WORKING OF EVAPORATIVE AIR COOLER ( SMART AHU )
The process of evaporation happens all the time. Our bodies, for example, perspire in hot weather. Through evaporation the sweat dries and drops our body temperature. Whenever dry air passes over water, some of the water will be absorbed by the air. That’s why evaporative cooling naturally occurs near waterfalls, at rivers, lakes and oceans. The hotter and drier the air, the more water that can be absorbed. This happens because the temperature and the vapor pressure of the water and the air attempt to equalize. When hot air enters the cooling pads evaporation occurs i.e., hot air absorbs the cool water molecules present in cooling pads and the cool breeze enters the room through the fan.
Small distribution lines supply water to the top of the pads. Water soaks the pads and, thanks to gravity, trickles through them to collect in a sump at the bottom of the cooler. A small re-circulating water pump sends the collected water back to the top of the pads.
Since water is continually lost through evaporation, a float valve – much like the one that controls the water in a toilet tank – adds water to the sump when the level gets low. Under normal conditions, a swamp cooler can use between 3 to 15 gallons of water a day.
A large fan draws air through the pads, where evaporation drops the temperature approximately 20 degrees. The fan then blows this cooled air into the house.