Evaluation of BIM-based LCA results for building design

Digital tools based on Building Information Modelling (BIM) provide the potential to facilitate environmental performance assessments of buildings. Various tools that use a BIM model for automatic quantity take-off as basis for Life Cycle Assessment (LCA) have been developed recently. This paper describes the first application of such a BIM-LCA tool to evaluate the embodied global warming potential (GWP) throughout the whole design process of a real building. 34 states of the BIM model are analysed weekly. The results show that the embodied GWP during the design phase is twice as high as for the final building. These changes can be mainly attributed to the designers\u27 approach of using placeholder materials that are refined later, besides other reasons. As such, the embodied GWP is highly overestimated and a BIM-based environmental assessment during the design process could be misleading and counterproductive. Finally, three alternatives to the established automatic quantity take-off are discussed for future developments

A parametric method for building design optimization based on Life Cycle Assessment

The building sector is responsible for a large share of human environmental impacts. Architects and planners are the key players for reducing the environmental impacts of buildings, as they define them to a large extent. Life Cycle Assessment (LCA) allows for the holistic environmental analysis of a building. However, it is currently not employed to improve the environmental performance of buildings during the design process, although the potential for optimization is greatest there. One main reason is the lack of an adequate means of applying LCA in the architectural design process. As such, the main objective of this thesis is to develop a method for environmental building design optimization that is applicable in the design process. The key concept proposed in this thesis is to combine LCA with parametric design, because it proved to have a high potential for design optimization. The research approach includes the analysis of the characteristics of LCA for buildings and the architectural design stages to identify the research gap, the establishment of a requirement catalogue, the development of a method based on a digital, parametric model, and an evaluation of the method. An analysis of currently available approaches for LCA of buildings indicates that they are either holistic but very complex or simple but not holistic. Furthermore, none of them provide the opportunity for optimization in the architectural design process, which is the main research gap. The requirements derived from the analysis have been summarized in the form of a catalogue. This catalogue can be used to evaluate both existing approaches and potential methods developed in the future. In this thesis, it served as guideline for the development of the parametric method – Parametric Life Cycle Assessment (PLCA). The unique main feature of PLCA is that embodied and operational environmental impact are calculated together. In combination with the self-contained workflow of the method, this provides the basis for holistic, time-efficient environmental design optimization. The application of PLCA to three examples indicated that all established mandatory requirements are met. In all cases, environmental impact could be significantly reduced. In comparison to conventional approaches, PLCA was shown to be much more time-efficient. PLCA allows architects to focus on their main task of designing the building, and finally makes LCA practically useful as one of several criteria for design optimization. With PLCA, the building design can be time-efficiently optimized from the beginning of the most influential early design stages, which has not been possible until now. PLCA provides a good starting point for further research. In the future, it could be extended by integrating the social and economic aspects of sustainability

A parametric method for building design optimization based on Life Cycle Assessment - Appendix

The building sector is responsible for a large share of human environmental impacts, over which architects and planners have a major influence. The main objective of this thesis is to develop a method for environmental building design optimization based on Life Cycle Assessment (LCA) that is applicable as part of the design process. The research approach includes a thorough analysis of LCA for buildings in relation to the architectural design stages and the establishment of a requirement catalogue. The key concept of the novel method called Parametric Life Cycle Assessment(PLCA) is to combine LCA with parametric design. The application of this method to three examples shows that building designs can be optimized time-efficiently and holistically from the beginning of the most influential early design stages, an achievement which has not been possible until now

A Pathway to Climate Neutral Buildings：Definitions, Policy and Stakeholder Understanding in Sweden and China

In recent years, \u27climate neutral buildings\u27 has become one of the most popular emerging terms in the context of global warming and the built environment. However, due to a vague definition, the term still lacks real-world uptake in practice. While initial research focuses on \u27climate neutral buildings\u27, few have discussed this term from the perspective of different countries or stakeholders. To address this gap, this paper explores the current understanding and future development of the term \u27climate neutral buildings\u27 in Sweden and China. Through a literature review of related definitions, an investigation of current regulations, and stakeholder interviews in both countries, we find that Sweden and China are in different stages of development towards climate neutral buildings. Sweden seems to surpass China in terms of theoretical research, regulation development and stakeholder understanding. Despite this, the two countries share similar issues regarding the future development of climate neutral buildings. Both countries lack an official interpretation of \u27climate neutral buildings\u27, sufficient regulations, and collaborations among different stakeholders. This paper suggests a foundation for the future development of climate neutral buildings

Procedural digital twin generation for co-creating in VR focusing on vegetation

An early-stage development of a Digital Twin (DT) in Virtual Reality (VR) is presented, aiming for civic engagement in a new urban development located in an area that is a forest today. The area is presently used for recreation. For the developer, it is important both to communicate how the new development will affect the forest and allow for feedback from the citizen. High quality DT models are time-consuming to generate, especially for VR. Current model generation methods require the model developer to manually design the virtual environment. Furthermore, they are not scalable when multiple scenarios are required as a project progresses. This study aimed to create an automated, procedural workflow to generate DT models and visualize large-scale data in VR with a focus on existing green structures as a basis for participatory approaches. Two versions of the VR prototype were developed in close cooperation with the urban developer and evaluated in two user tests. A procedural workflow was developed for generating DT models and integrated into the VR application. For the green structures, efforts focused on the vegetation, such as realistic representation and placement of different types of trees and bushes. Only navigation functions were enabled in the first user test with practitioners (9 participants). Interactive functions were enabled in the second user test with pupils (age 15, 9 participants). In both tests, the researchers observed the participants and carried out short reflective interviews. The user test evaluation focussed on the perception of the vegetation, general perception of the VR environment, interaction, and navigation. The results show that the workflow is effective, and the users appreciate green structure representations in VR environments in both user tests. Based on the workflow, similar scenes can be created for any location in Sweden. Future development needs to concentrate on the refinement of buildings and information content. A challenge will be balancing the level of detail for communication with residents

Effects of Sustainability Policy – Evaluating Social Consequences of Carbon Targets using Trip Completion Rates

Sustainability is widely recognised as having social, economic, and environmental dimensions. Strategies to combat global climate change inherently have an environmental focus. However, in line with the sustainability agenda, the social and economic dimensions must also be addressed. Evaluating the social consequences of decisions is often challenging due to a lack of relevant tools and indicators to measure and track them. This paper presents the Trip Completion Rate (TCR) as an indicator currently under development to evaluate the social consequences of climate change policies such as Personal Carbon Allowances (PCA). TCR is an accessibility indicator that evaluates the proportion of a population that can perform their daily activities against a performance metric. Two examples demonstrate the sensitivity of social impacts based on the geographic and demographic variations in different locations, one at the region level and another at the municipal level, through a national household travel survey (NHTS). The V\ue4stra G\uf6taland region of Sweden is taken as a test case to illustrate how the indicator may be used, comparing TCR on the entire region and then comparing it to TCRscalculated at the municipal level. The greenhouse gas emissions of the trips are calculated based on assumptions for different modes of transport. Finally, the results are evaluated against a hypothetical PCA based on the climate goals for the city of Gothenburg, Sweden. The results show that the ability to satisfy one\u27s daily travel needs depends on individual characteristics such as behavioural patterns of travel, travel mode choices and access to local amenities. We find that PCAs may disproportionately affect certain groups more than others. Policymakers must understand who is most affected by sustainability targets to ensure that disproportionately affected groups have an equal opportunity to achieve their daily needs and that adequatemeasures are taken to mitigate the local policy effects on social equity

Towards digitalisation of socially sustainable neighbourhood design

Digital tools for performance-assessment are commonly used to shorten the feedback loop in testing designs for buildings and neighbourhoods. However, these tools do not extend to the social dimension in the same way as the economic and environmental dimensions. This paper aims to contribute to the development of digital tools to design socially sustainable neighbourhoods. We analyse 115 academic articles to establish a theoretical understanding of Social Sustainability (SoSu). Based on these results, we propose a digital user-interaction model to operationalise SoSu in the digital design process of buildings. In the literature, we observe a lack of consensus on the theoretical discussion on SoSu. Several extrinsic and intrinsic factors are identified contributing to this fuzziness; the dependency on stakeholder value systems, the qualitative nature of social indicators, and comparison to environmental sustainability being the most common. Still, we distinguish two overarching categories, social equity and social capital, that are further divided into sub-themes. Having mapped the categories and hierarchies of social themes, we propose a user-interaction model that incorporates these findings into a digital environment. The user-interaction model creates a guided decision-making framework for architects and urban planners by enabling stakeholders to make conscious and informed decisions grounded in theory

Detailed Assessment of Embodied Carbon of HVAC Systems for a New Office Building Based on BIM

The global shift towards embodied carbon reduction in the building sector has indicated the need for a detailed analysis of environmental impacts across the whole lifecycle of buildings. The environmental impact of heating, ventilation, and air conditioning (HVAC) systems has rarely been studied in detail. Most of the published studies are based on assumptions and rule of thumb techniques. In this study, the requirements and methods to perform a detailed life cycle assessment (LCA) for HVAC systems based on building information modelling (BIM) are assessed and framed for the first time. The approach of linking external product data information to objects using visual programming language (VPL) is tested, and its benefits over the existing workflows are presented. The detailed BIM model of a newly built office building in Switzerland is used as a case study. In addition, detailed project documentation is used to ensure the plausibility of the calculated impact. The LCA results show that the embodied impact of the HVAC systems is three times higher than the targets provided by the Swiss Energy Efficiency Path (SIA 2040). Furthermore, it is shown that the embodied impact of HVAC systems lies in the range of 15–36% of the total embodied impact of office buildings. Nevertheless, further research and similar case studies are needed to provide a robust picture of the embodied environmental impact of HVAC systems. The results could contribute to setting stricter targets in line with the vision of decarbonization of the building sector

Where to focus? Developing a LCA impact category selection tool for manufacturers of building materials

Life cycle assessment (LCA) has been widely applied to improve the environmental performance of the building sector. However, due to the complexity of LCA results including the multitude of impact categories, decision makers of the building materials manufacturing industry are grappling with allocating their limited resources to the most influential impact categories. The aim of this article, therefore, is to propose an impact category selection tool that enables performance improvement of building materials without sacrificing the validity of LCA results. The developed method selects common building materials, and defines foreground processes that can be influenced by manufacturers of building materials and background processes that can hardly be impacted using the US Input-Output database. Following the life cycle impact assessment (LCIA) analysis with the ReCiPe2016 Midpoint method, our results indicate that, among the 18 impact categories of the ReCiPe2016 Midpoint method, Global Warming Potential, Ozone Formation and Human Health, Fine Particulate Matter Formation, Ozone Formation and Terrestrial Ecosystems, Terrestrial Acidification, and Terrestrial Ecotoxicity should be considered the first priority group while Ionizing Radiation, Freshwater Eutrophication, Marine Eutrophication, Freshwater Ecotoxicity, Water Consumption should be placed in the last priority group. It further suggests that by shifting the limited available resources to the first priority group, decision makers can readily improve the environmental performance of building materials during the manufacturing process. The contribution of the proposed selection tool lies in that it can be adapted by decision makers to different geographical contexts, LCIA methods, and building materials to efficiently ameliorate the environmental performance of the building sector

Improving the collaboration between architects and energy consultants through design-integrated early BIM-tools

There is a lack of optimization of buildings towards energy performance in early design stages in practice. Interviews with architects and energy consultants showed that one reason is the inefficient communication between these two groups. This paper investigates how a design-integrated early-BIM tool can improve the relation between architects and energy consultants to support an optimization process in early design stages and facilitate issuing energy performance certificates. Two case studies show that the early-BIM tool provides meaningful results for the architects involved and can reduce the input time for energy consultants by 50%. Furthermore, the simple 3D model functions as boundary object between the two groups and supports the collaboration