How does evaporative cooling work?

The process of evaporative cooling, sometimes referred to as adiabatic cooling, uses the evaporation of water to cool the air to a comfortable temperature.

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This method of ventilation and cooling employs water as the refrigerant.

Water turns from a liquid to a gas by evaporation in an air stream during the evaporative cooling process. Heat is taken out of the air in order to provide the energy needed for this transfer. This mechanism cools the air as a consequence.

The operation of an evaporative cooling system

A motor-driven fan drives hot outside air through wet cooling pads in an evaporative cooling system. A water pump that constantly supplies water to the cooling pads keeps them wet. After cooling, the air is blasted within the structure. The remaining air can subsequently be cooled to between 60% and 90% of its wet bulb temperature, depending on how well the evaporative medium works. Although the outgoing air is 10 to 15 °C cooler, it is still rather humid. As a result, it is not advised to use direct evaporative cooling to cool homes or offices.

As opposed to direct evaporative cooling methods, two-stage evaporative cooling generates efficiencies of up to 114% of the wet bulb, lowers temperatures by up to 7 °C, and results in a decreased humidity content by up to 70%.

Why is the importance of evaporative cooling?

For manufacturing facilities, distribution centers, and office buildings, evaporative cooling via an indirect/direct system is a highly sustainable and energy-efficient cooling technique that creates a pleasant and productive environment. Compared to conventional air conditioning systems, which utilize compressors and refrigerants to provide cooling, this cooling technique is more energy-efficient. While providing temperatures that are about equivalent to those of conventional mechanical cooling systems, the evaporative cooling process in an indirect/direct cooling system consumes 10% of the energy required for mechanical cooling. Furthermore, evaporative cooling ventilates 100% new, filtered, clean, and cooled air into a room or structure as opposed to mechanical cooling, which circulates the heated, contaminated air within. Indoor air quality significantly improves as a result.

Evaporative cooling’s past

Evaporative cooling, or the evaporative processes, have been utilized to cool living spaces since the dawn of human civilization. As early as 2500 BC, Egyptian paintings have been discovered that show how water-filled, porous clay jars were positioned beneath air intakes to provide for some cooling effect as air went through them. Although they were unable to employ electric fans or other contemporary methods, evaporative cooling was incorporated into the construction and design of their homes to give a modality of temperature control. Other than that, a classic Iranian architectural feature for cooling buildings is evaporative cooling with wet rags combined with a wind tower (wind catcher).