Ventilation requirements for diesel generator set

by Generator D. Diesel Generator

As the main standby power generation equipment of the power system, the diesel generator set also has requirements on the environment during use, such as dustproof conditions, and the temperature of the working environment. In addition, ventilation is also crucial for the diesel genset. The ventilation environment of a diesel generator set is an important condition to ensure its working environment temperature. However, in order to ensure good ventilation, dustproof measures must be taken, which requires certain requirements on ventilation. So what are the ventilation requirements and cooling methods of the diesel generating set?

1. Ventilation requirements for diesel generator set

Space

The location of the generator room should be as far away from the residential area as possible to reduce the impact of the noise and emissions of the unit on the residents. The generator room should be built on an open site as far as possible to facilitate the access and ventilation and heat dissipation of the unit and accessories. The space of the machine room should fully consider the volume of the unit and accessories to ensure that the unit and accessories have sufficient installation space.

Ventilation and dust protection

Dust-proof design

Good ventilation, dust-proof performance will inevitably be appropriate to decline, too much consideration of dust-proof, it will affect the ventilation of the machine room. This requires machine room designers to calculate and coordinate according to the actual situation. The calculation of ventilation mainly involves the air intake system and exhaust system of the machine room. It is calculated based on the amount of gas required for the combustion of the unit and the amount of ventilation required for the unit's heat dissipation. The sum of gas and ventilation volume is the ventilation quantity of the machine room. Of course, this is a change value, which changes as the temperature rise in the machine room.

Ventilation design

The ventilation of the diesel generator room should be paid special attention to in the design of the engine room, especially when the machine room is located in the basement, otherwise it will directly affect the operation of the diesel genset. Exhaust air from the unit should generally be organized in hot air ducts. It is not advisable to let the diesel engine radiator dissipate heat in the engine room and then extract it by the exhaust fan.

There should be sufficient fresh air in the machine room to supplement. When the diesel engine is running, the ventilation volume of the engine room should be equal to or greater than the sum of the fresh air volume required for the diesel engine's combustion and the fresh air volume required to maintain the room temperature. The amount of fresh air required to maintain room temperature is calculated by the following formula: C = 0.078PT: C - the required fresh air volume (m³/s), P - the rated power of the diesel engine (kW), T - the temperature rise of the engine room (°C).

diesel generator set

Generally, the ventilation volume of the machine room is calculated based on the temperature rise of the machine room being controlled within 5°C -10°C, which is also a relatively high requirement. When the temperature rise of the machine room is controlled within 5°C - 10°C, the gas volume and air ventilation volume are the ventilation volume of the machine room at this time, and the size of the air inlet and outlet can be calculated according to the ventilation volume. The machine room is not well dustproof, which will also cause damage to the equipment. Under the condition of ensuring the ventilation of the equipment room, at the same time, taking into account the dustproof effect of the equipment room, air intake and exhaust shutters are installed to ensure the air quality and air volume of the equipment room.

2. Cooling methods of diesel generator set

There are two common ways of cooling diesel generators, air cooling and water cooling. It is the same principle as the engine. Both use the fast-heating and highly fluid substance to take away the temperature in the environment to control the working environment temperature. Water cooling is mainly performed by a water circulation system. The water pump draws cold water into the cold water pipeline and takes away the heat through the water flow wound in the water cooling pipeline on the equipment.

Air cooling is generally installed in the generator room ventilation system, through the exchange of hot and cold air to control the indoor temperature, there are four common ventilation systems:

1). Normal ventilation system: For the ventilation of generator room, it is generally the ventilation volume of 10 to 15 times of ventilation, and only exhaust fans can be set; if there is gas for water supply and drainage, this system must also undertake the exhaust system after the fire extinguishing.

2). The generator process inlet and exhaust system: The generator itself has a large exhaust pipe, which is the generator's own. It only needs to cooperate with an air shaft. At the same time, the inlet system is designed to supplement the exhaust air volume and the combustion air volume of the generator set.

3). Generator exhaust gas system: It involves environmental protection issues, usually called “smoke exhaust pipe”. The generator comes with it, and the electrical standard atlas has a special well for the system. In fact, it is difficult for the engineering design and construction to have so much open space. Most are discharged from the generator exhaust shaft.

4). Exhaust system of oil storage room: It can be used with the usual ventilation system. At this time, the branch pipe leading to the oil storage room is equipped with check valve and fire valve; it can also be set up a separate system and adopt explosion-proof ventilator.

3. Matters need attention

1). Diesel generator room shall be equipped with the gas fire extinguishers. Solenoid valves shall be set on the inlet and exhaust channels. When a fire occurs and the gas fire extinguisher starts, these valves can be closed to ensure the fire extinguishing effect.

2). Exhaust smoke of diesel generators is pressure exhaust smoke, high flue gas temperature, high air velocity, and flue gas needs to be discharged at high altitude. The flue pipe should consider heat insulation, at the same time need to set up shock absorber hanger.

3). Ventilation door or shutters plays the role of isolating the machine room from the surrounding environment. The operation of opening and closing shall be controlled by the running state of the generator set.

4). The movable ventilation door installed in the machine room in cold areas should allow the airflow in the machine room to recirculate, so as to heat the machine room during the cold machine, thereby improving the utility of the unit.

5). In areas with a cold climate, not only should pay attention to the cooling and ventilation of diesel generator set, but also make corresponding insulation measures for standby and rarely-operated gensets. It should also be noted that, for a standby generator set that is automatically put into operation when the main power fails, it is usually necessary to install a standard thermostatic controlled immersion cooling water heater.

In actual use, diesel generator sets need to work in a certain temperature environment, the working environment has a certain degree of ventilation, so it is necessary to ensure the ventilation requirements of diesel generator sets.