Nonwoven fabrics developed from agriculture and industrial waste for acoustic and thermal applications

Numerous researchers in the field of noise control and acoustics have found success in using biomaterials to create a porous sound absorber that is both effective and environmentally friendly. This paper discusses the utilization of fibers extracted from the waste from coffee husk (CH) and waste from the cotton (CO) spinning industry to be an alternative to synthetic-based acoustic materials. The study was conducted within the range of 50–6300 (Hz) frequency. Five well-known mathematical prediction models, namely Delany–Bazley (D–B), Garai–Pompoli (G–P), Miki, Allard Champoux (AC), and Johnson–Champoux–Allard (JCA) models are theoretically used to predict the sound absorption coefficient of nonwoven fibrous materials. When compared with the experimental data, it was discovered that the JCA and AC model is the most acceptable model for predicting the absorption behavior of CH/CO nonwoven fibrous materials. Additionally, the thermal insulation of nonwoven fibrous materials has been experimentally and numerically studied. It is noteworthy that, when compared to the Herman model, the Bhattacharyya model’s results showed slightly greater thermal conductivities. Overall, this work used an environmentally friendly way to turn waste into a valuable product.