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MAN B&W Diesel A/S 2.10
SFOC calculations, example
Data at nominel MCR (L 1 ): 7S65ME-C
Power 100% 20,090 kW
Speed 100%
Nominal SFOC:
95 r/min
• High efficiency turbocharger 169 g/kWh
• Conventional turbocharger 171 g/kWh
M 1 power <strong>is</strong> selected as 85% of L 1 = 17,077 kW
M 1 speed <strong>is</strong> selected as 97% of L 1 = 92.2 r/min
M 2 <strong>is</strong> in th<strong>is</strong> example selected on the same
propeller curve as M 1
If the power of M 2 were selected as 76.5% of
L 1 = 15,369 kW and the corresponding speed <strong>is</strong>
93.7% of that in L 1 = 89.0 r/min
The savings in g/kWh compared to SFOC in L 1 :
Power in Matching point
SFOC
saving
M = 85% 1
1
2
85% x 100% = 85.0%
85% x 70% = 59.5%
4.3
9.3
of L1 3 85% x 50% = 42.5% 5.1
4 76.5% x 100% = 76.5%
M = 76.5% 2 5 76.5% x 70% = 53.6%
6.4
11.4
of L1 6 76.5% x 50% = 38.3% 6.6
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Data of specified MCR = M1 M2 Power 17,077 15,369 kW
Speed 92.2 89.0 r/min
SFOC found: 164.7 162.5 g/kWh
SFOC
g/kWh
+4
-16
30%
Diagram a
Part Load SFOC curve
Nominal SFOC
40% 50% 60% 70% 80% 90% 100% 110%
42.5
59.5
% of nominal MCR (L 1)
85
Fig. 2.10.01: Examples of SFOC for different specified MCR points for 7S65ME-C with fixed pitch propeller,
high efficiency turbocharger
178 50 91-2.2
S65ME-C/ME-GI 198 48 91-7.0
+3
+2
+1
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
-11
-12
-13
-14
-15
6
3
5
2
38.3 53.6
M 2
4
76.5
M 1
1