Binderless Thermal Insulation Panels Made of Spruce Bark Fibres

Gößwald, Jakob; Barbu, Marius Cătălin; Petutschnigg, Alexander; Tudor, Eugenia Mariana

doi:10.3390/polym13111799

Cited by 27 publications

(15 citation statements)

References 35 publications

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“…In the case of the small pores in panels, the air in the voids is static and the convection effect is minor. The results concerning the density and porosity influence on the thermal conductivity were confirmed for bark insulation board by [ 55 , 56 ], and also for fiberboards [ 57 , 58 ], OSB [ 51 ] and other insulation boards [ 59 ]. An interesting phenomenon was observed for insulating materials by Haupl [ 60 ], where the decrease of the thermal conductivity diminishes with decreasing density for very low densities.…”

Section: Resultsmentioning

confidence: 81%

Thermophysical Properties of Larch Bark Composite Panels

et al. 2021

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The effects of using 100% larch bark (Larix decidua Mill) as a raw material for composite boards on the thermophysical properties of this innovative material were investigated in this study. Panels made of larch bark with 4–11 mm and 10–30 mm particle size, with ground bark oriented parallel and perpendicular to the panel’s plane at densities varying from 350 to 700 kg/m3 and bonded with urea-formaldehyde adhesive were analyzed for thermal conductivity, thermal resistivity and specific heat capacity. It was determined that there was a highly significant influence of bulk density on the thermal conductivity of all the panels. With an increase in the particle size, both parallel and perpendicular to the panel´s plane direction, the thermal conductivity also increased. The decrease of thermal diffusivity was a consequence of the increasing particle size, mostly in the parallel orientation of the bark particles due to the different pore structures. The specific heat capacity is not statistically significantly dependent on the density, particle size, glue amount and particle orientation.

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Section: Resultsmentioning

confidence: 81%

Thermophysical Properties of Larch Bark Composite Panels

et al. 2021

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“…In the case of the first base model [ 45 ], the material density and the bulk density of the insulation were sufficient because the glass fibers are both solids. However, the influence of the density and porosity of the heat transfer in natural-based materials also depends on the type of raw materials as well as the size and orientation of fibers, particles, or grains [ 19 , 51 ]. In the case of straw stems, one more density parameter must be introduced to take into consideration the porosity of the stems and the gaps among the stems.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer in Straw-Based Thermal Insulating Materials

2021

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An analytic-empirical model was developed to describe the heat transfer process in raw straw bulks based on laboratory experiments for calculating the thermal performance of straw-based walls and thermal insulations. During the tests, two different types of straw were investigated. The first was barley, which we used to compose our model and identify the influencing model parameters, and the second was wheat straw, which was used only for validation. Both straws were tested in their raw, natural bulks without any modification except drying. We tested the thermal conductivity of the materials in a bulk density range between 80 and 180 kg/m3 as well as the stem density, material density, cellulose content, and porosity. The proposed model considers the raw straw stems as natural composites that contain different solids and gas phases that are connected in parallel to each other. We identified and separated the following thermal conductivity factors: solid conduction, gas conduction in stem bulks with conduction factors for pore gas, void gas, and gaps among stems, as well as radiation. These factors are affected by the type of straw and their bulk density. Therefore, we introduced empirical flatness and reverse flatness factors to our model, describing the relationship between heat conduction in stems and voids to bulk density using the geometric parameters of undisturbed and compressed stems. After the validation, our model achieved good agreement with the measured thermal conductivities. As an additional outcome of our research, the optimal bulk densities of two different straw types were found to be similar at 120 kg/m3.

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“…The phenolic compounds in tree bark also provide fire-retardant properties to such composites, together with the protective role of bark as fire-stopping found in many species [ 17 ]. As a by-product of wood processing industry, tree bark has an enormous potential in applications as adhesive filler to reduce formaldehyde emissions [ 18 ], thermal [ 19 , 20 ] and acoustic insulations [ 21 ], as raw materials for MDF [ 22 ], particleboard [ 23 ], pellets [ 24 ] or for medicinal purposes [ 25 ]. The combination between tree bark and cement results in lightweight concrete composites with densities around 800 kg/m 3 [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

Fire Retardancy of Cementitious Panels with Larch and Spruce Bark as Bio-Admixtures

et al. 2022

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The aim of this study is to investigate the production of fire-resistant panels made out of bark from spruce (Picea abies), larch (Larix decidua Mill.) and cement. This research included test panels produced from bark, cement, water and cement-bonded recycling material aiming for the target density of 750 kg/m3. The physical (density, dimension stability, thickness swelling) and mechanical properties such as tensile strength and compressive strength together with fire resistance were tested. Considering the results, appealing values have been achieved: max. compressive strength: 3.42 N/mm2; max. thickness swelling: 5.48%; and density: 515 to 791 kg/m3. In principle, the properties of the produced panels depend not only on the density, but also on the hydration and, above all, on the compaction and the composition of the boards. The fire tests demonstrated that the produced panels have an enormous potential in terms of fire resistance and could be utilized for fire-retardant applications.

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Binderless Thermal Insulation Panels Made of Spruce Bark Fibres

Cited by 27 publications

References 35 publications

Thermophysical Properties of Larch Bark Composite Panels

Thermophysical Properties of Larch Bark Composite Panels

Heat Transfer in Straw-Based Thermal Insulating Materials

Fire Retardancy of Cementitious Panels with Larch and Spruce Bark as Bio-Admixtures

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