System was never built. I had some personal issues going on at the time that prevented me from dedicating the time necessary to build the system before the summer heat. As I needed a ready to go solution, I purchased a chiller. I may try it next summer.
Hey Matt, I missed this thread when initially posted. When looking at the injection system you're proposing within a 4" (or 6") PVC tube, you might be able to achieve a better efficiency using a venturi valve for injecting the water in lieu of a 'spray bar' that's only 4" long. You'd get the mist you're looking for and the fan at the bottom should be raised to about 1/3 up the vertical height of the PVC.
Looks like an interesting design though. I like the tweaks I mentioned to make it a bit more efficient (I think).