I was given a design challenge by the residents of foot rot flats*, build an air conditioner that requires no mains power and no piped water. After a bit of thinking I decide to have a go at a solar powered evaporative cooler and it worked so well I thought I would make another one, and make it a bit different to make it even easier to build. The first cooler was not photographed during the build so the second cooler is better documented for instructables.
*Foot rot flats small community with no power, water, toilet or pretty much anything else you would expect in a western country. There are a number of permanent residents living in illegal shacks, caravans, buses, shipping containers or camper-vans and a number of others who stay for a few weeks or months of the year but usually leave before the hot weather as it can get to 45 degrees C (113 F) for days at a time and is not unlike a small version of slab city in the US.
Before you start you need to understand that an evaporative (or swampy) cooler will only work if you live in an area with low humidity. If your not sure if your area is suitable, a good indication is have a look at houses in the area, do they have swampy coolers on the roof, or are they all refrigerated coolers?
Swampy coolers have some advantages over a refrigerated coolers, the most attractive though is there low energy consumption.
The good stuff
The technology for evaporative coolers is very simple, and there are fewer working parts, which means maintenance and repair costs are low.
The not so good stuff