*****It is a simple evaporative device, dribbling small amounts of water across absorbent panels, and as the water evaporates, the air around it is cooled (Latent heat of vapourisation, I seem to recall from Physics classes, from 40 years ago) then sucking the cooled air down inside the house, and pumping it around. You need to have an open door or window to allow the moist air to escape. So, it has a large fan, the evaporative panel, a (small) water supply, and lots of dedicated air ducting. Pretty damned good, and requires none of the nasty chemicals empoyed in Air Conditioning.
Appropriate technology rules, OK?