[Excaliber]

Evaporative Cooler. Water is pumped to the top of all four sides and "dribbles" down to the bottom of the "air conditioner" enclosure. The water passes over a woven medium in appearance like "straw". This breaks up the water into smaller droplets on the journey. Hot dry air is then drawn through the woven medium coming in close contact with the water droplets. The droplets evaporate and in so doing draw heat from the air to make the "phase change" from liquid to gas (evaporation).

The air now INSIDE the box is cooler and is blown out into the air conditioning room. The air is also "humidified", containing the previoulsy liquid water now held as a "gas".

Most things that go through a "phase change" require LARGE amounts of energy to make that change. This energy is the hot air. The air MUST be "dry" in order to absorb the evaporated liquid water and thus become "cool". A "swamp cooler" does not work well in a more humid climate, such as Hawaii (bummer).

Could you say Atom Bombs go through a kind of "phase change", releasing HUGE amounts of energy during the process? The principle is the same, all though "phase change" is not the correct wording for it.