HP Generating Set - Manual (Page 15)

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FIG 9.2 REMOTE RADIATOR CONNECTED DIRECTLY FIG 9.3 REMOTE RADIATOR ISOLATED FROM
TO ENGINE COOLING SYSTEM ENGINE COOLING SYSTEM BY HEAT
EXCHANGER
9.2 Remote Radiator
A remote radiator with electric motor-driven can be
installed in any convenient location away from the
generating set. See figure 9.2. A well-designed
remote radiator has many useful features and
advantages that provide greater flexibility of
generating set installations in buildings.
More efficient venturi shroud and fan provide a
substantial reduction in horsepower required for
engine cooling. The fan may be driven by a
thermostatically controlled motor, which will only
draw power from the generating set when required
to cool the engine. A remote radiator can be
located outdoors where there is less air flow
restriction and air is usually cooler than engine
room air, resulting in higher efficiency and smaller
size radiator; and fan noise is removed from the
building.
Remote radiators must be connected to the engine
cooling system by coolant piping, including flexible
sections between engine and piping.
9.3 Remote Radiator/Heat Exchanger
System
Another type of remote radiator system employs a
heat exchanger at the engine . See figure 9.3 and 9.4.
In this application, the heat exchanger functions as
an intermediate heat exchanger to isolate the engine
coolant system from the high static head of the
remote radiator coolant. The engine pump
circulates engine coolant through the engine and
the element of the heat exchanger.
A separate pump circulates radiator coolant
between the remote radiator and the heat exchanger
tank.
Heat exchangers also are used for cooling the
engine without a radiator, as described in the
following section.
9.4 Heat Exchanger Cooling
A heat exchanger may be used where there is a
continuously available supply of clean, cool raw
water. Areas where excessive foreign material in the
air might cause constant radiator clogging - such as
in saw mill installations - may be logical sites for
heat exchanger cooling. A heat exchanger cools the
engine by transferring engine coolant heat through
passages in the elements to cool raw water. Engine
coolant and raw cooling water flows are separated
completely in closed systems, each with its own
pump, and never intermix.
A heat exchanger totally replaces the radiator and
fan. See figure 9.5. It usually is furnished as part of
the generating set assembly, mounted on the
engine, although it can be located remotely. Since
the engine does not have to drive a radiator fan,
there is more reserve power available.
The raw water side of the heat exchanger requires a
dependable and economical supply of cool water.
Soft water is desired to keep the heat exchanger in
good operating condition. For standby service, a
well, lake or cooling tower is preferred over city
water since the latter may fail at the same time that
normal electric power fails, making the generator
useless.