Noise pollution has become a significant environmental concern in urban areas. Low-frequency sounds, especially those coming from aviation activities present a major difficulty among noise sources, due to their ability to travel long distances and easily penetrate different structures. In response to the growing need for mitigating such environmental challenges, green roof structures are becoming an increasingly effective potential. Green roof systems provide several environmental benefits, including thermal insulation, enhanced air quality and stormwater attenuation that have been extensively studied. However, the potential of these systems to mitigate low-frequency noise pollution remains underexplored.
This study aims to investigate the acoustic absorption capabilities of green roof systems, emphasizing their role in reducing noise pollution and the importance of certain sustainability aspects. To achieve this, the use of resonance absorbers is being investigated, focusing on integrated Helmholtz resonators targeting low-frequencies. Initially, acoustic measurements are conducted to assess the acoustic performance of five different green roof systems provided by SemperGreen. Based on the measurements’ results, different integrated resonator design concepts are developed and evaluated systematically in order to find the most optimal solution. FEM numerical simulations are performed in COMSOL Multiphysics by modeling a large impedance tube to assess the impact of different resonator configurations on the green roof system’s overall acoustic performance.
The findings of the study demonstrate that the integration of Helmholtz resonators in the growing medium layer can improve the acoustic performance of the system at lower frequencies, however within a particular limited range. As a final step, optimization strategies including the introduction of cross-structure fins in the resonators’ neck or adding a secondary neck alongside the primary one are explored as potentials to broaden the absorption peaks. From the findings it can be concluded that the development of more acoustically efficient green roof systems is feasible; however, further experimental validation is required to confirm and refine the proposed solutions.