Quote Originally Posted by DTLarca View Post
Yes, we're talking about the same thing - I started reading at only the last few recent posts in the thread. I'm just wondering then how reliable is a statement that the ice starts forming on the coil inlet face - under what conditions is it true and under what conditions is it not true - I was thinking along those lines.
I think as was mentioned above that the factors are so innumerous that its very hard to say.
Fin spacing - Icing would not form as rapidly at the air on contact point and would be drawn further into the coil.
Air velocity - The faster the air is moving the more likely the moisture will travel into the coil before condensing will take place.
Coil Depth - The deeper the coil the more your temp drop across your evap, the greater amount of moisture deposited
Humidity - The higher the humidity, the quicker it will condense and therefore ice closer to the air on side - the converse is also true
Etc Etc

Change any one of those factors in your coil design and I'd imagine you'd come up with a vastly different outcome.
The best solution as I see it is to examine the market and prevailing weather conditions you are planning to sell to - in Mikes case canada for a start - then adapt your coil to suit the prevailing weather conditions.
So he'll need to prevent snow ingress - Horizontal or angled coil, low humidity, and a short but intense heating season.