Manufacture and characterisation of prototype straw bale insulation products

Platt, Shawn; Maskell, Daniel; Walker, Pete; Laborel-Préneron, Aurélie

doi:10.1016/j.conbuildmat.2020.120035

Cited by 23 publications

(11 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Piégay et al used a self-consistent modeling technique to predict the equivalent thermal conductivity of vegetal-based fibrous thermal insulations as a function of thermal conductivities of solid and liquid phases and material porosity. Platt et al [ 28 ] investigated the effect of fiber orientation on the thermal conductivity of straw bales. Yang et al [ 29 ] investigated the thermal transmittance of straw bale walls and the effects of different structural details concerning straw bale joints; using the guarded hot box method, Conti et al [ 30 ] realized a metering chamber within a climate chamber to be able to measure and calculate rectangular straw-bale sample′s thermal conductivity, while Costes et al [ 31 ] used a specific guarded hot plate which was designed to measure straw bale samples of up to 50 cm thickness.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer in Straw-Based Thermal Insulating Materials

2021

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

Heat Transfer in Straw-Based Thermal Insulating Materials

2021

View full text Add to dashboard Cite

show abstract

“…Straw bales are a breathable (vapour permeable) construction material; they allow water vapour to pass through it in response to differences in Relative Humidity (RH) between two faces of a wall [11]. However, as straw is vulnerable to decay at higher levels of moisture content, it is important that moisture is not trapped with the wall construction for prolonged periods.…”

Section: Introductionmentioning

confidence: 99%

Structural characteristics of load bearing straw bale walls

Peng

Walker

Maskell

et al. 2021

Construction and Building Materials

Self Cite

View full text Add to dashboard Cite

“…The European Straw Building Association (ESBA) conducted a significant number of studies on the thermal conductivity of bales in 2010, and according to the report, the straw bales with a density of about 126 kg/m 3 , when the fibers are parallel to the heat flux, have a thermal conductivity of 0.078 W/m•K, and in the direction perpendicular to the flow, it is 0.056 W/m•K. The conclusion from the above results indicates that the proper orientation of the straw stalks can improve the thermal resistance by up to 28% [41].…”

mentioning

confidence: 67%

The Fire Resistance and Heat Conductivity of Natural Construction Material Based on Straw and Numerical Simulation of Building Energy Demand

et al. 2022

View full text Add to dashboard Cite

The motivation for research to help address climate change is a continuous process of searching for eco-friendly materials in the building industry, which will allow minimizing the negative impact of this sector on the environment. The main objective of the paper is to assess the properties of a natural resource such as straw as an eco-friendly material in various variants for use in low-energy demand construction. The research results will fill the knowledge gap in the field of numerical analyses of the energy demand of straw material buildings based on the results of the conducted laboratory tests. A test of a heat transfer coefficient was conducted with different orientation of straw stalks. Then, samples were subject to a fire resistance test to determine material behavior at 1000 °C. During the fire resistance test, the clay-based plaster was ‘burnt out’, which hardened its structure, effectively preventing flames from reaching the insulation layers in the form of straw stalks. As a result of shrinkage (no plaster mesh), the plaster cracked and turned brick-red in color. The insulation layer of straw under the plaster was charred to a depth of 3.0 mm due to the high temperature. However, when the torch was turned off, no fire spread was observed in any layer of the sample. The 3D models of the buildings were created for different eco-friendly materials applied to make external walls. The results of numerical simulation allowed determining the amount of final energy needed to heat the designed building at the level of 26.38 (kWh/m2·year). Conclusions of the above-mentioned tests indicate very good thermal insulating properties determined using the lambda coefficient of 0.069 (W/m·K) and the possible application of straw bales as an alternative for conventional construction. Research has proven that it is possible to construct a building with low energy requirements using natural, easily available waste and completely biodegradable material.

show abstract

Manufacture and characterisation of prototype straw bale insulation products

Cited by 23 publications

References 13 publications

Heat Transfer in Straw-Based Thermal Insulating Materials

Heat Transfer in Straw-Based Thermal Insulating Materials

Structural characteristics of load bearing straw bale walls

The Fire Resistance and Heat Conductivity of Natural Construction Material Based on Straw and Numerical Simulation of Building Energy Demand

Contact Info

Product

Resources

About