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How does Evaporative Cooling function? It is crucial to be able to distinguish between heat, air, and water vapor. Direct type is the most popular type of Evaporative Cooler. It uses hot outside air to cool the unit. Other types include the Indirect and Air Washer types.

International discusses direct cooling by evaporative cooling in this remarkable work;

What Is Heating?

Before we can explain the cooling process we need to have a basic understanding of heat. Heat comes in two forms: sensible (the heat you feel) and hidden (the heat that is not detectable with a thermometer).

The latent heat of evaporation is the heat that is required to evaporate water to make it vapor. The heat from the pavement can be used to evaporate water after a summer storm, while the heat from a stove burner is used to evaporate water in a boiling kettle. When liquid water evaporates it absorbs heat from its surroundings. However, the temperature does not change. The molecular structure of the vapor includes the amount of heat and energy it absorbs. This natural phenomenon, Latent Heat, makes it possible to evaporate cool.

What Is The Origin Of Latent Heat?

It is formed from the air and materials around it. A substance absorbs heat when it changes from solid to fluid (ice to water), and from liquid or liquid to vapor (water, vapor, or steam). This is because the liquids, solid objects, or air surrounding them cool down as they heat up to melt or evaporate.

The Evaporative Air Cooling Process

Direct Evaporative Air Cooling devices facilitate heat exchange by using a water pump to provide water to evaporative cooler pads and a motor-driven fan that blows a hot outside breeze through those media panels. These components combine to accelerate the natural heat-exchanging process.

A portion of the air's sensual heat (the heat that you can feel) is converted to latent heat (the heat that you cannot feel). The Evaporative Air Cooler converts water into water vapor.

As explained previously, the transformation of sensible warmth into latent heat causes hot air temperature to drop because some of its sensible heat is no longer being used. Thus, the air temperature falls. The cold air is then pushed inside the building before it is emitted out. It is never distributed.

A structure's relative humidity will be slightly increased by air coolers that rely only on evaporation. However, the temperature has decreased. Because of their ability to provide comfortable conditions, evaporative coolers are used widely around the world. Evaporative air coolers are more comfortable than 80% humidity or 16degC (61degF). Evaporative coolers can increase comfort by increasing air velocity in hot environments. They also help to reduce humidity by generating enough air movement.

As you can see, the relationship between temperature (and relative humidity) is inverse. Temperatures are higher and relative humidity lower. Evaporative Cooling works best when the relative humidity is high.

Therefore, even in places that are usually considered to be extremely humid, the combination of temperature and humidity will still allow for effective cooling.

By Parker