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A life-cycle energy and carbon analysis of hemp-lime bio-composite building materials
Abstract
Conventional, concrete-based building materials have a high level of embodied energy in their production – as do typical insulation materials, which are crucial for addressing operational energy demands for building climatization. Here, a life-cycle energy (LCEA) and carbon (LCCO2A) analysis is performed to evaluate the potential benefits of using an alternative, bio-composite building material made from hemp shives mixed with a lime binder, in the context of an arid environment. The physical properties and thermal performance of the hemp-lime building material are compared with conventional materials through lab tests, temperature measurements in test cells and thermal simulations. This study concludes that hemp-lime not only has a clear advantage over comparable conventional materials in terms of embodied energy, but also in terms of net CO2 emissions over the entire life cycle of a typical building. This is primarily due to the active carbon sequestration of the hemp plant during its growing phase, and the gradual sequestration of carbon emitted during the production of lime. The thermal properties and behaviour of a hemp-lime wall material were found experimentally to be virtually identical to those of a commonly-used lightweight concrete insulation material with a similar density.
... Materials that can be applied in the process of renovating a country house according to the principles of sustainable development and reducing energy consumption are related to this research. Thus, sheep's wool can be a material with suitable use [41][42][43][44][45][46][47], as well as hemp [48][49][50][51][52][53][54][55][56]. The popularity of hemp as a construction material is growing in the world, including in Serbia. ...
... The popularity of hemp as a construction material is growing in the world, including in Serbia. Replacing mineral aggregates with plant aggregates in building materials can significantly affect energy consumption in this sector [48][49][50][51][52][53][54][55][56]. In this context, energy efficiency, eco-materials, and eco-design are presented in order to indicate the importance of searching for environmentally friendly and natural materials and technologies that enable the reduction of material and energy consumption in buildings. ...
... Some of them are hempcrete, hempcrete blocks, hemp-based insulation wool ("hemp wool"), plywood/chipboard, hemp-based mortar and bricks. The thermal conductivity of hempbased materials ranges from 0.035 to 0.043 W/mK [57], which makes them acceptable thermal insulation materials [48][49][50][51][52][53][54][55][56]. ...
In the last few years, Stara planina (the Balkan Mountains) and its surroundings have been improving their tourist offer. The area is protected by law, as a nature park, and the construction of new buildings requires a complex administrative procedure. Renovation of country houses is part of the usual construction procedures and is easier to carry out. Typical renovation solutions involve application of industrial materials with significant impact on the environment from the process of their production and further on. The traditional houses found in many mountains across Serbia and the Balkans are constructed using natural materials. Hence, this paper tackles the problem of renovating such dwellings by application of natural materials to improve their usability and reduce their energy and carbon footprint. An analysis is performed on a case study model of a typical house from Stara planina. The advantages of using natural materials in the process of renovating a traditional house are analysed. By using TRNSYS software, the total amount of energy demands of the house during a typical meteorological year with four scenarios (current state, walls isolated with sheep and hemp wool panels and EPS) was simulated. These materials were further analysed for their environmental impact by means of Life Cycle Analysis (LCA). In the synthesis of the research, the best results were brought into connection with the sustainable development of the architectural heritage. The results prove that natural products provide the necessary thermal comfort and have a significantly more positive impact on the environment than artificial materials. Based on this study, recommendations were created for the sustainable renovation of vernacular architecture in Serbia. The goal of the paper is to create scientific and professional evidence that local and natural materials must be used to reduce the impact of climate change and that such sustainable renovation is in accordance with modern architectural design and thermal comfort. The goal is also to fill the gap in renovation methods in Serbia, according to the principles of sustainable design.
... Hempcrete's unique ability to store energy and release it at a slow rate to stabilize temperature fluctuations makes it the ideal building material for all Indian weather conditions (2-59). Industrial Hemp hurds are able to store considerable amounts of moisture because of their porous structure (40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59). This moisture gets absorbed into the large internal surface area of the Industrial hemp (fiber type) plant and moves to the cellular structure . ...
... This resilience gives hempcrete an edge over other insulation materials, making it a desirable choice in both hot and cold climates as well as anywhere where humidity levels are high (1-21). India's average humidity levels go as high as 70% in the north, 81% in the east, 79% in the south, and 76% in the west (40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59). Therefore, industrial hemp fiber is the right plant based building construction material that is hempcrete in India (1-60). ...
... Tarun Jami who founded GreenJams Infrastructures LLP with a vision to integrate the "Built Environment" with the "Natural Environment" (40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59). They found that adopting carbon-negative materials was the only way to realise their vision, the birth of their Hempcrete R&D (49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59). ...
This review paper highlights about the Industrial hemp (fiber type) used as a plant based building construction material, Hempcrete. Industrial hemp (Cannabis sativa L.) is an emerging food and fibre crop. It is a non-drug variety of Cannabis sativa with low Δ9-tetrahydrocannabinol (THC) content of less than 0.3 per cent. The use and performance of hempcrete suggested that hempcrete can be considered as an environmentally friendly material. In a first of its kind in India, an architect couple, Namrata Kandwal and Gaurav Dixit have built a house made of using hemp fibre-hempcrete in Uttarakhand state, India. Industrial Hemp (fiber-type) is both an agricultural and industrial commodity and stem supplies both cellulosic and woody fibers. Hempcrete is a construction material made from hemp fibres, lime and water. Hemprete showed a negative carbon footprint making it a suitable material in the construction industry. This composite, hempcrete breathes, as well as having a good thermal and acoustic-insulation properties. However, hempcrete does have several key drawbacks that make it less than ideal as a building material. In addition to poor mechanical performance, hempcrete also has a high capacity to absorb and retain water. Therefore, future in detail study is warranted for the commercialization of hempcrete as a building material.
... Hempcrete, or hemp-lime concrete, is a sustainable construction material made of the inner woody core of the hemp plant (also known as hemp shives or hemp hurds) mixed with a lime-based binder and water (de Bruijn et al., 2009). Hempcrete combines plant-based components for insulation and sustainability with an inorganic binder for strength and durability (Florentin et al., 2017). Although hempcrete technologies have been increasingly used in Europe since the early 1990s (Rhydwen, 2006;Scrucca et al., 2020), the experimental studies on hempcrete are relatively recent, and the earliest study dates back to the 2000s (Glé et al., 2011), mainly due to hemp's guilty association with Marijuana which has led to legality issues. ...
... Depending on the mix design, hempcrete based-construction can be used in walls, floors, and roof insulation (see Fig.1). Hempcrete's thermal properties vary over a wide range depending on its mixture (which sometimes contains cement, sand, or clay) (Florentin et al., 2017) and the type of lime (Arizzi et al., 2015). Previous studies have emphasized hempcrete's relatively low thermal conductivity and medium-low density. ...
... Due to its vapor-permeable nature, hempcrete is considered a "breathable" material, meaning it regulates humidity by adsorbing and absorbing water from the air, which eventually prevents moisture accumulation, resists mold, and creates a healthy airflow (Walker and Pavía, 2014). Further, hempcrete is pest-resistant, toxic-free, 100% decomposable, and low-cost (particularly in countries where hemp cultivation is abundant and already integrated into the building industry) (Florentin et al., 2017). Due to its low-density properties (weights only one-seventh the weight of concrete by volume), hempcrete is easy to transport and implement on-site, adaptable to all climate zones, cures within a few hours, is more flexible than concrete and complies with European fire resistance and acoustic standards (Arrigoni et al., 2017;Florentin et al., 2017). ...
Hempcrete is a bio-composite material with excellent environmental and thermal properties. This material has
been increasingly adopted in Europe as an alternative to concrete and traditional insulation. However, hemp
hurds, as the raw materials for hempcrete, are discarded in the world’s largest producer (Morocco) and
considered biomass waste due mainly to their association with marijuana production. Thus, research on
hempcrete remained limited in Morocco, with fewer stakeholders aware of the benefits of hempcrete in green
buildings. The objective of this paper is to assess the potential use of Moroccan hemp biomass in the construction
industry using a life-cycle assessment comparison of a residential house in Marrakech (Morocco) with three
different exterior walls systems, two insulated conventional wall systems (i.e., double hollow clay brick (DHB),
composite wall (CW) with extruded polystyrene (XPS) insulation), and a bio-composite material (i.e., hempcrete)
to identify environmentally preferable wall systems. Our study demonstrated that hempcrete is advantageous
over other comparable conventional wall systems in terms of embodied energy and performs best in terms of the
environmental performance associated with its entire life cycle achieving relatively low carbon emissions
(484.42 tCO2) compared to insulated DHB and CW systems (546.27 tCO2 and 546.55 tCO2 for DHB and CW,
respectively) over a lifetime of 100 years. Significant savings (i.e., 61.85–62.13 tCO2 if hempcrete is used instead
of DHB and CW) can be made from the exterior wall choice for a single house. These savings become much more
significant if scaled up to the national level of Moroccan homes. Consequently, by exploiting the hemp biomass
currently available in Morocco, results show a reduction of 1.91 MtCO2–1.92 MtCO2, equivalent to 2.81%–2.83%
of overall Moroccan emissions. Thus, strong policy support and hemp legalization in Moroccan are essential to
boost and expand hempcrete utilization for a greener construction industry
... It can also be implemented as an insulation layer. Life Cycle Assessment (LCA) revealed that a building made of LHC instead of conventional materials leads to significant savings of CO 2 emissions and energy consumption [29,30]. ...
... These results are compared to a building made of standard LHC, and several buildings made of conventional materials: AAC, HCB, EPS. While several works already dealt with assessment of energy requirements and CO 2 emissions for standard LHC [15,24,30,38,39], the novelty of the research conducted here is its focus in the replacement of the lime in LHC with unfired binders, which is expected to reduce the EE and EC of LHC, therefore, diminishing the environmental impact of the building. Moreover, the uniqueness of this research is that the assessment conducted here refers to a specific case study sited in a desert region characterized by arid climate, with extreme diurnal and seasonal fluctuations of both temperature and relative humidity. ...
... The EE and EC values of LHC, with and without alternative unfired binders, were calculated based on the values presented in Table 1, which were taken mainly from the Inventory of Carbon and Energy (ICE) database [33]. This database does not include values for hemp shives, thus these were taken from other sources [13,15,17,30,32,34]. In addition, no values are given for unfired binders, thus the values used are the ones for sand and aggregates, which are the best alternative available. ...
This work assesses the energy requirements and CO2 emissions of a building made of Lime Hemp Concrete (LHC) with alternative unfired binders as lime replacement, compared to buildings made of standard LHC, and several conventional building materials. The assessment is based on ISO 14040, which deals with Life Cycle Assessment (LCA), and examines two aspects: energy, including pre-use phase Embodied Energy (EE), and use phase Operational Energy (OE); and CO2 emissions, including pre-use phase Embodied Carbon (EC), and use phase Operational Carbon (OC). The EE and EC calculations are based on published databases, while OE and OC were obtained with EnergyPlus simulations. The assessment refers to a specific case study in an arid region, with extreme diurnal and seasonal fluctuations of temperature and relative humidity. Using LHC with 100% unfired binder as lime replacement was shown to save up to 90% of the total energy consumption and CO2 emissions, as compared to conventional building materials. The findings of this research clearly demonstrate the high potential of LHC with unfired binders as lime replacement, which possesses the lowest energy requirements and CO2 emissions, illustrating the potential for a building with significantly low environmental impact over its life cycle, i.e., when calculating both EE and EC, and OE and OC.
... For example, at the material scale, Ganne-Chédeville and Diederichs [75] and Arellano-Vazquez et al. [76] apply LCA under the lens of the Environmental Product Declaration approach. Meanwhile, at the building scale, Shang and Tariku [63], Florentin et al. [77], and Sodagar et al. [78] use sub-forms of LCA, such as Life-Cycle Energy Assessment and Life-Cycle Carbon Emissions Assessment. Nonetheless, using the LCA methodology to assess the climate change impact of bio-based materials may have limitations. ...
... This paper and related research have been conducted during and with the support of the Italian inter-university PhD course in Sustainable Development and Climate change. [117] Bio-based biocomposite Oil palm fibres Petroleum-based composite þ þ [53] Sheep wool Sheep wool Plasterboard and mineral wool [109] Eco-sandwich material Cork Traditional one þ ------ [134] Straw bales Straw Concrete þ þ [63] Hempcrete Hemp shiv fibreglass batt þ [77] Hemp lime Hemp shiv Aerated Autoclaved Concrete þ þ [65] Bio-concrete Invasive alien wood chips ...
Circular bio-based building materials are “materials wholly or partly derived from renewable biological origins, or by-products and biowaste of plant and/or animal biomass that can be used as raw building materials and decorating items in construction, in their original forms or after being reprocessed”. Literature shows that using these materials can represent a coherent solution to mitigate the climate impacts of the building sector according to the circular economy model. However, previous studies are fragmented due to the heterogeneity in the studied material types, scales of case studies, and sustainability assessment methods applied. Therefore, this systematic and bibliometric literature review of 97 articles aims to categorise case studies, review the state-of-the-art of sustainability assessment of case studies and highlight the pros and cons of circular bio-based building materials. Results indicate that the material scale is the most researched compared to the other scales. Environmental analysis, primarily employing life cycle assessment, is the most frequently researched, followed by economic analysis, while social impact research is still in an early stage. Concerning the pros and cons, circular bio-based building materials outperform traditional materials in reducing initial production costs and mitigating environmental impacts, especially climate change and abiotic resource use. However, some materials perform worse in categories like eutrophication, land use, etc., and may not be economically viable from an entire life cycle perspective.
... Notwithstanding open methodological discussion, recent studies increasingly highlight the importance of moving away from currently dominating, conventional and often fossil-fuel intensive construction material choices towards a more environmental friendly ''material diet" for buildings, heavily based on lowcarbon, bio-based materials [13,14]. Much of the attention around bio-based materials focused on (mass) timber for building construction [15], interest increases in the use of fast-growing, biobased materials -such as, for example, straw [8,[16][17][18], hemp [19,20] or bamboo [21,22] -due to their potentials in terms of biogenic carbon fixation as well as availability as agricultural sideproducts supporting ambitions of a circular bioeconomy [11,14,23]. Another strategy for reducing both operational and embodied impacts is the reduction of complexity and use of technical systems in buildings, towards a more architectural designled, low-tech approach. ...
... An important note to add is that the scientific literature further suggests that the use of bio-based materials in building envelopes (such as hempcrete or straw) can result in less energy consumption for air-conditioning because of their excellent thermal and moisture buffering capacity [20,41]. ...
In order to achieve the necessary reduction of greenhouse gas (GHG) emissions and decarbonization of building construction and operation, both high- and low-tech building design strategies are promoted. Amongst particularly promising strategies are the deployment of energy efficiency measures, for reducing operational energy use and related impacts, as well as the application of low-carbon, bio-based construction materials, for reducing embodied impacts.
In part two of our study on the life cycle assessment (LCA) of regenerative design strategies, LCA is applied to investigate the environmental impacts and reduction potentials of strategies at building level by analyzing two low-tech, passive building concepts – the be2226 building and the N11 SolarHouse – in both their original designs as well as optimized alternatives applying bio-based material solutions.
The analysis includes three steps. In a first step the life cycle GHG emissions of the original buildings are assessed, revealing strengths and weaknesses on both operational and embodied GHG emissions. Environmental hotspots are identified across environmental indicators, life cycle stages and building elements. In a second step the case studies are remodeled with bio-based building element alternatives showing substantial embodied GHG emissions reduction potential compared to the original case studies. Finally, the results of all building variants are compared with climate targets for buildings revealing that the N11 building meets established climate targets already in its original version, and that a straw-based material optimization can even enable meeting more ambitious climate targets.
... Além disso, o desenvolvimento de materiais de construção que reduzam os impactos ambientais é uma necessidade [2]. Uma alternativa para solucionar esta problemática é a produção de bioconcretos que associam ligantes inorgânicos e agregados de origem lignocelulósica [3]. ...
... escória de alto forno a partir de 60% as emissões líquidas de GEE apresentam valores negativos, variando de -200,63 kgCO2-eq/m³ até -43,98 kgCO2-eq/m³.Figura 4. Emissões de GEE3.2 Impactos ambientais considerando o indicador de desempenho mecânico (em m 3 /MPa)Obteve-se os dados de resistência a compressão conforme apresentado na Tabela 1, de todas as misturas analisadas através do ensaio de compressão uniaxial realizado no laboratório, sendo assim foi calculado o indicador de desempenho mecânico ambiental que retrata quantos kg de CO2 eq são emitidos para produzir 1 m³ de bioconcreto com resistência de 1MPa (kgCO2-eq / m3 . MPa) conforme Figura 5. Figura 5. Desempenho ambiental da categoria Mudanças Climáticas em função da resistência mecânica (kgCO2eq/m³. ...
Resumo A utilização de bio-agregados de madeira para a produção de bioconcreto tem mostrado elevado potencial para o desenvolvimento de materiais com baixo impacto ambiental, uma vez que estes armazenam carbono biogênico. Entretanto, o elevado consumo de cimento é responsável por emissões significativas de carbono na atmosfera. Portanto, este estudo tem por objetivo avaliar o desempenho ambiental de bioconcretos de madeira (BCM) substituindo parcialmente o cimento por cinza volante e escória de alto forno em teores de 60%, 70% e 80%, em massa. A metodologia de Avaliação de Ciclo de Vida (ACV) foi utilizada, com escopo do berço ao portão, para a avaliação de sete misturas de BCM produzidas em laboratório. Os potenciais impactos ambientais foram relacionados com a resistência à compressão dos BCM (em MPa) como um indicador de ecoeficiência. Os principais resultados mostraram que o cimento e o tratamento dos bio-agregados de madeira são responsáveis pelas maiores emissões de CO2. A substituição do cimento por pozolanas acarretou numa diminuição das emissões, com destaque às misturas produzidas com escória de alta forno que apresentaram resistência mecânica maior ou similar em relação à referência, com menores impactos ambientais. Palavras-chave: Bioconcreto de madeira, ACV, Cinza volante, Escória de alto forno Abstract The use of wood bio-aggregates for the production of bioconcrete has shown a high potential for the development of materials with low environmental impact, since these materials store biogenic carbon. However, the high consumption of cement is responsible for significant carbon emissions in the atmosphere. Therefore, this study aims to evaluate the environmental performance of wood bioconcrete (WBC) partially replacing cement by fly ash and blast furnace slag in the contents of 60%, 70% and 80%, by weight. The Life Cycle Assessment (LCA) methodology was used, with scope from cradle to gate, for the evaluation of seven WBC mixtures produced in the laboratory. The potential environmental impacts were related to the compressive strength of WBC (in MPa) as an eco-efficiency indicator. The main results showed that cement and the processing of wood bio-agreggates are responsible for the highest CO2 emissions. The replacement of cement by pozzolans resulted in a reduction in emissions, with emphasis on mixtures produced with blast furnace slag that presented greater or similar mechanical resistance compared to the reference, with lesser environmental impacts.
... Notwithstanding open methodological discussion, recent studies increasingly highlight the importance of moving away from currently dominating, conventional and often fossil-fuel intensive construction material choices towards a more environmental friendly "material diet" for buildings, heavily based on low-carbon, bio-based materials [13,14]. Much of the attention around bio-based materials focused on (mass) timber for building construction [15], interest increases in the use of fast-growing, bio-based materials -such as, for example, straw [8, [16][17][18], hemp [19,20] or bamboo [21,22] -due to their potentials in terms of biogenic carbon xation as well as availability as agricultural side-products supporting ambitions of a circular bioeconomy [11,14,23]. Another strategy considered for reducing both operational and embodied impacts is the reduction of complexity and use technical systems in buildings, towards a more architectural design-led, low-tech approach. ...
... An important note to add is that the scienti c literature further suggests that the use of bio-based materials in building envelopes (such as hempcrete or straw) can result in less energy consumption for air-conditioning because of their excellent thermal and moisture buffering capacity [20,43] 3. ...
In order to achieve the necessary reduction of greenhouse gas (GHG) emissions and decarbonization of building construction and operation, both high- and low-tech building design strategies are promoted. Amongst particularly promising strategies are the deployment of energy efficiency measures, for reducing operational energy use and related impacts, as well as the application of low-carbon, bio-based construction materials, for reducing embodied impacts.
In part two of our study on the life cycle assessment (LCA) of regenerative design strategies, LCA is applied to investigate the environmental impacts and reduction potentials of strategies at building level by analyzing two low-tech, passive building concepts – the be2226 building and the N11 SolarHouse – in both their original designs as well as optimized alternatives applying bio-based material solutions.
The analysis includes three steps. In a first step the life cycle GHG emissions of the original buildings are assessed, revealing strengths and weaknesses on both operational and embodied GHG emissions. Environmental hotspots are identified across environmental indicators, life cycle stages and building elements. In a second step the case studies are remodeled with bio-based building element alternatives showing substantial embodied GHG emissions reduction potential compared to the original case studies. Finally, the results of all building variants are compared with climate targets for buildings revealing that the N11 building meets established climate targets already in its original version, and that a straw-based material optimization can even enable meeting more ambitious climate targets.
... Because of the carbon dioxide storage in the plant-based aggregate, hemp concrete has a normally positive balance in its climate change indicator [110,111]. Commercial binders, notably Portland cement, are the most hazardous binders [112]. Several research [111] agree on values of − 0.3 to − 1.0 kg CO 2 per kg of hemp concrete as a rough guideline. ...
... Commercial binders, notably Portland cement, are the most hazardous binders [112]. Several research [111] agree on values of − 0.3 to − 1.0 kg CO 2 per kg of hemp concrete as a rough guideline. With a density of 275 kg/m 3 , a 1 m 2 unrendered 30 cm thick hemp-lime formulation sequesters 82.7 kg of CO 2 . ...
A simple mixture of hemp hurd, water, and lime is used to make hemp concrete. It is indeed one of the few materials that can continue to absorb carbon after being employed in construction, storing more carbon in the atmosphere over the building's lifetime than was emitted during construction. Furthermore, hemp can be harvested in as little as 60 days. Hemp concrete is a “carbon-negative” or “better-than-zero-carbon” substance because the hemp plant absorbs more carbon from the atmosphere than it emits during its production and application on site. It is a bio-composite material that can be utilised as an alternative to concrete and standard insulation in building. Hemp concrete is also recyclable at the end of the building's lifespan. This study summarises the fast-developing body of knowledge about hemp concrete, which was recently developed.
... HC has good thermal and acoustic insulation properties and can passively regulate humidity in a built environment [53]. The thermal properties and behavior of an HC wall were found experimentally to be virtually identical to those of a commonly used lightweight concrete insulation material with a similar density [54]. Thanks to the CO 2 uptake associated with hemp plant photosynthesis and the negative GHG emissions from its manufacture and installation, HC is carbon negative [55]. ...
The embodied carbon of building materials is a significant contributor to greenhouse gas (GHG) emissions. Hemp is widely acknowledged as the most used vegetal insulation in building and construction due to its comparable thermal properties and better environmental performance than that of mainstream insulation materials (MIMs). However, the application of hemp insulation materials (HIMs) in Canada is still in its infancy. Canada is currently the largest hemp oil and seed producer in the world. Most recent research on hemp in Canada has focused on the impact of legalising marijuana and the popularisation of hemp health products and cannabidiol (CBD). There is a lack of studies addressing the holistic impact of hemp in reducing emissions in Canadian residential buildings. This paper exams the feasibility of large-scale hemp cultivation in Canada and the suitability of HIMs for Canadian private dwellings. Material flow analysis (MFA) and life cycle assessment (LCA) were applied to evaluate different levels of carbon mitigation over time produced by HIM substitution. The results show that Canada has sufficient farmland and perfect geographic location and weather to implement large-scale hemp cultivation. HIM substitution can be accomplished for 81% of Canadian residential buildings. Full HIM substitution fulfilled through 5% hemp fibre insulation (HF) and 95% hempcrete (HC) will mitigate 101% of the GHG emissions caused by existing MIMs and contribute up to a 7.38% reduction in emissions to achieve the net zero emissions target by 2050.
... Among these bio-sourced materials, hemp composite has recently gained much attention due to its hygrothermal properties. Hemp clay is an eco-friendly building material that is made from fibers, shives, or hurds of the hemp plant, along with lime and water [19]. It is known to be a lot lighter, easier to use, and more durable than conventional concrete material. ...
Hemp-based building envelopes have gained significant popularity in developed countries, and now the trend of constructing houses with hemp-clay blocks is spreading to developing countries like Morocco. Investigating the hygrothermal behavior of such structures under actual climate conditions is essential for advancing and promoting this sustainable practice. This paper presents an in-depth experimental characterization of a commercial hemp-clay brick that has been exposed to the outdoor environment for four years, in addition to field measurements on a building scale demonstration prototype. Additionally, the study simulates 17 representative cities to assess the hygrothermal performance and energy-saving potential in each of Morocco's six existing climate zones, using the EnergyPlus engine. The experimental campaign's findings demonstrate excellent indoor air temperature and relative humidity regulation within the hemp-clay wall building, leading to satisfactory levels of thermal comfort within hemp-clay wall buildings. This is attributed to the material's good thermal conductivity and excellent moisture buffering capacity (found to be 0.31 W/mK and 2.25 g/m2%RH), respectively). The energy simulation findings also point to significant energy savings, with cooling and heating energy reductions ranging from 27.7% to 47.5% and 33.7% to 79.8%, respectively, as compared to traditional Moroccan buildings.
... Several studies in the literature focused on the development of green technologies using energyefficient materials (Limam et al., 2016;Ostad-Ali-Askari, 2022b;Ramesh et al., 2017). Among the plant-based materials used, there is hemp concrete studied by Florentin et al. (2017) which used lime as a binder, or the addition of natural fibers such as corn pith and barley fibers in a compressed earth composition (Palumbo et al., 2016). In developing countries, the utilization of these resources is an essential solution to the scourge of fossil fuel energy depletion (Ba et al., 2020a). ...
This paper deals with two major aspects. The first aspect is the design and characterization of cementitious materials based on Typha Australis. In the experiment first, cement is used as a binder. Secondly, stabilized clay with 25% of cement is used as a binder. The characterization of these composites shows that an addition of Typha Australis in the cementitious matrix improves the thermal properties. Typha Australis when added with a rate of 15% in the composite shows a decrease in the thermal conductivity from 0.8 (CT0100\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\mathrm{CT}}_{0}}^{100}$$\end{document}) to 0.1 W/mK (CT5545\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\mathrm{CT}}_{55}}^{45}$$\end{document}) (cementitious composite without clay) and it decreased from 12.06 (CAT0100\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\mathrm{CAT}}_{0}}^{100}$$\end{document}) to 0.15 W/mK (CAT5545\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\mathrm{CAT}}_{55}}^{45}$$\end{document}) (for the clay composite stabilized by cement). However, the incorporation of Typha Australis does not improve the mechanical properties. The incorporation of 0–50% Typha Australis in the cementitious matrix reduces compressive strength from 48.86 (CT0100\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\mathrm{CT}}_{0}}^{100}$$\end{document}) to 6.78 MPa (CT5545\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\mathrm{CT}}_{55}}^{45}$$\end{document}) and from 12.06 (CAT0100\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\mathrm{CAT}}_{0}}^{100}$$\end{document}) to 3.96 MPa (CAT5545\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\mathrm{CAT}}_{55}}^{45}$$\end{document}). Incorporation of the same proportions of Typha Australis also reduces tensile strength performance, which drops from 4 to 1.4 MPa and from 2 to 0.5 MPa. Typha Australis has a high tensile strength of up to 100 MPa with an elongation at break of 0.3%. The second aspect concerns the evaluation of the energy performance of the building using the Typha Australis material. This study is carried out with Transient Systems Simulation Program (TRNSYS) which is dynamic thermal simulation software. We carried out a comparative study with an existing conventional building. This classical building was taken as reference building. The materials were used in two configurations such as insulating panels and as load bearing walls according to the International Union of Testing and Research Laboratories for Materials and Structures (RILEM) classification. The results showed the insulating power and the reduction of energy consumption.
... Hempcrete stores more carbon than it creates during manufacturing, making it net carbon negative [31][32][33][34][35]. However, due to a lack of industry standardisation, hempcrete carbon storage levels vary as global hempcrete production differs in composition. ...
Bio-based alternatives for existing construction materials can be used to reduce the carbon footprint of the built environment. Hempcrete is one of these materials and is both an excellent hygric/thermal regulator and is carbon negative. However, this novel material is still incompletely researched, especially its fungal growth potential
specifically within warm and humid environments. The incorporation of significant biological material within hempcrete can enable it to act as a microbial growth medium, with the corresponding potential for the release of bioaerosols. The aim of this research was thus to investigate the overall practicality of hempcrete implementation in a humid climate. To achieve this, the endogenous fungal genera on a sample of hempcrete were identified, fungal propagules aerosolized from a hempcrete sample enumerated, and a range of temperatures tested to
determine their effect on fungi growth determined. Trials were performed to determine whether hempcrete can be effectively decontaminated with common materials to manage microbial growth. Under high humidity, fungal propagule emissions were high with low diversity, with potentially allergenic fungi detected. Disinfection of high fungal load hempcrete samples was able to reduce ~94% of the fungal observations and reduce aerosolized
counts to average background tropical fungal counts. The range of temperatures tested were not found to effect
fungal growth, contrary to the consensus of the literature. Overall, these properties make hempcrete suited to
humid areas, however, further research to investigate the potential effects of fungi on the material remains
lacking.
... Therefore, it is primarily used to construct non-load-bearing walls of timber-frame residential houses [37,96]. Despite the mechanical strength limitation, the use of hempcrete has rapidly spread over hundreds of low-and medium-rise buildings since the 1990s in a number of European countries, such as France, Great Britain, Germany and Italy [107,108], and lately is gaining popularity in Canada [89] and Australia [71]. ...
Sustainable construction should navigate the trade-offs between minimising pressure on scarce resources and the environment and maximising economic viability and human wellbeing through the whole building lifetime. In the pursuit of improving the environmental performance of the construction sector, there is growing interest in substituting conventional materials with bio-based materials. In the last decade, the use of industrial hemp (Cannabis sativa L.) as an aggregate for bio-based materials has attracted significant attention because of its ability to sequester carbon dioxide (CO2) during plant development, its fast-growing nature, the reduced level of agricultural input requirements and its good technical properties, which could potentially result in better sustainability performance across their life cycle. This review discusses the outcomes published in the scientific literature that have dealt with the use of hemp-based construction materials in the global and Australian construction sectors, with particular emphasis on the evaluation of their sustainability aspects (i.e., environmental, economic and social) throughout their lifetime. Relevant studies were identified from a structured keyword search in the Scopus database. The results found that research on hemp-based materials has mainly focused on assessing the environmental dimension, with an emphasis on greenhouse gas (GHG) emissions and little consideration for economic and social aspects. The existing literature showed a strong geographical bias towards Europe; thus, the outcomes of the life cycle studies conducted may not be representative of Australia. In that line, the development of a region specific of the life cycle sustainability approach is recommended to evaluate whether hemp-based construction materials can assist in achieving GHG targets in a sustainable manner in Australia.
... Segundo Florentin et al. (2017) é fundamental analisar os processos que afetam o consumo de energia e as emissões de GEEs ao longo do ciclo de vida de uma construção e isso inclui examinar o potencial de materiais alternativos. Onuaguluchi e Banthia (2016) complementam que, para melhorar a sustentabilidade no uso de materiais de construção, a indústria da construção civil deve adotar a reutilização de subprodutos industriais e materiais renováveis (MATOS; PICANÇO;FILHO, 2023, TRANNIN;PANCIERI, 2019, JÚNIOR;GOMES, 2020). ...
... Segundo Florentin et al. (2017) é fundamental analisar os processos que afetam o consumo de energia e as emissões de GEEs ao longo do ciclo de vida de uma construção e isso inclui examinar o potencial de materiais alternativos. Onuaguluchi e Banthia (2016) complementam que, para melhorar a sustentabilidade no uso de materiais de construção, a indústria da construção civil deve adotar a reutilização de subprodutos industriais e materiais renováveis (MATOS; PICANÇO;FILHO, 2023, TRANNIN;PANCIERI, 2019, JÚNIOR;GOMES, 2020). ...
... Segundo Florentin et al. (2017) é fundamental analisar os processos que afetam o consumo de energia e as emissões de GEEs ao longo do ciclo de vida de uma construção e isso inclui examinar o potencial de materiais alternativos. Onuaguluchi e Banthia (2016) complementam que, para melhorar a sustentabilidade no uso de materiais de construção, a indústria da construção civil deve adotar a reutilização de subprodutos industriais e materiais renováveis (MATOS; PICANÇO;FILHO, 2023, TRANNIN;PANCIERI, 2019, JÚNIOR;GOMES, 2020). ...
... Segundo Florentin et al. (2017) é fundamental analisar os processos que afetam o consumo de energia e as emissões de GEEs ao longo do ciclo de vida de uma construção e isso inclui examinar o potencial de materiais alternativos. Onuaguluchi e Banthia (2016) complementam que, para melhorar a sustentabilidade no uso de materiais de construção, a indústria da construção civil deve adotar a reutilização de subprodutos industriais e materiais renováveis (MATOS; PICANÇO;FILHO, 2023, TRANNIN;PANCIERI, 2019, JÚNIOR;GOMES, 2020). ...
... Segundo Florentin et al. (2017) é fundamental analisar os processos que afetam o consumo de energia e as emissões de GEEs ao longo do ciclo de vida de uma construção e isso inclui examinar o potencial de materiais alternativos. Onuaguluchi e Banthia (2016) complementam que, para melhorar a sustentabilidade no uso de materiais de construção, a indústria da construção civil deve adotar a reutilização de subprodutos industriais e materiais renováveis (MATOS; PICANÇO;FILHO, 2023, TRANNIN;PANCIERI, 2019, JÚNIOR;GOMES, 2020). ...
... Segundo Florentin et al. (2017) é fundamental analisar os processos que afetam o consumo de energia e as emissões de GEEs ao longo do ciclo de vida de uma construção e isso inclui examinar o potencial de materiais alternativos. Onuaguluchi e Banthia (2016) complementam que, para melhorar a sustentabilidade no uso de materiais de construção, a indústria da construção civil deve adotar a reutilização de subprodutos industriais e materiais renováveis (MATOS; PICANÇO;FILHO, 2023, TRANNIN;PANCIERI, 2019, JÚNIOR;GOMES, 2020). ...
... Segundo Florentin et al. (2017) é fundamental analisar os processos que afetam o consumo de energia e as emissões de GEEs ao longo do ciclo de vida de uma construção e isso inclui examinar o potencial de materiais alternativos. Onuaguluchi e Banthia (2016) complementam que, para melhorar a sustentabilidade no uso de materiais de construção, a indústria da construção civil deve adotar a reutilização de subprodutos industriais e materiais renováveis (MATOS; PICANÇO;FILHO, 2023, TRANNIN;PANCIERI, 2019, JÚNIOR;GOMES, 2020). ...
... Segundo Florentin et al. (2017) é fundamental analisar os processos que afetam o consumo de energia e as emissões de GEEs ao longo do ciclo de vida de uma construção e isso inclui examinar o potencial de materiais alternativos. Onuaguluchi e Banthia (2016) complementam que, para melhorar a sustentabilidade no uso de materiais de construção, a indústria da construção civil deve adotar a reutilização de subprodutos industriais e materiais renováveis (MATOS; PICANÇO;FILHO, 2023, TRANNIN;PANCIERI, 2019, JÚNIOR;GOMES, 2020). ...
... Another factor that attracted some farmers to the hemp plant is its potential uses. Farmers are fascinated by the fact that a single plant such as hemp can offer holistic medicinal [36][37][38][39][40], nutritional [41,42], cloth manufacturing [43][44][45][46], constructional [47][48][49], and environmental benefits [50]. Hemp has been shown to improve soil structure, water-holding capacity, and nutrient availability [51]. ...
The North Carolina hemp industry has fallen short of its projected success despite its potential economic benefits and opportunities for farmers. The floral hemp sector specifically has been struggling due to excessive production and decreasing prices. The objective of the research was to examine the experiences and obstacles faced by early adopters and stakeholders of the hemp industry in NC. Through structured focus group discussions and interviews, data were collected and analyzed to gain insight into the industry’s direction. The results revealed that many floral hemp farmers have abandoned the crop because of financial setbacks, leading to a reduced interest in cultivation compared to five years prior. The floral hemp industry’s rapid growth and decline have tempered farmers’ expectations of the crop’s potential. The findings will provide a foundation for further research into NC’s hemp production and economy, enabling the provision of necessary information and extension services for profitable hemp farming in the state.
... grey energy is accounted for is open to broad interpretation (Achenbach et al., 2016). Methods derived from this, such as life cycle energy assessment (LCEA) and life cycle carbon emissions assessment (LCCO2A), are specifications with focus on the corresponding aspects (Chau et al., 2015, Cabeza et al., 2014, Florentin et al., 2017. Using the LCA method, Environmental Product Declarations (EPDs) are defined according to DIN EN 15804:2014-07. ...
... HL blocks are insulating materials, nontoxic, recyclable and meet building safety codes, production process is net zero carbon. [81]. ...
Cities are under pressure to deal with a wide range of challenges such as environmental, social and economic challenges that together threaten the resilience of urban areas and the residents who live and work there. The investments in advancing urban infrastructures to deal with demographic and climate changes. Nature-based solutions (NBS) have been evolved as a promising strategy to address various potentials they can foster wellbeing for communities through making cities healthier and resource-efficient. This paper aims at reviewing NBS as a driver for sustainable urban planning aiming for enhancing the Circular Economy (CE), Social Cohesion (SC), and Ecological Networks (EN). A literature review will provide an overview of studies addressing NBS concepts and strategies for implementation. Finally, recommendations on the conceptualization for nature-based solutions will be synthesized, in addition to identifying requirements and considerations that need to be addressed at each stage of the planning, implementation and evaluation.
... In the first stage, CA, CCA, and BCA are conducted using VOSviewer to break down significant exploration groups or fields and review collective energies (Tetlow et al. 2017). In CA assumes that the frequency of citation mirrors the impact, notoriety, worth, or achievement of a source (Florentin et al. 2017;Pruvost and Scherer 2017). CCA and BCA refer to hypothetical inputs and associations. ...
This study aims to assess the performance of thermophysical materials in the construction and building industry to establish the necessary academic basis for the interpretation of trends, developments, and status in this research field. The Scopus database contains 159 papers on this topic, which were published between 1968 and 2021 and originated in 60 countries. The International Organization for Standardization published significant information on thermal insulating materials, mer-chandize, elements, and applications. Several forms of insulation currently exist: (i) solid-state foam insulation composed of fibers, grains, and matrix; (ii) liquid-state insulation that encloses humidity within the filling; and (iii) gasifier form, which incorporates air, steam, or alternative gases. To reduce the amount of energy demanded, thermal insulation materials must be extended, current solutions must be modified, and new materials must be developed. Because high-temperature thermal insulation materials have more complex working conditions than alternative materials, their application requires further consideration.
... A potential strategy to reduce the embodied impacts of buildings is to substitute conventional, fossil fuel-based construction materials with bio-based alternatives [1]. Nowadays it is possible to produce construction materials from biomass that achieve similar mechanical, thermal, acoustic etc. properties as conventional construction materials and, on top of it, that provide better environmental performance during their life cycle [18][19][20][21][22]. Some even enhance atmospheric carbon reduction through their potential of storing carbon in the construction product [23]. ...
The focus in reducing environmental impacts of buildings is shifting from the operational stage to the full life cycle, with particular attention to embodied greenhouse gas (GHG) emissions of construction materials. The application of bio-based construction materials is promoted for potentially reducing material-related embodied GHG and even enabling carbon fixation.
In part one of this study (1/2), we apply life cycle assessment (LCA) to critically examine regenerative design strategies, starting by investigating embodied GHG emissions as well as other environmental impact indicators of different bio-based building element variants – assessing timber-, straw- and hemp-based solutions – in a European context.
The results show that bio-based building elements tend to have considerably lower embodied GHG emissions than conventional solutions, e.g. brick or concrete-based elements. Analyzing the environmental hotspots across the life cycle of selected bio-based construction options, we identify their most contributing environmental indicators to be global warming potential (GWP), particulate matter (PM) and land use (LU); and the most important life cycle stages to be material production, maintenance and replacement, particularly of finishes. To investigate carbon removal potentials, we calculated biogenic carbon contents of selected bio-based options, identifying straw-based building elements as the most promising solution due to high biogenic carbon content and fast (yearly) re-growth cycles.
Our study highlights the environmental potentials of using bio-based construction solutions to substitute conventional building materials. In addition, the study identifies important environmental trade-offs within bio-based material alternatives that demand consideration and further study in future research.
... Therefore, in order to significantly reduce both operational and embedded energy and carbon emissions of building materials, for the same thermo-hygrometric performance, nature-based solutions should be preferred, whose life cycle assessment has shown drastically reduced net carbon emissions during the entire production process compared to a traditional building material. Embodied carbon coefficients (ECCs) are expressed in kg of CO 2 e (kgCO 2 e) per kg of material (kgm), where CO 2 e represents the carbon dioxide equivalent of greenhouse gases (GHG) produced for the production and transport of these materials (Florentin et al., 2017). ...
The goal of optimizing material resources and the polyvalent use of space lead to the development of new technologies within a renewed architectural spatiality, which from the point of view of effectiveness of choices allow for low-carbon buildings. The climate emergency, in fact, asks us today to reinterpret Vitruvius’ concept of Firmitas according to the criteria of durability reliability and resilience associated with widespread usability functionality and circularity (Utilitas) traceable throughout the life cycle a building. The paper illustrates the results of a scientific research project that led to the construction of a prototype of a “minimal” residence, designed and built with the “total low” approach, characterized by regenerative design, economy, lightness, ease of assembly, recyclability, as well as excellent overall performance and high levels of comfort. The idea of a building, easily assembled and disassembled, is a strength of the “Petite-Cabane” design concept: a 3x3 m single-user minimum residential unit made with the Light Gauge Steel Building System (LGS) produced with controlled automatically roll forming machine, for which high technological and energy performance envelope packages. The design of a small house becomes the “mise en forme” of a space in which “essential” equipment, energy performance, architectural qualities, economic and environmental costs are linked to the ease and immediacy of construction but also to the flexibility and circularity of technological choices.
... Therefore, in order to significantly reduce both operational and embedded energy and carbon emissions of building materials, for the same thermo-hygrometric performance, nature-based solutions should be preferred, whose life cycle assessment has shown drastically reduced net carbon emissions during the entire production process compared to a traditional building material. Embodied carbon coefficients (ECCs) are expressed in kg of CO 2 e (kgCO 2 e) per kg of material (kgm), where CO 2 e represents the carbon dioxide equivalent of greenhouse gases (GHG) produced for the production and transport of these materials (Florentin et al., 2017). ...
La Petite Cabane: the flexible and circular technological structure VITRUVIO 7 | 2 (2022) International Journal of Architecture Technology and Sustainability Abstract: The goal of optimizing material resources and the polyvalent use of space lead to the development of new technologies within a renewed architectural spatiality, which from the point of view of effectiveness of choices allow for low-carbon buildings. The climate emergency, in fact, asks us today to reinterpret Vitruvius' concept of Firmitas according to the criteria of durability reliability and resilience associated with widespread usability functionality and circularity (Utilitas) traceable throughout the life cycle a building. The paper illustrates the results of a scientific research project that led to the construction of a prototype of a "minimal" residence, designed and built with the "total low" approach, characterized by regenerative design, economy, lightness, ease of assembly, recyclability, as well as excellent overall performance and high levels of comfort. The idea of a building, easily assembled and disassembled, is a strength of the "Petite-Cabane" design concept: a 3x3 m single-user minimum residential unit made with the Light Gauge Steel Building System (LGS) produced with controlled automatically roll forming machine, for which high technological and energy performance envelope packages. The design of a small house becomes the "mise en forme" of a space in which "essential" equipment, energy performance, architectural qualities, economic and environmental costs are linked to the ease and immediacy of construction but also to the flexibility and circularity of technological choices.
... A potential strategy to reduce the embodied impacts of buildings is to substitute conventional, fossil fuelbased construction materials with bio-based alternatives [1]. Nowadays it is possible to produce construction materials from biomass that achieve similar mechanical, thermal, acoustic etc. properties as conventional construction materials and, on top of it, that provide better environmental performance during their life cycle [18][19][20][21][22]. Some even enhance atmospheric carbon reduction through their potential of storing carbon in the construction product [23]. ...
The focus in reducing environmental impacts of buildings is shifting from the operational stage to the full life cycle, with particular attention to embodied greenhouse gas (GHG) emissions of construction materials. The application of bio-based construction materials is promoted for potentially reducing material-related embodied GHG and even enabling carbon fixation.
In part one of this study (1/2), we apply life cycle assessment (LCA) to critically examine regenerative design strategies, starting by investigating embodied GHG emissions as well as other environmental impact indicators of different bio-based building element variants – assessing timber-, straw- and hemp-based solutions - in a European context.
The results show that bio-based building elements tend to have considerably lower embodied GHG emissions than conventional solutions, e.g., brick or concrete-based elements. Analyzing the environmental hotspots across the life cycle of selected bio-based construction options, we identify their most contributing environmental indicators to be global warming potential (GWP), particulate matter (PM) and land use (LU); and the most important life cycle stages to be material production, maintenance and replacement, particularly of finishes. To investigate carbon removal potentials, we calculated biogenic carbon contents of selected bio-based options, identifying straw-based building elements as the most promising solution due to high biogenic carbon content and fast (yearly) re-growth cycles.
Our study highlights the environmental potentials of using bio-based construction solutions to substitute conventional building materials. In addition, the study identifies important environmental trade-offs within bio-based material alternatives that demand consideration and further study in future research.
... In this design science experimental research, we analyzed the TESH bricks on these particular indicators under the ecosystem quality category ( Table 6). The results of the assessment indicate that TESH bricks have much lower values relative to conventional burnt clay-fired bricks, suggesting that TESH bricks do not pose a threat to aquatic (Hammond and Jones 2008) 4.30 MJ=kg Solid clay-fired bricks (Reddy and Jagadish 2003) 4.25 MJ=kg Solid clay-fired bricks (Kua and Kamath 2014) 2.89 MJ=kg Fly ash blocks (Ramesh et al. 2012) 1.34 MJ=kg AAC blocks (Florentin et al. 2017) 4.0 MJ=kg and terrestrial ecosystems because of the choice of their development materials and the methodology used. ...
The consumption of natural resources by the construction industry has increased in an unprecedented manner, which has been coupled with a consequential trail of immense environmental impacts due to unsustainable practices. This study was undertaken to develop a sustainable brick from a combination of waste glass and oil palm industry waste. The focus of this study was to provide a sustainable brick that contributes to minimal environmental impact and better insulation capability to enhance thermal comfort levels. The developed bricks showed an acceptable strength of 7.21 MPa, which complies with the standard criteria for non-load bearing bricks. Additionally, thermal conductivity was found to be approximately 0.38 W=m 2 K, an improvement of almost 50% compared with common red clay brick. In addition, the numerically obtained conjugate heat transfer analysis of the thermally efficient sustainable hybrid (TESH) brick revealed that thermal resistance offered by TESH brick is approximately four times that of fired clay brick. This research also analyzed the embodied energy consumption and environmental impact assessment of TESH bricks. The results pointed to the sustainability aspect of the developed TESH bricks having positive impacts relative to commercially available red clay bricks.
... Based on literatures, the emissions of OPC and NaOH are 840 kg CO 2 /ton and 1200 kg CO 2 /ton, respectively (Alsalman et al., 2021;Guo et al., 2017). The unit emission of CH is 1170 kg CO 2 per ton, considering 750 kg CO 2 per ton as process emission and 420 kg CO 2 per ton as fossil fuel and other possible emissions (Florentin et al., 2017). Also, the costs of OPC, CH and NaOH as industrial products are much higher, whereas CGFA is regarded as a waste material with no cost, since the recycling of CGFA will cut the cost which are present during the dumping and landfill (Xiao et al., 2021c). ...
This study explored the feasibility of utilizing lowly-reactive coal gasification fly ash (CGFA) for stabilizing road aggregate bases. Three types of aggregate stabilizers including the ordinary Portland cement (OPC)-CGFA, hydrated lime (CH)-CGFA and alkali-activated CH-CGFA were evaluated based on the performances of compacted base specimens. It was found that the OPC-CGFA stabilized bases showed better mechanical and durability properties while the CH-CGFA samples had low water stability and freeze-thaw durability due to the dissolution of unreacted CH. However, the reaction degree of CGFA associated with the performances of CH-CGFA stabilization could be considerably enhanced by the alkali-activation. The sustainability and economic feasibility analyses showed the use of CGFA could significantly reduce the CO2 emissions and costs, highlighting the synergy between the recycling of CGFA and the construction of sustainable road bases. A framework of selecting CGFA-based stabilizers for road bases was proposed considering the performance ratings of the material properties.
... Indeed, researches, showed that bio-based concretes are highly suitable for building applications since they exhibit an excellent thermal performance and enable moisture management by adsorbing and desorbing water vapor [8,9]. Moreover, they allow to design a carbon negative building material due to carbon sequestration, thanks to the absorption of CO 2 present in the atmosphere through photosynthesis during the plant's growing stage, and to the absorption of high quantities of CO 2 during the carbonation of lime (curing process) [10][11][12]. In fact, according to Boutin et al. [13] and Ip and Miller [14], hemp concretes enables to store approximately 0.35-0.36 ...
In order to reduce the consumption of energy and the emissions of greenhouse gases and CO2 generated by the construction industry, bio-based concretes made of plant aggregates are increasingly used in the optimization of building envelopes, thanks to their good hygrothermal performances, their renewable origin, and biodegradability. The present study focuses on the effect of combining different proportions of rice straw (RS) with rice husks (RH) on mechanical and hygric, and thermal properties of straw/husk concrete. The experimental investigation seeks to evaluate the thermal conductivity, moisture buffer value (MBV) and mechanical compressive properties of these concretes. The results evidences clearly that it is interesting to associate these two residues. The thermal conductivity of the bio-based concretes slightly decreases with increasing rice straw content and rises almost linearly with concretes density. The MBV measurements reveal that rice straw confers to concretes an excellent moisture buffering capacity. Finally, the compression test results highlight that the addition of rice straw induces high deformability and enables concretes to store a high quantity of energy.
Graphical Abstract
... Additionally, the minimal number of operations necessary to manufacture the wall (electricity is required to combine hemp and lime) affected the outcomes favorably. Gradual carbon sequestration by lime carbonation after construction, as seen in previous studies, might further enhance the carbon balance, and this could be the subject of future study [41,42]. ...
It is widely established that the building industry has a negative impact on the environment and a significant influence on the phenomena that contribute to climate change. Traditional construction materials, such as cement, contribute considerably to environmental pollution. Given the enormous quantity of energy and materials used by the construction sector, this industry must adopt more sustainable practices. Nowadays, an increasing number of natural building materials are used in the structural component or the insulation of buildings. As a result, natural construction materials may be a superior alternative to accomplish this goal. This article discusses the features and applications of hempcrete in the building industry. Hempcrete is a sustainable material composed of industrial hemp, lime as a binder, and water. Due to hemp’s porous structure, it has deformation capacity, sound-absorbing qualities, better hygrothermal properties than conventional concrete, and, depending on the proportions of hemp, lime, and water, fire resistant capabilities due to the presence of lime.
... Binders (which range from clays to lime) serve to aggregate the hemp hurd and play an integral role in enhancing its strength, durability, hydroscopicity, pyrolysis threshold, resistance to insect damage, and acoustical and thermal performance. (Arizzi et al. 2015;Florentin et al. 2017;Jami et al. 2018). Hemp can absorb most of the water existing in the binder matrix. ...
After a decades-long legal hiatus, hemp (Cannabis sativa L.) has begun to experience a renaissance as a plant for all reasons. Although much hyperbole has been given to hemp’s potential to “save the world,” the crop has historical precedent as a source of fibers, feed/food, fuel, biomolecules, and more. The crop’s numerous potential uses and unique characteristics could help support the transition of our current linear consumer economies into more circular economies that allow for greater recycling or upcycling of products and lower carbon footprints. This chapter reviews a number of the current and potential uses for hemp and some of the challenges that may be faced on the path to making hemp a vital component of sustainable societies.
... In order to prove the presence of an environmental advantage, the wall of agro-concrete blocks was compared to the usual building practice, specifically a traditional wall of common performed bricks covered with insulation coating of fiberglass along with expanded polystyrene (EPS) (Florentin et al., 2017;Pretot et al., 2014). A further comparative analysis was performed between the wall of agro-concrete blocks and a wall composed by a single casting of the same mixture of wheat husk and lime-based binder, called bio-composite mixture. ...
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.
... Moreover, according to the study [13], the heat flux fluctuation decreases with increasing PCM thickness and latent heat. Bio-based concrete has also attracted attention in recent years, as its raw material comes from nature, thus lowering the cost of application [14] and reducing carbon emissions [15]. Furthermore, bio-based concrete is a lightweight thermal insulation material that contributes to indoor thermal comfort and energy efficiency [16]. ...
Phase change materials (PCMs) can improve indoor thermal comfort and reduce energy consumption, while bio-based concrete is an environment-friendly material that enables indoor humidity regulation and heat insulation. However, only a few studies have explored the integrated application of the two materials and comprehensively analyzed the energy and hygrothermal performance. In this study, a passive envelope solution that integrates PCM and hemp concrete is proposed to improve buildings' energy, thermal, and hygric performances simultaneously. Four integrated scenarios were considered and compared with a baseline scenario (hemp concrete only). The performance of the integrated envelope was studied numerically based on the impact of the PCM's properties and its location in the envelope. The results highlight the indispensable role moisture transfer plays in determining the indoor hygric environment and heat load, as well as the valuable effect of the integrated envelope on improving both energy and hygrothermal performance. Scenario 4/5 (with PCM closest to the interior) in the summer showed the greatest performance improvement compared to the baseline scenario, with reductions of 8.2%, 46.3%, and 43.7% for heat load, temperature fluctuation, and partial water vapor pressure fluctuation, respectively. The impact of the PCM properties in scenario 4/5 illustrate that the optimization of the integrated envelope can be achieved by increasing the thickness and latent heat of the PCM and identifying its appropriate phase transition range. From a year-round perspective, scenario 4/5 is also notable, as it shows great potential for saving energy and adapting to climate humidity variation while guaranteeing moisture equilibrium within the hemp concrete. The three-year assessment confirmed a lack of condensation and no risk of mold growth for such an integrated envelope, as the relative humidity in key locations remains below 75%.
Aerogel is a high-performance thermal resistance material desired for high-temperature applications like dye-sensitized solar cells, batteries, and fuel cells. To increase the energy efficiency of batteries, an aerogel is required to reduce the energy loss arising from the exothermal reaction. This paper synthesized a different composition of inorganic-organic hybrid material by growing the silica aerogel inside a polyacrylamide (PAAm) hydrogel. The hybrid PaaS/silica aerogel was synthesized using different irradiation doses of gamma rays (10-60 kGy) and different solid contents of PAAm (6.25, 9.37, 12.5, and 30 wt %). Here, PAAm is used as an aerogel formation template and carbon precursor after the carbonization process at a temperature of (150, 350, and 1100 °C). The hybrid PAAm/silica aerogel was converted into aluminum/silicate aerogels after soaking in a solution of AlCl3. Then, the carbonization process takes place at a temperature of (150, 350, and 1100 °C) for 2 h to provide C/Al/Si aerogels with a density of around 0.18-0.040 gm/cm3 and porosity of 84-95%. The hybrid C/Al/Si aerogels presented interconnected networks of porous structures with different pore sizes depending on the carbon and PAAm contents. The sample with a solid content of 30% PAAm in the C/Al/Si aerogel was composed of interconnected fibrils whose diameter was about 50 μm. The structure after carbonization at 350 and 1100 °C was a condensed opening porous 3D network structure. This sample gives the optimum thermal resistance and a very low thermal conductivity of 0.073 (w/m·k) at low carbon content (2.71% at temperature 1100 °C) and high vpore (95%) compared with carbon content 42.38% and vpore (93%) which give 0.102 (w/m·k). This is because at 1100 °C, the carbon atoms evolve to leave an area between Al/Si aerogel particles, increasing the pore size. Furthermore, the Al/Si aerogel had excellent removal ability for various oil samples.
Lightweight concrete (LWC) panels are becoming popular in buildings because of being lightweight, which allows easy transportation, handling, and installation. They provide the opportunity for modular construction. They also have insulating properties with thermal conductivity of 0.026-1.0 W/m-K. However, they have low thermal mass, which causes overheating during the heatwave period in Mediterranean and temperate climates. Therefore, Phase Change Materials (PCM) are integrated into LWC panels to increase thermal storage, mitigate overheating, and increase energy efficiency. However, the integration of PCM in LWC panels also increases their thermal conductivity, which is not favorable for a sustainable building. There is a need to reduce the thermal conductivity of PCM-integrated LWC panels. Thus, this study aimed to develop new lightweight heat-resistive and thermal storage panels (HRSPs) using porous fillers and PCM for energy-efficient building applications.
First, the optimum PCM melting point for cool temperate climates of Melbourne was identified through parametric analysis considering a typical Victorian house as a case study. The result showed that the optimum PCM melting point for free-running and air-conditioned houses is 30°C and 25°C, respectively. Based on these findings, capric acid (CA) PCM with a 29-32°C melting point was selected. The integration of PCM in cementitious composites may suffer from leakage issues during mixing with cement and other aggregates. The leaked PCM, such as fatty acids, may acidify concrete and reduce its compressive strength. The traditional leakage test proposed by previous researchers was insufficient to identify the microscopic leakage of PCM and its potential acid attack on concrete. Moreover, the conventional Form Stable PCM (FSPCM) synthesis procedures are energy-intensive, increasing the embodied energy of FSPCM. This study proposed a new FSPCM synthesis procedure to reduce energy use, eliminate acid attacks and increase PCM absorption capacity in porous material for energy-efficient buildings. The proposed method was energy-efficient, with CA absorption of 75% in porous hydrophobic expanded perlite (HEP). However, due to acid attack, the compressive strength and thermal conductivity at 75% CA absorption were lower than one with 60% CA.
Hence, the absorption of PCM should not be the only criterion for developing FSPCM. More indicators should be considered to develop an optimum FSPCM.
This study proposed six indicators, including absorption, thermal conductivity, strength, thermal inertia, latent heat storage, and thermal storage, to select the best porous materials to absorb PCM. American Society for Testing and Materials (ASTM) standards were adopted to measure proposed indicators. A comparative study was conducted to select the best porous materials amongst Silica Aerogel Granules (SAG), Hydrophobic Expanded Perlite (HEP), Nano-clay (NC), Recycled Expanded Glass (REG), and Silica Fume (SF) to absorb CA and develop FSPCM. In this study, the FSPCM-integrated concrete panels were named thermal energy storage panels (TESP). The comparative analysis revealed that SAG-based TESP was meeting all five indicators accept compressive strength (3.66 MPa), which was lower than the
minimum compressive strength (4.14 MPa) criteria for non-structural applications. However, HEP-based TESP had acceptable compressive strength and thermal conductivity with the second-best thermal inertia and heat storage, making it a suitable porous material for absorbing polar PCM for buildings. However, the thermal conductivity of TESPs was still higher than LWC because of the higher thermal conductivity of PCM and concrete, although the TESPs have higher thermal storage. Thus, there is a need to develop a TESP with high latent heat storage, low thermal conductivity, and acceptable mechanical properties.
To reduce the thermal conductivity of TESP, sand was volumetrically replaced with SAG to prepare Heat Resistive and Storage Panels (HRSP) using the proposed particle-density-based approach. The developed SAG-based HRSP had lower thermal conductivity than TESP with similar thermal storage. Although HRSP had higher thermal conductivity than SAG-based LWC, it resulted in higher energy savings (9%), emission (24%), and comfort than SAG-based LWC because of higher thermal inertia and storage. Moreover, the HRSPs had lower embodied energy and carbon than SAG-based LWC. However, the SAG-based HRSP still had higher embodied energy than normal concrete panels. Consequently, the SAG was replaced entirely with REG particles to develop eco-friendly HRSP for buildings. Results revealed that REG based HRSP had 27% lower thermal storage then SAG-based HRSP due to high thermal conductivity and slightly lower latent heat storage. The compressive strength of REG-based HRSP (17.77 MPa) was very close to the minimum compressive strength for the structural application of concrete. Applying REG-based HRSP in a building envelope had slightly higher discomfort hours than SAG-based HRSP, and it also reduced annual energy use and CO2 emission by 8.24% and 20% lower than SAG-based HRSP in a typical Victorian house, respectively.
In conclusion, the REG-based HRSP was the best eco-friendly material for buildings with acceptable structural properties and moderate energy savings potential. However, the SAG based HRSP was the most energy-efficient material with acceptable mechanical and thermal properties of the non-load-bearing structure.
The growing attention to sustainability and life cycle issues by European and international policies has recently encouraged the adoption, in the construction sector, of environmental labels able to quantify the impacts on environment associated with the fabrication of several building materials, e.g., their embodied energy and carbon. Within this framework, since walls represent a large percentage of building mass and therefore of embodied impacts, this article collects and analyzes nearly 180 Environmental Products Declarations (EPDs) of wall construction products such as masonry blocks and concrete panels. The data related to the primary energy (renewable and non-renewable) and the global warming potential extracted from the EPDs were compared firstly at the block level (choosing 1 kg as functional unit), enabling designers and manufacturers to understand and reduce the impacts from wall products at the early design stage. As the design progresses, it is therefore necessary to evaluate the environmental impacts related to the entire wall system. For this purpose, this paper proposes a further investigation on some simple wall options having similar thermal performance and superficial mass (the functional unit chosen in this case was equal to 1 m2 with R ≈ 5 m2K/W, Ms ≈ 260 kg/m2). The outcomes showed how the durability of the materials and the potential of disassembly of the wall stratigraphies can play a crucial role in reducing the environmental impact. This paper provides a methodological reference both for manufacturers to reduce impacts and for designers committed to the application of environmental labeling in the design process since they will now be able to compare their products with others.
Kenevir ilaç ve sanayi
Since the mid-1990s, the French public authorities have changed regulations to allow commercial building conversions into housing. The COVID-19 crisis has affected the global economy, social connections, environmental trajectories and energy demand/supply. Countries have been considering measures to reduce the pandemic’s long-term impact and since the beginning of 2020, national governments have recommended that companies facilitate remote work. Thus, COVID-19 has prompted some office building depopulation. With working from home expected to continue after the pandemic, due to technological, environmental and economic considerations, there is a growing impetus to convert empty office space into residential uses. The present research aims, through the Parisian case study, to consider the impacts of the pandemic and the acceleration of homeworking. Using a mixed qualitative and quantitative methodology, the study aims to (1) critically analyse the policy tools implemented by the Paris municipality following the COVID-19 pandemic to accelerate commercial building conversions and (2) evaluate the potential for such conversions, considering former policies. We found that adaptive reuse policies have been implemented following the beginning of the COVID-19 crisis. However, according to the collected data, conversion potential is limited, due to the continuing demand for office space despite the changes and economic considerations.
Increasing urbanization has made lightweight construction materials with low thermal conductivity important. One of these materials, which has gained importance recently, is bio-composite materials consisting of agricultural wastes. The usability of camelina stalks, an agricultural waste, in the production of bio-composite has not been studied. The aim of this research is to develop new lightweight bio-composites with camelina stalks filled. For this, 11 composite mixtures using unsaturated polyester resin as the binder were created. Camelina stalks at 25, 30, 35, 40 and 45 % substitution ratios were used in half of 10 mixtures outside reference. Later, five more different mixtures by adding expanded perlite (EP) up to 5 % of the amount of camelina stalks in each mixture were produced. The physical, mechanical and thermal properties of the bio-composites produced with polyester binder were examined and the microstructure analysis was performed by SEM. The results showed that thermal conductivity, unit weight, compressive strength and ultrasonic pulse velocity (UPV) decreased as the ratio of the camelina stalks increased. The lowest thermal conductivity value was determined as 0.0842 W/(mK) in the 45 % camelina + 5 % EP filled specimen. The highest compressive strength value of the mixtures excluding the reference specimen was found to be 35.78 MPa in the 25 % camelina + 5 % EP-filled specimen. The addition of EP to the composites increased the water absorption, UPV and compressive strengths, but decreased the thermal conductivity. The results showed that camelina stalks can be used to produce sustainable bio-composites.
In this study, the thermal, energy, economic, and environmental perspectives of a smart Cannabis plantation are investigated. A commercial R-32 air conditioning at a cooling capacity of 12,300 BTU/h is implemented for the 5-lighting sets. One 300 We-violet-light-emitting diode (LED) and two 100 We-daylight-LEDs are designed for one lighting set at a photosynthetic photon flux density of 100 µmol/m²⋅s. A smart watering system is designed to automatically control a watering period of 62 hours, an operating time of 40 minutes, and a watering rate of 41.5 L/time. The smart Cannabis plantation can produce a fresh inflorescence of 250 g and a dried inflorescence of 46.3 gdy, respectively. A power consumption of 126.9 kWh/plant is mainly driven the environmental impacts of a climate change of 6.22E+02 kg CO2 eq/kgdy. The economic result of a levelized cost is approximately 262.85 USD/kgdy.
Energy use in the building is responsible for one-third of total carbon dioxide (CO2) emissions globally. Nearly half of the energy loss occurs through the building envelope due to heat transfer to/for the surroundings. Therefore, there is a need to design an optimum building envelope to reduce energy use in buildings that depend on several parameters. This study aims to review different building parameters and provide a conceptual framework to optimize the building envelope. In total, 260 papers were reviewed, and the building envelope design consideration was categorized into: 1) Design Parameters (design and geometry), 2) environmental conditions (indoor and outdoor) and 3) performance criteria (energy, environment, economic, comfort). Energy use and CO2-emission in buildings increase with high thermal conductivity, low thermal mass, and low solar absorption of its envelope. Geometrically, building orientation impacts energy use more than the building shape factor. Changing set point temperature according to surrounding conditions has reduced energy use and CO2-emission by 30% and 56%, respectively. However, indoor air quality, velocity, and occupancy have meagerly affected building energy use. Energy and emission optimization criteria are directly related, but the emission-based optimized envelope is thicker than the energy one. Other criteria such as economy and comfort (thermal and visual) are inversely proportional to the energy-efficient building envelope. Based on the comprehensive review, this study proposed a conceptual framework to design a sustainable building envelope that includes life cycle assessment, occupant's satisfaction, and social benefits. Several future research recommendations were made, including 1) the use of switchable reflective materials to minimize heat transfer, 2) dynamic insulation material to control insulation value as needed, and 3) smart windows with tunable optical properties.
In recent years there has been renewed interest in innovative solutions for coating mortars. Previous research has clarified the importance of substituting a percentage of cement by other binders, and thus focused on a good balance between structural and thermal properties. However, the effect on the economic cost and the carbon footprint is yet to be fully understood. In this context, the present aimed at investigating the role of hydraulic lime as a partial substitute for cement and expanded perlite in the structural and thermal properties of mortars, while considering the economic cost and the carbon footprint as fundamental variables. We employed a combination of laboratory tests and theoretical calculations to clarify the optimal balance between all considered variables. The findings showed that thermal conductivity can be reduced up to 87.25% and density up to 78.94% if compared with a standard mortar; on the contrary, mechanical properties are compromised yet sufficient for rendering purposes. The final product is affordable, and its carbon footprint is remarkably lower than other alternatives. We concluded that these mortars can deliver optimal properties for rendering purposes, except for the mechanical resistance, which demands further research. In turn, our findings provide evidence for devising feasible options to maintain or repair buildings on a constrained budget, as in the case of social dwellings.
Purpose
Residential buildings play an important role in consumption of energy resources. About 40% of all primary energy is used in buildings all over the world. This paper is the second part of the study on the life cycle energy (LCEA), emissions (LCCO2A) and cost (LCCA) assessment of two residential buildings constructed in urban and rural areas.
Methods
In the first part, the methodology, formulations and procedure for such a comprehensive analysis are provided while this paper provides an application of the methodology that considers two actual buildings located in Gaziantep, Turkey. The proposed model focused on building construction, operation and demolition phases to estimate energy use, carbon emissions and costs per square meter over a 50 year lifespan. The optimum thickness of insulation used to reduce energy consumption and emissions per square meter is determined.
Results
It is found that the operating phase is dominant in both urban and rural residential buildings and contributes 87-85% of the primary energy requirements and 88-82% of CO2 emissions respectively. Life-cycle greenhouse gas emissions were 5.8 and 3.9 tons CO2 eqv. for BT1 and BT2 respectively. It is calculated that the life cycle energy consumption and CO2 emissions of the residential buildings can be reduced by up to 22.8% and 23.4% respectively by using a proper insulation material for the external walls. The life cycle cost, consisting of mortgage, energy, maintenance, service and demolition payments are calculated to be 7.28 and 1.72 million USD for BT1 and BT2, respectively.
Conclusions
Building envelope developments, such as better wall insulation provide noteworthy potential energy savings and contribute to the reductions from cooling and space heating. Therefore, primary strategies and technologies needed for efficient buildings include optimal insulation of external walls. The economic insulation thickness of the residential buildings in Gaziantep is determined to be 80 mm by using a life-cycle cost analysis. The results show that, because of the differences in building structures and living standards, life cycle energy intensity and CO2 emissions in urban residential buildings are 29% and 25% higher than in rural conditions.
Keywords: Life-cycle energy analysis, greenhouse gas emissions, life-cycle cost analysis, residential buildings.
Purpose
Buildings are responsible for more than 40% of global energy used, and as much as 30% of global greenhouse gas emissions. In order to quantify the energy and material inputs and environmental releases associated with each stage of construction sector, life cycle energy, greenhouse gas emissions, and cost analysis of contemporary residential buildings have been conducted within two parts.
Methods
This paper is the first part of the study which includes the literature review and methodology used for such a comprehensive analysis. It was determined that there are three basic methods used in life cycle analysis: process analysis, input-output (I–O) analysis and hybrid analysis. In this study, Inventory of Carbon and Energy (ICE) is used for the calculation of primary energy requirements and greenhouse gas emissions. The second part of this study is about the application of the methodology which considers two actual buildings constructed in Gaziantep, Turkey.
Results
The proposed research focused on building construction, operating and demolition phases. Energy efficiency, emission parameters and costs are defined for the building per square meter basis. It is seen that the primary energy use and emissions of residential buildings around the world falls in the range of about 10 to 40 GJ/m2 and 1-10 tons CO2/m2 respectively.
Conclusions
The literature survey demonstraties that there are limited number of studies about LCCA of residential buildings in the world. It was decided to use ICE database as it is one of the most comprehensive databases for building materials, globally. The results of the study show that minimizing energy, material and land use by considering potential impacts to the environment on a life cycle basis are the basic steps in designing an energy efficient and environmental friendly building.
Keywords: Life-cycle energy analysis, greenhouse gas emissions, life-cycle cost analysis, residential buildings.
The Israeli standard 5282 for energy rating of buildings includes, besides a Prescriptive path, a Performance Approach that requires using an hourly energy simulation model to demonstrate compliance. In this work, we present the development of a Graphical User Interface (GUI), in which most of the expert knowledge needed to run such complex simulation model is embedded in it. The output of the evaluation is a certificate specifying the energy rating of each unit in the building, as well as the energy rating of the whole building. Although IS5282 includes different building types, in this work we will demonstrate the tool using the Residential building type. One of the advantages of the system is that it suits any stage of the design process and not only the detailed one. In such a way, the user can design buildings being more aware of the energy performance features and their impact on the energy performance of the building. The GUI has been adopted by the Standards Institution of Israel for energy rating of buildings. The paper presents the tool, ENERGYui, and its application demonstrated with a case study.
Some preliminary studies, dealing with the process optimisation of pre-cast building elements made of Lime and Hemp Concrete (LHC), have shown that compression during casting lead to significant improvements: better mechanical characteristics and facing. However, this compaction leads to an increase of the weight to volume ratio and to a decrease in porous volume. Thus, the amount of entrapped air inside material, which contributes to decrease the thermal conductivity, is lower. Our data actually show a slight increase in thermal conductivity when compactness increases. The goal of this study is to compare the effect of compaction during casting on both mechanical and thermal characteristics of hardened specimens in order to evaluate the relevance of such a process.
The concept of thermal mass as a means of ameliorating diurnal temperature swings seems to be ideally suited for hot dry regions, which are characterized by wide daily temperature fluctuation in summer, and a considerable number of sunny days in winter. Furthermore, recent years in Israel (and the Middle East in general) have been following a worrying pattern of climate changes and "freak" weather events. Under such conditions, within an energy market where demand grows faster than supply, and with an ever increasing awareness of the environmental consequences of uncontrolled energy consumption patterns, thermal mass and its storage potential seem to be one of the most appropriate strategies to deal with energy conservation and thermal comfort issues within the broader framework of indoor air quality (Givoni, 1976). A SHORT NOTE ON HOT DRY REGIONS AND CLIMATE CHANGE One of the most profound characteristics of hot dry climates is that of wide fluctuation of temperatures, daily and seasonal. In many arid regions, summer days may be very hot and dry (especially in continental areas and on the mountains), while nights may be cool and even cold. Diurnal swings of 15-20deg.C or more are common with minima often reaching below 15deg.C. Winter days are generally sunny with clear skies, whereas nights are cold, with temperatures close to, and even below zero, frost being a common occurrence. Rainfall is usually limited and concentrated in a small number of downpours during the winter months, resulting in violent floods. Dust and sand storms are common, especially during the transition seasons. Such conditions may vary from year to year, drought being an endemic phenomenon in arid regions. However, in recent years, the Israeli arid south has experienced a strange change in climatic conditions, expressed in an ever increasing occurrence of adverse conditions and "freak" events, both in winter and summer. Hot spells common in summer and the transition seasons, but not unknown in winter, too, may cause a sharp rise in temperature, reaching within a few hours 10deg.C or more above the previous days' maxima. Such conditions may be considered characteristic of a large part of the deserts in the Middle East, although each region's altitude and distance from the sea do play a major role in defining the "continentality factor", and thus the final formation of local meso and microclimate.
The development of an open-access, reliable database for embodied energy and carbon (dioxide) emissions associated with the construction industry is described. The University of Bath's inventory of carbon and energy database lists almost 200 different materials. The data were extracted from peer-reviewed literature on the basis of a defined methodology and a set of five criteria. The database was made publicly available via an online website and has attracted significant interest from industry, academia, government departments and agencies, among others. Feedback from such professional users has played an important part in the choice of 'best values' for 'cradle-to-site' embodied energy and carbon from the range found in the literature. The variation in published data stems from differences in boundary definitions (including geographic origin), age of the data sources and rigour of the original life-cycle assessments. Although principally directed towards UK construction, the material set included in the database is of quite wide application across the industrial sector. The use of the inventory is illustrated with the aid of 14 case studies of real-world new-build dwellings. It was observed that there was little difference between embodied energy and carbon for houses and apartments until external works were taken into account (energy inputs for roads, connecting pathways, etc.).
Energy use is a widely used measure of the environmental impact of buildings. Recent studies have high-lighted the importance of both the operational and embodied energy attributable to buildings over their life-time. The method of assessing lifetime building energy is known as life-cycle energy analysis. With Kyoto target obligations necessitating the quantification of greenhouse gas emissions at the national level, it seems increasingly probable that analyses of this kind will increase in use. If conducted in primary energy terms, such analyses directly reflect greenhouse gas emissions, except for a few processes which involve significant non-energy related emissions such as cement manufacture. A Life-Cycle Assessment would include these issues, as well as other environmental parameters, though probably with a corresponding decrease in system boundary completeness. This paper briefly explains some of the theoretical issues associated with life-cycle energy analysis and then uses an Australian based case study to demonstrate its use in evaluating alternative design strategies for an energy efficient residential building. For example, it was found that the addition of higher levels of insulation in Australia paid back its initial embodied energy in life-cycle energy terms in around 12 years. However, the saving represented less than 6% of the total embodied energy and operational energy of the building over a 100-year life cycle. This indicates that there may be other strategies worth pursuing before additional insulation. Energy efficiency and other environmental strategies should be prioritized on a life-cycle basis.
Recent investigations on heat and mass flows through building materials in dynamical conditions show the importance of considering moisture transport and storage when analyzing the global performance of the building envelope. Lime-Hemp Concrete (LHC) is an insulation material made out of hemp chips mixed with an appropriate rich lime binder. It can be use either in old or new buildings, to cover masonry walls or to fill walls, floors or roofs in timber frame structures. This paper analyzes drying process, final density and vapour permeability of different type of LHC-wall mixtures to point out influence of mixing, implementation and water input on material's final properties. Experiments inspired by the Nordtest project are then presented to assess moisture buffer effect in LHC material and retarded sorption effect is pointed out. Results from dry thermal conductivity measurements are also reported and influence of moisture content on this parameter is discussed. These results show why the use of LHC can help to reach high comfort feeling with low energy demand for indoor temperature and humidity regulations in sustainable buildings.
Policies for supporting biofuels, such as the EU's Renewable Energy Directive RED), the Renewable Fuel Standard in the US, and the UK's Renewable Transport Fuel Obligation (RTFO), require life cycle carbon reporting to ensure that biofuels achieve greenhouse gas reductions relative to fossil fuels. These policies tend not to distinguish between two types of life cycle analysis (LCA); consequential LCA (CLCA) and attributional LCA (ALCA). Failure to distinguish between CLCA and ALCA can result in the wrong method being applied, a combination of the two approaches within a single analysis, a misinterpretation of the results, or an unfair comparison of results derived from different methods. This paper sets out the key differences between CLCA and ALCA and assesses which method is applied in the carbon reporting guidance for the RTFO and RED, or whether a mixture of the methods is used. We find that the RTFO guidance adopts a partial CLCA approach but that there are inconsistencies in the treatment of co-products and ALCA derived fossil fuel comparators are compared to partial-CLCA biofuel values. The LCA method used in the RED is largely consistent with ALCA, but this may not be the most suitable method for determining total greenhouse gas impacts, which is one of the main purposes of carbon reporting in relation to biofuels policy.
This work is part of a wider research programme that aims at producing alternatives to conventional building materials. The aim of this project is to investigate several physical properties of a sustainable, carbon-negative, lime-hemp biocomposites which can partially replace existing, non-biodegradable, non-sustainable, building materials of high embodied energy and high CO 2 emissions. The shrinkage, flexural and compressive strengths of these lime-hemp concretes, made with either calcium lime or a commercial binder with a cement content and varying lime:hemp proportions (1:9, 1:1 and 3:1), were investigated according to the relevant European standards. The shrinkage and strength development at 7, 28 and 90 days were monitored. The relationship between shrinkage and binder type, hemp content and water content was observed. The development of the flexural and compressive strengths shared several characteristics but their behaviour departed in relation to increasing hemp content with compressive strength continuously decreasing while flexural strength varied little between 50% and 75% hemp content.
Some preliminary studies, dealing with the process optimisation of pre-cast building elements made of Lime and Hemp Concrete (LHC), have shown that compression during casting lead to significant improvements: better mechanical characteristics and facing. However, this compaction leads to an increase of the weight to volume ratio and to a decrease in porous volume. Thus, the amount of entrapped air inside material, which contributes to decrease the thermal conductivity, is lower. Our data actually show a slight increase in thermal conductivity when compactness increases. The goal of this study is to compare the effect of compaction during casting on both mechanical and thermal characteristics of hardened specimens in order to evaluate the relevance of such a process.
The climate change discourse is touching all fields and aspects of scientific inquiry and research, as well as everyday life. This paper reviews some of the more pronounced aspects of planning and building design that are directly related to climatic issues. It attempts to show how the exacerbation of climatic extremes and 'freak' weather events influences people's living and working environments, and why the formulation of alternative, climate adapted principles and practices is no longer a 'luxury' that can remain along the fringes of the planning and building disciplines.
Buildings demand energy in their life cycle right from its construction to demolition. Studies on the total energy use during the life cycle are desirable to identify phases of largest energy use and to develop strategies for its reduction. In the present paper, a critical review of the life cycle energy analyses of buildings resulting from 73 cases across 13 countries is presented. The study includes both residential and office buildings. Results show that operating (80–90%) and embodied (10–20%) phases of energy use are significant contributors to building's life cycle energy demand. Life cycle energy (primary) requirement of conventional residential buildings falls in the range of 150–400 kWh/m2 per year and that of office buildings in the range of 250–550 kWh/m2 per year. Building's life cycle energy demand can be reduced by reducing its operating energy significantly through use of passive and active technologies even if it leads to a slight increase in embodied energy. However, an excessive use of passive and active features in a building may be counterproductive. It is observed that low energy buildings perform better than self-sufficient (zero operating energy) buildings in the life cycle context. Since, most of the case studies available in open literature pertain to developed and/or cold countries; hence, energy indicative figures for developing and/or non-cold countries need to be evaluated and compared with the results presented in this paper.
Considerable amount of energy is spent in the manufacturing processes and transportation of various building materials. Conservation of energy becomes important in the context of limiting of green house gases emission into the atmosphere and reducing costs of materials. The paper is focused around some issues pertaining to embodied energy in buildings particularly in the Indian context. Energy consumption in the production of basic building materials (such as cement, steel, etc.) and different types of materials used for construction has been discussed. Energy spent in transportation of various building materials is presented. A comparison of energy in different types of masonry has been made. Energy in different types of alternative roofing systems has been discussed and compared with the energy of conventional reinforced concrete (RC) slab roof. Total embodied energy of a multi-storeyed building, a load bearing brickwork building and a soil–cement block building using alternative building materials has been compared. It has been shown that total embodied energy of load bearing masonry buildings can be reduced by 50% when energy efficient/alternative building materials are used.
The monolithic walls of hemp-lime construction enclose and protect a structural timber frame to provide a healthy, breathable building fabric that meets current UK building regulations. It has been proposed that by using hemp as a building material it is possible to actually remove carbon from the atmosphere. Whether or not ‗hemp-crete‘can be considered carbon sequestering, or even neutral, depends largely on the binder. All the lime based binders have high embodied energy, meaning they limit this possibility. Earth construction uses clay as the binder. Could clay substitute for lime in hemp-crete? This experimental research focuses mainly on the thermal properties of stabilised and unstabilised hemp-clay blocks which are tested using a transient heat-transfer probe to measure thermal conductivity, volumetric heat capacity, and derive thermal diffusivity and effusivity. Results are compared with industry-published data for hemp-lime (eg Lhoist, 2009) and found to be similar. The results of the experiments and the literature review indicate that the use of clay as an alternative binder has potential to reduce the environmental impact of the hemp-binder method and facilitate the move towards developing a building material that can used for new build or renovation works, that removes carbon from the atmosphere at this time of need. Published (publisher's copy) Peer Reviewed
In the last decades, sustainable aspects of human development as energy savings, comfort, health and life-cycles, led to an increased interest on new insulation materials. Lime-Hemp Concrete (LHC) is a light, porous and hygroscopic insulation material made out of hemp chips mixed with an appropriate lime binder. It can be use either to cover masonry walls or to fill timber frame structures, in old or new buildings. The paper first presents this innovative material on the basis of a thorough literature survey. Laboratory experiments were conducted in the Fraunhofer-Institut for Building Physics and corresponding transport and storage parameters are defined. Dynamical interactions between heat and mass flows in material’s porous structure are then analyzed though numerical simulations.
Industrial hemp is a variety of Cannabis sativa and is of the same plant species as marijuana. However, hemp is genetically different and distinguished by its use and chemical makeup. Hemp has long been cultivated for non-drug use in the production of industrial and other goods. Some estimate that the global market for hemp consists of more than 25,000 products. It can be grown as a fiber, seed, or other dual-purpose crop. Hemp fibers are used in a wide range of products, including fabrics and textiles, yarns and raw or processed spun fibers, paper, carpeting, home furnishings, construction and insulation materials, auto parts, and composites. The interior stalk (hurd) is used in various applications such as animal bedding, raw material inputs, low-quality papers, and composites. Hemp seed and oilcake are used in a range of foods and beverages, and can be an alternative food protein source. Oil from the crushed hemp seed is an ingredient in a range of body-care products and also nutritional supplements. Hemp seed is also used for industrial oils, cosmetics and personal care, and pharmaceuticals, among other composites. Precise data are not available on the size of the U.S. market for hemp-based products. Current industry estimates report that U.S. retail sales of all hemp-based products may exceed $300 million per year.
Today, buildings are responsible for more than 40% of global energy used, and as much as 33% of global greenhouse gas emissions, both in developed and developing countries. In this paper, a life cycle energy (LCEA) and carbon dioxide emissions (LCCO2A) analysis of two residential buildings has been conducted. The study includes the literature review, the data used for such a comprehensive analysis, and methodology and provides an application of the methodology that considers two actual residential buildings constructed in Gaziantep, Turkey. The proposed model focused on building construction, operation and demolition phases to estimate total energy use and carbon emissions over a 50 year lifespan. Energy efficiency and emissions parameters are defined for the buildings per square meter basis. It is found that the operation phase is dominant in both urban and rural residential buildings and contributes 76-73% of the primary energy requirements and 59-74% of CO2 emissions respectively. The embodied energy (EE) of the buildings accounts for 24-27% of the overall life-cycle energy consumption. The results show that, because of the differences in building structures, living standards and air conditioning habits, the life cycle energy demand in rural residential buildings is 18% lower than in urban conditions.
This review summarizes and organizes the literature on life cycle assessment (LCA), life cycle energy analysis (LCEA) and life cycle cost analysis (LCCA) studies carried out for environmental evaluation of buildings and building related industry and sector (including construction products, construction systems, buildings, and civil engineering constructions). The review shows that most LCA and LCEA are carried out in what is shown as "exemplary buildings", that is, buildings that have been designed and constructed as low energy buildings, but there are very few studies on "traditional buildings", that is, buildings such as those mostly found in our cities. Similarly, most studies are carried out in urban areas, while rural areas are not well represented in the literature. Finally, studies are not equally distributed around the world.
Over half of the global raw materials are consumed in the construction of buildings and roads, their associated greenhouse gas emissions from excavation to final disposal are pivotal to the change in global climate. Hemp is a natural resource that has recently been used as a low environmental impact material in a number of composite products. In buildings, it is increasingly used with a lime base binder in wall constructions. There are limited data available to evaluate the environmental impact of this type of construction in the UK. This research aims to identify the processes and materials involved in the construction of hemp-lime walls and to establish their life cycle impact on climate change. The study follows assessment procedures and guidelines of international (ISO14040) and UK (PAS2050) standards. The functional unit defined for the hemp-lime wall construction is 1 m square in area, 300 mm thick with timber frame support inside. Primary data were collected for processes and materials that have no existing information. Other processes with impact data available from credible database were adapted in the assessment by taking into account the conditions and practice in the UK. Assessment was carried out using the SimaPro LCA tool over a lifetime of 100 years. Within the boundary and assumptions made, results showed the functional unit could sequestrate 82.7 kg of carbon dioxide with a net life cycle reduction of greenhouse gas emission of 36.08 kg CO2e. Crown Copyright
We discuss certain compact, translation-invariant subsets of the set \({\mathcal {R}}\) of the generalized reflectionless potentials for the one-dimensional Schrödinger operator. We determine a stationary ergodic subset of \({\mathcal {R}}\) whose Lyapunov exponent is discontinuous at a point. We also determine an almost automorphic, non-almost periodic minimal subset of \(\mathcal {R}\) .
In this paper we discuss the experience of the construction of an 80 square metre single storey eco house in County Down, Northern Ireland. The house is constructed from a timber post and beam frame with hemp and lime walls. Sheepswool insulation in the roof and other natural or second hand materials have been used, including a grass roof. The house was begun in the summer of 2008 and largely complete in August 2009. We discuss how the design was developed and the buildability and detailing issues that were discovered during construction. Test results on the thermal performance of the house will be available in 2010 as we hope that independent monitoring will be carried out by University of Ulster. The authors of the paper have also written a book about hemp lime construction and the paper will examine what has been learned from putting ideas into practice. 1. Searching for low carbon building It has long been recognised that buildings and their use contribute significantly to C0 2 emissions, perhaps more than 50% of total emissions. Finding ways of meeting our housing and building needs while having a low impact on the planet has been the aim of many self-builders, architects and environmentalists. However there are two main differences in approach. There are those who have focused on getting the main stream construction industry to make buildings more energy efficient, even though they rely on high embodied energy petrochemical based insulations, cement, bricks and concrete. Others have tried to search for lower impact alternatives that also are healthier and less polluting. There is now a range of building methods and materials derived from natural low impact sources (Woolley 2006) such as earth, (Morton 2008) straw, recycled materials and so on. We first learned about hemp and lime construction from pioneering Suffolk architect, Ralph Carpenter (Carpenter 2009) and soon realised that this was a form of eco-construction that could achieve low energy buildings using low impact materials. While it was a natural alternative material, it appeared to have great potential in mainstream construction.
In a context of sustainable development and energy sparing, a life cycle assessment (LCA) may be useful to make good choices. Thus, this study concerns the LCA of an environmentally friendly material used for building construction, hemp concrete. The functional unit is first defined per square such that the wall may provide the function of bearing wall meter and its thermal performance is described by a thermal resistance of 2.78 m².K/W. The results then showed that the production phase of raw materials is mainly responsible for the environmental impact of the wall, mostly due to the binder production. It was also shown that, compared to traditional construction materials, hemp concrete has a low impact on environment. Moreover, hemp concrete contributes to reduce climate change as photosynthesis-mediated carbon sequestration and carbonation serve to reduce atmospheric carbon dioxide. A sensitivity analysis is performed on three criteria: wall thickness, renewal of coatings and compounds of the indoor coating. Our results show that environmental indicators evolve with wall thickness, except for the climate change indicator. It improves with thickness due to carbon sequestration and carbonation. Moreover the increase in the wall's thermal resistance with wall thickness is not taken into account in such an LCA performed at the material level. The renewal of coating slightly impacts the environmental indicator for small numbers of renewals but it leads to negative effects if they are too numerous. It appears that hemp-lime coating has a greater impact than sand-lime coating as it embeds more binder.
The effect of using different binding agents in combination with hemp shives and fibres in Lime–Hemp Concrete (LHC) building material was examined. LHC is a light composite building material with building lime as binding agents and hemp (Cannabis sativa) as a renewable raw material from agriculture. Contemporary LHC only uses the woody core part of the hemp, the shive. However, using both hemp shives and fibres may improve the mechanical strength, eliminating the need for a fibre separation process.
The aim was to elucidate the feasibility of using the entire fragmented hemp stalk in an LHC, and to determine some important material properties such as compressive strength, splitting tensile strength, water sorption and frost resistance. LHC with varying inclusions of the lime-based binders were tested, as were five mixes using the binding agents hydrated lime, hydraulic lime, and cement.
Specimens were cured for 12 weeks at room temperature and 40 days in a carbonation room (4.5 vol% CO2), and tested for mechanical properties, water sorption and frost resistance. Using both shives and fibres in LHC may be advantageous for countries such as Sweden where facilities for separating hemp from shives are not commercially available.
A new thermal simulation model, QUICK II, is presented and numerous verification case studies performed on naturally ventilated buildings are discussed. Four new case studies performed on two buildings located in the Negev desert in Israel are discussed in detail. All the measurements pertaining to these new case studies were taken independently by the Desert Architecture Unit of the Jacob Blaustein Institute for Desert Research. These measurements are provided, along with a description of the buildings. The verification results show a good correlation between the measured and simulated parameters. The simulated temperatures were found to be within 1 °C of the measured temperatures for 73% of the time, and within 2 °C for 95% of the time.
This study examines the potential life-cycle energy savings that may be achieved by combining an innovative alternative building material and a bioclimatic approach to building design under the distinctive environmental conditions of a desert region. A residential building in the Negev region of Israel is used as a model for the assessment. Designed with a number of climatically-responsive design strategies and conventional concrete-based materials, the building was energy-independent in terms of summer cooling and had only modest requirements for winter heating. As a second step to the assessment, the integration of an alternative building material based on industrial waste and local raw materials in the building's walls was considered through thermal simulation. The alternative materials are produced through a process developed to make productive utilization of fly-ash from oil shale and coal combustion. Material properties were analyzed using laboratory specimens, and it was established that high-quality building components could be produced using the developed technological procedure with standard manufacturing equipment. The consumption of both embodied and operational energy was analyzed over the building's useful life span, and this life-cycle analysis showed the clear advantage of integrating alternative materials in a building under environmental conditions in a desert environment.
Cement is an important construction ingredient produced in virtually all countries. Carbon dioxide (CO2) is a by- product of a chemical conversion process used in the production of clinker, a component of cement, in which limestone (CaCO3) is converted to lime (CaO). CO2 is also emitted during cement production by fossil fuel combustion and is accounted for elsewhere. However, the CO2 from fossil fuels is accounted for elsewhere in emission estimates for fossil fuels. The Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories (IPCC Guidelines) provide a general approach to estimate CO2 emissions from clinker production, in which the amount of clinker produced is multiplied by the clinker emission factor. The IPCC Guidelines recommend two possible methods for calculating the clinker emission factor. The first method is to use the IPCC default value for the fraction of lime in clinker. The second method is to calculate the average lime concentration in clinker by collecting data on clinker production and lime fraction by type. The IPCC Guidelines state that the difference between the default value and a value based on collected data is expected to be small. If clinker production data are not available, it is recommended that countries back-calculate clinker production from the cement data while applying a correction factor for clinker imports/exports. Once an estimate has been derived, emissions can be estimated by means of the clinker emission factor. The IPCC recommends using clinker data, rather than cement data, to estimate CO2 emissions because CO2 is emitted during clinker production and not during cement production. If clinker is traded internationally, using cement production data results in a biased emissions estimate because the cement could potentially be produced from clinker that was made in another country. Although clinker data are the preferred data source, cement data may be more readily available in some countries. In this case, the recommended approach is to estimate the fraction of clinker in the cement and back-calculate clinker production. Quality assurance and quality control activities should be implemented at several stages in the emission estimation process. At the plant level, key activities include internal quality control on production data and emission factors, as well as documenting data and methods for reviewers. The inventory agency must ensure the accuracy of plant submissions as well as the compiled inventory. It is also responsible for providing documentation and sufficient information to the United Nations Framework Convention on Climate Change (UNFCCC). One or more types of external review may also be appropriate.
The aim of the present paper is to assess the sustainability of a natural fiber, such as hemp (Cannabis sativa), and its use as thermal insulator for building applications. The sustainability of hemp was quantified by Life Cycle Assessment (LCA) and particular attention was given to the amount of CO2eq of the whole process, and the indicator Greenhouse Gas Protocol (GGP) was selected to quantify CO2eq emissions. In this study also CO2 uptake of hemp was considered. Two different allocation procedures (i.e. mass and economic) were adopted. Other indicators, such as Cumulative Energy Demand (CED) and EcoIndicator99 H were calculated. The production of 1 ha yielded 15 ton of hemp, whose global warming potential (GWP100) was equal to about -26.01 ton CO2eq: the amount allocated to the technical fiber (20% of the total amount of hemp biomass) was -5.52 ton CO2eq when mass allocation was used, and -5.54 ton CO2eq when economic allocation was applied. The sustainability for building applications was quantified by considering an insulation panel made by hemp fiber (85%) and polyester fiber (15%) in 1 m2 of wall having a thermal transmittance (U) equal to 0.2 W/m2_K. The environmental performances of the hemp-based panel were compared to those of a rockowool-based one.
Concrete blocks, made of a mixture of lime and hemp shives (also called “hemp hurds”), have been manufactured by a recently developed projection process. Lime carbonatation kinetics is determined by X-ray diffraction. Density measurements are made within blocks, and thermal and mechanical properties are measured (flexural strength, compression strength and hardness). The main observations are moderate density variations within a given block, and an influence of the projection distance on density. Both thermal conductivity and mechanical properties increase with the mortar density, which is well described by existing theoretical models. Compression tests induce a compaction, or densification, of the material.
A literature survey on buildings' life cycle energy use was performed, resulting in a total of 60 cases from nine countries. The cases included both residential and non-residential units. Despite climate and other background differences, the study revealed a linear relation between operating and total energy valid through all the cases. Case studies on buildings built according to different design criteria, and at parity of all other conditions, showed that design of low-energy buildings induces both a net benefit in total life cycle energy demand and an increase in the embodied energy. A solar house proved to be more energy efficient than an equivalent house built with commitment to use "green" materials. Also, the same solar house decreased life cycle energy demand by a factor of two with respect to an equivalent conventional version, when operating energy was expressed as end-use energy and the lifetime assumed to be 50 years. A passive house proved to be more energy efficient than an equivalent self-sufficient solar house. Also, the same passive house decreased life cycle energy demand by a factor of three - expected to rise to four in a new version - with respect to an equivalent conventional version, when operating energy was expressed as primary energy and the lifetime assumed to be 80 years.
Environmental quality has become increasingly affected by the built environment—as ultimately, buildings are responsible for the bulk of energy consumption and resultant atmospheric emissions in many countries. In recognizing this trend, research into building energy-efficiency has focused mainly on the energy required for a building's ongoing use, while the energy “embodied” in its production is often overlooked. Such an approach has led in recent years to strategies which improve a building's thermal performance, but which rely on high embodied-energy (EE) materials and products. Although assessment methods and databases have developed in recent years, the actual EE intensity for a given material may be highly dependent on local technologies and transportation distances. The objective of this study is to identify building materials which may optimize a building's energy requirements over its entire life cycle, by analyzing both embodied and operational energy consumption in a climatically responsive building in the Negev desert region of southern Israel—comparing its actual material composition with a number of possible alternatives. It was found that the embodied energy of the building accounts for some 60% of the overall life-cycle energy consumption, which could be reduced significantly by using “alternative” wall infill materials. The cumulative energy saved over a 50-year life cycle by this material substitution is on the order of 20%. While the studied wall systems (mass, insulation and finish materials) represent a significant portion of the initial EE of the building, the concrete structure (columns, beams, floor and ceiling slabs) on average constitutes about 50% of the building's pre-use phase energy.
This research is concerned with the mechanical and physical properties of hemp fibre reinforced concrete (HFRC). An experimental program was developed based on the statistical method of fractional factors design. The variables for the experimental study were: (1) mixing method; (2) fibre content by weight; (3) aggregate size; and (4) fibre length. Their effects on the compressive and flexural performance of HFRC composites were investigated. The specific gravity and water absorption ratio of HFRC were also studied. The results indicate that the compressive and flexural properties can be modelled using a simple empirical linear expression based on statistical analysis and regression, and that hemp fibre content (by weight) is the critical factor affecting the compressive and flexural properties of HFRC.
The paper discusses issues of thermal comfort standards, including the ASHRAE comfort zone, techniques of graphical climate data analysis, as well as the uses of building bioclimatic charts in the formulation of building design guidelines, especially for hot climates. The problematics of applying the Olgyay bioclimatic charts and the ASHRAE comfort standards for unconditioned buildings, especially in developing hot countries, are discussed. Revised building bioclimatic charts are described for the first time in this paper. The boundaries of applicability of various building design strategies and passive cooling systems in different climates are discussed. These strategies are based on the expected indoor temperatures achievable with the different strategies and include daytime ‘comfort” ventilation, the utilization of the structural mass for thermal storage in conjunction with nocturnal ventilation, and direct and indirect evaporative cooling.
The Embodied Energy of Building Materials in Israel: Development of a National Database
- D Pearlmutter
- I A Meir
- N Huberman
D. Pearlmutter, I. a. Meir, N. Huberman, The Embodied Energy of Building
Materials in Israel: Development of a National Database, 2013.
Fibre hemp and marihuana: assessing the differences between distinct varieties