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... Construction assemblies are systematised and detailed in several sources, such as the "Architects' data" book (Neufert and Neufert, 2012), and scientific articles (e.g. Stephan and Athanassiadis, 2017;Weththasinghe, 2020). Assemblies relating to the building services (e.g. ...
... This will help model the built environment in a more robust manner, enabling a better quantification of environmental performance and addressing the climate emergency. A parametric approach to defining archetypes for an integrated material stocks and flows analysis and life cycle assessment of built stocks Stephan, A. and Athanassiadis, A. (2017) Quantifying and mapping embodied environmental requirements of urban building stocks, Building and Environment, 114, 187-202. Stephan, A., Crawford, R. H., Bunster, V., Warren-Myers, G. and Moosavi, S. (2022a) Towards a multiscale framework for modeling and improving the life cycle environmental performance of built stocks, Journal of Industrial Ecology. ...
... There is currently a lack of consideration of life cycle GHGE in park design, notably embodied GHGE in construction materials. Given that sturdy and hardwearing materials are used in the park design, recurrent embodied GHGE represented 6% of initial embodied emissions, unlike in buildings where they usually represent 30-50% over 50 years, depending on material choices (Stephan and Crawford, 2014;Stephan and Athanassiadis, 2017). As such, landscape architects need to carefully choose their construction materials. ...
Conference Paper
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The global sustainability movement has developed a variety of new design and building methodologies. Regenerative Design (RD) focuses on understanding the dynamic relationship between people, a place and ecosystems. By weaving together the natural and social systems, RD maximises humans' and nature's creativeness and abundance. Projects are not seen as an end product but rather as the beginning of a process that will continue to evolve long after completion. RD approaches to building are receiving increased attention in industry and academia. In this context, developing a clear shared understanding and evaluating the practical implications of this new approach remains an open issue. This critical review attempts to fill this gap by reviewing the concept, its aims, the existence of any performance measurement criteria, design methods and the expected outcomes of the RD approach to design and building. A summary process workflow diagram and an Assessment Methodology (AM) for evaluating RD project progress are proposed. The AM is presented as a series of questions to be answered qualitatively and quantitatively to aid track progress through time. Both diagram and AM may become valuable tools for further discussion about the methodological implications of RD project delivery for the architecture profession and for upgrading architectural education accordingly.
... Buffat et al. [47], Garcia et al. [21], Mastrucci et al. [19], Österbring et al. [23] Prediction model at building level based on topdown data using machine learning algorithms -building-by-building data are scaled up to the urban level -use of GIS/data driven predictive model -possible to assess indoor conditions -fills data gaps of building parameters, occupancy, or energy data -higher accuracy than theoretical building energy model -purely data-driven approaches lack underlying thermodynamic modelling to ascertain how energy retrofits might affect future energy performance -availability/quality of data -accuracy for each part of the study may differ (e.g., each renovation measure) Gao A second type is the archetype approach [20][21][22][23]27,32,[38][39][40][41][42][43]46,48,49]. In this approach, the buildings are represented by archetype buildings based on a classification system. ...
... This approach is interesting in case a building-by-building approach is preferred, but not all features are known for each building in the stock, or in case extra building specific information is useful in an archetype approach. By including GIS data in the general archetype information, the model becomes more accurate and reliable [21][22][23][25][26][27]32,40,43,[46][47][48]. These GIS data can be supplemented using building heights or using LiDAR data to create a 2.5D or even 3D city model [51]. ...
... For example, García-Pérez et al. [21] perform an environmental assessment at the urban level using a bottom-up methodology combining GIS and Life Cycle Assessment (LCA) methods. In the study of Stephan and Athanassiadis [32], a spatially defined bottom-up model is developed using building archetypes to represent the land use, construction period, and building height for Melbourne, Australia. Using these models, the material flows of the building stock can be analysed in order to quantify the inputs, the outputs, and the materials stored in the building stock of cities and to assess the corresponding environmental impacts. ...
Article
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The existing building patrimony is responsible for 36% of the global energy use and 37% of the greenhouse gas emissions. It is hence a major challenge to improve its energy performance. According to the Renovation Wave, the average annual renovation rate should be doubled by 2030 up to 3% and deep energy renovations should be encouraged. The Belgian city of Leuven works towards this target and is even more ambitious, setting their goal on becoming climate neutral by 2050. The strategy investigated in this study is to increase the renovation rate by clustering renovations, which is challenging since the Belgian building stock is highly privatised. Based on a thorough literature study, this paper examines various methodologies for building stock modelling. The main focus is comparing the required input data with the data availability, handling the data gaps, and defining their influence on the model’s accuracy. The findings are applied to Leuven by analysing the main drivers to cluster renovation measures. However, many data gaps appeared, leading to the selection of a GIS-enhanced archetype model enriched by energy data as the most suitable approach. To avoid misinterpretation due to differences in data quality, transparent reporting in stock modelling is recommended.
... To this point, 80% of reviewed studies analyzed materials accumulated in both structural and nonstructural components without differentiating between the two component categories. Few articles (19% of reviewed studies) constrained their system boundaries to structural components [25,30,34,[44][45][46][47][48][49][50], whereas only Stephan and Athanassiadis [4,51] quantified and spatialized materials in non-structural components (i.e. floors, external walls, internal walls, windows, doors, roofs, pipes, wires) of Melbourne's building stock. ...
... population, floor area) [10,18,29,36,37,49,55,59,66,69,[72][73][74][75]. Prospective studies (8% of reviewed articles) predicted and characterized building stocks in the future [4,24,51,63,68,76]. In addition to these dynamic approaches, retro-prospective studies investigated the building material's metabolism from the past to future [26-28, 30, 35, 44, 48, 50, 60, 65]. ...
... As an example, timber from beams has a different recovery path than timber retrieved from doors and windows. Although some studies combined the surface area or volume of components with their materials intensity, similar materials from different components were summed up and reported in an aggregated fashion [4,16,25,51,63,65,71,73]. Therefore, the outcomes of these studies were not useful for identifying more circular obsolescence or recovery pathways with less downgrading based on building components. ...
Article
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Buildings account for the largest share of accumulated materials and waste. Tracking material composition, quantity, and location of these materials, known as building material stock analysis (MSA), is a first step enabling the reuse or repurposing of materials, key strategies of the circular economy. While the number of building MSAs is growing, there is a need to coalesce methods, data, and scope. Therefore, in this work, we reviewed and evaluated 62 journal and conference articles on MSA of buildings from different angles including scope, boundaries, archetype classification, material intensity determination, approaches (i.e., bottom-up, top-down, remote sensing), and quantity of materials to identify barriers, gaps, and opportunities of the area along with its implications on decision making, policy, and regulations. We cataloged the three major approaches of MSAs and discussed their advantages and shortcomings. We also created a comprehensive directory of building archetypes, references, and materials for future researchers. Most of the studies expectedly estimated that concrete had the largest mass compared to other materials; however, mass-based distribution of materials showed significant variations in different building stocks across the world. Also, embedded plastics and their types remained under-represented in current studies. A major barrier to MSA is related to lack of physical attributes, GIS, design, and construction data. Policy makers can play a role in mitigating data barriers through instituting regulations, which enforce reporting building-related data during permitting process. Furthermore, outcomes of building MSA can help policy makers in considering incentives for design and construction that utilize these abundant building materials.
... The typical material intensity of each building cohort is usually derived based on one or several sampled building representatives. Sampling 145 representative buildings inevitably leads to bias in the quantification result due to building heterogeneity (Mollaei et al., 2021;Stephan & Athanassiadis, 2017). Furthermore, no research explains why a building is representative (Brøgger & Wittchen, 2018). ...
... Building features are independent variables. Previous studies indicate that BMS is correlated with building geometrical features such as GFA (Nasiri et al., 2021), building height (Kleemann et al., 2017), and perimeter-area ratio (i.e., perimeter per unit floor area) (Stephan & Athanassiadis, 2017); as well as semantic features such as building type (e.g., residential, non-residential) (Gontia et al., 2019). We also referred to the building features used in other 250 ...
Article
Urban material stock (UMS) represents an elegant thinking by perceiving cities as a repository of construction materials that can be reused in the future, rather than a burdensome generator of construction and demolition waste. Many studies have attempted to quantify UMS but they often fall short in accuracy, primarily owing to the lack of proper quantification methods or good data available at a micro level. This research aims to develop a simple but satisfactory model for UMS quantification by focusing on individual buildings. Generally, it is a ‘bottom-up’ approach that uses building features to proximate the material stocks of individual buildings. The research benefits from a set of valuable, ‘post-mortem’ ground truth data related to 71 buildings that have been demolished in Hong Kong. By comparing a series of machine learning-based models, a multiple linear regression model with six building features, namely building type, building year, height, perimeter, total floor area, and total floor number, is found to yield a satisfactory estimate of building material stocks with a mean absolute percentage error of 9.1%, root-mean-square error of 474.13, and R-square of 0.93. The major contribution of this research is to predict a building’s material stock based on several easy-to-obtain building features. The methodology of machine learning regression is novel. The model provides a useful reference for quantifying UMS in other regions. Future explorations are recommended to calibrate the model when data in these regions is available.
... The installation labour hours related to the annual inflow of black steel pipe is 221 khours which is equivalent to the annual working time of 138 workers (based on an annual working time of 1 600 hours per worker). Figure 2 confirms the importance of presenting multiple indicators at the same time to capture the multifaceted environmental effects of the built environment more comprehensively, as previously identified by [23] and [13]. As expected, the highest correlation is between embodied primary energy use and the embodied greenhouse gas emissions, with R²=0.999. ...
... The proposed model follows previous attempts to model the building stock of cities [5,23], but provides a more detailed approach to building services products quantity estimation. This level of detail enables decision-makers to trace back embodied environmental and economic flows to a particular building services product, which is rarely available in existing studies. ...
Article
Full-text available
An increasing number of cities and regions are promoting reuse as a key strategy in the transition towards a more circular economy in the construction sector. However, the reuse supply chains for building services are currently underdeveloped in most cities and regions. There is a need for a better understanding of the material flows at the city and regional levels. This study describes a bottom-up approach to quantify material flows related to building services as well as their embodied environmental and economic flows. It relies on the selection of a minimum of 1 new construction or renovation project representing material inflows and 1 demolition or renovation project representing material outflows. Actual products from bill of quantities and pre-demolition audits are mapped against a list of 234 archetypes, and archetypal inflows and outflows are extrapolated to the city or regional level. This model is applied to all office buildings in the Region of Brussels, Belgium. Results show that rectangular ductwork is responsible for almost 30% of annual inflows of building services, which amount to 32 km/year, 1,6 kt/year, require 96 thousand m ³ of freshwater/year, 131 TJ of primary energy/year, emit 9,9 kt CO 2 eq/year, cost 3;4 MEUR/year to project developers, and whose installation in buildings represents 51 khours/year. In addition, results show that the outflows of black steel pipes, recessed luminaires and electrical cables exceed the inflows on an annual basis, suggesting that there is significant potential for covering needs through the reuse of those products.
... The installation labour hours related to the annual inflow of black steel pipe is 221 khours which is equivalent to the annual working time of 138 workers (based on an annual working time of 1 600 hours per worker). Figure 2 confirms the importance of presenting multiple indicators at the same time to capture the multifaceted environmental effects of the built environment more comprehensively, as previously identified by [23] and [13]. As expected, the highest correlation is between embodied primary energy use and the embodied greenhouse gas emissions, with R²=0.999. ...
... The proposed model follows previous attempts to model the building stock of cities [5,23], but provides a more detailed approach to building services products quantity estimation. This level of detail enables decision-makers to trace back embodied environmental and economic flows to a particular building services product, which is rarely available in existing studies. ...
Conference Paper
Full-text available
An increasing number of cities and regions are promoting reuse as a key strategy in the transition towards a more circular economy in the construction sector. However, the reuse supply chains for building services are currently underdeveloped in most cities and regions. There is a need for a better understanding of the material flows at the city and regional levels. This study describes a bottom-up approach to quantify material flows related to building services as well as their embodied environmental and economic flows. It relies on the selection of a minimum of 1 new construction or renovation project representing material inflows and 1 demolition or renovation project representing material outflows. Actual products from bill of quantities and pre-demolition audits are mapped against a list of 234 archetypes, and archetypal inflows and outflows are extrapolated to the city or regional level. This model is applied to all office buildings in the Region of Brussels, Belgium. Results show that rectangular ductwork is responsible for almost 30% of annual inflows of building services, which amount to 32 km/year, 1,6 kt/year, require 96 thousand m³ of freshwater/year, 131 TJ of primary energy/year, emit 9,9 kt CO 2 eq/year, cost 3;4 MEUR/year to project developers, and whose installation in buildings represents 51 khours/year. In addition, results show that the outflows of black steel pipes, recessed luminaires and electrical cables exceed the inflows on an annual basis, suggesting that there is significant potential for covering needs through the reuse of those products.
... For cities, transitioning to a circular economy requires the introduction of circular (industrial) activities into the region, such as recycling, remanufacturing, storage, and (reverse) logistics; which are affected by spatial factors such as proximity to materials, clients, suppliers, and other companies. Because of this, scholars have started to recognize the importance of adding a geographical or spatial perspective to the study of circular cities and regions (Stephan and Athanassiadis 2017;Wandl 2020; Van den Berghe and Verhagen 2021;Sprecher et al., 2021;Furlan et al., 2022). The development of this perspective is still at an early stage, and the increasing accessibility and quality of spatial material flow data presents new possibilities. ...
... Mapping of stocks includes visualization for urban mining purposes, such as construction material stock mapping (Tanikawa et al., 2015;Stephan and Athanassiadis 2017;Sprecher et al., 2021); while mapping of flows include visualization of material flows (Furlan et al., 2022;Sileryte et al., 2022), and activity based spatial material flow analysis (Dijst et al., 2018). ...
Article
Full-text available
In recent years, implementing a circular economy in cities has been considered by policy makers as a potential solution for achieving sustainability. Existing literature on circular cities is mainly focused on two perspectives: urban governance and urban metabolism. Both these perspectives, to some extent, miss an understanding of space. A spatial perspective is important because circular activities, such as the recycling, reuse, or storage of materials, require space and have a location. It is therefore useful to understand where circular activities are located, and how they are affected by their location and surrounding geography. This study therefore aims to understand the existing state of waste reuse activities in the Netherlands from a spatial perspective, by analyzing the degree, scale, and locations of spatial clusters of waste reuse. This was done by measuring the spatial autocorrelation of waste reuse locations using global and local Moran’s I, with waste reuse data from the national waste registry of the Netherlands. The analysis was done for 10 material types: minerals, plastic, wood and paper, fertilizer, food, machinery and electronics, metal, mixed construction materials, glass, and textile. It was found that all materials except for glass and textiles formed spatial clusters. By varying the grid cell sizes used for data aggregation, it was found that different materials had different “best fit” cell sizes where spatial clustering was the strongest. The best fit cell size is ∼7 km for materials associated with construction and agricultural industries, and ∼20–25 km for plastic and metals.The best fit cell sizes indicate the average distance of companies from each other within clusters, and suggest a suitable spatial resolution at which the material can be understood. Hotspot maps were also produced for each material to show where reuse activities are most spatially concentrated.
... For cities, transitioning to a circular economy requires the introduction of circular (industrial) activities into the region, such as recycling, remanufacturing, storage, and (reverse) logistics; which are affected by spatial factors such as proximity to materials, clients, suppliers, and other companies. Because of this, scholars have started to recognize the importance of adding a geographical or spatial perspective to the study of circular cities and regions (Furlan et al. 2022;Wandl 2020; Van den Berghe and Verhagen 2021;Sprecher et al. 2021;Stephan and Athanassiadis 2017). The development of this perspective is still at an early stage, and the increasing accessibility and quality of spatial material flow data presents new possibilities. ...
... Mapping of stocks includes visualization for urban mining purposes, such as construction material stock mapping (Stephan and Athanassiadis 2017;Tanikawa et al. 2015;Sprecher et al. 2021); while mapping of flows include visualization of material flows (Furlan et al. 2022;Sileryte et al. 2022), and activity based spatial material flow analysis (Dijst et al. 2018). ...
Preprint
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In recent years, implementing a circular economy in cities has been considered by policy makers as a potential solution for achieving sustainability. Existing literature on circular cities is mainly focused on two perspectives: urban governance and urban metabolism. Both these perspectives, to some extent, miss an understanding of space. A spatial perspective is important because circular activities, such as the recycling, reuse, or storage of materials, require space and have a location. It is therefore useful to understand where circular activities are located, and how they are affected by their location and surrounding geography. This study therefore aims to understand the existing state of waste reuse activities in the Netherlands from a spatial perspective, by analyzing the degree, scale, and locations of spatial clusters of waste reuse. This was done by measuring the spatial autocorrelation of waste reuse locations using global and local Moran's I, with waste reuse data from the national waste registry of the Netherlands. The analysis was done for 10 material types: minerals, plastic, wood and paper, fertilizer, food, machinery and electronics, metal, mixed construction materials, glass, and textile. It was found that all materials except for glass and textiles formed spatial clusters. By varying the grid cell sizes used for data aggregation, it was found that different materials had different 'best fit' cell sizes where spatial clustering was the strongest. The best fit cell size is 7km for materials associated with construction and agricultural industries, and ~20-25km for plastic and metals.The best fit cell sizes indicate the average distance of companies from each other within clusters, and suggest a suitable spatial resolution at which the material can be understood. Hotspot maps were also produced for each material to show where reuse activities are most spatially concentrated.
... Currently, we either have detailed and holistic analyses conducted at a building scale (e.g., Birge and Berger (2019), or generally rough analyses conducted at the neighbourhood or urban scale (e.g., Lausselet, Ellingsen, Strømman, and Brattebø (2019). While significant efforts have been deployed in recent years to combine a high level of detail with a high coverage of environmental flows (e.g., Stephan and Athanassiadis (2017), there is still a significant amount of research required to achieve both and thus enable a high environmental performance of built stocks. This paper highlights the main features digital models would require to effectively quantify material stocks and flows and associated life-cycle environmental Abstract. ...
... Links to all publications and data sources will also be available on the website. Stephan & Athanassiadis, 2017& Athanassiadis, , 2018. ...
Article
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Buildings and infrastructure assets represent a significant share of human anthropogenic material stocks, energy use, and related environmental flows, including greenhouse gas emissions. Current methods for assessing built stocks at a city scale are neither detailed nor comprehensive enough, however. This piece provides and discusses requirements for digital models to quantify the combined life-cycle environmental performance and material-flow analysis of urban built stocks. It justifies why these models need to be bottom-up, parametric, multi-scale over the life cycle, and spatially explicit, and why they need to integrate uncertainty. The potential and limitations of such digital models are discussed. Résumé. Les bâtiments et infrastructures représentent une grande partie du stock matériel anthropogénique, de l’utilisation d’énergie, et des flux environnementaux associés. Cependant, les méthodes actuelles d’évaluation des stocks bâtis à l’échelle urbaine ne sont pas assez détaillées et holistiques. Cet article présente et discute les exigences des modèles informatiques qui visent à quantifier à la fois la performance environnementale sur l’ensemble du cycle de vie et les flux de matière des stocks bâtis urbains. Ces modèles nécessitent des approches bottom-up, paramétriques, multi-échelle sur le cycle de vie. Ils doivent aussi être spatialisés et intégrer les incertitudes. Ces nécessités sont justifiées et discutées dans l’article, ainsi que les potentialités et les limites de ce type de modèles informatiques.
... Resch et al. (2021) improve that model to account for emissions reduction over time, adding a dynamic modeling approach to recurrent embodied greenhouse gas emissions and end-of-life greenhouse gas emissions, which is laudable, but also does not consider operational or mobility-related flows. To this date, only a few studies have attempted to combine top-down and bottom-up approaches, for example, urban metabolism and life cycle assessment (Goldstein et al., 2013), or material stock and flow modeling and life cycle assessment (Lausselet et al., 2021;Stephan & Athanassiadis, 2017, 2018. ...
... The model will be linked to geographic information systems (GIS) to enable both inputs from GIS databases and the visualization of results on maps (e.g., Stephan & Athanassiadis, 2017, or Lanau & Liu, 2020. This is a critical feature that tends to be systematically called for in recent reviews in the field of material stock modeling and life cycle assessment at the urban scale, inter alia Mastrucci et al. (2017) and Lanau et al. (2019). ...
Article
Cities are complex sociotechnical systems, of which buildings and infrastructure assets (built stocks) constitute a critical part. As the main global users of primary energy and emitters of associated greenhouse gases, there is a need for the introduction of measures capable of enhancing the environmental performance of built stocks in cities and mitigating negative externalities such as pollution and greenhouse gas emissions. To date, most environmental modeling and assessment approaches are often fragmented across disciplines and limited in scope, failing to provide a comprehensive evaluation. These approaches tend to focus either on one scale relevant to a discipline (e.g., buildings, roads, parks) or particular environmental flows (e.g., energy, greenhouse emissions). Here, we present a framework aimed at overcoming many of these limitations. By combining life cycle assessment and dynamic modeling using a nested systems theory, this framework provides a more holistic and integrated approach for modeling and improving the environmental performance of built stocks and their occupants, including material stocks and flows, embodied, operational, and mobility‐related environmental flows, as well as cost, and carbon sequestration in materials and green infrastructure. This comprehensive approach enables a very detailed parametrization that supports testing different policy scenarios at a material, element, building, and neighborhood level, and across different environmental flows. We test parts of our modeling framework on a proof‐of‐concept case study neighborhood in Melbourne, Australia, demonstrating its breadth. The proposed modeling framework can enable an advanced assessment of built stocks that enhances our capacity to improve the life cycle environmental performance of cities.
... This has led research communities in industrial ecology and material flow analysis to work intensively on understanding existing stocks through characterization of their patterns and impacts. Topics of material stock analysis include: the dynamics of stock accumulation over time (Fishman et al., 2014;Müller, 2006) and relationships between stocks, flows, and services , as well as the quantification of materials accumulated in buildings and infrastructure (Tanikawa et al., 2015) to better understand secondary resource recovery (Lanau & Liu, 2020;Oezdemir et al., 2017), embodied carbon emissions (Lanau et al., 2021;Mao et al., 2021;Stephan & Athanassiadis, 2017), and end-of-life scenarios (Mastrucci et al., 2017;Schiller et al., 2017). ...
Article
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The transition toward a circular economy (CE) is key in decarbonizing the built environment. Despite this, knowledge of—and engagement with—CE philosophies remains limited within the construction industry. Discussion with practitioners reveals this to be contributed to by a lack of clarity regarding CE principles, with numerous organizations recommending implementation of differing and sometimes conflicting principles. In addition, a systematic assessment of how building designs consider CE is made difficult by the multiple design areas required to be considered and the large amount of design data required to do so. The absence of a systematic CE assessment causes a lack of comparability across designs, preventing benchmarking of CE practices in building design at present. This paper details the development of Regenerate, a CE engagement tool for the assessment of new and existing buildings, established in an effort to overcome the aforementioned barriers to the adoption of CE within the construction sector. A CE design workflow for the built environment is proposed, comprising four overarching circularity principles (Design for Adaptability; Design for Deconstructability; Circular Material Selection; Resource Efficiency) and contributing design actions. In addition to engaging stakeholders by enabling the assessment of building designs, the tool retrieves key data for further research. Information on completed design actions as well as recycling and waste metrics is collected to facilitate future CE benchmarking. “Bill of materials” data (i.e., material quantities) is also compiled, with this being key in material stock modeling research and embodied carbon benchmarking.
... Recent studies conducted in Vienna (Gassner et al., 2020;Virág et al., 2021) and other global cities (Mao et al., 2021) revealed that auxiliary supporting structures play a vital role in railway MS but are neglected in most studies. Moreover, not many spatially explicit MS studies have considered other environmental factors or socio-economic indicators with the exception of several building cases (Ajayebi et al., 2020;Mollaei et al., 2021;Stephan & Athanassiadis, 2017). To date, no spatially explicit temporal studies have been conducted on transport infrastructure MS and variables such as on-road vehicles and CO 2 emissions from these vehicles. ...
Article
Development of transportation infrastructure that extends roads and railways in Bangkok has overlooked the negative environmental impact of construction material accumulation. To analyze the extent of this impact, we originally established road and railway's material intensity coefficients and investigated spatially explicit roadway and railway material stock (MS) for the years of 2004, 2009, 2014, 2019, and 2037, based upon the master plans’ target year. We further analyzed how MS evolution relates to the city's socio‐economic indicators and CO2 emission. Significant growth is found in transportation MS during 2004–2019, and roadways particularly increased from 122 to 164 million metric tons (Mt). The master plans would require 43 and 6.55 Mt construction materials for roadway and railway extension, respectively, by 2037. More material‐intensive roads (cross‐provincial highways and major local roads) built to the suburbs of the cities and underground/elevated structures of the mass rapid transit system in dense urban areas will require three times the annual cement and steel consumption of that in the 2004–2019 period. Furthermore, a 2–3 fold increase in the number of registered vehicles and associated CO2 emissions during the study period have brought questions to the transportation infrastructure MS efficiency. The findings of this study will enable informed decision‐making regarding the concern of resource consumption and for considering environmentally friendly approaches in urban transportation planning for Bangkok and other developing cities.
... 'Water', fundamental to life, is a crucial resource to be managed in a more systemic manner [68] through an implementation of water-sensitive principles [69] that could enable the water cycles inside and outside project boundaries [70], and at all phases, including the aspects of embodied water [71]. A systemic application of this framework should also consider how the use of nature-based solutions could enable the circularity of water systems [72], linking with category 4.3 ecosystem services provision. ...
Article
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Despite the increasing use of neighbourhood sustainability assessment tools (NSAT), their linear approach may be insufficient to tackle the global and local social and ecological challenges. The circular economy (CE) has recently emerged as a new pathway, adopted by corporations and public organisations. Understanding how to apply CE to existing communities, while addressing some of its shortcomings, particularly the strong focus on resource management, is the main goal of this paper. Building upon a Regenerative Circularity for the Built Environment (RC4BE) conceptual model that merges circular economy and regenerative design concepts, a framework with criteria for its implementation in the transition of existing urban areas is proposed. A preliminary framework structure with criteria mapped from literature is proposed and validated through a 2-round Delphi consultation with 31 international experts. The final framework, with 136 criteria, addresses some of the identified gaps and different urban cycles related to physical resources, ecosystems, liveability, infrastructure, governance, participation, local economy, and other socioeconomic aspects of urban communities. This expanded take on CE should be useful for built environment professionals and other urban stakeholders interested in regenerating their communities and precincts by going beyond current green approaches and existing tools to effectively generate positive impact for people and the planet.
... Nested Phoenix addresses existing gaps (see Figure 1) in environmental performance models at the urban scale by implementing spatialisation, using hybrid life cycle assessment, implementing a bottomup approach to quantifying and reporting on environmental performance using a dynamic approach, and including both buildings and infrastructure assets. These features enhance environmental modelling of built stocks, as compared to existing models such as [24], [25] or [26]. ...
Article
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Buildings and infrastructure assets in cities represent the dominant majority of the anthropogenic material stock and with the expected population growth this is set to double by 2100. It is therefore critical to quantify the life cycle environmental performance of built stocks, existing and forthcoming, to better manage them, modify their designs and mitigate climate change and resource depletion. Yet existing models fail to provide the required spatial and temporal resolution, are not comprehensive enough and often do not capture shifts in environmental effects. This paper presents Nested Phoenix, a bottom-up Python model that addresses these gaps and provides one of the most sophisticated models for built stocks to date. We present the scope of the model, its functionalities and development solutions before describing the different Python packages used, the overall approach and the database and model architecture. Nested Phoenix enables quantifying material stocks and flows and life cycle embodied, operational and transport environmental flows, alongside carbon sequestration in green infrastructure and biogenic carbon. This is coupled with a dynamic modelling approach that enables the investigation of myriad scenarios over time. This capacity, coupled with spatialization using geographic information systems, represents the breadth of Nested Phoenix.
... Hashimoto [17] quantified building stock in Japan by using statistical data to relate building stock in physical quantities per unit area to material intensity rates for several building types. Similar bottom-up approaches have also been conducted in Singapore [18], Norway [19], Sweden [20], Australia [21], Luxembourg [22], London [23], Rio de Janeiro [24] and Switzerland [25] with respect to residential buildings. All sources conclude that the quality of the identification of materials in existing buildings strongly depends on the origin and the available information content of the documents. ...
Article
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This article describes an approach for comparing material intensity values for residential buildings with different construction types. Based on the working drawings of the different construction types (wood and mineral), material intensities are calculated at the building level. Material intensities describe the materials used in a building in mass (tonnes (t)) in relation to the square meters (m2) of gross floor area (GFA) or the cubic meters (m3) of gross volume (GV). The method for determining material intensities at the building level is demonstrated. The results show that material intensities range from 0.61 t/m2 GFA to 1.95 t/m2 GFA for single-family residential buildings and from 1.36 t/m2 GFA to 1.54 t/m2 GFA for multi-storey residential buildings. The average material intensity for mineral buildings is twice as high as that for wood buildings, which means that there is a beneficial resource efficiency in building with wood instead of mineral materials. Therefore, benchmarks for a resource efficient building can be conducted based on these values. These values demonstrate a possibility to influence resource efficiency in buildings.
... For greater reuse of construction materials from existing building assets, urban designers and planners ought to share data that quantifies and maps the embodied environmental flows of urban stocks. Indeed, by treating existing buildings as material banks, urban planners can contribute to more effective circular economies that reduce embodied environmental flows over time (Stephan & Athanassiadis, 2017). Determining the optimal maximum building height for planning schemes based on environmental flows requires a multidisciplinary multi-scale approach that assesses life cycle performance across the built environment. ...
Thesis
Urgent changes are needed in the construction industry to meet short term mitigation goals for climate change. Traditionally, operational environmental flows have been the primary focus of regulations and current attempts to improve the environmental performance of buildings. However, studies have revealed that embodied environmental flows are often underestimated and rarely considered. Embodied environmental flows are particularly significant in the structural systems of tall buildings due to the substantial influence of wind and earthquake loads on structural material requirements. This thesis presents a framework for integrating embodied environmental flow assessment into the structural design of tall buildings using comprehensive hybrid methods for life cycle inventory analysis and advanced structural design and finite element modelling techniques. An advanced software tool was developed to formalise the framework and automate the structural design, modelling, analysis, optimisation and embodied energy and embodied greenhouse gas emissions assessment of more than 1,000 structural systems. Through regression analyses, predictive models were constructed for the embodied energy and embodied greenhouse gas emissions per net floor area of 12 unique combinations of structural typologies and structural materials. These models were integrated into a purpose-made online dashboard, which enables engineers and designers to compare alternative structural materials (i.e. 32/40/50 MPa reinforced concrete and steel), structural typologies (i.e. shear wall, outrigger and belt and braced tube) and geometries (i.e. rectangular floor plan geometries) according to the embodied energy and embodied greenhouse gas emissions per net floor area of structural systems. Two case studies were used to illustrate the potential of the framework and software tool in reducing the embodied environmental flows of structural systems for tall buildings of varying heights. Results show that all considered building parameters are significant and cannot be neglected in assessing alternative structural systems for tall buildings based on their embodied environmental flows. The developed framework and software tool have been shown to provide the most precise and sophisticated integration of embodied environmental assessment into the parametric structural design of tall buildings as of yet. Through a simple and user-friendly interface, they enable tall building designers to utilise environmental assessment as a design-assisting tool, rather than as an appraisal method to evaluate a completed building. This will potentially lead to reductions in the environmental effects associated with the construction of tall buildings.
... Refs. [2,11,15,23,24]). Still, these studies focus on a single building type or are sector-/region-specific rather than economy-wide, meaning that their assessment of the macroeconomic effects of energy efficiency improvements remains limited. ...
Article
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Investments in energy efficiency are vital for reducing greenhouse gas emissions by 2030 given that changes in the structure of the main energy sources cannot be expected in the short to medium term. The greatest potential for energy savings and cutting emissions lies in buildings due to their significant carbon intensity and rapid growth rate. However, gaps remain in what is known about integrating decarbonisation of the built environment into the economy-wide system. The paper addresses such gaps by examining the socio-macroeconomic implications of different scenarios related to building stock investments in a small open economy. The effectiveness of the measures implemented for various building types and the possibility of a rebound effect are also considered. The study is valuable for the peculiarities of the recursive dynamic computable general equilibrium model, GreenMod Slovenia, which was established to analyse the effects of decarbonisation. Two major contributions emerge: (1) projected energy efficiency in buildings is presented separately for commercial services, public services and households in two investment scenarios, namely, the business-as-usual scenario and the energy efficiency scenario with additional investments; and (2) the disaggregation of households into income quintiles to project their consumption of energy inputs. The study reveals vital macroeconomic benefits flowing from the energy efficiency scenario, including higher GDP and employment. Second, energy efficiency improvements in commercial services might encourage higher energy consumption. Finally, low-income households reduced the consumption of energy products the least. In this quintile group, energy efficiency improvement can lead to greater energy consumption, denoting policy failure.
... However, to present a comprehensive evaluation of the potential environmental effects of a particular material or product in urban mining, it is required to integrate the life cycle assessment, urban building stock model, and energy requirement model. In addition, among the previous papers, only one study [64] focused on a specific construction product, while the others [65][66][67][68] aimed to map and quantify the material weights and volumes in the urban areas. ...
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The traditional linear economy (LE) approach based on a “take-make-dispose” plan that has been used in building activities over a long period has a significant impact on the environment. In the LE approach, the used materials are usually sent to landfills rather than recycled, resulting in resource depletion and excessive carbon emissions. A circular economy (CE) is expected to solve these environmental problems by promoting material “closed-loop systems”. This study was intended to quantify and analyse the global warming potential (GWP) values of specific metal roofing and cladding products to promote CE thinking. A spatiotemporal model integrated with the life cycle assessment (LCA) tool was used to quantify the GWP value of the steel products in the investigated buildings. The study analysed ten case buildings located in six different cities in New Zealand: Auckland, Wellington, Hamilton, Palmerston North, Tauranga, and Christchurch. The production stages (A1–A3), water processing (C3), disposal (C4), and re-cycle, reuse, and recovery stages (D) were the focus of the study in analyzing the GWP values of the product’s life cycle. The study found that the production stages became the most significant emitters (approximately 99.67%) of the investigated steel products’ GWP values compared to other selected life cycle stages. However, when considering the recycling stages of the steel products, the GWP value was reduced up to 32%. Therefore, by implementing the recycling process, the amount of GWP can be reduced, consequently limiting the building activities’ environmental impacts. In addition, the integration of spatial analysis and LCA was found to have potential use and benefit in future urban mining and the development of the CE approach in the construction industry.
... In addition, most studies focus on material circularity [5,6,13,16], and only a few studies consider the component level [7,17]. Some components are integrated and not easy to split into explicit materials [17]; for instance, windows and doors need to be replaced and recycled as the integrated component [24]. Thus, the component level needs to be considered in addition to MSs, which helps stakeholders better manage building stocks. ...
Article
The building sector is material-intensive and responsible for embodied energy and greenhouse gas (GHG) emissions. Comprehensively analysing the evolution of material stocks (MSs) and associated environmental impacts in the building sector can support better decision-making on material management and energy conservation. However, there is a gap in the literature to evaluate the spatial patterns and dynamics of residential building stocks systematically and comprehensively. A simulation-based bottom-up approach is proposed to systematically analyse the spatiotemporal evolution of residential buildings’ MSs and their environmental impacts at initial and replacement stages with a high resolution. Notably, the development of the material intensity dataset is essential for analysing MSs in the building sector. The proposed innovative approach links different building characteristic factors for developing a specific material intensity dataset. The approach is demonstrated for Inner Melbourne, which has more than 260,000 residential buildings. The results illustrate the spatially and temporally explicit MSs, embodied energy and GHG emissions in the case study area. The initial spatial maps visualise that large quantities of MSs, embodied energy and GHG emissions are located in areas with clusters of houses or apartments. The replacement maps indicate the locations with large replacement material outflows where a cluster of historic buildings exist. The temporal analysis shows that the residential buildings’ MSs in Inner Melbourne have increased by a factor of 9.6 over the past 120 years, reaching 27,488 kt in 2019. The growth rate has accelerated since 1990, particularly in areas (e.g. Melbourne CBD, Docklands, Southbank and South Yarra) with a large number of apartments have been built during this period. The high resolution of the results shows the benefits of the proposed simulation-based bottom-up approach compared to the traditional approach. This result is significant as it provides new insights for evidence-based decision-making on material management and energy conservation towards a more circular construction.
... According to an estimate, the construction sector consumes approximately 50% of natural raw materials, 40% of global energy, emits 50% of CO 2 , and produces 40% of total global waste streams. 1 In addition, a large quantity of construction and demolition waste, mostly disposed in landfills, inevitably brings environmental hazards and land occupation. Partial or full replacement of natural aggregates in concrete by recycled aggregates (RAs) is perceived as an effective measure for mitigating the aforementioned issues. ...
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This research aims to investigate the cyclic behavior of prestressed assembled precast frame structures that contain various amounts of recycled aggregates. A series of half-scale model precast frame structures with different recycled aggregate substitutions, varying from 0 to 100%, were constructed and tested to failure to eval�uate their structural performance indexes in terms of strength, stiffness, cumulative energy dissipation, and damping ratio. The tests showed that all tested prestressed assembled precast frame structures maintained the features of a low-damage and self�centering seismic resistant system before the drifts attained 4%. The occurrence of adverse effects in seismic behavior is more likely if more natural aggregates are substituted by recycled aggregates. However, those adverse effects observed in the experiments are not severe. Therefore, this type of recycled aggregate concrete precast frame has the potential to provide adequate seismic capacity. It is definitely possible to be used in regions of high seismicity with a rational design. Empirical equations for estimating the equivalent damping and self-centering efficiency are proposed.
... For the additional materials included in the construction sector in Figure 7, it is difficult to estimate the added percentage in the total mass of materials, as they are either transformed materials (and these are not represented in the EW-MFA dataset) or the materials are not unique to the construction sector (for instance, iron can be used to make steel for very different applications). Therefore, the additional materials were selected by looking at material stock analysis case studies (Stephan and Athanassiadis 2017). In terms of sector or sector-wide circularity, it was concluded that for investigating it, the circularity of the different material streams will be the ones considered and added up to represent the sector itself. ...
Technical Report
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The document presents an accounting method for cities to evaluate the circularity of their construction and biomass sector(s). Firstly, it goes through some general definitions and concepts of circularity in cities and sectors. The next section showcases the proposed sector-wide circularity assessment method and discusses related data needs, processing, and analysis. This method combines material flow accounting and key “circularity” indicators to assess circularity in economic sectors. The developed method seeks to find a balance between scientific rigor and comprehensiveness on the one hand, and operability by urban policy makers and practitioners on the other. Finally, this document provides a handbook for urban policy makers and practitioners on how to apply this method for the biomass and construction sector of their city.
... smart structures are those intelligent structures that are made up of smart data collected by monitoring devices and sensors connected throughout the city connected to the smart grids and IoT systems [28][29][30]. The structure of the network can be divided into two partitions 'indoor'; like, home and office or corporate buildings or and 'outdoor'. ...
... It is possible to obtain more comprehensive data for products (including not only the built environment but also durable goods) in each social system using statistical data, and at the same time, it is easier to describe long-term time series for changes in flows and stocks to reveal dynamic change mechanisms. Research has gradually evolved to more specific end-use categories such as buildings (Stephan and Athanassiadis, 2017;Arora et al., 2019;Cao et al., 2019), infrastructure (Han et al., 2018;Zhang et al., 2019;Hou et al., 2015), household appliances (Zhang et al., 2011), and automobiles (Serrenho and Allwood, 2016), and has been targeted at multiple types simultaneously (Fu et al., 2019;Wiedenhofer et al., 2015;Tanikawa et al., 2014). However, exsiting bottom-up applications are basically showing "snapshots", i.e. accumulation stocks at the end of the previous year. ...
Article
The functional roles and environmental effects of long-lived buildings, infrastructure, and durable goods can determine both the benefits to natural environment and a city's human residents. However, their overall lifecycle metabolic processes are complicated and previous studies mainly considered specific materials or products. Here, we provide a more comprehensive picture of flows and stocks for Beijing's materials, products (61), and sectors (9). Based on a multi-level material stock–flow network model, we obtained insights into the city's material inputs and outputs of each urban sector, the cumulative flows of materials and products, and the waste sources for end-of-life products. From 2000 to 2018, the total system throughflow increased from 269 to 435 Mt by 2007, then decreased to 317 Mt. Beijing's main sector of consumed resources and discharged wastes both shifted from Fabrication and Manufacturing to Construction. The local extraction and production weights decreased by half, whereas the inflows to the Construction and Transportation sectors increased greatly, mainly (92%) as imports (from regions other than Beijing). The main destinations of these materials were buildings and pipelines, which were also main waste sources. Notably, resource demand and waste discharge from vehicles and railways increased greatly. Although Beijing's recycling increased, it must increase further to meet final waste generation, which has increased 5-fold, to 52 Mt in 2018 during the city's socioeconomic development. Additional actions should be taken to reduce waste streams and promote reuse and recycling to achieve the UN Sustainable Development Goals.
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With 60% of the world's raw materials extraction, the construction sector is the largest consumer of raw materials. The consumption can be reduced through reuse and recycling of building materials which reached their end-of-life; however, there is lack of information on the building stock. This paper presents a bottom-up approach based on Building Information Modeling (BIM) and Geographic Information System (GIS) to assess material quantities. To test this approach, a real-world building is used. The material intensity is calculated based on existing planning documentations, on-site investigations, laser scanning and a BIM-model. The gross volumes (GVs) obtained from GIS enable the modelling and prediction of cities' building stocks. The results of this paper demonstrate the method of calculating material intensities and present how the applied method can be used to predict building stocks. The latter is presented as a framework which can support various cities in assessing their material stock.
Book
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This open access book provides new perspectives on circular economy and space, explored towards the definition of regenerative territories characterised by healthy metabolisms. Going beyond the mere reuse/recycle of material waste as resources, this work aims to understand how to apply circularity principles to, among others, the regeneration of wastescapes. The main focus is the development over time, and in particular the way how spatial planning and strategies respond to new unpredictable urgencies and opportunities related with territorial metabolisms. The book specifically focuses on living labs environments, where it is possible to tackle complex problems through a multidisciplinary and multi-stakeholder approach - including the use of digital spatial decision support environment – which could be able to include all the involved stakeholders. Through a spatial scope of circularity, this book describes several examples including among others ideas from different contexts such as Italy, The Netherlands, Belgium and Vietnam. Through including reflections on methodology and representation, as well as on solutions for circular and healthy metabolisms, the book provides an excellent resource to researchers and students.
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City and regional planners have recently started exploring a circular approach to urban development. Meanwhile, industrial ecologists have been designing and refining methodologies to quantify and locate material flows and stocks within systems. This Perspective explores to which extent material stock studies can contribute to urban circularity, focusing on the built environment. We conducted a critical literature review of material stock studies that claim they contribute to circular cities. We classified each article according to a matrix we developed leveraging existing circular built environment frameworks of urban planning, architecture, and civil engineering and included the terminology of material stock studies. We found that, out of 271 studies, only 132 provided information that could be relevant to the implementation of circular cities, albeit to vastly different degrees of effectiveness. Of these 132, only 26 reported their results in a spatially explicit manner, which is fundamental to the effective actuation of circular city strategies. We argue that future research should strive to provide spatial data, avoid being siloed, and increase engagement with other sociopolitical fields to address the different needs of the relevant stakeholders for urban circularity.
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Cities consume a large amount of energy and discharge massive greenhouse gas emissions, which are key areas supporting low-carbon development and combating the global warming crisis. Conducting regional impact assessments has been a trending research topic, but not without its challenges; especially, foreground data acquisition and temporal dynamics consideration. This study integrates City Information Modeling (CIM) and Dynamic Life Cycle Assessment (DLCA) to develop a new regional carbon impact assessment model, including five parts: goal and scope definition, CIM module, foreground elementary flows analysis, dynamic assessment, and interpretation. In the integration model, CIM is used to extract the geometric and semantic data of the physical elements and geospatial information of built environment. Temporal variations in foreground elementary flows, background inventory datasets, characterization factors, and weighting factors were quantified and involved. A university campus was used to verify the CIM-DLCA integration model, and the impact results were visualized and analyzed from temporal and spatial dynamic perspectives. The influences and sensitivity of dynamic factors were quantified and compared. In addition, the uncertainty issues, data acquisition advantages, and CIM-DLCA integration strategies were discussed. Some valuable future research directions were proposed. This study takes an exploratory step and demonstrates that combining CIM with DLCA is both feasible and operable. This provides a theoretical foundation for intelligent assessment and can be used to promote low-carbon city management.
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Anthropogenic stocks are increasingly seen as potential reserves for secondary resources, which has led to a rapid development in research of urban metabolic systems. With regard to buildings and their associated material stocks and flows, one of the most critical shortcomings in the state-of-the-art is the knowledge gap for drivers, dynamics, patterns and linkages that affect the urban metabolism. This paper is premised on the idea that urban planning stirs up these material flows, so it should also adopt their sustainable management on its agenda. It presents an approach that highlights the intertwined nature of changing urban morphology and building material stocks and flows in space and time. An analytical framework, based on the principles of material flow analysis, is provided for an integrated, spatiotemporal study of urban morphology and urban metabolism of buildings, using building and plot data as the input and identifying internal processes of the urban metabolism as the output. The identified processes include greenfield development, infill construction , building replacement and shrinkage, each of which can be expected to have tangible yet very different material and environmental consequences in the form of embodied materials and CO2. The use of the framework is demonstrated with a case study in the Finnish city of Vantaa in 2000-2018. The case study shows patterns pertaining to a growing city unrestricted by geographic or historic factors, manifested as vast greenfield developments and replacement of a notably young building stock. As sustainability may soon call into question both these strategies, uncovering the material consequences of a city's past urban (re)development strategies lay the foundation for using the presented approach proactively in planning support, in pursuit of more circular economy-based and low carbon cities.
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Our global demand for resources currently exceeds the Earth’s carrying capacity (ECC), defined as the limit of anthropogenic pressure that our ecosystem can withstand within its regenerative and assimilative capacities. Representing a significant share of global environmental degradation, cities are seen as having the potential to catalyze a transition to a truly sustainable state in compliance with ECC. However, in order to do so, urban decision-makers must rely on robust measurement tools representing the complex dynamics or urban systems to guide their actions. This paper asks what tools exist to bridge this gap between theory and practice, what role urban planners are now giving to the ECC, and what the sustainability status of high-income reductionleading cities is in relation to the ECC. Ten assessment frameworks and four sustainability indicators were identified as compatible with the One Planet goal and adapted to measure key urban flows. Sustainability is primarily considered through the lens of climate at the urban scale, and existing assessment standards lack comprehensibility, leading to an overall underestimation of cities’ total environmental footprint. To select and analyze the leading cities in impact reduction, we used the following criteria : achievement of an absolute GHG emission reduction greater than 15 % over the period 1990-2020, and intentionality/commitment to sustainability through active membership in specific environmental knowledge transfer groups. Twenty-four cities were identified whose GHG reductions since 1990 range from 24-49 %, which is between 2-4 times lower than what is required by high-income cities by 2050 to reach the goal of living within ECC. To achieve a "one-planet life", cities must address their overconsumption using systemic tools that incorporate the notion of ECC and consider indirect emissions related to urban consumption. Various obstacles to this approach have been identified, of a practical, economic, cultural and geopolitical nature, and must be taken into account in order to promote the wider use of ECC as the ultimate goal of sustainability. Achieving a global state that respects ECC is everyone’s concern. Hence, the establishment of specific reduction targets, based on collaboration and effort-sharing approaches, must be promoted to ensure an environmentally efficient and socially just transition.
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PURPOSE The purpose of this research is to estimate the renovation potential of a city’s building stock and evaluate the environmental impact reduction and greenhouse gas emission reduction realized by clustered renovation. These reductions are compared to the climate goals for 2050 by the city of Leuven, i.e., 81% reduction in CO2-eq. compared to 2011 to support the development of an optimal renovation strategy for the city. METHODS The building stock of Leuven is analyzed and subdivided into various clusters of buildings with a similar renovation potential. This paper presents the existing status of one cluster consisting of terraced buildings built between 1946 and 1970 and assesses its required renovation measures using a life cycle approach by applying the Belgian LCA method for buildings. The environmental impact of this cluster and the potential reductions obtained by the renovation are upscaled and compared to the city climate goals. Based on these results, the total impact of this cluster on the greenhouse gas emissions of Leuven is calculated and the most impactful renovation measures identified. RESULTS AND DISCUSSION The results reveal that renovating the walls, floors, and roofs of the houses in this cluster in Leuven (representing ca. 5% of the stock) can lead to a reduction in CO2-eq. emissions of 0.9 to 1.9% compared to the emissions by Leuven households in 2011. This estimate ignores the improvement of the airtightness and the renewal of heating systems. So, higher reductions may be possible. The renovation impact of each of the building elements is evaluated separately, indicating that the highest improvements can be obtained by improving the insulation level of the walls. A sensitivity on the original state of the building has been performed by assuming the absence of (a small) insulation layer in the original roof state. This reveals a significant higher CO2-eq. reduction potential due to renovation. CONCLUSIONS The results demonstrate the appropriateness of the clustering approach in estimating the greenhouse gas emissions of a certain housing type and the potential contribution of renovating these to reduce the city greenhouse gas emissions. By extending this analysis to all identified clusters, the full potential of renovating the housing stock in Leuven can be estimated and can help in setting priorities in the overall goal to reduce greenhouse gas emissions.
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The built environment plays a central role in the transition towards the circular economy as they concentrate major consumer and polluter human activities. However, the way BEs are – and need to be – driven by policy to reach cities’ circular goals is still an under-researched aspect. Particularly, there is limited knowledge of policy instruments aimed to foster the transition towards a circular built environment. Therefore, we conduct a systematic literature search and a review of scientific publications to characterize the relation between the circular built environment and policy instruments suggesting its implementation from a circular city development perspective. We do so by answering: (1) how many publications elaborate on CBE policy instruments, (2) what type of circular actions in relation to circular city development are mentioned, and (3) what policy instruments are proposed to implement a CBE. The literature search is performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Our results show that 53% of publications address policies instruments for circular built environment transitions. Although different circular actions are identified, looping actions prevail. Adapting and ecologically-regenerating actions, which are essential for circular city development, remain insufficiently researched. Finally, among policy instruments for circular built environment implementation there is a clear tendency towards regulation as means for leverage, which calls for bigger research efforts concerning the mix of policy instruments, as well as in more general challenges in governance and policy coherence.
Article
Due to severe sustainability problems caused by the built environment, calls for adopting circular economy principles in building design, such as flexibility and reversibility, are increasing. However, there is still a lack of quantitative studies on the corresponding environmental benefits in this regard. In the present study, a life cycle assessment of a multi-storey residential reference building is carried out, comparing a flexible, reversible building design using a load-bearing steel structure and wooden ceiling elements to a conventional, monolithic design based on reinforced concrete. The assessment is carried out on a whole building level, including construction, operation, maintenance, and the end-of-life phase. Both building designs show similar results for a regular life cycle of 60 years without major refurbishment (13 and 14.5 kg CO2-eq/m² per operational year). When longer building lifetimes are considered, the environmental impact of the reference building per operational year decreases significantly. In this context, flexible building design is advantageous as it facilitates the refurbishment of buildings, while monolithic building design often leads to premature demolition due to low adaptability. Further advantages of reversible building design include the increased potential of materials to be recirculated at the end-of-life stage of a building and in the potential reuse of structural elements. This study shows that 14% of the embodied greenhouse gas emissions of the flexible building can be avoided if the foundation, load-bearing structure and ceiling elements are kept in place for a subsequent building. Such direct reuse leads to a substantially higher environmental value retention than recycling of the same materials.
Chapter
Human activities are responsible for vast environmental impacts, including carbon emissions contributing to climate change. The urban environment is a main source of many of these impacts, and accordingly, the European Union has launched the “100 climate-neutral cites” mission to operationalize a carbon-free urban future. This paper investigates the various evaluation tools supporting the Decision-Makers (DMs) and stakeholders in their effort to achieve the carbon-neutral transition. Using the scientific database Scopus, we conducted a literature review focused on different keywords comprising widely used evaluation methods. The focus of the research is on different aspects and scales of the urban systems, considering the multi-dimensional nature of the decision problems at such scale. Specifically, the study presented here analyzes the way in which these methods deal with large scales, either with a bottom-up or a top-down approach, and how different categories of Key Performance Indicators (KPIs) and changes in the DMs system of values can influence their preferences. We find that Lifecycle Assessment (LCA) is the most used support tool at the district or city level, and most indicators focus on energy consumption and carbon emissions. A smaller share of studies reviewed are based on multi-domain evaluation methods. KeywordsClimate-neutral citiesLow carbonEnergy transitionUrban regenerationDecision-making toolsDistrictNeighborhoodUrban scale
Article
From the production of raw materials to the construction of a building, construction activities consume large quantities of water as embodied water. In fact, over 16% of global water use occurs in construction activities. Total embodied water of a building includes water directly used in construction activities, water indirectly consumed in the production and delivery of construction materials, and water used by the energy sources powering the construction activities as embodied energy. However, the number of comprehensive studies on embodied water of buildings is lacking. In this study, an input-output-based hybrid model is developed to determine and analyze not only direct and indirect embodied water intensities, but also the energy related embodied water intensities of construction materials and higher education buildings. The results indicate that, similar to embodied energy, using an aggregated input-output-based hybrid analysis may return misleading embodied water values as compared to a disaggregated analysis because embodied water intensities vary for each material. The results also show that the amount of energy related embodied water could be significant (7%–12% of total embodied water at the building level), highlighting the significance of energy related water use when evaluating total embodied water. Results further underscore the significance of applying a more energy-water nexus perspective when evaluating the environmental and resource consumption impacts of buildings.
Article
Rapid urbanization generates substantial demand, use, and demolition waste of construction materials. However, the existing top‐down or bottom‐up frameworks combining material flow analysis (MFA) and geographic information system (GIS) tend to underestimate both input and output of construction material flows due to insufficient descriptions of key processes in building construction and demolition. To address this limitation, this study identifies four important and complementary processes—construction, demolition, replacement, and maintenance, and integrates them into an improved framework to capture all material flows. We take Xiamen, a rapidly urbanizing city, as a case study to verify this framework. The results show that ∼40% of material inputs and ∼65% of outputs are underestimated by previous frameworks because they fail to capture material inputs in building maintenance and outputs in construction. These findings indicate a better estimation of such key flows in the modeling framework helps to accurately characterize building material metabolism. Based on systematic counting of material stocks and flows, the improved framework can help design effective policies for urban resource management by explicitly recognizing the spatiotemporal patterns and processes of material metabolism.
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Nowadays, the circularity concept dominates the debate on resource management in cities and territories. The idea is often used as a vehicle towards a more sustainable socio-ecological transition, based on the circular economy (CE) framework. Unlike other sustainability frameworks, CE originates in ecological and environmental economics and industrial ecology. It focuses on developing an alternative economic and technological model for production and consumption, avoiding natural resource depletion and redesigning processes and cycles of materials (closed-loops). However, when CE is translated to cities and territories, its environmental, economic and design agency is often neglected. On the one hand, it demands to acknowledge the need for a relational understanding of space, place and actors involved and, on the other, to explore the spatial specificity of CE. Therefore, there is a need for a broader theoretical discourse on the CE’s territoriality as the predominant. Research on circular urban and territorial development demands more than merely upscaling industrial ecosystems diagrams and generating circular businesses. Consequently, what is the role of territory in the CE conceptualisation in the urbanism literature? How to interpret territories through the lens of circularity, which tools, methods are needed? Therefore, territory, its role and meaning in the CE contribution to urban regeneration is the key focus of this text.
Chapter
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Advancing circularity in metropolitan areas involves planning, co-designing and implementing spatially explicit interventions with a multitude of stakeholders who are required to work with waste and resource management information. For the stakeholders, understanding information on these flows of resources and materials, and the spatial implications of these flows across the territory, is crucial when proposing new interventions and assessing the effects of these interventions. Spatial decision support systems constitute potential tools for supporting groups of stakeholders involved in the collaborative process of shaping the future of urban areas while achieving sustainability and increased circularity. This chapter focuses on the digital representation and portrayal, and the use of different types of information in a digital spatial decision support tool aimed at helping decision-makers through stages of the collaborative process that starts at problem identification and status quo understanding, and finishes at the proposed circular economy strategies for a metropolitan area. The way in which information is modeled and presented in the tool is largely based on the geodesign methodology, and is specific to individual stages of the planning process. The tool presents information relevant to a peri-urban area through different mediums: web maps and charts to describe the study area, Sankey diagrams linked with dynamic flow maps to portray its resource flow streams, and the integration of the above to portray and assess the scenarios developed jointly by the stakeholders. The tool was implemented in an interactive web application and applied to the collaborative process of developing spatial strategies for advancing circularity in the Amsterdam Metropolitan Area. A series of interconnected workshops were held with stakeholders, who used the tool to guide them through the stages of the co-development of the strategies. Stakeholders were presented with spatial information about the study area’s current resource and waste management situation in the form of web maps and the spatial distribution and dynamics of resource flows. This chapter describes how all this information was portrayed, presented, and used within the interactive web application at the collaborative workshops.
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In this chapter, the understanding of circularity goes beyond material resource management, deepening the spatial implications of a more circular management and use of wastescapes, investigated at the urban and metropolitan scale. Besides the health (care) related challenges presented by the current outbreak of the COVID-19 pandemic, additional ones related to our living environment have been—and will continue to be—an urgent call for academic researchers, designers and policymakers to find (eco)innovative solutions and strategies for enhancing the quality of life of all and the availability of more and more safe public (open) spaces and facilities to sustain this. In this situation, the spaces most at risk of urban and peri-urban areas could be found in the unresolved places which are defined as wastescapes, since they are in general still poorly used and valued. Building on the European H2020 research project REPAiR, the definition of wastescapes, provided in this study, builds upon work for two main cases: the metropolitan areas of Amsterdam (The Netherlands) and Naples (Italy). Wastescapes are discarded territories, however, they can also be understood as opportunities to realize regenerative concepts and support strategies related to environmental, spatial and social challenges of the territories and their surroundings. Core is then to improve the socio-ecological values of such territories. Wastescapes are different case by case, being affected by site-specific challenges and characterized by high complexity. The research presented in this chapter shows that the route towards a Circular Economy requires the consideration of wastescapes as ‘spatial resources’ important to be included in strategies of transition. It represents a fundamental step to overcome problems related to both resource (and land) scarcity, land use in general and spatial fragmentation, while providing opportunities to include through eco-innovative services other values than just the monetary ones to society. The spatial regeneration of wastescapes in the built environment involves a re-thinking of the structure of these areas in a larger (metropolitan) context. Within such metropolitan settings, in particular peri-urban territories, also referred to as the areas in-between urban and rural landscapes, are most affected and characterized by this problem of wastescapes.
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Urban Regeneration (UR) is an approach to urban development contrasting soil consumption by catalyzing social energies to reuse urban existing heritage (brownfields and dismissed buildings). The authors of this chapter are professionals within KCity Ltd., a bespoke consultancy specialized in UR design strategies adopting an interdisciplinary approach, derived in particular from policy analysis and urban planning. The aim of this chapter is investigating the potential of UR practices to give a contribution to the scientific debate about Circular Economy and its application into urban development.
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A great deal of the contemporary discourse around circularity revolves around waste—the elimination of waste (and wastelands) through recycling, renewing and reuse (3Rs). In line with industrial ecological thinking, the discourse often focuses on resource efficiency and the shift toward renewables. The reconstitution of numerous previous ecologies is at most a byproduct of the deliberate design of today’s cyclic systems. Individual projects are often heralded for their innovative aspects (both high- and low-tech) and the concept has become popularly embraced in much of the Western world. Nevertheless, contemporary spatial circularity practices appear often to be detached from their particular socio-cultural and landscape ecologies. There is an emphasis on performative aspects and far too often a series of normative tools create cookie-cutter solutions that disregard locational assets—spatial as well as socio-cultural. The re-prefix is evident for developed economies and geographies, but not as obvious in the context of rapidly transforming and newly urbanizing territories. At the same time, the notion of circularity has been deeply embedded in indigenous, pre-modern and non-Western worldviews and strongly mirrored in historic constellations of urban, rural and territorial development. This contribution focuses on two contexts, Flanders in Belgium and the rural highlands, the Mekong Delta and Ho Chi Minh City in Vietnam, which reveal that in spite of the near-universal prevalence of the Western development paradigm, there are fundamentally different notions of circularity in history and regarding present-day urbanization. Historically, in both contexts, the city and its larger territory formed a social, economic and ecological unity. There was a focus is on the interdependent development of notions of circularity in the ever-evolving relations of landscape, infrastructure and urbanization. In the development of contemporary circularity, there are clear insights that can be drawn from the deep understandings of historic interdependencies and the particular mechanisms and typologies utilized. The research questions addressed are in line with territorial ecology’s call to incorporate socio-cultural and spatial dimensions when trying to understand how territorial metabolisms function (Barles, Revue D’économie Régionale and Urbaine:819–836, 2017). They are as follows: how can case studies from two seemingly disparate regions in the world inform the present-day wave of homogenized research on circularity? How can specific socio-cultural contexts, through their historical trajectories, nuance the discourse and even give insights with regard to broadened and contextualized understandings of circularity? The case studies firstly focus on past site-specific cyclic interplays between landscape, infrastructure and urbanization and their gradual dissolution into linearity. Secondly, the case studies explicitly focus on multi-year design research projects by OSA (Research Urbanism and Architecture, KU Leuven), which underscore new relations of landscape, infrastructure and urbanization and emphasize the resourcefulness of the territory itself. The design research has been elaborated in collaboration with relevant stakeholders and experts and at the request of governmental agencies.
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Recent international—UN-Habitat and European Environment Agency—and Italian reports have pointed out that urbanization is incessantly expanding at the expense of biodiversity and of rural lands. The radical growth of land consumption and change of land-use contribute to the increase of territorial risks and vulnerability. In particular, such phenomena are more visible within the peri-urban interface, considered as hybrid and malleable areas straddling between city and countryside realities. Even in the absence of a univocal definition, peri-urban is understood as a space where urban expansion occurs. Moreover, it emerges that such space also lacks local governance. Such uncertainty of form, identity and regulation catches the attention of a new urban agenda, which considers the peri-urban the most suitable place where to enact social, ecological and economic challenging changes. In this light, this paper aims to underline how peri-urban areas, although ecologically, socially and weak from a legislation point of view, constitute challenging territories to enact regenerative design and practices. In particular, new policies in sustainable agriculture are considered as potential solutions for the rapid soil consumption in Europe. Therefore, Campania region has been taken as our case study, because the region has a long history of agricultural practices and currently, it is closely linked to risk dynamics. It also represents an emblematic example for its innate exposure to natural hazards (related to its geological nature and geographical location), and for the ongoing man-made risks as causes of ecological and territorial damages. Moreover, land consumption in the region reached a record level in 2019, with 10% of agricultural land lost in a year (corresponding to 140,033 hectares). More than 70% of the consumed lands coincided with areas already exposed to natural hazards, both seismic and hydrogeological (Munafò, 2020). This paper assesses the results of an experimental application developed as part of the REPAiR (This research has been conducted within the framework of the European Horizon 2020 funded research “REPAiR: REsource Management in Peri-urban AReas: Going Beyond Urban Metabolism” [ http://h2020repair.eu/ ]. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 688920. This article reflects only the author’s view. The Commission is not responsible for any use that may be made of the information it contains). Horizon 2020 European research project. We argue that the project results underline the relationship between the peri-urban interface and the soil regeneration through eco-innovative solutions. This has allowed us to link the spatial condition of the peri-urban with the production of waste and its subsequent recycle. This paper aims to further explore the research field experimented during REPAiR, expanding the materials available on the peri-urban and adding information with respect to the risk to which these places are linked.
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Port and city authorities all over Europe and beyond are striving with finding solutions able to combine sustainability with economic growth. Several global urgencies in fact, such as climate change, energy transition, the exponential changes in the scale of ports and ships and last but not least the economic and health shock related to the coronavirus pandemic, are challenging the spaces where ports physically meet their cities, generating processes of caesura within the urban patterns with consequent impacts on the quality of life. In port cities, infrastructures and energy flows overlap with city flows and patterns that change with different rhythms and temporalities. This discrepancy creates abandonment and marginality between port and city. This today is no longer sustainable. New approaches and solutions that look at integration and circularity rather than separation are necessary. Circularity has been widely discussed in the literature. However, the concept still remains very controversial, especially when it comes to port cities where new definitions are needed in particular to better understand the spatial dimension of circularity. The Rotterdam therefore case study stands exemplary. Here, the concept of the circular economy refers mostly to the theme of obsolete industrial buildings and marginal that are reinserted again within the urban metabolism. The case of Rotterdam points out that the competition of the port today goes through the quality of its relationship spaces and the ability of the different actors involved in the planning process to hold together economic growth and environmental sustainability. The areas along the river are in fact the most fascinating places in the city and today they are ready for a different use. In order for the city to become an attractive place to live it is necessary to build new, innovative and sustainable spatial visions. This will lead to scenarios of sustainable coexistence between port and city. Therefore, these two agendas (sustainable port and city attractiveness) came together in the area known as Makers district (M4H) which, together with RDM campus, represents the Rotterdam testing ground for innovation. Therefore, this chapter, by arguing that ports will play a crucial role in the transition towards more circularity investigates how to make it happen and how to transform the challenges of the port into opportunities for a territorial regeneration towards new forms of integration. In order to answer the question, the case of Rotterdam is presented to analyse a model of urban regeneration where different planning agencies—mainly port authority, municipality, universities and private parties—work together at different scales to define a sustainable coexistence of interests. The research, which draws data on existing literature and policy documents analysis, firstly introduces the spatial and governance structures of the city of Rotterdam as part of a bigger metropolitan region. Secondly, it analyses the case of “Stadshavens strategy” as an emblematic example to overcome conflicts and path dependencies at the intersection of land and water. Finally, it concludes by highlighting some limitations and path dependencies that could make the transition to new forms of the circular economy very difficult in the future.
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Cities are like “heterotrophic organisms” because they are dependent on inflows of air, water, food, matter, and energy. Unlike nature, they pollute their own habitat through the production of waste outflows and emissions, extending beyond their own footprint. Data on the ecological footprint of cities have quantified, emblematically, the imbalance between in- and outflows but also what remains: polluted air, water, and soil. The rapid growth of urbanization is a matter of serious concern, but as a part of new development, it can be turned around with an approach in which cities become an “autotrophic organism”. In 2012 Taranto, a coastal city in Southern Italy with an important commercial and military port, was declared as the city “with the highest risk of environmental crisis” in Italy due to a large industrial area developed in the proximity of a highly populated urban settlement. The cause of pollution, a steel production plant, directly employs approximately 12.000 people and another 8.000 contractors indirectly, making it Taranto’s main economic driver. The conflict between economy and environment in the city of Taranto, make it a peculiar case study to be approached with the concept of a Democratic Landscape. This concept reads the territory beyond the natural environment, also recognizing the wellbeing of the inhabitants. After the analysis of a Democratic Landscape in relation to the concept of an “autotrophic organism”, this contribution explores the transformation by regeneration of the ecosystem and the economic regime. In redeveloping a city like Taranto, changing its function from a heterotrophic organism to an autotroph organism, the approach of the so-called “linking open-loop system circularity” is more appropriate. It more adequately describes the system than what is commonly understood for circularity at the building scale of “reduce, reuse, recycle of resources”. Circularity as an attitude brings together many elements that can be considered generic for each project: it can be about recycling or reuse, cutting costs or time, and output of CO2 through reducing material inflow and the transport of materials. In the context of the Democratic Landscape and an autotropic organism, the approach of “linking open-loop system circularity” is tested on two scales in Taranto. One, on the large scale, proposing multiple reuses of agricultural crops after remediation and two, at the local scale, in rebuilding a portion of the city by reusing the demolished buildings materials. The need to rethink and redesign the flow of resources such as building materials, water, food, and energy is essential to the future sustainability of cities. It involves thinking about how to use existing resources rather than dispose of them as in the linear model. It also means establishing new economic models in order to make a sustainable city, flows of intelligent growth and the creation of an identity for a communal sense of belonging. Together, these create a democratic, autotrophic landscape that can sustain a future.
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The United Nation’s 17 Sustainable development Goals (SDG) can be considered as the lighthouse of the great challenges which humanity will be confronted with. Many of these goals are related to our behaviors and our “take, make, and dispose,” namely, the linear dominant economic model that, in the last centuries, is leading to an ongoing increase of resource consumption and, consequently, a huge generation of waste. In fact, the rate of both natural resource consumption and waste generation are urgent issues, especially in the urban and peri-urban areas that will require proper solutions. The city is and will be even more in the future the most affected and the major drivers of resource consumption since it is expected that by 2050 more than 70% of the population will live in urbanized areas, and cities will grow in number and size. It means that land, water, food, energy, and other natural resource are increasingly necessary, but because resources are limited, it is required to change the linear consumption model in a new circular model of use and consumption where waste is avoided. In the last few years, emerged that waste management practices are improving according to the European Waste Hierarchy guidance, but there is still a wide possibility of improvement. This chapter explores, on one hand, what means the circular city, and on the other hand how to build it suggesting some policy recommendations. Considering urban and peri-urban areas as the space of material and people flows, thus optimizing the space used by flows and improving their interactions, it will be possible to construct another step toward circularity. In that view, the circular city acquires an urban and territorial perspective that can be managed with the urban and territorial tools, measures, policies, and plans, able to link also issues like climate adaptation, resilience, and sustainability. Finally, we argue that important work must be done in the immediate future in order to re-think and re-design urban spaces, urban practices, and infrastructures, thus shift from linear to circular city.
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More and more nowadays, the Circular Economy is at the heart of European public policies. As a result of the “Next Generation EU” Recovery Plans, a huge amount of financial resources will be available in the coming years to give shape the concept of “ecological transition". For that purpose, radical vision and operational concreteness are needed. In order to strengthen the territorial dimension of public policies aimed at ecological transition, the paper points to consider the status quo of the European territory, looking for recurring elements and differences. In this perspective, a return of “hard” urban studies, focusing on the issues of land ownership, land parcelling, infrastructural and urbanization procedures (and their relationships with the environment and the landscape) should be conducted at the European scale. A central role for the future of contemporary territories is recognized in the so-called “fringe area”, the part of the urban region where patterns of building development and unbuilt space interwave: its intermediary character, as a place between the compact city and the suburban countryside, makes this zone favourable to the collaboration between the two worlds. In addition, its easy accessibility from both the denser contexts and the outer areas makes it the perfect place to locate the equipment required to create short supply chains, so relevant for the circular economy and the ecological transition. These transition areas need to be rethought as new collective spaces of the contemporary city, areas for the proliferation of biodiversity, inhibited from settlement increase and subject to restrictions on car traffic. In them, the circular dimension of the new green economy could give shape to certain spatial conditions and new landscapes. Two main spatial models can describe this sustainable reform of the peri-urban territories. The first one assumes the figure of the “cluster”: a territorially and functionally defined region with one or more reference centres and an edge marking the discontinuity from other clusters. The second model is based on the figure of the “grid”: an unlimited mesh, which gives measure and organizes space according to a replicable and open system. This spatiality is built on a redundant and weak infrastructure, devoid of hierarchy, which can give rise to a sponge rich in pores, with neither internal nor external boundaries. The concept of the materiality also deals with the physical status of each context where the clusters of shortening flows would define local metabolisms, self-sufficient, marked by the use and recycling of what can be produced or “extracted” in the cluster itself. The closing of short supply chains for the use and recycling of materials, also with reference to the construction cycle and CDW recycling, would have direct consequences on the architectural character of the new arrangements: a kind of hyper-contextualism in which the landscape takes on grains, colours, materiality, closely linked to the local condition. Finally, a reflection on the rationales of the project is outlined. What is proposed, in fact, requires going beyond the traditional way in which the project has been conceived. In fact, these urban reconfiguration processes, structurally open to uncertainty, would take advantage of a programmatic choice of spatial incompleteness: a condition of “unfinished”, open to the accumulation over time of functions, forms, aggregations and densifications.
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Peri-urban is an intermediate land. On the one hand, its hybrid nature makes it particularly vulnerable to speculation, indiscriminate use of soil resources, erosion of agricultural residues, and so on; on the other hand, it is difficult to control through planning instruments and policies. Starting from this background, the chapter will investigate the territories of the large Campania Plain, in the South of Italy, between Naples and Caserta. Until the middle of twentieth century, this territory was known as Campania Felix due to its agricultural vocation. Subsequently, a series of development policies and a misinterpreted concept of valorization and modernization of the territory have changed its characteristics and identity, giving many parts of it to disorder: industrial settlements, plants, logistics, landfills, and large infrastructures that clash with the residential, agricultural, or residual areas and in-between natural ones. In this context, the chapter summarizes the first results of a research project that aims to rethink the role of the large Industrial Development Areas, established in the peri-urban contexts of the plain in the province of Caserta, in Italy.
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In recent years, the modernisation process has led to a radical transformation of the territory, producing waste in various forms (José Zapata Campos and Michael Hall in Organising waste in the city, Bristol University Press, 2013). Waste, not only in the sense of domestic or industrial waste but also in a broader concept linked to the territory and landscape’s spatial context. The concept relates to the degraded and subsequently abandoned area. Places understood as waste, areas expelled from the city and extraneous as they have no use and are now at the end of their life cycle. These areas, recognised as wastescapes (Amenta and Attademo in CRIOS 12:79–88, 2016) or a waste of land (Berger in Drosscape: Wasting land in urban America, Princeton Architectural Press, 2007), draw the and landscape’s mosaic increasingly fragmented. Also, current mobility requirements lead to a discussion on the design of road infrastructure. While in some cases the tendency is to upgrade existing ones, in others the choice is to design and build new routes. These new routes are causing many problems for the landscape, which is becoming even more devastated. A territory made up of linear elements, and ecosystem networks that physically connect urban space to environmental space create multiple landscapes within which transport networks act as a glue between the different urban poles and as a generator of abandoned areas (Russo in Techne 15:39–44, 2018). With this in mind, the study aims to analyse and assess, through spatial indicators, the potential that abandoned sites close to major road infrastructures can offer to society not only in economic but also in environmental terms. Starting from the Focus Area’s municipalities identified in the Horizon 2020 REPAiR project (Geldermans et al., in REPAiR project: REsource Management in Peri-urban AReas: Going beyond urban metabolism, 2017) for the Neapolitan context, only four of the eleven municipalities identified by the project are considered to make the analyses exhaustive and replicable in other contexts. The methodology defined the relationships between the built environment and abandoned infrastructure spaces, which cross and fragment the city and are devoid of functionality. The study had structured in three main phases: Identification of the abandoned interstitial areas of the road and neighbouring infrastructures in the municipalities of Afragola, Cardito, Casalnuovo di Napoli and Casoria (municipal territories of the metropolitan city of Naples); Analysis of the indexes of proximity to the urbanised areas and connectivity between the abandoned interstitial areas and the urbanised fabric; Evaluate these indices for the suburban areas to identify the attractiveness for future urban regeneration processes. In this sense, the attractiveness potential of abandoned interstitial spaces of road infrastructures had assessed. If included in a decision support system, these analyses and evaluations would support the definition of urban regeneration actions. In this sense, it evaluated the potential for the attractiveness of abandoned interstitial areas of road infrastructure. In this context, particular attention is paid to the environment in which we live and its protection and preservation.
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The construction and maintenance of residential, commercial, and industrial buildings are associated with a significant environmental footprint. Resource efficiency and innovation in the built infrastructure sector are essential for achieving sustainable development goals, and timely information is required to support sustainability policies in cities and towns. Therefore, we estimated the material and environmental footprint of Australian residential, commercial, and industrial buildings in 2016. Our analysis combines spatially explicit gross floor area (GFA) data, building materials per GFA for eleven building types in two construction periods, and estimates of key building materials’ emissions, energy, and water footprint. We estimated the material footprint of 8.8 million buildings at 3.8 billion tonnes with associated emissions of 1,804 million tonnes of CO2e and consumption of 24,218 terajoules (TJ) of energy and 31.5 billion litres of water. Concrete accounts for 59% of the material footprint, followed by sand and stone, ceramics, and timber with 23%, 8%, and 4%, respectively. Most materials, 70.7%, are in residential buildings, while commercial and industrial buildings account for 24.7% and 4.6%, respectively. By 2060, the projected material demand for new buildings and replacing ageing buildings ranges from 4.3 to 7.5 billion tonnes for alternative population growth scenarios. The upper range of the demand signals a two-fold increase in building materials and associated environmental impacts by 2060. Considering this, if Australia does not change the way construction materials are produced and buildings are designed towards sustainable outcomes, the country may not be able to achieve its net-zero emissions target by 2050.
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Understanding the built environment’s impacts is essential to support strategic planning and policy design for sustainable development now, and in the future. Modelling individual buildings and infrastructure at high level of detail is resource intensive. Thus, urban scale analyses demand simplifications that balance level of detail and scope broadness. For combining simplified modelling and extended scope, classification by archetypes emerge as a promising methodological approach to extend assessment scope beyond energy use simulation. Archetypes that include life cycle assessment (LCA) parameters can support circularity challenges diagnosis, mapping and predictions, strategies to close material and energy loops and their monitoring within urban built environments. We hypothesized that, upon limited complementation, operational and pre/post construction (embodied) datasets coupled with building grouping techniques satisfactorily represent the built stock to support cradle to grave LCA of built environments. Studies on the use of archetypes for this purpose are scarce, so this article reports findings of a Systematic Literature Review (SLR) on archetypes-based approaches for energy assessment that could inspire application in LCA studies at urban scale. The SLR highlighted a lack of methodological consensus, and that data availability seems to be the major limitation for archetype creation in most studies, which rarely present in-depth information on their development. The few investigations providing consistent methodological procedures actually detail the initial classification process. Transposing the archetype strategy from energy assessment to LCA at urban scale faces practical limitations. Several databases support operational energy studies, but the same does not apply to LCA. Urban building energy models typically overlook infrastructure. Also, statistical results depend directly on data input quality and data availability may compromise the quality of variable selection.
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Abstract: The cumulative primary energy input (CEI) over a service life of 80 years has been compared for six construction standards (Fig. 1). For poorly insulated buildings (complying to the 1984 German Thermal Insulation Ordinance), the primary energy input for building production (PEI) only amounts to some 5% of the consumption of natural gas and primary energy for house-hold electricity. With the low energy house (LEH standard), the volumes of elec-tricity and natural gas consumption over the service life are brought to similar levels, amounting each to 45% of the total, so that further progress can above all be achieved by the efficient use of electricity (Low E House + electr. Eff.). Improving to the passive house standard, very good thermal protection reduces the heat requirement to such a low level that a separate heating system is not necessary any longer. The PEI of future passive houses can be even lower than that of conventional new-build houses. Projects with cost-effective passive houses that cut the cumulative energy input by a factor of 4 are close to realisation. The approach to improve the building even more to a self-sufficient houses makes the cumulative energy input higher again than for a passive house, caused by the high primary energy input for production and replacement (R-PEI) of extensive technical systems.
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Over the past decades, detailed individual building energy models (BEM) on the one side and regional and country-level building stock models on the other side have become established modes of analysis for building designers and energy policy makers, respectively. More recently, these two toolsets have begun to merge into hybrid methods that are meant to analyze the energy performance of neighborhoods, i.e. several dozens to thousands of buildings. This paper reviews emerging simulation methods and implementation workflows for such bottom-up urban building energy models (UBEM). Simulation input organization, thermal model generation and execution, as well as result validation, are discussed successively and an outlook for future developments is presented.
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The built environment is recognized as a major hotspot of resource use and environmental impacts. Life cycle assessment (LCA) has been increasingly used to assess the environmental impacts of construction products and buildings during the last 25 years. A new trend stems in the application of LCA to larger systems such as urban islets or neighborhoods. This review aims at compiling all papers related to LCA of the built environment at the neighborhood scale. A focus is carried out on 21 existing case studies which are analyzed according to criteria derived from the four phases of LCA international standards. It sums up current practices in terms of goal and scope definition, life cycle inventory (LCI) and life cycle impact assessment (LCIA). The results show that the case studies pursue different goals. They are either conducted on existing or model neighborhoods with an aim at building knowledge to feed urban policy making. Or they are conducted on actual urban development projects for eco-design purpose. Studies are based on different scopes, resulting in the selection of different functional units and system boundaries. A comparison of data collection strategies is provided as well as a comparison of LCIA results for cumulative energy demand and greenhouse gases emissions. Methodological challenges and research needs in the field of application of LCA to neighborhood scale assessment are identified, such as the definition of the functional unit and the need for contextualization methodologies aligned with data availability at the design stages of a neighborhood development project.
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Certifications such as the Passive House Standard aim to reduce the final space heating energy demand of residential buildings. Space conditioning, notably heating, is responsible for nearly 70% of final residential energy consumption in Europe. There is therefore significant scope for the reduction of energy consumption through improvements to the energy efficiency of residential buildings. However, these certifications totally overlook the energy embodied in the building materials used to achieve this greater operational energy efficiency. The large amount of insulation and the triple-glazed high efficiency windows require a significant amount of energy to manufacture. While some previous studies have assessed the life cycle energy demand of passive houses, including their embodied energy, these rely on incomplete assessment techniques which greatly underestimate embodied energy and can lead to misleading conclusions. This paper analyses the embodied and operational energy demands of a case study passive house using a comprehensive hybrid analysis technique to quantify embodied energy. Results show that the embodied energy is much more significant than previously thought. Also, compared to a standard house with the same geometry, structure, finishes and number of people, a passive house can use more energy over 80 years, mainly due to the additional materials required. Current building energy efficiency certifications should widen their system boundaries to include embodied energy in order to reduce the life cycle energy demand of residential buildings.
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Buildings are directly responsible for 40% of the final energy use in most developed economies and for much more if indirect requirements are considered. This results in huge impacts which affect the environmental balance of our planet. However, most current building energy assessments focus solely on operational energy overlooking other energy uses such as embodied and transport energy. Embodied energy comprises the energy requirements for building materials production, construction and replacement. Transport energy represents the amount of energy required for the mobility of building users. Decisions based on partial assessments might result in an increased energy demand during other life cycle stages or at different scales of the built environment. Recent studies have shown that embodied and transport energy demands often account for more than half of the total life cycle energy demand of residential buildings. Current assessment tools and policies therefore overlook more than 50% of the life cycle energy use. This thesis presents a comprehensive life cycle energy analysis framework for residential buildings. This framework takes into account energy requirements at the building scale, i.e. the embodied and operational energy demands, and at the city scale, i.e. the embodied energy of nearby infrastructures and the transport energy of its users. This framework is implemented through the development, verification and validation of an advanced software tool which allows the rapid analysis of the life cycle energy demand of residential buildings and districts. Two case studies, located in Brussels, Belgium and Melbourne, Australia, are used to investigate the potential of the developed framework. Results show that each of the embodied, operational and transport energy requirements represent a significant share of the total energy requirements and associated greenhouse gas emissions of a residential building, over its useful life. All the scales of the built environment and the different life cycle stages should therefore be taken into consideration in order to reduce energy use in the built environment. Also, results have demonstrated that current building energy efficiency regulations may paradoxically lead to an increase in energy use. The use of the developed tool will allow building designers, town planners and policy makers to reduce the energy demand and greenhouse gas emissions of residential buildings by selecting measures that result in overall savings. This will ultimately contribute to reducing the environmental impact of the built environment.
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Life cycle assessment enables the identification of a broad range of potential environmental impacts occurring across the entire life of a product, from its design through to its eventual disposal or reuse. The need for life cycle assessment to inform environmental design within the built environment is critical, due to the complex range of materials and processes required to construct and manage our buildings and infrastructure systems. After outlining the framework for life cycle assessment, this book uses a range of case studies to demonstrate the innovative input-output-based hybrid approach for compiling a life cycle inventory. This approach enables a comprehensive analysis of a broad range of resource requirements and environmental outputs so that the potential environmental impacts of a building or infrastructure system can be ascertained. These case studies cover a range of elements that are part of the built environment, including a residential building, a commercial office building and a wind turbine, as well as individual building components such as a residential-scale photovoltaic system. Comprehensively introducing and demonstrating the uses and benefits of life cycle assessment for built environment projects, this book will show you how to assess the environmental performance of your clients’ projects, to compare design options across their entire life and to identify opportunities for improving environmental performance.
Article
Reduction in energy and resource consumption, as well as other environmental impacts, can be achieved for end of life building stock by recovering building waste after demolition through material reuse and recycling; or building repurposing through selective deconstruction and building system reuse. This research investigates and compares the potential life cycle environmental impacts of building repurposing through reuse of structure and demolition scenarios followed by new construction involving an existing library tower. New building design variations, with and without a Trombe wall, are detailed for both types of scenarios. The Athena EcoCalculator for Commercial Assemblies was used in analysis of life cycle stages of resource extraction and construction; maintenance, repair, and replacement of building assemblies; and disposal. Impacts from energy consumption for building operations were not included. Repurposing scenarios showed a potential reduction, between 20-41%, in six of the seven environmental impact categories assessed. The highest reduction is achieved for the Eutrophication Potential followed by Smog Potential at 37% reduction. Human Health Criteria is the impact category with the least reduction at 20% followed by Acidification Potential at 29%. Global Warming Potential and Fossil Fuel Consumption which are closely correlated show an avoided impact of 33 and 34% respectively as a result of the decision to go for repurposing after selective deconstruction rather than complete demolition and new construction. The benefits of repurposing compared to new construction demolition go beyond avoided environmental impacts. Comprehensive consideration of all relevant factors pertinent to the local context is also discussed.
Article
Urban metabolism (UM) is a way of characterizing the flows of materials and energy through and within cities. It is based on a comparison of cities to living organisms, which, like cities, require energy and matter flows to function and which generate waste during the mobilization of matter. Over the last 40 years, this approach has been applied in numerous case studies. Because of the data-intensive nature of a UM study, however, this methodology still faces some challenges. One such challenge is that most UM studies only present macroscopic results on either energy, water, or material flows at a particular point in time. This snapshot of a particular flow does not allow the tracing back of the flow's evolution caused by a city's temporal dynamics. To better understand the temporal dynamics of a UM, this article first presents the UM for Brussels Capital Region for 2010, including energy, water, material, and pollution flows. A temporal evaluation of these metabolic flows, as well as some urban characteristics starting from the seminal study of Duvigneaud and Denayer-De Smet in the early 1970s to 2010, is then carried out. This evolution shows that Brussels electricity, natural gas, and water use increased by 160%, 400%, and 15%, respectively, over a period of 40 years, whereas population only increased by 1%. The effect of some urban characteristics on the UM is then briefly explored. Finally, this article succinctly compares the evolution of Brussels’ UM with those of Paris, Vienna, Barcelona, and Hong Kong and concludes by describing further research pathways that enable a better understanding of the complex functioniong of UM over time.
Article
The building stock is not only a huge consumer of resources (for its construction and operation), but also represents a significant source for the future supply of metallic and mineral resources. This article describes how material stocks in buildings and their spatial distribution can be analyzed on a city level. In particular, the building structure (buildings differentiated by construction period and utilization) of Vienna is analyzed by joining available geographical information systems (GIS) data from various municipal authorities. Specific material intensities for different building categories (differentiated by construction period and utilization) are generated based on multiple data sources on the material composition of different building types and combined with the data on the building structure. Utilizing these methods, the overall material stock in buildings in Vienna was calculated to be380 million metric tonnes (t), which equals 210 t per capita (t/cap). The bulk of the material (>96%) is mineral, whereas organic materials (wood, plastics, bitumen, and so on) and metals (iron/steel, lead, copper, aluminum, and so on) constitute a very small share, of which wood (4.1 t/cap) and steel (3.2 t/cap) are the major contributors. Besides the overall material stock, the spatial distribution of materials within the municipal area can be assessed. This research forms the basis for a resource cadaster, which provides information about gross volume, construction period, utilization, and material composition for each building in Vienna.
Article
Building energy efficiency regulations often focus solely on operational and thermal energy demands. Increasing building thermal energy efficiency is most often undertaken by increasing insulation thickness and installing high performance windows. These measures can result in a significant increase in embodied energy which is currently not considered in building energy regulations. This study uses a case study house in Melbourne and Brisbane, Australia to investigate the life cycle primary energy repercussions of increasing building energy efficiency levels over 50 years. It uses the comprehensive hybrid approach and a dynamic software tool to quantify embodied and operational energy, respectively. It considers material and design-related changes in order to improve energy efficiency as well as a combination of both. Results show that while increasing the envelope thermal energy performance yields thermal operational energy savings, these can be offset by the additional embodied energy required for supplementary insulation materials and efficient windows. The point at which supplementary insulation materials do not yield life cycle energy benefits is just above current minimum energy efficiency requirements in Australia. In order to reduce a building's life cycle energy demand, more comprehensive regulations are needed. These should combine embodied and operational energy and emphasise design strategies.
Article
This literature review addresses the Life Cycle Energy Analysis (LCEA) of residential buildings. As the fluctuation in the choice of functional units, boundaries of the system, life cycle inventory (LCI) methods, metrics and impact indicators complicated the potential comparability, the guidelines of Product Category Rule (PCR) 2014:02 for buildings were applied for the normalization procedure. Even though PCR provided a clear statement of the boundaries and a complete presentation of the results, uncertainty deriving from the LCI methods and the omissions in the system boundaries indicates that further standardization is needed. The sample consisted of 90 LCEA case studies of conventional, passive, low energy and nearly zero energy residential buildings (nZEB). Additional analysis identified an underestimation between case studies that use process instead of hybrid analysis, as the average value of embodied energy in hybrid analysis appears to be 3.92 times higher than in process analysis case studies. The highest value of embodied energy for an nZEB case study quantified with process analysis appears to be lower than all the input-output hybrid case studies. A revised definition, according to current trends and requirements in energy efficiency regulations, was also provided as an update of their consistency in time. Operating energy appeared to dominate in life cycle energy of residential buildings in the past. The results of this review show an increasing share of embodied energy in the transaction from conventional to passive, low energy and nZEB, despite the reduction in the total life cycle energy that could reach up to 50%. The share of embodied energy dominates, mainly in low energy and nearly zero energy buildings, with a share of 26%–57% and 74%–100% respectively. In passive buildings, the share of embodied energy varies within a range between 11% and 33% that reaches the embodied energy limits of both a conventional and a low energy building. The use of renewable energy sources (RES) in a passive house, for the production of electricity, classifies it in the range of embodied energy of an nZEB. A significant gap of 17% in the share of embodied energy, between the nearly zero and the most energy efficient building examined in the current review, is identified. This difference appears to be more important for the conventional and passive buildings, indicating the relative significance of embodied energy through time and towards the nZEB. Furthermore, if uncertainty and the underestimation of embodied energy deriving by process analysis were considered this gap could be different. The increase of embodied energy in buildings, indicates that a whole life cycle energy analysis may be needed in the methodological framework of current energy efficiency regulations. The article could be downloaded for free until 31 of July 2016 at the following link: http://authors.elsevier.com/a/1TBel1HudMoGgY
Conference Paper
Urban areas cover 2% of the Earth's land surface, while hosting more than half of the global population and are estimated to account for around three quarters of CO 2 emissions from global energy use. In order to mitigate existing and future direct and indirect environmental pressures resulting from urban resource use, it is necessary to investigate and better understand resource and pollution flows associated with urban systems. Urban Metabolism (UM) is an urban environmental assessment framework that measures resource and pollution flows that enter and exit urban systems. However, UM presents an important shortcoming, namely its " black box " approach. Indeed, standalone, UM figures are not enough to explain why they are specific and exclusive to a city and whether this city is heading towards a more sustainable state. In this study, four transversal aspects that attempt to overcome this " black box " approach are presented. These additional layers of understanding include temporal evolution, spatialisation and disaggregation, identification of resource use and pollution drivers and finally the indirect resource use and pollution emissions that occur outside of the urban boundaries.
Article
In this study, annual precipitation was forecast by coding in MATLAB software environment based on a non-linear autoregressive neural network (NARNN), non-linear input–output (NIO) and NARNN with exogenous input (NARNNX). Historical precipitation data (27 precipitation gauge stations located in Gilan, Iran) were used as two 21 year sets from 1968 to 1988 and from 1989 to 2009 for calibration and testing of the networks, respectively. Results showed that the accuracy of the NARNNX was better than that of the NARNN and NIO, based on r values. However, performance of the networks was not satisfactory because the number of neurons in the hidden layer and the roles of training, validation and testing phases were lacking flexibility and change. Optimization of the number of neurons in the hidden layer and the determination of the best role among the different phases led to improvement of network accuracy. The r values were <0.73 only for five stations in the optimized NARNN and <0.74 only for those stations with optimized NIO.
Article
A large amount of demolition waste was generated due to the rapid urbanization. Prior to designing corresponding management measures, it is imperative to understand the amount, composition, and flows of the generated waste. This study proposes a novel approach to quantifying the demolition waste from generation to final disposal and, consequently, formulates corresponding strategies to managing the demolition waste, by using spatial and temporal dimensions in the Geographic information system. Specifically, a GIS-based model is proposed and consequently applied to a case study. Results show that over 135 million tons of demolition waste will be generated in the Nan Shan District between 2015 and 2060, and the recycling potential is valued at $ 6072 million under the optimistic scenario. By contrast, under the worst-case scenario, over 54 million m3 of land area which equals to approximate $ 218 billion could be needed for landfill. Compared to the worst-case scenario, the optimum scenario would reduce the amount of waste to be disposed in landfills by 80% and increase the value of recycling by 65%. The results revealed that, as a rapidly developing city, Shenzhen would likely experience the peak in the generation of demolition waste. Therefore, it is imperative to improve the recycling rate as it helps to raise the potential economic benefits and to reduce the landfill demand. This research is innovative in terms of the systemization, visual representation and analysis of quantifying the demolition waste flows via a novel method. The findings about the generation trends, economic values and environmental effects provide valuable information for the future waste management exercises of various stakeholders such as government, industry and academy.
Article
In this article, we suggest a methodology that combines geographic information systems (GIS) and material flow analysis (MFA) into a secondary reserve-prospecting tool. The approach is two-phased and couples spatially informed size estimates of urban metal stocks (phase 1) to the equally spatially contingent efforts required to extract them (phase 2). Too often, even the most advanced MFA assessments stop at the first of these two phases, meaning that essential information needed to facilitate resource recovery, i.e., urban mining, is missing from their results. To take MFA one step further, our approach is characterized by a high resolution that connects the analysis of the stock to the social practices that arrange material flows in the city, thereby enabling an assessment of the economic conditions for secondary resource recovery. To exemplify, we provide a case study of the hibernation stock of copper found in disconnected power cables in Linköping, Sweden. Since 1970, 123 tonnes of copper or ≈1 kg per person have accumulated underneath the city, predominantly in old, central parts of the city and industrial areas. While shorter cables are more numerous than long ones, the longer ones contribute to a larger share of the stock weight. Resource recovery in specific projects reliant on digging comes at great costs, but integrating it as an added value to ordinary maintenance operations render eight locations and 2.2 tonnes of copper (2% of the stock) profitable to extract. Compared to the budget sizes of regular maintenance projects, the integrated recovery of a significant share of the stock comes with relatively small economic losses. Therefore, we suggest integrated resource recovery and regular maintenance as an interesting environmental measure for any infrastructure provider to engage with.
Article
The construction industry is an important contributor to urban economic development and consumes large volumes of building material that are stocked in cities over long periods. Those stocked spaces store valuable materials that may be available for recovery in the future. Thus quantifying the urban building stock is important for managing construction materials across the building life cycle. This article develops a new approach to urban building material stock analysis (MSA) using land-use heuristics. Our objective is to characterize buildings to understand materials stocked in place by: (1) developing, validating, and testing a new method for characterizing building stock by land-use type and (2) quantifying building stock and determining material fractions. We conduct a spatial MSA to quantify materials within a 2.6-square-kilometer section of Philadelphia from 2004 to 2012. Data were collected for buildings classified by land-use type from many sources to create maps of material stock and spatial material intensity. In the spatial MSA, the land-use type that returned the largest footprint (by percentage) and greatest (number) of buildings were civic/institutional (42%; 147) and residential (23%; 275), respectively. The model was validated for total floor space and the absolute overall error (n = 46; 20%) in 2004 and (n = 47; 24%) in 2012. Typically, commercial and residential land-use types returned the lowest overall error and weighted error. We present a promising alternative method for characterizing buildings in urban MSA that leverages multiple tools (geographical information systems [GIS], design codes, and building models) and test the method in historic Philadelphia.
Article
We present a comprehensive review of modelling approaches and associated software tools that address district-level energy systems. Buildings play an important role in urban energy systems regarding both the demand and supply of energy. It is no longer sufficient to simulate building energy use assuming isolation from the microclimate and energy system in which they operate, or to model an urban energy system without consideration of the buildings that it serves. This review complements previous studies by focussing on models that address district-level interactions in energy systems, and by assessing the capabilities of the software tools available alongside the theory of the modelling approaches used. New models and tools that address these district-level interactions are reviewed and their competences assessed. These are divided into the following sections: district energy systems (including heat networks, multi-energy systems and low-temperature networks), renewable energy generation (including solar, bioenergy, wind and the related topic of seasonal storage), and the urban microclimate as it relates to energy demands. The scope and detail covered by twenty cross-disciplinary tools is summarised in a matrix; many other tools that focus on specific areas are also discussed. We end by summarising the current state of district-scale urban energy modelling as it relates to the built environment, along with our perspective on future challenges and research directions.
Article
A prerequisite of the efficient recycling of demolition waste and its evaluation in terms of the material specific recycling rates is information on the composition of the building material stock (as the source of future demolition waste). A practical method is presented that characterizes the material composition of buildings prior to their demolition. The characterization method is based on the analysis of available construction documents and different approaches of on-site investigation. The method is tested in different buildings and the results from four case studies indicate that the documents are useful to quantify bulk materials (e.g. bricks, concrete, sand/gravel, iron/steel and timber). However, on-site investigations are necessary to locate and determine the trace materials such as metals (e.g. copper and aluminium), or different types of plastics. The overall material intensity of the investigated buildings ranges from 270 to 470 kg/m³ gross volume. With ongoing surveys about the composition of different buildings, the collected data will be used to establish a building-specific database about the amount of materials contained in Vienna's building stock.