28
5.4.2
Positioning of the steam distributor
The location of the steam distributor should be determined at the time of dimensioning the air condition-
ing system. Please note the following instructions to ensure proper humidification of the duct air.
Calculating the absorption distance
The steam, emitting from the steam distributor, requires a certain distance to be absorbed by the air so
that it is no longer visible as steam. This distance is referred to as
absorption distance "B
N
"
and serves
as a basis for the determination of the minimum distances from the upstream components in the system
Fig. 10: Absorption distance "B
N
"
The calculation of the absorption distance "B
N
" is dependent on several factors. For a rough estimation
of the absorption distance "B
N
", the following table is useful. Recommended standard values listed in
this table are based on a supply-air temperature range of 15 °C to 30 °C. The values given in bold type
apply to steam distribution pipes DV81-...
, the values
in brackets apply to the MultiPipe steam
distribution system.
Humidity at inlet
ϕ
1 in %rh
Length of absorption distance B
N
in m
Humidity at outlet
ϕ
2 in %rh
40
50
60
70
80
90
5
0,9
(0,22)
1,1
(0,28)
1,4
(0,36)
1,8
(0,48)
2,3
(0,66)
3,5
(1,08)
10
0,8
(0,20)
1,0
(0,26)
1,3
(0,34)
1,7
(0,45)
2,2
(0,64)
3,4
(1,04)
20
0,7
(0,16)
0,9
(0,22)
1,2
(0,30)
1,5
(0,41)
2,1
(0,58)
3,2
(0,96)
30
0,5
(0,10)
0,8
(0,17)
1,0
(0,25)
1,4
(0,36)
1,9
(0,52)
2,9
(0,88)
40
–
0,5
(0,11)
0,8
(0,20)
1,2
(0,30)
1,7
(0,45)
2,7
(0,79)
50
–
–
0,5
(0,13)
1,0
(0,24)
1,5
(0,38)
2,4
(0,69)
60
–
–
–
0,7
(0,16)
1,2
(0,30)
2,1
(0,58)
70
–
–
–
–
0,8
(0,20)
1,7
(0,45)
φ1 in %rh: Relative supply air humidity prior to humidification at the lowest supply air temperature
φ2 in %rh: Relative supply air humidity after the steam distribution pipe at maximum capacity
For duct widths <600 mm the absorption distance for the MultiPipe system increases by approx. 50%
φ1
: Supply air humidity
before
humidification
φ2
: Supply air humidity
after
humidification
Expansion and mixing zone
Absorption
distance B
N
Safety humidistat /
Humidity sensor
