A lot of folks have been spending a lot of time and effort to cool their towers to keep from getting foaming beer. The simplest solution that I have found is a 2 line aquarium air pump that I sit on the bottom of my kegerator, run the ac line out to an outlet, and connect 2 small airlines that reach all the way to the top of my draft tower. Very simple and it works great. It just pumps cold air up to the top of the tower!!