stargeezer wrote:Yes, if done incorrectly, this will make a big mess.
. . .
Just so you don't think I am totally crazy, imagine ten 1/2 GPH drippers spaced around your structure to spread the water out
Okay, I was just about to call you totally crazy. . .
I think you're suggestion for multiple super-low flow drippers is the key. One of the issues with the pump based units that I've seen in real life is the inability to control the flow of the water; most are designed around one central pump that is intended to flow equally in a 360 degree pattern. But based on wind, leveling, and variances in adhesion, the water ends up dripping down a much smaller portion of the intended evaporation area. Usually much less than 50%. While in many designs this simply makes the system less efficient, in your suggestion it could end up with some fairly unpleasant side-effects. (Indoor Grey water rain shower, anyone?)
So one step is getting the flow low enough that it can't overwhelm an area not capable of handling it, but it seems to me if the flow is too low, there will be trouble with dispersion.
I'm not a plummer or an irrigation specialist, so this seems a bit daunting to me. Although if someone can get it to work, I totally agree it's a great idea, and I would love to give up my evap pond.