Useful Information; Air And Water; Relative Humidity; Dew Point - KALEAS KlimaDetector Operating Instructions Manual

Useful information

Air and water

The ambient air always contains dissolved water in the form of water vapor.
The amount of water in the air is commonly referred to as atmospheric hu-
midity; physically, it is called "momentary vapor pressure."
The maximum quantity of water that air can absorb depends upon the air
temperature and barometric pressure. Physically, this is considered satura-
tion of air with water and is referred to as "saturated vapor pressure."
If the air is saturated with water, then it cannot take up any additional wa-
ter. If, however, additional water is introduced into the air, e.g. through
human breath, this water condenses, resulting in condensation, fog or pre-
cipitation.
Since barometric pressure varies little in the normal environment of residen-
tial areas, it can be disregarded when determining the dew point. The Cli-
mateDetector is permanently set to a value of 1013 hPa (standard pressure).

Relative humidity

Relative humidity (RH) indicates the actual volume of water in the air as a
percentage [%] of the maximum water volume that can be absorbed in the
air (saturation volume). Physically, this is the ratio between momentary va-
por pressure and saturated vapor pressure.
If relative humidity reaches 100%, then there is so much water in the air
that it cannot absorb any more water. The momentary vapor pressure thus
equals the saturated vapor pressure. Additional water results in condensa-
tion formation or fog.

Dew point

The temperature at which water condenses out of the air is called the dew
point. At this temperature, the relative humidity is 100%. The colder the
air, the less water it can absorb and vice versa. Stated another way, the dew
point increases when the temperature remains the same and the water con-
tent (vapor pressure) increases and vice versa.
A numeric example should make this clear:
Air temperature
Example 1
Example 2
 The smaller the differential between air temperature and dew point, the
greater the likelihood of moisture and mildew formation.
20
Relative humidity
AT
18 °C
25 °C
RH
92 %
60 %
KlimaDetector ENGLISH
Dew point Differtial
AT – DP
DP
16,7 °C 1,3 °C
16,7 °C 8,3 °C
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