Worth,
"Fogger" is probably the wrong phrase. We need to mist chilled water onto the plants from overhead without having to run hundreds of feet of parallel pipe - so the 10 foot radius (20 foot diameter) seemed to be the optimum design goal. We need "mist" - not large droplets of water landing on the plants. (I keep thinking of your fire suppression work you did up on the North Slope some years ago...)
Raybo