Development of Environmental Noise Impact Assessment Method of Cogeneration System

Cogeneration systems (CGS) are set up in the energy demand site so environmental noise impact must be took care of. If necessary, sound barriers and acoustic absorbents are set up, and the environmental noise impact is assessed for the optimum design. The propagation of noise is calculated by the computer simulation, and the geometry acoustic method is used for the calculation of industrial noises. However, wave phenomenon such as interference and diffraction is calculated with the physical model in this method. Therefore, it is necessary to confirm whether the low frequency sound with strong influence of the wave phenomenon can be appropriately calculated. Then the physical model of the geometrical acoustic method and the wave acoustic method which can, although requiring heavy computation load, calculate wave phenomena were verified by the experiment, and the calculation method that is suitable for the noise influence evaluation of the CGS has been developed.