HP Generating Set - Manual (Page 8)

5
5.3 Inlet Ventilator Size
Before calculating the inlet ventilator size, it is
necessary to take into account the radiator cooling
air flow requirements and the fan static pressure
available when the generating set is operating at its
rated load. In standard room installations, the
radiated heat is already taken into account in the
radiator air flow.
For generator room installation with remote
radiators, the room cooling airflow is calculated
using the total heat radiation to the ambient air of
the engine and alternator and any part of the
exhaust system.
Engine and alternator cooling air requirements for
FG Wilson generating sets when operating at rated
power are shown on specification sheets. Exhaust
system radiation depends on the length of pipe
within the room, the type of insulation used and
whether the silencer is located within the room or
outside. It it usual to insulate the exhaust piping
and silencer so that heat radiation from this source
may be neglected in calculating air flow required for
room cooling.
After determining the required air flow into the
room, calculate the size of inlet ventilator opening
to be installed in the outside wall. The inlet
ventilator must be large enough so that the
negative flow restriction will not exceed a maximum
of
10 mm (0.4 in) H
2
O. Restriction values of air filters,
screens and louvres should be obtained from
manufacturers of these items.
5.4 Exit Ventilator Size
Where the engine and room are cooled by a set
mounted radiator, the exit ventilator must be large
enough to exhaust all of the air flowing through the
room, except the relatively small amount that enters
the engine intake.
FIG 5.3 INLET AND EXIT VENTILATORS