Thermal Conductivity and Volumetric Specific Heat of Low-Density Wooden Mats

Using wooden waste as insulation material benefits society by using waste products, reducing building thermal load, and sequestering carbon dioxide. In this study on heat insulating materials, a novel low-density wooden mat was fabricated from wood shavings and kenaf fibers. This research addressed the influences of fabrication conditions on the thermal conductivity and volumetric specific heat of the materials used. The raw materials (wood shavings and kenaf fibers) were mixed with a binder component, and the mixture was thermoformed. The thermal conductivity and volumetric specific heat of the mats were measured, and the influence of mixing ratio, density, and heat flux was evaluated. The results demonstrated that thermal conductivity was largely affected by the mat density and mixing ratio but was largely unaffected by changes in the heat flux. The volumetric specific heat of the mats was largely unaffected by the raw material mixing ratio but was greatly affected by the mat density. The tendency of the thermal conductivity decrease was changed according to the combination ratio of the wood shavings and the kenaf. The wood shavings are flake shaped and curled, and the kenaf is fibrous. It was thought that the internal void was made smaller effectively by mixing two different shaped fibers and the thermal conductivity was minimized. As a result, the thermal performance of the subject mats, as compared with glass wool, exhibited a slightly lower thermal insulation level and higher heat capacity. The results are important in improving efficiency and the commercial design of insulation materials.