30
Doc653/30CV02A
1 kcal = 4.187 kJ
1 kWh = 3.6 Mj
Effi ciency at the fl ue gas side
The difference between gross and nett calorifi c values is the heat of evaporation of the combus-
tion produced water. At 298.15 K (25°C), this is 2442.5 kJ/kg (583.38 kcal/kg).
For non-condensating boilers:
η
b
CO
T
=
−
+
×
90
0 339
0 008
2
.
.
∆
η
o
CO
T
=
−
×
×
100
0 377
0 009
2
.
.
∆
For condensating boilers:
As a result of condensation, the effi ciency at the lower value increases.
η
b
CO
T A
=
−
+
× +
+
90
0 339
0 008
7 5 0 006
2
.
.
.
.
∆
∆
T
(
)
η
o
/
η
b
= 1.11
∆t
= Difference in temperature between the fl ue gases and the environmental temperature (K)
η
b
= Fuel effi ciency at the gross calorifi c value
η
o
= Fuel effi ciency at the nett calorifi c value
CO
2
= The volume of CO
2
in the fl ue gas (%)
O
2
= The volume of O
2
in the fl ue gas (%)
A
= The quantity of condensed water in the appliance per m
3
gas in kg (kg/ m
3
gas).
meg/l
°dH
°f
°e
Mg
CaCO
3
/l
meg/1
1
2.8
5
3.51
50
°dH
0.37
1
1.78
1.25
17.8
°f
0.2
0.56
1
0.7
10
°e
0.285
0.8
1.43
1
14.3
MgCaCO
3
/1
0.02
0.056
0.1
1.54
1
Table 14
Derivation of degrees of hardness
1 degree English hardness (°e)
= 65 mg CaCO
3
/imp. gallon
1 Grain/US Gallon
= 0.958 odH
1 milligram equivalent per l (mval/l)
= 2.8 odH
1 ppm (parts per million) CaCO
3
= 1 mg CaCO
3
/1
For information:
The public water supply in general has a pH value of approximately 7-8.
The temporary hardness will be 60 to 80% of the total hardness, which can vary considerably
form one place to another.
Summary of Contents for ECONOFLAME R30
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