MIL-HDBK-1003/11
sufficient output to satisfy the lads, jacket coolant and lubricant heat
recovery should be considered, and then the use of auxiliary oil-fired
heating boilers. A life-cycle economic analysis is required to justify the
increased construction cost and maintenance of heat recovery systems.
15.6.1.2 Auxiliary Heating Boilers. Auxiliary oil-fired low-pressure
heating boilers should be used to provide building heat for
standby/emergency duty diesel-electric generating plants during periods when
the plants are not in operation. For standby/emergency duty generating
plants the use of exhaust and jacket coolant heat recovery systems usually
are not economically feasible if plants are not operated on an extensive and
regular basis. An economic analysis is required to justify the increased
construction and maintenance cost of the auxiliary boilers and accessories,
if the waste heat is available only on a part-time basis.
15.6.1.3 Combustion Air. Diesel engines may require heated combustion air
if taken directly from the outside during periods of low outside ambient air
temperature. Low combustion air temperature results in engine starting
problems with most diesel engines. If combustion air is taken from inside
the building during those periods, the makeup air will require filtering and
heating or tempering before being delivered to the engine room. It may be
more economical in some cases to provide engine jacket water and lubrication
oil heating to provide minimum starting temperatures during such
low-temperature applications.
15.6.2
Ventilating Diesel-Electric Generating Plant Buildings.
15.6.2.1 Engine Rooms. The following minimum considerations shall be used
to determine ventilation requirements:
a) Radiant and conducted heat from the engine and may be as high
as 7 percent of fuel input. Exact data should be secured from the diesel
engine manufacturer.
b) Air intake requirements for ventilation (space cooling) and
combustion air (if taken from the room interior) must be considered in
sizing louvers and/or openings.
c) Consider radiator fan air requirements, if radiator units are
installed inside the main generator room without dedicated cooling air
supplied from the outside. Discharge air should be ducted to the outside.
Provide bypass air to the interior during cold weather.
d) When the engine is running, cooling air makeup may be brought
in through gravity roof ventilators, for engines with radiator units
installed inside the main generator room. Roof ventilators will act as a
natural draft exhaust when the engine is not operating.
e) Sidewall louvers should be provided for cooling air makeup and
for room ventilation when roof ventilators are not practicable.
f)
Consider freeze protection in all cases.
g)
In no case shall ventilation be provided at lower rates than
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