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The Benefits of Evaporative Cooling: An Energy-Efficient and Cost-Effective Solution

CEO Khai Intela
An Egyptian qullah, set in drafts to cool interiors. Porous pottery and coarse cloth maximize the area for evaporation. Evaporative cooling, also known as evaporative air conditioning, swamp cooling, or wet air cooling, is a...

Ancient Persian passive design taking advantage of evaporative cooling An Egyptian qullah, set in drafts to cool interiors. Porous pottery and coarse cloth maximize the area for evaporation.

Evaporative cooling, also known as evaporative air conditioning, swamp cooling, or wet air cooling, is a method of cooling air by evaporating water. Unlike traditional air conditioning systems that use refrigeration cycles, evaporative cooling uses the natural process of evaporation to cool the air. This method is highly energy-efficient and cost-effective, making it a popular choice in dry and arid climates.


Evaporative cooling has a long history, with its roots dating back to ancient Egypt and Persia. In ancient times, wind shafts were used to catch the wind, pass it over subterranean water in qanats, and discharge the cooled air into buildings. This early form of evaporative cooling was later adopted by modern Iranians.

In the 20th century, evaporative coolers gained popularity, and numerous patents were issued for their design and functionality. Excelsior pads made of wood wool were commonly used in evaporative coolers in the American Southwest, where they were also used to increase humidity. The term "swamp cooler" originated from the odor of algae produced by early units in the United States.

How Evaporative Cooling Works

Evaporative cooling takes advantage of the fact that water absorbs a significant amount of heat when it evaporates. The process involves the conversion of liquid water into vapor using the thermal energy in the air, resulting in a lower air temperature. This conversion of sensible heat to latent heat occurs at a constant enthalpy value.

By passing dry air over wet evaporative media, the air is cooled as the water evaporates. The temperature of the air can be dropped significantly through the phase transition of liquid water to water vapor. This process requires much less energy than traditional refrigeration methods.

The Benefits of Evaporative Cooling

Energy-efficient and Cost-effective

Evaporative cooling is highly energy-efficient compared to traditional air conditioning systems. It uses only a fraction of the energy required by vapor-compression or absorption air conditioning. The cooling effect is achieved through the evaporation of water, which consumes less energy than the compression of refrigerants used in traditional systems.

Furthermore, evaporative coolers have lower installation and operating costs. The equipment is less expensive to install, and the operating costs can be up to 80% less than those of refrigerative air conditioning.

Improved Air Quality

Evaporative cooling can improve air quality in buildings as the evaporative media act as air filters. The pads capture contaminants in the air, such as urban ozone, dust, and other particles, enhancing indoor air quality. This is particularly beneficial in arid climates where the air can be dry and dusty.

Comfort and Health Benefits

In dry climates, evaporative cooling increases humidity, providing relief from dry skin, dry eyes, and dry nasal passages. It can also help alleviate symptoms of allergies and asthma by reducing airborne particles and maintaining a comfortable level of humidity.

Environmental Friendliness

Evaporative cooling systems use water as the working fluid, eliminating the need for harmful refrigerants that contribute to ozone depletion and global warming. The systems have a minimal impact on the environment and are considered a more sustainable cooling solution.

Applications of Evaporative Cooling

Evaporative cooling is commonly used to cool buildings for thermal comfort. It is particularly effective in dry and arid climates, such as the southwestern United States, northern Mexico, and Rajasthan. It is widely used in residential, commercial, and industrial applications.

Evaporative cooling systems are suitable for various environments, including residential homes, commercial kitchens, laundries, dry cleaners, greenhouses, and industrial facilities. They are also used in agricultural settings, such as poultry ranches and dairy farms.

Evaporative cooling towers are used in large-scale cooling applications, such as power plants, to cool water or other heat transfer media to near-ambient wet-bulb temperature.


Evaporative cooling is a reliable and energy-efficient method of cooling air in arid and dry climates. It offers numerous benefits, including lower installation and operating costs, improved air quality, and environmental friendliness. Evaporative cooling is a cost-effective solution for residential, commercial, and industrial applications, providing comfort and health benefits while reducing energy consumption and environmental impact.

A traditional air cooler in Mirzapur, Uttar Pradesh, India A traditional air cooler in Mirzapur, Uttar Pradesh, India