Yeah as Zombie stated using a cooler with a tray in it like that is refered to as the "Fog on the rocks" design and is the subject of much controversy as it's designer has made a few chillers that, on the outside, look like ones others in the community have built, the only problem is he's pantented his design and is selling them.
That is an earlier version of it. The fog community (if there is such a thing) doesn't like a direct pipe connection to the fogger. Normally you want 3 to 4 inches between the fogger and the intake to the chiller as physics tells you hot gas needs to exapand. If you do a direct connection you'll get a lot of residue and less fog. The "Y" connection seen here
http://i2.photobucket.com/albums/y32/Zombie-F/Fog%20on%20the%20Rocks/fog_on_the_rocks-14.jpg
was an attempt at getting air into the process, it was later determined that just giving it 4 inches saves you from having to deal with the "Y" pipe and you get less condensation.
Now as for something I can speak about with personal knowledge of:
a good chiller will actually create a light "suction" pulling air out of the cold and into the warmer outside air (basic physics behind why wind happens in nature) so my personal fogger we've turned this to our advantage and slowed the speed of the fog comming out of the fog machine as much as possible and let "wind" and gravity do it's job to give us a nice even, well chilled, output. As I'm sure you know, the longer the fog is in the chiller the colder it becomes.
Zombie is right on the money though about wind. I'm praying for a still night. but my new house is up agenst a hill so I think I'll get my wish.