23
4.1
Selecting the unit version
To select the unit version the following planning steps are required:
1. Calculating the required maximum steam capacity according chapter
4.1.1
2. Selecting the unit version from the table in chapter 4.1.2
4.1.1
Calculating the maximum required steam capacity
The maximum required steam capacity must be calculated based on one
of the following formulas:
V • ρ
m
D
=
• (x
2
- x
1
)
1000
4
Notes for the planning engineer
m
D
: maximum steam demand in
kg/h
V
: volume of supply air portion per hour in
m
3
/h
(for indirect room humidi
fication) or room volume to be humidified 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
,
ε
,
x
2
and
x
1
can be gathered from the
h,x-diagram
or the
Carrier-Diagram
for moist air respectively.
Important notes:
– The required maximum steam capacity depends on the specific ap
plication and the installation. The calculated steam capacity based on
the above formulas, the h,x diagram and the condition of the air to be
humidified does not consider any steam loss (e.g. due to condensation
in the steam hoses and the steam distributors), any heat loss of the unit
as well as any absorption or release of humidity of materials located in
the room being humidi fied.
In addition, the calculated steam capacity does not consider any losses
caused by the draining rate depending on the water quality as well as
any losses occur if the steam humidifier is operated on a mains circuit
with a ground fault circuit interrupter.
The total amount of losses depends on the entire system and must be
taken into consideration when calculating the required steam capacity. If
you have any questions regarding the calculation of the steam capacity
please contact your Nordmann supplier.
– 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 Nordmann supplier.
or
V
m
D
=
• (x
2
- x
1
)
1000 • ε
Summary of Contents for AT4 13064
Page 2: ......
Page 64: ...64 Notes...
Page 65: ...65 Notes...
Page 66: ...Notes...
Page 67: ...Nordmann Engineering Ltd Printed in Switzerland Technical modifications reserved...
