The savings come from Ontario Hydro.wasserware wrote: ↑Apr 30th, 2010 5:49 pmI am wondering how you derived the $250 electrical cost savings? Is that the cost of operating the fan blower at full RPM 24/7/365?
Regarding the oxidation and heat transfer, my engineers were only pointing out that in theory and in actual lab experiments, the heat transfer ability is not impeded by the thin layer of platina. They are not HVAC experts so I guess they cannot conclusively say if oxidation will affect the heat transfer in the outdoor coils. When you mentioned fouling, are they referring to other types of dirt/contaminant that actually acts as a insulating barrier to prevent the heat from exchanged? It will be interesting to see some conclusive testing data in residential HVAC but those were hard to find (maybe you have access to trade/tech journals?)
This is why you and I think that copper or aluminum is better/superior but its unfortunate I cannot find any hard data I do agree that in high corrosive environment such as ocean climate, copper is bad idea as I've seen some really bad coil rot picture:
[IMG]http://www.free-air-conditioning.com/ce ... une_up.jpg[/IMG]
Fouling definition from NACE: An accumulation of deposits on a surface. This term includes accumulation and growth or marine organisms on a submerged metal surface and also includes the accumulation of deposits (usually inorganic) on heat exchanger tubing.
Now, although this doesn't talk about a layer of copper oxide, you still have to agree that the layer is affecting it somewhat. And as soon as you have that layer, you get an oxygen depletion zone, and then it speeds up corrosion.
The picture you show actually has the fins completely gone, and the tubing intact. The fins are aluminum and the tubes are copper. This is an unprotected coil in a corrosive environment (salt). It wouldn't matter whose air conditioner was there - if there was no coating done to the heat exchanger, it would have the same result - copper or aluminum fins. But copper fins would dissolve a lot quicker than aluminum in my opinion.
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