ABB VortexMaster FSV430 - Calculation of the Net Energy for Steam; Steam Mass Calculation; Density Diagrams

VortexMaster FSV430, FSV450 SwirlMaster FSS430, FSS450 | CI/FSV/FSS/430/450-EN Rev. G 53
For the energy measurement, the media types "saturated
steam", "superheated steam" or "hot water“ can be selected.
The calculation is done according to IAPWS-IF97.
Calculation of the net energy for steam


watersteammp
HHQQ 
Calculation of the net energy for hot water / condensate


outwaterinwatermp
HHQQ
__

Formula elements used
Q
p
Net energy
Q
m
Mass flow
H
steam
Steam enthalpy
H
water
Water enthalpy
H
water in
Water enthalpy (feed flow)
H
water
_
out
Water enthalpy (return flow)
Prerequisites for the energy measurement:
— For energy measurement of steam, this must condense
completely.
— The process must form a closed system, energy losses
through leaks are not recorded.
Steam mass calculation
The following options are available for the steam mass
calculation:
— Density calculated from the temperature (saturated steam
only)
— Density calculated from the pressure (saturated steam
only)
— Density calculated from pressure and temperature
— Constant density
If a pressure transmitter is connected, the steam state is
checked automatically. A distinction is made between wet
steam, saturated steam, and superheated steam. The correct
density is always calculated regardless of the selected media
type.
If a pressure transmitter is not connected and steam type
"Overheated Steam" is selected, a constant pressure must be
entered for the state to be detected and, if applicable, the
density to be calculated.
A value must always be stored for the steam density value
(constant) in the transmitter in order to define the measuring
range limits for Q
max
DN in mass flow units.
An approximation is sufficient here, the density diagrams
provide an indication for determining the steam density.
Density diagrams
The following diagrams show an extract from the density table
for saturated steam at different temperatures / pressures.
Fig. 48: Saturated steam density vs. temperature
ρ Steam density T Temperature
Fig. 49: Saturated steam density vs. pressure
ρ Steam density p Pressure
G11882
ρ [kg/m ]³
T
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
100 115 130 145 160 175 190 205 220 235 250 265 280 [°C]
0
0.1
0.2
0.4
0.5
0.6
0.7
0.9
1.0
1.1
1.2
1.4
1.5
1.6
1.7
1.9
2.0
2.1
212 239 266 293 320 347 374 401 428 455 482 509 536 [°F]
ρ [lb/ft ]³
G11883
ρ [kg/m³]
0
1
2
3
4
5
6
7
8
9
10
11
12
0
0.06
0.12
0.19
0.25
0.31
0.37
0.44
0.50
0.56
0.62
0.69
0.75
024681012141618202224
(0) (29) (58) (87) (116) (145)
(174) (203) (232) (261) (290) (319)
(348)
p [bar abs (psia)]
ρ [lb/ft³]