Since swamp coolers work by putting water into the dry air, they act as humidifiers. Too much humidity can prevent perspiration, which is how we cool ourselves naturally. The result is a drier room, and in humid climates, that can be a good thing. The water drains outside - that's the distinctive drip you'll feel if you stand under a window air conditioning unit long enough. Standard air conditioners also dry the air, condensing water vapor from the cooled room as it passes over the cold coils.
Swamp coolers can also use ducts in some cases, but they need to be larger than traditional air conditioner ducts to account for a greater flow of air from the swamp cooler.
#BUILDING A VINTAGE SWAMP COOLER WINDOWS#
Opening and closing windows and doors controls the air flow from the swamp cooler to different parts of the house, while central air conditioners use ducts to direct the flow. Both systems can use either a large central unit or small window units, but air from the swamp cooler needs a way out. They rely on the flow of air through the building to direct the cool air, and since they always need hot, dry air to evaporate the water, it needs to displace the air already in the house. It's a closed process - leaving a window or door open allows the cool air to escape and makes the air conditioner work harder to supply cold air. (For more about standard air conditioners, see How Air Conditioners Work). The air is cooled by the coils, sent into your house, and then re-circulated over and over through the machine, venting hot air generated in the process to the outside. Standard AC units work by employing the same operating principles as your home refrigerator. The process also cools the remaining liquid, as hotter, faster-moving molecules are the most likely to escape into the air. As they become suspended in the air, the molecules draw some of the heat from the hotter air, cooling it down as the water and air find equilibrium. Liquid evaporates by shedding molecules into the air, changing from a liquid state to a gas. What he described in his letter is evaporative cooling. He discovered that the evaporation of liquids caused heat loss. Later, he tried some experiments - wetting the bulb of a thermometer and watched as the temperature dropped. Franklin theorized that he wasn't being cooled by the hot air blowing through his room, but by the perspiration evaporating off his skin. As he later wrote in a letter, Benjamin Franklin was in his room, reading and writing with "no other cloaths on than a shirt, and a pair of long linen drawers, the windows all open, and a brisk wind blowing through the house." Even founding fathers sweat, and as he changed to a dry shirt, he noticed something - it felt warm, like it had been near a fire, compared to the damp shirt he had just removed. July 1758 was a scorcher in Philadelphia, Pennsylvania, with temperatures reaching 100 degrees Fahrenheit (37 Celsius).
Nowadays, we use electric fans instead of servants, but the principle of cooling the air by evaporation remains the same. When hot dry air passes over water (or better yet, through it), the air cools off. They accomplished it by hanging wet blankets across the doors of their homes or, if they happened to be royalty, having servants fan them across jugs of water. The ancient Egyptians had a great need for air conditioning. They're cheap, efficient and good for the environment, but they come with some limitations, so don't push your standard air conditioner out the window just yet. as swamp coolers, modern evaporative coolers can trace their lineage to ancient Egypt. The same principle cools you off after a swim, and also powers one of the oldest and simplest forms of air conditioning.
If you've ever tested the wind by holding a wet finger in the air, you've used evaporative cooling. A worker does preventative maintenance on a commercial rooftop swamp cooler.