Alternative Insulation Materials Research Articles

Environmental potential of fungal insulation: a prospective life cycle assessment of mycelium-based composites

PurposeBio-based insulation materials are one of the most promising solutions for reducing the environmental impacts of building envelopes. Among these materials, the environmental benefits of mycelium-based materials have merely been investigated, despite their promising technical and thermal properties. In this paper, we perform a first prospective cradle-to-grave life cycle assessment (LCA) of mycelium-based composite blocks.MethodsAn attributional cradle-to-gate LCA of the laboratory production of mycelium-based composites was first performed, including 11 environmental impact indicators. Then, scenarios were defined to scale up the technology to the level of industrial production, including the remaining life cycle modules to perform a cradle-to-grave analysis. Biogenic and metabolic carbon were considered by applying the static −1/+1 approach and following the current LCA standards. Future-oriented energy and transport mixes were also included as an additional scenario, systematically modifying both the foreground and background data. Finally, the industrially scaled-up technology and alternative insulation materials were compared with these future conditions (as applied to both materials).Results and discussionConsidering climate change, the results are encouraging in comparison to those for traditional plastic insulation, but do not necessarily surpass those for other existing materials such as rock wool. However, trade-offs are observed in other indicators, for which mycelium-based composites tend to perform worse than traditional insulation materials. The industrial scale-up reduced impacts for most indicators, but a considerable trade-off was observed with regard to terrestrial ecotoxicity. The main driver for the remaining greenhouse gas (GHG) emissions was found to be the electricity use during the manufacturing phase. We consider the inclusion of the other life cycle stages as relevant, as this increased the GHG emissions by 10%. Limitations of the current LCA standards, however, are noted and discussed, especially regarding the cascading use of biogenic materials, and highlight the relevance of this case study.ConclusionsMycelium-based composites show a potential for future development, but careful attention should be paid to reducing electricity needs in their manufacturing process. Further improvements could also be made by using fast-growing biogenic materials as a substrate. In particular, we encourage researchers to include all of the life cycle stages in future studies, especially if biogenic emissions are considered.

Effect of Nylon Membrane Thickness on the Value of Sound Transmission Loss as an Alternative Insulation Material

Measurements of sound transmission loss have been successfully carried out on various thicknesses of nylon membrane as an absorbing material. Nylon membrane were prepared using hydrogen chloride (HCl) and acetyl aceton in the casting solution by phase inversion methods. Nylon membrane with different thickness used in this reseach were 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm. Measurement of sound transmission loss was carried out using a reverberation chamber with sound frequencies of 125 Hz, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz. The results show that, with the increase of thickness of nylon membrane, sound transmission loss of nylon membran was improved. The sound transmission loss of nylon membrane with thickness of 4 mm is the best, whose sound trasnmission loss was up to 46.39 dB at 4000 Hz. This nylon membrane is suitable for lightweight sound barriers and is promising and worthy of further study.

Life cycle assessment of wheat husk based agro-concrete block

In recent years the development of alternative insulation materials has increased, such as agro-concretes, a mix between inorganic binder and aggregate of vegetable origin, including farming waste, such as wood fiber, rice husk, hemp hurd. These type of insulator materials are more eco-sustainable, thanks to their renewable origin, and equally thermal efficient compared to the traditional ones. In particular, this study focused on the sustainability evaluation with Life Cycle Assessment (LCA) methodology of a wall made of wheat husk and a lime-based binder. The case study was analysed considering the entire life cycle of the wall, where thermal performances of the material, investigated in previous experimental activities, were taken into account for the use phase damage calculation associated with energy demand for winter heating and summer cooling. The obtained results were compared with two alternative scenarios, consisting in a wall made of traditional bricks fitted with a cladding and a wall composed with a unique casting of mixture of wheat husk and lime, having the same thermal transmissivity. The presence of the cladding influenced the choice of the most suitable end of life for the traditional wall, identified in landfill disposal, due to the presence of heterogeneous materials joined together by glue, while material recovery through recycling could be foreseen for the wheat husk-based materials. The comparative LCA analysis demonstrates that the two wheat husk based walls are characterized by better environmental performances compared to the traditional scenario for the production phase and end of life phase, where the main observed damage contribution are the natural gas consumption for the production of clay bricks and the emissions for landfill construction, respectively.

Hygrothermal performance of multilayer straw walls in different climates

Straw is becoming a promising alternative insulation material to improve the building energy performance because of its low cost, large availability as cereal waste, its good hygrothermal properties, and its low embodied energy. The goal of this paper is to assess the hygrothermal performance of multi-layered straw walls with different boundary conditions. The study consists of evaluating five different straw-based wall assemblies, under a continental (Arkhangelsk, Russia), a tropical climate (Brasilia, Brazil), a temperate Mediterranean climate (Nice, France), and a cold desert climate Xinjiang (China). Numerical models of the heat and moisture transfer through the walls using WUFI software are developed, calibrated, and validated through experimental results from the literature. The chosen evaluation criteria are the total water content, the drying rate, the condensation risk, the mold growth, the moisture quantity, the time lag, and the decrement factor. Results show that straw walls with cement and/or wood covering can be used in tropical and temperate climates, coated straw walls with additional air layers in dry climates, while insulated straw walls are best fitted in continental climates. In the latter, the dryness rate varies between 7 and 40% with a low condensation risk of value in the range of 0–12%. It can be concluded that the straw wall’s performance strongly depends on the interior and exterior added thermal insulation layers since they affect the ability of the material to dry out.

Mechanical and thermal properties of lateritic soil mixed with cement and polymers as a non-bearing masonry unit

Masonry units are self-insulation wall blocks that are among the most common construction materials, owing to their fast and straightforward wall construction, high strength, and low cost. However, the high thermal conductivity of masonry units results in increased energy consumption. The current research investigated polymers, namely polyvinyl pyrrolidone, polyvinyl alcohol, and polyethylene glycol, as alternative insulation materials in building walls. The effect of variables, including cement (C) content, liquid (L) type, liquid content, and curing time, on the mechanical and thermal properties of lateritic soil (LS) mixed with C and L was investigated via the unconfined compressive strength (UCS), indirect tensile strength (ITS), and thermal conductivity. The results indicated that the UCSs and ITSs of LS-C samples mixed with polymer were higher than those mixed with water. The specimen with the optimal liquid content and 3 wt% C content performed best for all L types. Furthermore, the thermal conductivity of the LS-C with polymers was lower than that of the sample with water for all C contents. The equations for estimating dry unit weight, UCS, ITS, and thermal conductivity of samples were proposed.

Carbon Footprint Assessment of a Novel Bio-Based Composite for Building Insulation

This research explores the carbon removal of a novel bio-insulation composite, here called MycoBamboo, based on the combination of bamboo particles and mycelium as binder. First, an attributional life cycle assessment (LCA) was performed to define the carbon footprint of a European bamboo plantation and a bio-insulation composite, as well as its ability to remove CO2 along its lifecycle at a laboratory scale. Secondly, the Global Worming Potential (GWP) was estimated through a dynamic LCA with selected end-of-life and technical replacement scenarios. Finally, a building wall application was analyzed to measure the carbon saving potential of the MycoBamboo when compared with alternative insulation materials applied as an exterior thermal insulation composite system. The results demonstrate that despite the negative GWP values of the biogenic CO2, the final Net-GWP was positive. The technical replacement scenarios had an influence on the final Net-GWP values, and a longer storage period is preferred to more frequent insulation substitution. The type of energy source and the deactivation phase play important roles in the mitigation of climate change. Therefore, to make the MycoBamboo competitive as an insulation system at the industrial scale, it is fundamental to identify alternative low-energy deactivation modes and shift all energy-intensity activities during the production phase to renewable energy.

Thermal insulation and mechanical characteristics of polyester filled with date seed wastes

In this study, the feasibility of utilizing date palm seeds (DS), the primary waste in date industry, as a filler in unsaturated polyester (UPR) matrix to develop thermal insulation material was investigated. Stable homogenous DS-UPR composites with up to 70 vol% natural filler were prepared at room temperature following a thermoset curing process. The developed composites were subjected to different physical, thermal, and mechanical tests. Moreover, the developed composites were characterized using different techniques (such as scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR)). Density and water retention measurements were verified using different theoretical models. FTIR analysis suggests the existence of hydrogen bonding between DS fibers and UPR, which was more pronounced at high filler loadings. Replacing till 50 vol% of UPR with DS produced composites that possess promising thermal insulation and construction properties with relatively low thermal conductivity (0.126 – 0.138 W/(m∙K)), low thermal diffusivity (0.109 – 0.096 mm2/s), low water retention (0.47–3.44%), and high compressive (38.4–88.0 MPa) and tensile strengths (9.4 – 35.1 MPa). Moreover, addition of date seeds to unsaturated polyester matrix slightly increased its glass transition temperature and improved its thermal stability. The novel DS-UPR developed composite can be used as an alternative insulation material because of its superior properties compared with those of the traditional thermal insulators.

Utilization of devulcanized waste rubber tire in development of heat insulation composite

This study aims to investigate the possibility of recycling devulcanized rubber tires for their use as fillers for thermoplastic thermal insulators. A devulcanized rubber tire was ground into powder and then mixed with polystyrene in different proportions (0–50 wt%) using a melt extruder. The mixture was then transferred to a hot press for fabricating the final sample. The effect of devulcanized rubber tire content on the physical, thermal, and mechanical properties of devulcanized rubber tire–polystyrene composites was investigated. Thermal conductivity measurements were verified using series and parallel conduction models and the Hashin and Shtrikman model. Composites with less than 40 wt% devulcanized rubber tire content exhibited superior properties, with thermal conductivity ranging from 0.0502 to 0.07084 W/(m⋅K), density from 462.8 to 482.32 kg/m3, compressive strength from 11.66 to 7.47 MPa, and flexural strength from 40.4 to 19.26 MPa. Moreover, alkaline treatment of the devulcanized rubber tire further improved the mechanical properties and thermal stability of the composite. The results are supported by characterization techniques such as scanning electron microscopy, thermogravimetric analysis, and Fourier-transform infrared spectroscopy. The chemical treatment was found to enhance the coherence between treated devulcanized rubber tire and polystyrene. The novel devulcanized rubber tire–polystyrene composite can be used as an alternative insulation material because of its superior properties compared with those of conventional insulation materials. Furthermore, the environmental and economic implications of using devulcanized rubber tire–polystyrene composites as a new insulation material are discussed herein.

Chronic stability of local field potentials from standard and modified Blackrock microelectrode arrays implanted in the rat motor cortex

Utah electrode arrays (UEAs) enable the recording of neuronal activity that informs the understanding of cortical connectivity and function, and can be used to control brain-machine/computer interfaces. However, UEAs have shown a reduced ability to resolve single unit activity (SUA) over time, prompting efforts such as the use of alternative insulation materials and reliance of local field potentials (LFPs) to improve device robustness and stability of neuroprosthetic control signals, respectively. The effect of different electrode insulation materials on LFP stability, particularly with UEAs, has not been extensively investigated, especially in rats, which provide a well-studied model for behavior and motor cortex injury. Here, we report the chronic stability of LFPs from both Parylene-C- and amorphous silicon carbide-encapsulated UEAs implanted in the rat motor cortex. We observed a decrease in bandpower in anesthetized rats for both array types that converged to the same magnitude at 30 weeks. In awake, freely-behaving rats however, there was relatively stable bandpower in both array types across individual frequency bands. In total, our results are consistent with studies performed in non-human primates, suggesting that chronic LFP stability trends are similar across both animal models.

Performance assessment of water hyacinth–cement composite

Abstract Water hyacinth (WH) is an invasive aquatic with an extensive, rapid growth. Nowadays, the considerable amount of WH biomass generated is a waste management challenge for those areas where WH is present. In this paper, a new insulation building material based on WH’s petioles (WHP) and mixed with cement was analysed. Different WHPs particle sizes were processes (pulp WHPs and staple WHPs). As a consequence, two type of panel were studied. Both panels used different WHP content ranging from 40:60 (WHP:cement) to 100:0. According to the results, self-supporting WHP-cement board could be used as an alternative insulation material. The optimum percentage (WHP:cement) was 80:20 for panels made with pulp WHP and 75:35 for panels made with staple WHPs. Their thermal conductivity values were 0.63–0.45 W/mK respectively.

Tekstil kao održivi izolacioni materijal za zgrade

The introduction of the concept of "sustainability" in the construction industry has led to the production of alternative insulation products made of textiles from virgin or recycled materials, besides the conventional ones. Some of them are already present in the European market, while others are still being researched. There is no ideal insulation material, so it is useful to evaluate conventional and alternative insulating materials. The assessment of insulation materials is an issue which needs to be analyzed from different aspects: the physical properties of the material, their effect on people and the environment, installation difficulty and price. In this paper, conventional and alternative insulation materials from textiles are examined in terms of sustainability criteria. Insulation materials from recycled textiles are considered sustainable materials due to the possibility of recycling, reuse and low value of embodied energy. However, as a result of insufficient consumer awareness, insulating materials from textiles are not represented in the markets as much as they deserve to be.

Improvements to the Construction of Bubble Inception Formulae for Use With Transformer Insulation

Moisture in transformer insulation is a topic of major interest to power system equipment operators. Moisture plays a large role in the degradation of insulation within the transformer, impacting on the longevity and the failure rate of this crucial asset. Therefore, understanding of how moisture behaves in the transformer insulation has been the focus of many studies. One particular matter that can occur during high-temperature events is the formation of bubbles of water vapor which are released from the cellulosic paper wrapped on the transformer windings. During such events, the presence of these bubbles could lead to an electrical failure of the transformer, and so it is desirable to be able to set operational criteria which prevent such occurrences. A formula which can predict the temperature at which bubbles will form from the paper insulation can allow operators to restrict transformer operation in order to avoid such situations. However, it has proven difficult to generate a formula with global applicability that is simplistic enough for generic use. This paper assesses the current formula against existing data in literature and compares a suggested alternative, drawing on fundamental science to assist in development of both formulae. The alternative formula is based on a better representation of bubbling activity and requires fewer input variables. Finally, adjustments are suggested to the formulae which allow them to be used more generally throughout the transformer fleet, including on service-aged transformers and with alternative insulation materials.

Experimental and numerical study on the thermal performance of alternative insulation materials based on textile waste: A finite-difference approach

The aim of this work is a qualitative and quantitative analysis of the thermal performance of an external wall outfitted with new insulation materials based on textile waste using an experimental and numerical approach. The experimental study deals with the development and characterization of a new insulation material from wool and acrylic and then tests their thermal performance in a cavity which simulates a building room at reduced scale thermally controlled. The numerical study essentially centers on the development of a multilayer wall which simulates an external wall under laboratory conditions using finite difference method (implicit scheme method). First, a COMSOL tool is used to verify that the heat transfer in the external wall is unidirectional and then our numerical model is limited to a one-dimensional simulation. The numerical model is successfully validated owing to the experimental results. Using the numerical model, the thermal performance of the wall with the textile insulation is studied and their optimal thickness and location are determined. The variation of insulation thickness considerably influences the surface temperature up to a thickness of 6 cm and beyond the variation becomes less important. The results also show that the location and distribution of insulation has an effect on outdoor surface temperatures.

Solution of problems of ETICS with biocorrosion

To find solutions for maintenance and repair of existing structures ETICS becomes the current another issue of improvement thermal insulation proprieties of external cladding, which need to be answered necessarily till December 2020. Double thermal insulation technology can be achieved by jointly increasing of thermal insulation properties and by repairing surface porosity ETICS. The aim of the research is the analysis of alternative insulation materials in plaster repair by technology "double thermal insulation" ETICS in terms of technology, humidity and temperature conditions in the layers. Technology of double thermal insulation is analyzed in the context with solution biocorrosion surface thermal insulation. In the end of the research there is obtained the data from the comparisson of technology double thermal insulation with different insulation materials expressed by graph. Obtained data can be the basis for decision to choosing a repair, to solution for the structural details of double thermal insulation and also for experimentally assess the lifespan of the double ETICS.

An environment friendly new insulation material involving waste newsprint papers reinforced by cane stalks

Insulation is vital to most building design and aims to decrease the need for heating and cooling. This paper presents a procedure to obtain an alternative insulation material made with waste newsprint papers, cane stalks, vermiculite, perlite, zinc borax and plaster. Towards this end, waste newsprint papers were kept in water for one day until they formed dough. Then, different rates of vermiculite, perlite, and zinc borax were added to the dough. This mortar was placed in moulds of 4 × 16 × 16cm dimensions with its own weight. In the production of the samples plaster was used as the binder. For increasing the fire resistance vermiculite and zinc borax were added to the mix. In the production of some samples 5mm cane stalks were placed in grid forms of single and double rows and pressure was applied. After the production of the samples their unit weights, water absorption ratios, thermal and ultra sound transmission coefficients, and flexural and compressive strengths were determined. The samples produced with an additional double row of canes had the lowest thermal conductivity and ultra-sound permeability coefficients. The requirements of the standards were satisfied by the flexural and compressive strengths of all samples. Samples with both types of grids had rather low thermal conductivity coefficients. The flexural strengths of these samples were found to be higher than those of the others. These results indicate that the investigated materials can be used for thermal and ultrasonic sound insulation purposes. Furthermore, ASTM Standards’ fire resistance requirements are also satisfied. Hence, the proposed product has potential as a candidate to be commercialized with further improvements in the future.

Environmental and cost performance of building’s envelope insulation materials to reduce energy demand: Thickness optimisation

Thermal insulation materials play an important role in the challenge of nearly zero-energy buildings thanks to their potential in reducing building’s energy demand and carbon emissions. However, increasing the thickness of the insulation material in the building’s envelope has implications from the energy, environmental and economic viewpoints. In this context, efforts should be made to optimise insulation thickness to balance all these aspects.This study presents a methodology to analyse optimum insulation material for the building’s envelope (roof, façade and floor) and its thickness to achieve energy demand reductions in the operation phase of the building, which is based on the Life Cycle Assessment and Life Cycle Costing methodologies to integrate both environmental and economic aspects, respectively. The system boundary includes the life cycle stages of product and use defined by recent European standards. A selection of eleven alternative insulation materials, both conventional and emerging ones based on natural products, were chosen to conduct the study. After applying the methodology to a single-family house in Spain and performing a sensitivity analysis, the results revealed that sheep wool and recycled cotton, jointly with traditionally used mineral and glass wool, should be promoted in the construction industry as they offer the highest eco-efficient performance among the analysed insulation materials. Reductions of up to 40% in energy demand compared to regulations standards can be achieved in theeco-efficiency context.

Moisture migration in oil-impregnated film insulation under thermal ageing

Moisture produced in thermal degradation of insulating materials in transformer causes damage to the insulation system. To study the moisture diffusion and balance process in transformer insulation system and evaluate alternative insulation materials, three types of samples, including Kraft insulation paper, PC and PET film, were impregnated in oil and thermally aged under 90, 110 and 130 °C respectively. By analysing the moisture variation in oil and solid insulation, it was found that the moisture diffusion, balance and hydrolytic degradation process of oil-paper insulation are different from those of other two types of samples. During the thermal ageing process, the moisture produced by polymer is much more than that by oil, and most of which is absorbed by sample surface. The ageing temperature has considerable influence on the moisture migration in polymers.

Študij lastnosti in higrotermalno obnašanje alternativnih izolacijskih materialov na osnovi naravnih vlaken

Študij lastnosti in higrotermalno obnašanje alternativnih izolacijskih materialov na osnovi naravnih vlaken

Mechanical, thermal and acoustical characterizations of an insulation composite made of bio-based materials

Heating costs in winter and cooling costs in summer, nowadays, are very high and these costs a can be reduced by the insulation of buildings. This study is related to the development of bio-based composites and the determination of their thermal, mechanical and acoustical insulation properties. The composites were prepared using corn stalk particles as the reinforcement components. An experimental design was established to study the effect of the stalk particle size and the epoxy/corn stalk particle ratio on the thermal and mechanical properties of the composites prepared. Their mechanical properties and thermal performance characteristics are compared with the commercially available bio-based insulation materials.This study shows that waste corn-on-the-cob can be used for the reinforcement of epoxy resin to prepare insulation materials that can be used commercially. Natural products of high insulating value can be obtained that can provide alternative insulation materials and reduce the import of insulation materials and satisfy the criteria of the Turkish Standard TS 805 EN 601. The results of this study can solve two industrial problems. One of them is providing a new useful construction material and the other is utilizing agricultural wastes to reduce their harm to the environment.

Utilization of Alternative Insulation Materials for Thermal Insulating Ceramics Blocks Production

There has been a substantional increase of atributes for building constructions in area of thermal protection in last decade. This was shown as increasing of requirements for materials and components intended for building of cover constructions as well. In case of shaped bricks used for perimeter walls advanced production technologies were applied. These technologies consist of decreasing thermal conductivity coefficient for brick clinker, of decreasing inner ribs thickness and in last years this concerns the technology of filling inner cavities of shaped bricks with thermal insulating materials as well. This paper describes possibilities of using alternative raw material sources (natural fibres originated in agriculture, separate textile waste, ....) as integrated insulating layers in contemporary ceramic shaped bricks with high usable qualities.