{"id":106025,"date":"2026-10-15T11:59:55","date_gmt":"2026-10-15T09:59:55","guid":{"rendered":"https:\/\/firstcolo.net\/glossar\/adiabatic-cooling\/"},"modified":"2026-10-15T16:04:54","modified_gmt":"2026-10-15T14:04:54","slug":"adiabatic-cooling","status":"publish","type":"glossary","link":"https:\/\/firstcolo.net\/en\/glossary\/adiabatic-cooling\/","title":{"rendered":"Adiabatic cooling"},"content":{"rendered":"\t\t
\n\t\t\t\t
\n\t\t\t\t\t
\n\t\t
\n\t\t
\n\t\t
\n\t\t\t\t
\n\t\t\t\t\t

What is adiabatic cooling?<\/h1>\t\t\t\t<\/div>\n\t\t\t\t
\n\t\t\t\t\t\t\t\t\t

Adiabatic cooling<\/strong> refers to a thermodynamic process in which a system does not exchange heat with its surroundings. In HVAC engineering, the principle is primarily used for adiabatic cooling<\/strong>: water evaporates in an air stream. The energy required for evaporation comes from the air itself, which cools as a result. The heat does not disappear; it is merely transferred into the water vapor that forms. Because no heat is supplied or removed from outside, this is referred to as an adiabatic process. The air temperature drops without necessarily having to use a conventional, energy-intensive vapor-compression chiller.<\/p>\n

In data centers<\/strong>, adiabatic cooling can therefore help reduce the energy required for air conditioning. At the same time, the process requires water. To assess efficiency, both the PUE value (Power Usage Effectiveness)<\/strong> and the WUE (Water Usage Effectiveness)<\/strong> should therefore be considered.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

\n\t\t\t\t\t
\n\t\t\t\t
\n\t\t\t\t\t

How does adiabatic cooling work?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
\n\t\t\t\t\t\t\t\t\t

In adiabatic cooling, water is introduced into an air stream and evaporates. This phase change requires energy. That energy is drawn from the air in the form of heat, causing the air to cool.<\/p>\n

A simple example: on a hot, dry day, outside air can be cooled significantly by water evaporation before it is used to air-condition a building or data center.<\/p>\n

How strong the cooling effect is depends, among other factors, on the temperature and humidity of the outside air<\/strong>. The drier the air, the more water it can absorb and the greater the potential of evaporative cooling. The physical limit is the so-called wet-bulb temperature<\/strong>: the air cannot be cooled any further by evaporation alone. In humid weather, it is close to the air temperature, so the cooling effect is then low.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

\n\t\t\t\t\t

Direct and indirect adiabatic cooling<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
\n\t\t\t\t\t\t\t\t\t

In principle, a distinction is made between two methods:<\/p>\n

Direct adiabatic cooling:<\/strong>The water evaporates directly in the air stream. This lowers the temperature, but the humidity increases at the same time.<\/p>\n

Indirect adiabatic cooling:<\/strong>Evaporation takes place in a separate air stream, which cools as a result. The supply air then transfers heat to this cooled air stream via a heat exchanger. As a result, the air that reaches the IT area does not come into direct contact with the evaporated water, and its humidity remains unchanged.<\/p>\n

Controlled airflow is particularly important for data centers, as temperature and humidity must be kept within defined operating ranges. For this reason, the indirect variant is often used there.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

\n\t\t\t\t\t

What are the benefits of adiabatic cooling in the data center?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
\n\t\t\t\t\t\t\t\t\t

The key advantage of adiabatic cooling is its comparatively low electrical energy demand. Under suitable climatic conditions, it can reduce or temporarily replace mechanical cooling.<\/p>\n

This can:<\/p>\n