Thermal Conductivity of Hemp Based Boards

Abstract

<p class="R-AbstractKeywords"><span lang="EN-US">Energy and raw material costs, an increase in environmental pollution, greenhouse gas emissions, global warming, depletion of fossil raw materials stimulate to seek and study alternatives to the synthetic fibers and products made of them for full or partial replacement. Renewable raw materials, including natural fiber sources, are the future of storage resources with a variety of positive effects on both the planet ecosystem and the living and working environment, and the energy consumption of delivering the required functionality. One of the most important energy-saving types is to reduce energy consumption in buildings by insulating them.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">For Latvian conditions suitable crops are historically grown flax and hemp. Within the framework of the studies, hemp stems are being used. Hemp compared with flax, are less suffering from diseases and less damaged by pests, so hemp cultivation is practically free from use of chemical pesticides and herbicides reducing the risk to the ecosystem.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">One of the most frequently mentioned industrial hemp raw materials positive qualities are their very wide use, practically all plant parts can be used in production of different products. This work explores the possibilities and technologies within the Latvian grown hemp stems to work into board materials with insulation capability.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">Hemp fibers/shives mix boards can fulfill the main function of insulation materials, i.e., to reduce the transmission of heat, because they have a porous structure and low density. Material thermal insulation properties affect physical and structural properties of compounds. Cost effective particles board samples from chopped hemp stems with three types of adhesives and different thicknesses were produced and their thermal conductivity evaluated. The technologies applied and test results will be discussed in the paper. </span></p>

Applications of Hemp Polymers and Extracts in Food, Textile and Packaging: A Review

“…Addition of tapioca starch (10–40%) efficiently improved tensile strength, burst strength, abrasion resistance, apparent density and resistance to water absorption [ 59 ]. Kirilovs et al (2015) [ 60 ] developed hemp fibers/shives mix boards that can be utilized as insulating materials. Heat transfer was reduced due to their porous structure and low density.…”

A Sustainable Approach towards the Retrofit of the Public Housing Building Stock: Energy-Architectural Experimental and Numerical Analysis

“…As for the straw, it has been noted that, if the fibres are perpendicular to the flow, the thermal conductivity (λ) is between 0.045-0.056 W/m.K; whereas, if they are in a parallel direction, it is between 0.056-0.080 W/m.K, showing increasing values, depending on the density of the straw bale [39]. Regarding hemp, the thermal conductivity values that were found in the experimental analyses varied from 0.039 to 0.123 W/m.K [28,40], depending on fibres direction, with lower λ values for fibres positioned in perpendicular direction with respect to the heat flux, and higher ones for fibres in the parallel direction [41]. A further consideration concerns the fire resistance of these two materials, which is very low (category E) due to their organic origin [34]; however, it should be emphasized that the presence of natural origin binders, which are necessary for the realization of the panels, generates an increase in the fire resistance approximately around +30% [42].…”

“…These materials choice involves another great advantage; in fact, depending on the low values of water vapour diffusivity resistance µ of the two materials, respectively, 3.9 for straw and 2.0 for hemp [39,40], they are able to be applied in contact with a material as porous as tuff, without generating condensation phenomena, therefore eliminating needing of further layers application and allowing the free vapour circulation, thus increasing internal comfort.…”

Particleboard Creation from Agricultural Waste Residue of Seed Hemp

“…There has been research into alternative methods of hemp processing to bypass field retting or other traditional processes [33]. The produced hemp particles-shives and fibre-can be used to produce construction and board materials and enhance material properties by utilising them as main ingredients or additives [12,[34][35][36]. Efforts are being made to address the environmental impact and health concerns related to the utilisation of hemp residues, aiming to maximise their positive effects.…”