One of the design principles for Nurse Tree Design is to keep electrical use to a minimum in cooling and heating the arch. I’m working on an evaporative cooling system with a 12 volt variable speed fan powered by a deep discharge battery. The battery will be charged by a 100 Watt Polycrystalline Solar Panel. These pictures show the development process thus far. Next step will be to build the housing for the evaporative medium and polytube water delivery system, which will be connected to the drip irrigation system.