Evaporative air Cooling Principle and Environmental Application Analysis

Evaporative coolers operate by drawing hot air through moistened cooling pads, which are supplied with water from a reservoir at the base of the unit. Ducted and wall-mounted systems intake outdoor air, while portable units draw indoor air. Water evaporation within the pads absorbs heat from the air and increases its humidity. The cooled humidified air is then blown into targeted rooms (wall-mounted/portable units) or distributed throughout the entire house (ducted systems).

The operation of evaporative coolers involves both cooling the indoor air and generating a cool breeze. For them to work effectively, they require good weather conditions and some windows and interior doors to be open to allow the humidified air to escape outside.

Ducted and wall-mounted evaporative coolers draw in outside air, providing a continuous supply of fresh, cool air when in use. However, it is important to note that these devices should not be used when there is heavy outdoor smoke, as they can draw the smoke indoors, leading to poor indoor air quality.

Ducted evaporative systems also require additional maintenance to adapt to winter conditions and prevent warm air from rising through ceiling vents and ducts and escaping through the cooling unit on the roof, as this can increase winter heating costs.

The main cooling unit of the duct-type evaporative cooler is located on the roof and delivers cooled air to ceiling outlets in different rooms of the house through ducts.

Window-mounted, wall-mounted and portable evaporative coolers can be used to cool small rooms or provide spot cooling. These systems are relatively inexpensive, but have limited cooling capacity and generate considerable noise during operation.

The efficiency and effectiveness of evaporative cooling systems can vary significantly depending on outdoor weather conditions. Their cooling effect relies on the evaporation of water in the moist filter pads, which means they perform poorly in humid environments. They work best in hot and dry conditions. Under ideal conditions, they can cool outdoor air by a certain temperature - typically around 10 degrees Celsius - but unlike refrigerated air conditioners, they do not cool the indoor air to a specific thermostat setting. Therefore, if the outdoor temperature is 38 degrees Celsius, they might only cool the indoor air to 28 degrees Celsius.

If the outdoor air is humid, the cooling performance of the equipment will be limited because water does not easily evaporate from the cooling pads, and a higher fan speed may be required to feel comfortable.