172 205 16 07-01
If the barometer height, pressure and temperature of the gas deviate very much from the normal values this must
be taken into account as follows:
f
=
273+t
. 1013,25
273
B+P
u
t
= Temperature of the gas at the gas meter (15°C)
B
= Barometer height (945 mbar)
P
u
= Pressure of the gas at the gas meter (15,0 mbar)
f
= 273+15 . 1013,25
273
945+15
f
= 11,1
The gas volume read on the gas meter actually reads 1,11
.
12,9 = 14,4 m
3
/h.
Net calorific value
Gas quality
kWh/Nm
3
kJ/Nm
3
kcal/Nm
3
Natural gas
10,3
37 144
8 865
Propane
26,0
93 647
22 350
Butane
34,3
123 571
29 492
Town gas
4,9
17 653
4 213
Bio gas
7,0
25 219
6 019
V
=
Gas volume Nm
3
/h
Q
=
Boiler output 120 kW
H
u
=
Calorific value of the gas A. 37 144 kJ/Nm
3
, B. 10.3 kWh/Nm
3
η
=
Expected efficiency 90%
Ex. A
v=
Q .3 600
=
120 . 3 600
≈
12,9 Nm
3
/h
H
u
·
η
37 144 . 0,90
Ex. B
v=
120
≈
12,9 Nm
3
/h
10,3 · 0,90
Example how to calculate the gas volume (natural gas)
DETERMINATION OF GAS VOLUME FOR THE INSTALLATION
Specifications on natural gas, town
gas and bio gas vary. For more exact
information please contact the gas
distributor.
Summary of Contents for STG 146
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