140
A1
21 - O
2
A2
CO
2
APPENDIX C
Coefficients of the fuels and Formulas
The following table shows the coefficients of the saved fuels that will be used to calculate losses and efficiencies.
Coefficients for calculating combustion efficiency
Fuel
A1
A2
B
CO2t
(%)
PCI
(KJ/Kg)
PCS
(KJ/Kg)
M air
(Kg/Kg)
M H
2
O
(Kg/Kg)
V gas dry
(m
3
/Kg)
Natural gas
0.660
0.380
0.0100
11.70
50050
55550
17.17
2.250
11.94
Propane
0.630
0.420
0.0080
13.90
45950
49950
15.61
1.638
11.11
LPG
0.630
0.420
0.0080
13.90
45730
49650
15.52
1.602
11.03
Butane
0.630
0.420
0.0080
13.90
45360
49150
15.38
1.548
10.99
Diesel
0.680
0.500
0.0070
15.10
42700
45500
14.22
1.143
10.34
Combustible oil
0.680
0.520
0.0070
15.70
41300
43720
13.73
0.990
10.06
Propane air
0.682
0.447
0.0069
13.76
28250
30700
9.13
0.999
6.77
Biogaz
0.719
0.576
0.0086
16.81
19200
21250
6.38
0.840
5.82
8% granules
0.740
0.670
0.0071
19.01
18150
19750
6.02
0.660
4.58
Wood – 20%
0.761
0.686
0.0089
18.93
15450
17170
5.27
0.700
4.01
Shavings
0.8020
0.785
0.0108
20.56
11950
13565
4.20
0.660
3.25
Coal
0.7620
0.691
0.0023
19.06
31400
32300
10.70
0.370
8.14
Olive stones
0.749
0.689
0.0065
19.33
18780
20309
6.290
0.626
4.79
CO Off gas
0.775
1.164
0.0012
31.55
8610
8735
2.21
0.051
2.14
Rice balls
0.777
0.768
0.007
20.738
12558
13633
4.065
0.440
3.152
Details of fuel coefficients:
•
CO2 t
: CO2 value generated by combustion under stoichiometric conditions, i.e. without excess oxygen and therefore the
maximum.
•
A1, A2, B
: Coefficients of the Siegert formula for combustion (see European Standard EN50379-1). A1 is the parameter of the Siegert
formula when the O
2
measurement is available. A2 is used when CO
2
measurement is available.
Note: - In the United States, parameter A1 is the same as the "European" A1 but divided by 2.
- In Germany, coefficients A1 and A2 are inverted.
The heat losses from the combustion fumes are calculated from the measurement of oxygen using the formula:
q
A
= (t
A
- t
L
) x
+ B
The heat losses in the combustion fumes are calculated from the measurement of CO
2
using the formula:
q
A
= (t
A
- t
L
) x
+
The air index is calculated using the formula:
λ=21/(21
-
O
2
), where O
2
is the residual oxygen concentration in the combustion fumes. The air
excess is calculated using the formula:
e=(λ
-1)*100
•
CO conv
: Coefficient for the conversion of ppm into mg/KWh. It can be expressed as a function of the gas density (CO in this case)
and the volume of dry fumes.
•
NO conv
: The same as for the CO conv, but referenced with NO.
•
NOx conv
: The same as for the CO conv, but referenced with NOx.
•
SO
2
conv
: The same as for the CO conv, but referenced with SO
2
.
•
PCI:
Lower calorific value.
•
PCS:
Gross calorific value.
•
m H
2
O
:
Mass of air (H
2
O = water) produced during combustion under stoichiometric conditions, for each Kg of fuel.
•
m Air
:
Mass of air required for combustion under stoichiometric conditions.
•
V g.d.
:
Volume of dry smoke produced by combustion under stoichiometric conditions.
B
