Posted by GoodCooling Team
Evaporative cooling is not a trick but physics. We encounter it every day: when sweating, after swimming, or when washing dries in the air. An evaporative air cooler uses exactly this effect deliberately.
Evaporative cooling: what happens?
For water to change from a liquid to a gaseous state, it needs energy. It draws this energy from its surroundings, that is, from the air. The air loses heat and becomes cooler. This is called evaporative cooling.
The wet-bulb temperature
How far the air can be cooled depends on the humidity. The theoretical lower limit is called the wet-bulb temperature. The drier the air, the lower it is. With very humid air it is only just below the air temperature, so the cooling is slight. More on this on Wikipedia.
What this means in everyday life
- Dry heat: the effect is greatest.
- Muggy days: the effect is small, see Evaporative air coolers and humidity.
- Air exchange: humid air must be able to escape, otherwise the effect decreases.
From principle to unit
In an evaporative air cooler, a fan draws in warm air, passes it over a wet cooling pad and blows it into the room cooled. The steps in detail: How does an evaporative air cooler work? Why this works without refrigerant is explained in Air coolers as a sustainable alternative. You will find further background on our Technology page.
Frequently asked questions
How much does the temperature drop?
That depends on humidity, unit and room. An independent SRF test of household units found a maximum of 3.5 °C in the airflow.
Does this also work in winter?
The principle does, but it is mainly useful in hot weather.
Conclusion
Water evaporates, the air loses heat: simple and without refrigerant. Humidity sets the limits. If you would like to know whether this suits your room, ask us.
