How does Evaporative cool work knowing the properties of heat air and water vapor is crucial. Direct type is the most prevalent evaporative cooler. This allows the outside heat to be cooled inside the machine before being forced into the structure and then exhausted to the exterior. There are two types: the Air Washer type and the Indirect type.

What Exactly Is Heat?

Before we discuss the cooling process, let’s first understand what heat is. There are two kinds of heat. One is Sensible heat. This heat you can feel. The other is Latent heat.

Latent Heat of Evaporation is the heat that evaporates water to make it into water vapor. For example, heat from the hot pavement is given up to evaporate water after a storm, or heat from a stove burner is given up to evaporate the water in a boiling kettle. You cannot see it, but it absorbs heat from the surrounding environment. While the temperature does not change, the molecular arrangement of the vapor will determine how much heat or energy it absorbs.

Here Comes The Latent Heating

It comes from the surrounding environment and materials. A substance absorbs heat from its surroundings when it changes its state from solid or liquid (ice to water) to liquid or vapor (water, vapor, or steam). This means that air, solid objects, and liquids around you become cooler by absorbing heat from the melting or evaporating process.

Total Heat is the total of both sensible and latent heating. It is the total heat of a room. It includes both heats that you can feel as well as heat that you can’t. Total heat can be measured in kilojoules. One liter of water is evaporated in about 2000kJ. All this happens without any external energy input. Evaporative conditioners operate with very little electrical power. Only the pump and fan motors require power.

Evaporative Air Cooling

Direct Electro evaporative Air Cooling machines make heat exchange possible by using a water pump that cools the pads and a fan-driven motor that blows outside air through the media panels. These components can be combined to accelerate the natural heat transfer process.

During the process, some heat from the air (the heat which you can feel), is converted into latent warmth (the heat which you can’t touch). The Evaporative Cooler turns water into water vapor.

This process of sensible heat being converted into latent heating causes hot water to become cooler because some of its (sensible), warmth has been used. The cold is then pumped into and exhausted from the building. It is never recirculated.

Evaporative Air Coolers might slightly increase the humidity. The temperature has also dropped. Human comfort is a combination of temperature & humidity. Evaporative Air Coolers are popular worldwide because they create comfortable conditions. Additionally, increased air velocity in hot conditions can increase comfort. Evaporative air coolers produce sufficient air movement and reduce the impact of humidity.

As can be seen from the graph below, relative humidity and temperature are both inversely related. In other words, relative humidity is lower in the part of the day where temperatures are higher. The lower relative humidity means that evaporation can occur.

Therefore, even in very humid climates, you can still cool your body with effective cooling.