Weishaupt WG20-/1-C LN Series - Calculate Gas Throughput

Installation and operating instruction
Gas burner WG20…/1-C LN
7 Commissioning
83240802 1/2020-01 La
48-96
7.6 Calculate gas throughput
Formula symbol Explanation Example values
VB Operating volume [m
3
/h]
Volume measured at gas meter at current pressure and
temperature (gas throughput).
–
VN Standard volume [m
3
/h]
Volume gained by gas at 1013 mbar and 0 °C.
–
f Conversion factor –
QN Heat rating [kW] 200 kW
η Boiler efficiency (e. g. 92 % ≙ 0.92) 0,92
Hi Calorific value [kWh/m
3
] at 0 °C and 1013 mbar 10.35 kW/m
3
(Natural Gas
E)
tGas Gas temperature at gas meter [°C] 10 °C
PGas Pressure at gas meter [mbar] 25 mbar
PBaro Barometric air pressure [mbar], see table 500 m ≙ 955 mbar
VG Gas throughput determined at gas meter 0.74 m³
TM Measuring time [seconds] 120 seconds
Calculate normal volume
Calculate the normal volume (VN) using the following formula.
V
N
=
Q
N
η H
i
V
N
=
200 kW
0,92
10.35 kW/m³
=
21.0 m³/h
Calculate conversion factor
Determine gas temperature(tGas) and pressure(PGas) at gas meter.
Determine barometric air pressure (PBaro) from table.
Height
above
sea level [m]
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300
PBaro
[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+
25
1013
273
273 + 10
=
0.933
Calculate operating volume (gas throughput) required
V
B
=
V
N
f
V
B
= =
21.0 m³/h
0.933
22.5 m³/h
Determine current operating volume (gas throughput)
Measure gas throughput (VG) at gas meter, measuring time (TM) should be a min-
imum of 60 seconds.
Calculate operating volume (VB) using the following formula.
V
B
=
3600 V
G
T
M
V
B
=
3600
0.74 m³
120 s
=
22.2 m³/h