'Supercooling' method is not economical (buying, college, costs)

[veritased]

Originally Posted by Potential_Landlord

Doug is right - don't mist your condenser fins as that will create a mineral layer on them that makes them less efficient or may even corrode them. With our water rather quick. Don't do it.

Understood, which reminds me I need to reup on potassium for my softener.
It wouldn't take much buildup at all to clog up the air pathway between adjacent fins... mine are so close to each other.

Seems like a way to precool air before it goes through the radiator fins is a way to increase efficiency of the cooling process though.

[Potential_Landlord]

Originally Posted by veritased

Understood, which reminds me I need to reup on potassium for my softener.
It wouldn't take much buildup at all to clog up the air pathway between adjacent fins... mine are so close to each other.

Seems like a way to precool air before it goes through the radiator fins is a way to increase efficiency of the cooling process though.

It's the difference between theory and practice. It sounds good in theory, but in practice it causes more damage than good. I can imagine that some professional ac systems for big buildings use pre-misting with extremely well distilled water & some additional maintenance. But I don't see how it can be economical for households.

[veritased]

Assuming no reduction to efficiency from mineral buildup, then it's all about increasing efficiency of the condenser coil.
For sure cooler air passing over the cooling fins will increase efficiency. Question is how much? My AC bill from June 24 - Jul 24 was about $300. I have no idea how much a good misting system would save. 10%? 30?

I am going to try this mistbox system and see how it works. Downside is very little. They charge by the month, and I can stop at any time, if I see mineral build up in the fins.

[Hal Roach]

Seems like it wouldn't hurt to get just a bit more ventilation around the outside unit. Even a solar fan, or anything that would dicapate the very hot air it produces. I have heard of industrial systems that use a swamp cooler like device to chill air before the intake, but never in residential systems.

[veritased]

Hal, I think is what this mistbox.com system does, very small scale version of the industrial swamp cooler to pre-cool the air before it passes over the condenser fins. I am going to try one out and see how it works. It is supposed to cool the air before it hits the fans, but presumably not by placing water droplets on the cooling fins, at least from looking at their demo video. Like I said, it's pretty cheap to try... can't lose much, can only gain.

[Ripper3785]

Originally Posted by veritased

Hal, I think is what this mistbox.com system does, very small scale version of the industrial swamp cooler to pre-cool the air before it passes over the condenser fins. I am going to try one out and see how it works. It is supposed to cool the air before it hits the fans, but presumably not by placing water droplets on the cooling fins, at least from looking at their demo video. Like I said, it's pretty cheap to try... can't lose much, can only gain.

From the mistbox video, it looks like the condenser fins are getting wet.



If you speed up the rate at which your system corrodes, it seems to me you could lose a lot.

[Hal Roach]

Originally Posted by veritased

Hal, I think is what this mistbox.com system does, very small scale version of the industrial swamp cooler to pre-cool the air before it passes over the condenser fins. I am going to try one out and see how it works. It is supposed to cool the air before it hits the fans, but presumably not by placing water droplets on the cooling fins, at least from looking at their demo video. Like I said, it's pretty cheap to try... can't lose much, can only gain.

I was talking about swamp being used to cool air in the intake vent to the air handler in industrial systems, still somewhat experimental. But, I do see where you could benefit from having a cooler operating environment for the condensing unit. Those fins are pretty delicate though.

[DougStark]

This whole approach to improving AC efficiency for residential AC units was tried and discarded in the '70s and '80s. I remember reading articles about it. Again, the primary problem with "pre-cooling" the outdoor AC condenser in the Phoenix area is that our local tap water is loaded with minerals that deposit (precipitate) and greatly increase metal corrosion. Even if you don't spray the fins directly with our tap water (like by using an indirect way of cooling the condenser with a evap cooler, for instance), the coils will deteriorate prematurely due to the salts in the water (or water vapor in the case of using an evap cooler as a "pre-cooler")

Seems to me the only way around this problem is to make sure your condenser coil/fins are the "blue fin" type--these condensers/fins are made for use in marine or coastal locations so they are more resistant to salt corrosion. If you have one of these blue fin type condensers, go ahead and hook up an evap cooler to the inlet of your AC condenser. But realize evap coolers take maintenance. They're not a "plug and play" machine (pads eventually need to be replaced, cleaning pan, etc.)

The other way to increase efficiency is what I proposed: using de-ionized water (but, no easy, inexpensive way to produce and store demineralized water.) if it rained here more often, the water from roof gutters could be used, but our rainfall is inadequate.

BTW, this idea of cooling down the condenser is commonplace in commercial buildings where a lot of cooling is needed. That's what cooling towers do. Maintenance crews maintain the cooling towers religiously with water treatment chemicals, etc. until it (the water) is no longer useful and they dump it and start with fresh water again.

[veritased]

Thanks for the insights.

The mistbox system droplets probably would not evaporate in time before they are sucked onto and over the cooling fins and dropping there. I agree.

But otoh, it doesn't cost much to try it out. I assume I can watch the fins and see if they start to discolor and just return the misbox system.

[Potential_Landlord]

Originally Posted by DougStark

This whole approach to improving AC efficiency for residential AC units was tried and discarded in the '70s and '80s. I remember reading articles about it. Again, the primary problem with "pre-cooling" the outdoor AC condenser in the Phoenix area is that our local tap water is loaded with minerals that deposit (precipitate) and greatly increase metal corrosion. Even if you don't spray the fins directly with our tap water (like by using an indirect way of cooling the condenser with a evap cooler, for instance), the coils will deteriorate prematurely due to the salts in the water (or water vapor in the case of using an evap cooler as a "pre-cooler")

Seems to me the only way around this problem is to make sure your condenser coil/fins are the "blue fin" type--these condensers/fins are made for use in marine or coastal locations so they are more resistant to salt corrosion. If you have one of these blue fin type condensers, go ahead and hook up an evap cooler to the inlet of your AC condenser. But realize evap coolers take maintenance. They're not a "plug and play" machine (pads eventually need to be replaced, cleaning pan, etc.)

The other way to increase efficiency is what I proposed: using de-ionized water (but, no easy, inexpensive way to produce and store demineralized water.) if it rained here more often, the water from roof gutters could be used, but our rainfall is inadequate.

BTW, this idea of cooling down the condenser is commonplace in commercial buildings where a lot of cooling is needed. That's what cooling towers do. Maintenance crews maintain the cooling towers religiously with water treatment chemicals, etc. until it (the water) is no longer useful and they dump it and start with fresh water again.

That's what it is. If you want to improve residential AC efficiency, buy a new unit or at least compressor. Otherwise, just relax. Nothing gained by obsessing.