Condensation of water
vapour
Since the maximum water vapour
volume increases when the air is
heated, the contained water va-
pour volume remains the same
however, this results in a reduction
of the relative humidity.
In contrast, when the air is cooled,
the capacity to absorb the maxi-
mum water vapour volume re-
duces, the water vapour volume
contained in the air remains the
same and the relative humidity
increases.
If the temperature falls further, the
capacity to absorb the maximum
water vapour volume is reduced
until it is equal to the contained
water vapour volume.
This temperature is called dew-
point temperature. When the air
is cooled below the dew-point
temperature, the contained water
vapour volume is larger than the
maximum water vapour volume.
Water vapour is discharged.
This condenses to water. The air is
relieved of moisture.
Examples of condensing are misted
windows in winter or misting of a
cold drinks bottle.
The higher the relative humidity,
the higher the dew-point tempera-
ture, which is easier to fall below.
Building materials or structures can
absorb substantial amounts of wa-
ter, e.g. bricks 90-190 l/m³, heavy
concrete 140-190 l/m³, lime-sand
bricks 180-270 l/m³.
The drying out of moist materials,
e.g. masonry, takes place as fol-
lows:
■
The contained
moisture moves
from the inside of
the material to its
surface.
■
Evaporation takes place on the
surface = transition as water va-
pour to the ambient air.
Temp.
Water vapour content in g/m
3
at a humidity of
°C
40%
60%
80%
100%
-5
1.3
1.9
2.6
3.3
+10
3.8
5.6
7.5
9.4
+15
5.1
7.7
10.2
12.8
+20
6.9
10.4
13.8
17.3
+25
9.2
13.8
18.4
23.0
+30
12.9
18.2
24.3
30.3
■
The air enriched with water
vapour continuously circulates
through the REMKO dehumidi-
fier. It is dehumidified and lea-
ves the unit at a slightly higher
temperature to absorb water
vapour from anew.
■
In this way, the moisture con-
tained in the material is gradu-
ally reduced.
The material dries!
The produced condensate is col-
lected in the unit and discharged.
Verdampfer
Kondensator
°C
30
25
20
15
% r.F.
100
90
80
70
60
50
40
30
20
10
+
+
-
Lufttemperatur
Luftfeuchte
Verlauf
Luftrichtung
The air flow is cooled on its way through or via the evaporator to
below the dew point. The water vapour condenses and is collected
in a condensate trap and discharged.
Drying materials
Evaporator Condenser
Air temperature
Air flow direction
Air humidity
Trend
5
