Detailed Explanation of Noise Reduction Measures for Containerized Generator Sets

• Select Low-Noise Equipment: In the equipment selection stage, priority should be given to generator sets whose noise level meets national standards, and low-noise engines and generators should be preferred. For example, engines adopting four-stroke and high-pressure common rail technology have higher combustion efficiency and lower noise; high-efficiency silent generators are selected to reduce the generation of electromagnetic noise and mechanical noise. At the same time, containerized generator sets with built-in noise reduction structures can be selected to have basic noise reduction capabilities from the factory stage.
• Optimize Container Structural Design: The container shell adopts a double-layer structure design, and sound insulation materials are filled between the inner and outer layers to reduce the structural conduction of noise; the shell adopts thickened steel plates to increase structural stiffness, reduce the vibration of the container shell during equipment operation, and avoid the generation of secondary noise. In addition, the doors, windows, ventilation openings and other parts of the container adopt a sealed design to reduce noise leakage, and the positions of doors and windows are reasonably planned to avoid noise directly facing sensitive areas.
• Optimize Cooling System Design: Select low-noise cooling fans, reasonably design the blade angle and rotation speed of the fans to reduce airflow noise; adopt water-cooled cooling systems instead of air-cooled systems to reduce the operating load and noise of the cooling fans, and the noise propagation of water-cooled systems is easier to control. In addition, the cooling air duct adopts a streamlined design to reduce airflow turbulence and lower airflow noise.

(II) Propagation Path Noise Reduction: Block Noise Diffusion

For the air propagation and structural conduction paths of noise, measures such as blocking, sound absorption, and vibration reduction are taken to reduce noise diffusion and the impact on the surrounding environment, which is the core link of noise reduction for containerized generator sets.

1. Sound Absorption Noise Reduction Treatment

Sound absorption materials are laid inside the container to absorb the air-borne noise generated during equipment operation, reduce the reflection and superposition of noise inside the container, and thus reduce the intensity of noise leaking outward. Commonly used sound absorption materials must have the characteristics of high temperature resistance, fire resistance, moisture resistance, and good sound insulation effect, adapting to the high-temperature environment when the generator set is in operation.

• Sound absorption cotton is laid on the inner wall, top, and bottom of the container. Glass wool, rock wool, polyurethane foam and other sound absorption materials are preferred, with a thickness of 50-100mm. The surface of the sound absorption cotton is covered with fire-retardant perforated plates, which not only ensures the sound absorption effect but also protects the sound absorption materials from being damaged by equipment vibration or contaminated by oil stains.
• Sound absorption shutters are installed at the ventilation openings and air inlets. The interior of the shutters is filled with sound absorption materials, which can not only ensure the ventilation and heat dissipation needs but also absorb the noise transmitted through the ventilation openings and reduce noise leakage.

2. Vibration Reduction Noise Reduction Treatment

For structure-borne noise, vibration reduction measures are adopted to reduce the transmission of equipment vibration to the container shell and the ground, avoid secondary noise caused by vibration, and at the same time protect the equipment itself and extend its service life.

• Vibration isolators are installed between the generator set and the container base. Rubber vibration isolators, spring vibration isolators or composite vibration isolators are preferred. According to the weight and vibration frequency of the generator set, the model and quantity of vibration isolators are reasonably selected to ensure the vibration reduction effect. The vibration isolators must have good load-bearing capacity and anti-aging performance, and can adapt to the vibration intensity when the generator set is in operation.
• Flexible connections are adopted for the connection parts such as exhaust pipes and oil pipes, using rubber hoses or corrugated pipes to reduce the transmission of equipment vibration to the container shell through the pipes, and at the same time avoid fatigue damage of the pipes due to vibration, further reducing vibration noise.
• Vibration damping pads are laid between the bottom of the container and the ground to reduce the transmission of container vibration to the ground, which is especially suitable for sensitive areas, avoiding vibration transmitted to surrounding buildings or equipment through the ground and generating secondary noise pollution.

3. Sound Insulation Noise Reduction Treatment

Sound insulation structures are set up to block the air propagation of noise and reduce noise diffusion, mainly optimizing the parts of the container that are prone to noise leakage, such as doors, windows, ventilation openings, and maintenance openings.

• Sound insulation doors and windows are adopted, with double-layer insulating glass filled with dry air or inert gas between the glass to enhance the sound insulation effect; sealing strips are installed between the door frame and the door leaf, and the doors and windows are sealed with the container shell to reduce noise leakage through gaps. The maintenance opening adopts a sound insulation cover plate, and a sealing pad is set between the cover plate and the shell to ensure tight sealing when closed at ordinary times, and it can be opened during maintenance without affecting equipment maintenance.
• For large containerized generator sets, a sound insulation cover can be set outside the container. The sound insulation cover adopts a double-layer structure, with sound absorption materials laid on the inner layer and sound insulation steel plates on the outer layer. Ventilation openings and maintenance doors are set on the cover body to ensure the sound insulation effect without affecting the ventilation, heat dissipation and maintenance of the equipment. The design of the sound insulation cover must be combined with the size and operation needs of the generator set to avoid overheating of the equipment due to narrow space.

(III) End-of-Pipe Noise Reduction: Special Treatment of Exhaust Noise

Exhaust noise is the part with the highest intensity and the farthest propagation in the noise of containerized generator sets, which requires special treatment. The intensity of exhaust noise is reduced by installing mufflers and other equipment to make it meet national noise emission standards.

• Install Special Mufflers: Installing a muffler on the exhaust pipe of the generator set is the core measure for exhaust noise reduction. The muffler must be selected according to the power and displacement of the generator set, and priority should be given to reactive mufflers, resistive mufflers or composite mufflers. Resistive mufflers absorb exhaust noise through sound absorption materials and are suitable for medium and high-frequency noise; reactive mufflers offset noise through sound wave interference by changing the air flow channel and are suitable for low-frequency noise; composite mufflers combine the advantages of both and can effectively reduce full-frequency exhaust noise, with a noise reduction effect of 20-40dB(A).
• Optimize Exhaust Pipe Layout: The exhaust pipe should be arranged vertically upward as much as possible to avoid noise directly facing sensitive areas when arranged horizontally; the length of the exhaust pipe should be reasonably planned to reduce turbulence of air flow in the pipe and lower airflow noise; the exterior of the exhaust pipe is wrapped with sound insulation cotton to reduce noise generated by pipe vibration, and at the same time play a thermal insulation role to avoid high-temperature exhaust pipes affecting the surrounding environment.
• Set Exhaust Buffer Device: A buffer section is set between the exhaust pipe and the muffler to reduce the impact of exhaust air flow and lower noise intensity; for large generator sets, a muffler tower can be set at the exhaust port to further diffuse and absorb exhaust noise and reduce the noise propagation distance.

III. Notes on Noise Reduction Treatment

When carrying out noise reduction treatment of containerized generator sets, it is necessary to balance the noise reduction effect with the normal operation, heat dissipation and maintenance of the equipment, avoid affecting the equipment performance due to improper noise reduction measures, and at the same time meet the relevant national noise emission standards to ensure compliant use.

• Balance Heat Dissipation Needs: Noise reduction measures (such as sound insulation covers and sound absorption materials) must not block the ventilation openings, air inlets and exhaust ports of the generator set. The ventilation channel should be reasonably designed to ensure the heat dissipation effect when the equipment is in operation and avoid equipment failure due to overheating. A forced ventilation system can be adopted, combined with low-noise fans, to reduce ventilation noise while ensuring heat dissipation.
• Ensure Maintenance Convenience: The design of the noise reduction structure should facilitate the inspection, maintenance and fault diagnosis of the generator set. For example, the design of the sound insulation cover and maintenance opening should be flexibly openable, and the sound absorption materials should be easy to disassemble and replace, so as to avoid affecting the equipment maintenance efficiency due to the noise reduction structure.
• Comply with Noise Standards: The noise level of the generator set after noise reduction treatment must comply with relevant national standards such as the "Emission Standard for Industrial Enterprise Boundary Noise" (GB 12348-2008). According to different use scenarios (such as residential areas, industrial areas, construction sites), the corresponding noise limit should be selected to ensure no environmental noise pollution.
• Consider Environmental Adaptability: For containerized generator sets used outdoors, the noise reduction materials must have the performance of moisture resistance, rain resistance, anti-aging and high and low temperature resistance, so as to avoid the decline of noise reduction effect or damage of materials due to environmental factors and extend the service life of the noise reduction structure.

IV. Summary

The noise reduction treatment of containerized generator sets is a comprehensive project. It is necessary to combine the characteristics of noise sources and adopt a combination of various measures such as equipment selection optimization, sound absorption, vibration reduction, sound insulation, and exhaust noise reduction from the three dimensions of source control, propagation path blocking, and end-of-pipe treatment to achieve the ideal noise reduction effect. In practical applications, personalized noise reduction schemes should be formulated according to the power, use scenario, and noise limit requirements of the generator set, balancing noise reduction effect, equipment performance, maintenance convenience and compliance, so as to reduce noise pollution and ensure the stable and efficient operation of the generator set, providing safe and environmentally friendly support for the power supply needs of various scenarios.