Vibration Isolation Parameters Optimization and Structure-Borne Noise Control Engineering Verification for Parallel Air-Conditioning Outdoor Units

Aiming at the prominent problem of building structure-borne noise induced by vibration of row-type outdoor units of central air-conditioning, this paper takes the noise control project of a government office building in Guangzhou as the research background. Based on the vibration transmission principle, this paper simplifies the vibration model of an air conditioner outdoor unit as a single-degree-of-freedom (SDOF) system, and proposes a method to achieve vibration transmission attenuation and noise reduction by optimizing vibration isolation parameters. A finite element analysis (FEA) model consisting of row-type outdoor units, rubber vibration isolation pads and concrete base is established. After verifying the accuracy and effectiveness of the model by comparing the measured and calculated values of vibration acceleration, this paper systematically analyzes the influence laws of key parameters of rubber vibration isolation pads (including elastic modulus, cross-sectional area and thickness) on the vibration isolation performance of the system, and quantifies the vibration response of the concrete base under different parameter configurations.The results show that reducing the stiffness of rubber vibration isolation pads is the key to improving vibration isolation efficiency, which can be achieved by decreasing the elastic modulus, reducing the cross-sectional area, or increasing the thickness of the pads. After the implementation of comprehensive treatment measures combining theoretical analysis, numerical simulation conclusions and actual on-site working conditions, the average indoor noise levels in the 50 Hz and 100 Hz frequency bands are reduced by 12.2 dB and 10.9 dB respectively, which meets the limit requirements of indoor acoustic environment. This study can provide theoretical reference and engineering practice basis for structure-borne noise control of air-conditioning outdoor units.