One of the most prevalent misconceptions about evaporative cooling is that it would create a subtropical climate within a production facility or building. This misconception stems from the fact that some home ACs based on evaporative cooling humidify besides cooling. These systems pump humidified and cooled air through the building, but as there usually is no air outlet to extract the humid air, the moisture cannot escape, and the indoor climate becomes very humid. However, two-stage evaporative cooling is capable of reaching lower temperatures and by law of nature, lower temperatures can hold lower amounts of humidity. In fact due to the lower temperature two-stage evaporative coolers need only around 50% of the air volume needed to cool a building than direct evaporative coolers. Two-stage evaporative cooling systems used for cooling production facilities always ventilate the building with fresh, filtered outdoor air while removing the polluted indoor air. The fresh air is pumped into the area, absorbs the heat and is then extracted through an exhaust. This way, the moisture in the air doesn't get the chance to build up in the building or production facility.
Nonetheless, two-stage evaporative cooling does increase humidity to some degree. Below you can read more on the (beneficial) consequences of the increase in humidity and how evaporative cooling works in humid climates.
Does evaporative cooling increase humidity?
The short answer is yes, evaporative cooling does increase humidity. With how much the relative humidity within a space increases depends on the outside humidity level, the outside temperature, the desired temperature that is to be achieved, and the type of evaporative cooling system that is used. For instance, Oxycom's patented two-stage evaporative cooling technology ensures 60% less increase in humidity than other direct evaporative cooling systems. Ensuring a comfortable indoor climate for the occupants.
It is important to mention that bringing in some moisture into the air has its benefits. For example, a humidity level between 40 and 60% reduces the spread of dust and viruses within a production facility or building. Furthermore, it brings a level of comfort as the air that is too dry can irritate the eyes and throat. Thus it is essential to have a climate control system in place that provides the air with enough humidity for employees to feel comfortable as well as to protect them from the unlimited spread of viruses.
Degree of infectivity in relation to indoor humidity.
Does evaporative cooling work in humid climates?
Evaporative cooling is a physical process, meaning that the relative humidity does affect the effectivity with which an evaporative cooling system cools. The more humid a climate is, the harder it is for an evaporative cooling system to cool effectively. Nonetheless, the great benefit of two-stage evaporative cooling is that it makes use of both the indirect and the direct cooling process. As a result, Oxycom's IntrCooll can cool up to 7 ℃ deeper than other evaporative cooling systems. Yet, evaporative cooling remains a physical process: with a relative humidity of 80% or 90%, a two-stage evaporative system cannot cool as effectively as at lower humidity levels.
The graph shows that the humidity level (40-60%) which the IntrCooll guarantees falls in the “Optimum Zone” with regards to bacteria and infections.