“Swamp cooler” is actually a nickname for evaporative coolers. They are not a thing of the past, but they simply do not work everywhere. It is not clear why they are named swamp coolers, but it might have to do with the fact that they make the air more humid. As such, they need a hot, dry climate to work properly. In the United States, they work best in the arid southwest. In a humid climate, using evaporative cooling can cause uncomfortable levels of humidity and you will not be able to reach the desired comfort.
Evaporative cooling is based on using water evaporation to cool the temperature. People actually use evaporative cooling naturally, even if they may not realize, when they sweat. As the body warms up, sweating occurs to lower its temperature.
The basic design of a swamp cooler consists of a blower that draws hot air through pads soaked in water. The air moving through the pads cools down, and then it can be vented directly into a room or a duct system. Humidity will also increase slightly due to the water in the air, which can actually be beneficial in a very dry climate.
Unlike an air conditioner, an evaporative cooler is more rudimentary, but also inexpensive and it does not contain chemicals that may be damaging to the environment. For a great Denver HVAC consultation look to your local contractors.