The Misting system works on the principal of evaporation of water and it taking heat away from it. The Misting system is a very effective in dry areas where there is better chance of evaporation. When water strikes the surface of a hot surface, it evaporates and if the surface is cooled. If the area of the water drops very small, in the order of microns, it evaporates even faster and gets away with a lot of heat. This cools the surface. Wok on the other hand has a feature of absorbing water which seeps down and allows the lower layers to cool off. The way they work is very simple. First of all the water is made into a very fine mist that is sprayed under high pressure, this makes then even more fine and then that is used to put it on the surface of the room via rotor blade. They are micro and very small and therefore they flash evaporate as soon as they touch the surface of the room. They have one disadvantage though. First of all without the water they are just like any other fan running and the water to be used should not be salty as the salt can seriously decrease the life of the rotor and the inner machinery. Also another point to be noted is that they cannot be used in all environments, for instance they cannot be used as a cooling solution in hot and humid environment as the humid environment will not let the water evaporate and can lead to dampness in the room. For more information about these misting system and where you can get a good affordable set of coolers, make a simple Google search and get all the critical reviews on the topic.