Installation and operating instruction
Gas burner WG40…/1-A ZM-LN
7 Commissioning
83300002 1/2019-02 La
67-128
7.6 Calculate gas throughput
Formula symbol
Explanation
Example values
V
B
Operating volume [m
3
/h]
Volume measured at gas meter at current pressure and
temperature (gas throughput).
–
V
N
Standard volume [m
3
/h]
Volume gained by gas at 1013 mbar and 0 °C.
–
f
Conversion factor
–
Q
N
Heat rating [kW]
500 kW
η
Boiler efficiency (e. g. 92 %
≙
0.92)
0.92
H
i
Calorific value [kWh/m
3
] at 0 °C and 1013 mbar
10.35 kW/m
3
(Natural Gas
E)
t
Gas
Gas temperature at gas meter [°C]
10 °C
P
Gas
Pressure at gas meter [mbar]
30 mbar
P
Baro
Barometric air pressure [mbar], see table
500 m
≙
955 mbar
V
G
Gas throughput determined at gas meter
1.85 m³
T
M
Measuring time [seconds]
120 seconds
Calculate normal volume
Calculate the normal volume (V
N
) using the following formula.
V
N
=
Q
N
η
H
i
V
N
=
500 kW
0.92 10.35 kW/m³
= 52.5 m³/h
Calculate conversion factor
Determine gas temperature (t
Gas
) and pressure (P
Gas
) at gas meter.
Determine barometric air pressure (P
Baro
) from table.
Height
above
sea level [m]
0
100
200
300
400
500
600
700
800
900
1000 1100 1200 1300
P
Baro
[mbar]
1013 1001 990
978
966
955
943
932
921
910
899
888
877
866
Calculate conversion factor (f) using the following formula.
f=
P
Baro
+ P
Gas
1013
273
273 + t
Gas
f=
955 + 30
1013
273
273 + 10
= 0.938
Calculate operating volume (gas throughput) required
V
B
=
V
N
f
V
B
=
=
52.5 m³/h
0.938
56.0 m³/h
Determine current operating volume (gas throughput)
Measure gas throughput (V
G
) at gas meter, measuring time (T
M
) should be a min-
imum of 60 seconds.
Calculate operating volume (V
B
) using the following formula.
V
B
=
3600
V
G
T
M
V
B
=
3600 1.85 m³
120 s
= 55.5 m³/h
