quantifiable coastal atmosphere

[PagoMitch]

Corrosion between Cu tubes and Al fins is accellorated in coastal areas. Military HVAC units (on buildings) are usually specified with Cu/Cu tubes/fins for that reason. While I can find a reference (sort of) to air salinity (

http://www.arl.noaa.gov/faq_ac18.php),

I cannot find a reference indicating how the values would be applicable to Al corrosion when mechanicaly bonded to a copper coil. Has anybody ever seen a study that measures the galvanic potential between Cu tubes and Al fins, at various distances from the shore? It would probably vary with temperature, and be influenced by wind and humidity, but it would be a useful criteria to use as a basis for justifying the expense of an all copper coil. I can make an educated(?) guess...say, 0 to 5 miles (or 10, or ?)from the coast is all copper. But it would be nice to find something a little more authoritative.

 

[AbbyNormal]

Well Mitch, I am in the tropics and I cannot get much more than a few miles inland and no matter which direction it blows, the wind is passing over warm salt water.

One observation I have noted is our most inland Fire Station gets salt deposits on its flag pole. So if you can get far enough inland, look for signs of salt on flag poles, street light poles, traffic lights/signs etc.You could be correct on 5 miles, but I have no written reference for you.

The most durable coils I have found on smaller equipment is the all aluminum spinefin such as on the old GE equipment and now found on Trane and American Standard. The casing and compressor dome will rot out before the condenser coil.

Copper/copper does alright as long as there are no issues with electrical/magnetic fields as I have seen them fail miserably also and I attribute it to the proximity of several overhead electrical services.

All the coatings applied will eventually fail even if it is a factory applied coating.

Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[trashcanman]

Find out what is used on board ships and use that. Anyone know?

 

[IRstuff]

There are corrosion forums, here. You should redflag this posting and repost in forum338 or forum307

TTFN

FAQ731-376

 

[AbbyNormal]

ships will have water cooled condensers

Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[chicopee]

Isn't the reason they use bronze in salt water environment. You can do what the gold medalist did, he likes his medal so much he had it bronzed.

 

[AbbyNormal]

ships also use anodes

there have been "corrosion grenades" on the market for a while, its a zinc bead that you put on the refrigeration lines. Never tried them out yet

Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[KiwiMace]

Also, you can spec all-Aluminium coils to avoid the galvanic corrosion, and less cost than Cu.

You might be able to find Copper or Al coupon corron rate data online, but most data I have seen relates the site to some sort of corrosivity index, which exponentially falls off as you go further onshore.