E N G IN IN E R O O M V E N T I L A T I O N A I R F L O W C A L C U L A T IO IO N
a b c d e
Base on the following data: Main Engine Main Generator Bulk Air Compressor elect motor Bulk Ai Air Compressor air consumption Main Generator
:6000 kw x 2 sets : 790 kw x 2 sets : 132 kw x 2 sets : 27 m3 m3/min x 2 sets : 47 m3/hr x 2 sets
1 Airflow Airflow for for combus combustion tion 1.1 Airflow Airflow for combustion combustion for main main engines, qdp=
qdp
Pdp x mad r
where Pdp is the service standard power of the main propulsion diesel engine(s) at mad
maximum continuous power output,in kilowatts; is the air requirement for combustion for diesel engine(s),in kilograms per kilowatts second; Where specific data for m ad are not available, the following values may be used for calculation: mad= 0.0023kg/(kW.s) for 2-stroke engines,
0.002kg/(kW.s) for 4-stroke engine. o r = 1.13 kg/m (I.e. the density of air,at +35 C,70 RH and 101.3 kPa). 3
qdp= 6000 x 2 sets x 0.002 1.13 =
3
21.24 m /s
1.2 Airflow for combustion for main generator, q dg qdg= 790 x 2 sets x 0.002 = =
1.13 3
2.8 m /s
1.3 Sum of airflow airflow for combust combustion, ion, qc=
qc
( qdp + qg ) m /s 3
= (21.24 + 2.8) m /s 3
=
24.04 m /s
=
86,544 m /hr
3
E N G IN IN E R O O M V E N T I L A T I O N A I R F L O W C A L C U L A T IO IO N
2 Airflow for evacuation of heat emission 2.1 Heat emission from main engines, fdp=
where Pdp
Pdp x
dp
hd
100 is the service standard power of the main propulsion diesel engines) at
maximum continuous rating,in kilowatts; hd is the heat loss from the diesel engine(s),in percentage. Note : * - the data is provided by Wartsila (engine manufacturer). fdp= 180.0 * kW per set (with its standard service power of 6,005 kW). fdp= 180.0 kW x 2 sets = 360.0 kW
2.2 Heat emission from main generators, fdg=
where Pdg
Pdg x
dg
hd
100 is the service standard power of the diesel generator engine at maximum continuous rating,in kilowatts;
hd is the heat loss from the diesel engine(s),in percentage. Note : since the specific data are not available. fdg= 40 kW per set (with its standard service power of 790 kW). fdg= 40 kW x 2 sets = 80 kW
2.3 Heat emission from Bulk Air Compressor elect motor,
el
fel= 132 kW x 2 sets x 0.08 * fel= 21.12 kW
Note :* -
Assume heat emission from electric motor to be 8% of the motor rated power.
2.4 Airflow for evacuation of heat emission, q h qh=
( fdp + fdg )
- 0.4 ( qdp + qdg )
r x c x Tdiff 3
o
r = 1.13 kg/m (i.e. the density of air,at +35 C,70% RH and 101.3 kPa);
c = 1.01 kJ/(kg.K) (the specific heat capacity of the air); o
Tdiff = 10 C qh=
( 360 + 80 + 21.12)
- 0.4 ( 21.24 + 2.8 )
1.13 x 1.01 x 12.5 = ( 40.403 - 7.376 )
3
m /s
3
=
33.027 m /s
=
118,897 m /hr
3
3 Total airflow, Qt Air Compressor Consumption I Bulk Air Compressor (2 sets) ii Starting Air Compressor (2 sets) Dryers
Airflow, m3/hr :1620m3/hr x 2 sets = 3240 :47 m3/hr x 2 sets = 94 :1620m3/hr x 2 sets = 3240
Total q0
6574
Required air volume for engine room ventilation Qt= qc + qh + q0 3
= ( 86,544 + 118,897 + 6,574) m /hr =
3
212,015 m /hr
3
Note :There are two (2) nos of supply fans, each having airflow capacity of 1 10,000 m /hr 3 Total supply air is 220,000 m /hr
