Operation Manual

12
4.1.2 Calculating the maximum required steam capacity
V • ρ
m
D
= • (x2 - x1)
1000
V
m
D
= • (x2 - x1)
1000 • ε
m
D
: maximum steam demand in kg/h
V: volume of supply air portion per hour in m
3
/h (for indirect room humidification) or volume
space in case of simple air circulation per hour in m
3
/h (for direct room humidification)
ρ: specific gravity of air in kg/m
3
ε: specific volume of air in m
3
/kg
x
2
: desired absolute room air humidity in g/kg
x
1
: minimum absolute supply air humidity in g/kg
The values for ρ, x2 and x1 can be gathered from the h,x-diagram or the Carrier-Diagram for moist
air respectively.
For a rough estimate of the calculated steam capacity, the following table can be used. The values listed
in the table are based on a desired room air temperature of 20°C and a desired relative room air humidity
of 45 %rh.
Note: To roughly estimate the calculated maximum steam capacity for larger supply air portions or room
volumes, the values listed in the table can be projected accordingly.
Max. portion of supply air per hour in m
3
/h or volume space max. steam capacity
in case of simple air circulation per hour in m
3
/h in kg/h
Temperature / rel. humidity of supply air
-15 °C / 90%rh -5 °C / 80 %rh 5 °C / 60 %rh
500 650 800 4
1000 1250 1500 8
2000 2500 3000 15
4000 5000 6000 30
6000 7500 9000 45
Important notes:
– The listed formulas and values from the tables do not consider absorption or release of humidity of
materials located in the room being humidified.
– It is absolutely crucial to carefully calculate the maximum steam capacity. Over-dimensioned
steam humidifiers interfere with the control stability.
– For systems where the max. required steam capacity varies extensively (e.g. for test facilities or for
systems with variable air volume flow, etc.), please contact your Condair supplier.
Condair CP2 F30
The maximum required steam capacity is calculated from the following formulas:
or