Power plants FG WILSON
Ventilation
To ensure good ventilation, it is necessary to have a suitable flow entering and leaving the room, as well as free circulation of air inside the room. Therefore, the room should have a sufficient volume to ensure free air circulation, such that the temperature distribution is uniform and there are no areas with stagnant air. (Fig. 5.1.) The generator set should be located so that the engine receives air from the cold point of the room. If two or more units are installed, avoid placing the heated air from one unit into the inlet of the second unit. (Fig. 5.2.)
Circulation
When providing ventilation, it is necessary to maintain such a temperature in the room that efficient operation is achieved at maximum power, but, on the other hand, it should not be too low in winter so that there are no difficulties when starting the engine. Since problems rarely arise with properly selected ventilation, the customer and the distributor must be sure that there will be sufficient ventilation at each installation.
When cooling the engine with the help of a radiator, the fan must expel a large amount of air through the working area of the radiator. For effective cooling of the water passing through the radiator and entering the engine, it is necessary to have a temperature difference between the air and the water being cooled. It is sufficient to cool the water before recirculation to the engine. The temperature of the air at the entrance of the radiator depends on the temperature of the air entering the room through the fan. By injecting air into the room and releasing it outside through the air duct, the radiator fan allows you to maintain the temperature of the room in the required range.
Any internal combustion engine requires a sufficient supply of cold, clean air. If the air supplied to the engine is too hot or too cold, the engine will not develop rated power. When the engine and alternator are running, heat is emitted, which increases the temperature of the air in the room. Therefore, in order to limit the increase in temperature in the room and supply clean, cold air to the engine, it is necessary to have ventilation in the generator room.
Figure 5.1. Typical arrangement to obtain adequate circulation and ventilation
Figure 5.2. A typical installation to provide adequate ventilation when using multiple generator sets
Fans
For the intake of fresh air, the inlet of the fan through which the air passes must be on the opposite side or, at least, have an outlet through which the required amount of air will flow to another part of the building. In rooms with a small volume, an air duct can be used for air intake or its direct supply to the engine. In addition, the outlet fan opening should be located on the outside of the opposite wall to release warm air. (Figure 5.3.)
Inlet and outlet fans must have shutters to protect against external weather factors. They can be fixed, however, it is preferred that they be adjustable when used in cold climate areas. If the shutters are adjustable, they must open immediately when the generator sets are automatically started.
Figure 5.3. Input and output fans
The size of the inlet fan
Before calculating the inlet fan size, consideration must be given to the cooling air requirements and the static pressure that the fan must develop at the generator’s rated output. When installed in standard rooms, the amount of heat radiation is already taken into account when calculating the air flow through the radiator.
For generators with external radiators, the calculation of the flow of cooling air is carried out taking into account heat radiation into the surrounding space from the engine and alternator, as well as from the parts of the exhaust system.
Requirements for the flow of cooling air for generating units of the F.G. company. Wilson when operating at rated power are listed in the specification tables. The amount of heat emitted by the exhaust system depends on the length of the exhaust pipe outside the room, the type of insulation used, and whether the muffler is located indoors or outdoors. Usually, the exhaust pipe and muffler are insulated in order to neglect the radiation of heat from this source when calculating the required flow of cooling air.
After determining the required amount of air, calculate the size of the air intake of the fan installed on the outside of the wall. The size of the inlet fan must be sufficient so that the amount of backflow does not exceed 10 mm (0.4 in.) of water column. Limit values for air filters, screens and louvres should be provided by the manufacturers of these elements.
The size of the output fan
Where the engine and room are cooled by means of a radiator mounted on the unit, the outlet fan must be of sufficient size to exhaust all the air passing through the room except the small amount entering the engine inlet.