, the AC unit is 16-SEER and windows are Low-E tinted.
 
One thing I've noticed when I sprayed down the condenser from the garden hose, it takes a lot of water to run through the hose to get cool water. Spraying the condenser with warm water doesn't do any good. So, when I was coming up with the idea of creating a spray mister for the condenser, I wouldn't have enough volume going through the hose to provide cool water. With that little flow rate, by the time the water came from the spigot to the mister, it was already hot. Of course, to fix that, I'd have to bury the hose of keep it out of direct sunlight.
 
You could use an underground cistern to catch rain water. Use that cool water to mist the AC coils.
Has anyone seen the Lennox AC system that comes with the solar panels?
 
Originally Posted By: Schmoe
Spraying the condenser with warm water doesn't do any good.

Not so. It's still better than 100°F warm air, by about 14 times.

Just like the 190°F coolant in your engine -- better than air.
 
better, but not as efficient. If I'm going to up my water bill, then I want the biggest bang for the buck.
 
home depot 12$ misting kit ,
All heads spraying in front of condensor unit about a foot away.
Made a little difference.
 
Interesting.

And I thought I was the only one who went overboard on things like this. I love efficiency.

Compressor/condenser units are 10% less efficient in direct sunlight. Wish I could move ours.
 
Originally Posted By: Virtuoso
Interesting.

And I thought I was the only one who went overboard on things like this. I love efficiency.

Compressor/condenser units are 10% less efficient in direct sunlight. Wish I could move ours.


I planted two crepe myrtle trees to shade my two units. Fast growing, summer blooms and they love the heat. They also hid the units so they can't be seen from the street.
 
I have my old grill providing shade from noon sun.
Make you have enough air flow around unit
Virt, I am spray foaming my attic. There are more like out there.
 
For all the push in appliance efficiency, you'd think they somehow could add this feature to condensers. Though I can also see the drawbacks.

Some 10 or 20 years ago I remember reading an engineering journal, where - even though the area is scarce of water - they were considering spraying water on the roofs of buildings in the desert Southwest, to ease the energy requirements of air conditioning.
 
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