Kohler 20--2800 kW manual Liquid-Cooled Models, Unit-Mounted Radiator Cooling

4.6 Liquid-Cooled Models

The three most common liquid cooling systems used for generator sets are unit-mounted radiator, city water, and remote radiator cooling. Since each involves somewhat different installation considerations, they will be discussed separately.

4.7 Unit-Mounted Radiator Cooling

This is the most common cooling system used for engine-driven generator sets 20 kW and larger. The major system components are an engine-driven fan and circulating water pump, a radiator, and a thermostat. The pump circulates water through the engine until it reaches operating temperature. Then the engine thermostat opens and allows circulation through the radiator. It can also close, restricting the flow as necessary to prevent overcooling. The fan blows air from the engine side of the radiator across the cooling surface as shown in Figure 4-8.

Cooling air flow can be reversed by using a suction fan, but this is generally not recommended because it may interfere with generator cooling air flow, which moves in the same direction as the engine’s standard pusher fan. Also, a suction fan would result in higher temperature combustion air being drawn into the air cleaner, reducing the maximum engine power available.

Whenever a generator set is installed inside a building or enclosure, the radiator air should be ducted outside the room or enclosure. A typical arrangement is shown in Figure 4-8. Ductwork should be as short, straight, and unobstructed as possible. Static pressure restrictions of more than 1/2 inch (1.3 cm) water column on the radiator outlet or inlet air will reduce air flow to the point of limiting maximum power and/or ambient temperature that causes overheating.

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7.	Self-supporting duct work	10.	Pusher fan
8.	Air out	11.	Flexible section
9.	Air inlet opening	12.	Support legs

Figure 4-8 Radiator-Cooled Generator Set Installation

16 Section 4 Air Requirements TP-5700 7/93