bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbon budget for national building stock life-cycle emissions: a novel approach
Authors: Alaux N , Lackner T , Nabernegg S , Truger B , Röck M , Steininger K W , Passer A 
Published: December 2023

Abstract
Following the Paris Agreement, many countries such as Switzerland or Denmark have derived carbon budgets for their national building stock to support local policies by creating benchmarks. The aim is to calculate a quota for carbon emissions that a country can spend on its building stock by 2050 to ensure that it stays within a 1.5°C trajectory. The underlying allocation principle almost exclusively follows this procedure: (i) allocating the global budget to the national level, (ii) further allocating the national budget to the sectoral level, and (iii) to the building stock level (or even further down to the district or building level). However, this procedure of budget allocation does not do justice to the cross-sectoral and international nature of the national building stock’s life-cycle emissions. We propose a new approach for consistent, building stock-specific carbon budgets and demonstrate the proposed methodology for Austria. Adopting this approach for the building stock of other countries would enable consistent carbon budgets that reflect the field of action buildings for climate change mitigation.
Reuse practices in building construction: proposition of a life cycle assessment methodology and application to a case study in Switzerland
Authors: Frossard M , Lasvaux S , Petetin F , Gross L 
Published: December 2023

Abstract
This paper presents a life cycle assessment (LCA) methodology for evaluating the environmental impacts of reuse in building projects and apply it to a case study in Switzerland with 11% of reused components in its total mass. The results show that the life cycle GHG emissions on the construction domain that includes modules A1 to A4, B4, and C1-C4, are 487 kg CO2-eq./m2. In the other hand, the indirect effect of reuse lead to avoided GHG emissions of 76 kg CO2-eq./m2. At the level of a product’s supply chain, the analysis demonstrates a significant reduction in the embodied impacts of the reused components compared to newly manufactured ones. The potential benefits from avoided manufacturing and waste management depend on the type of material that is reused.
Stepwise renovation of buildings: what to refurbish first to minimize life-cycle carbon emissions?
Authors: Priore Y D , Schulthess L , Schwab S , Rollo D , Jusselme T 
Published: December 2023

Abstract
To tackle the upcoming renovation wave, this work evaluates renovation strategies with a life cycle GHG emissions perspective and includes time and sequencing in the decision-making process. A case study is used to conduct a full life cycle assessment of renovation strategies in line with the Swiss normative context. Improvements in the operational energy consumption are evaluated with an energy model using the software Lesosai and considering the normative limits from the SIA 380/1. GHG emissions are calculated using the Swiss KBOB data inventory and in line with the SIA 2032 methodology. The renovation measures are then examined individually with the carbon payback time indicator and strategies with cumulative emissions over time in contrast to carbon budgets. Results show that the sequence of the refurbishment steps can increase or decrease cumulative GHG emissions of ca. 30% over the lifetime of the building. Changing a fossil-fuel based heating system is the most impactful measure and must happen as soon as possible. Switching to decarbonized heating systems reduces the carbon effectiveness of subsequent renovation measures but poses the question of energy availability. Fully renovating a building but delaying the change of heating system by only 7 years can compromise the achievement of the carbon targets.
The GHG Emission Timeline – Integrating sustainability assessment into the early building design stage
Authors: Hischier I , Walker L , Piccioni V , Borkowski E , Galimshina A , Schlueter A 
Published: December 2023

Abstract
To address the challenges of integrating sustainability assessment such as life cycle assessment (LCA) in the early building design stage, we propose a new concept: The Greenhouse gas (GHG) Emission Timeline. The concept is derived from researching robustness assessment methods and personal experiences from teaching. Rather than aggregating environmental aspects into a single number, with the Timeline we want to highlight the temporality of GHG emissions in the context of ongoing transformation processes. Similarly to the previously proposed Material Pyramid for comparing the CO2 footprint of different materials, the Timeline is a pedagogical tool to visualize quantities, dynamics, and uncertainties aiming to provide a common ground for discussing sustainability in the early building design stage. The Timeline is compiled in a few simple steps with readily available resources. Hence, it does not need prior expert knowledge. The concept, as well as the first application examples of the Timeline from an architectural design studio at ETH Zurich are presented and discussed. By using GHG emission calculations for the compilation of a historic timeline, students created new lenses that addressed sustainability from a holistic viewpoint beyond GHG emissions.
Building within planetary boundaries: setting and assessing absolute sustainability targets at the building level
Authors: Francart N , Clausen C A , Bjørn A , Birgisdottir H 
Published: December 2023

Abstract
The planetary boundaries (PBs) are a widely used framework defining a “safe operating space” for environmental sustainability at the global level. However, they do not straightforwardly translate into indicators applicable in a building project. This paper proposes a procedure to set and assess absolute sustainability targets related to the PBs in a building project, exemplified in the case of Denmark. The first step is to ensure that the targets and the assessment method use comparable indicators. Common building life cycle assessment (LCA) tools use impact categories that do not directly match the PBs. Two options are considered to address this issue. Dedicated characterization factors can be used to convey LCA results in indicators consistent with the PBs. Alternatively, PB targets can be converted into LCA impact categories. Then, several distributive justice principles are reviewed to allocate a share of planetary sustainability targets to an individual country, to the housing sector within that country, and to an individual project. We argue that principles that conserve existing unsustainable paradigms are not appropriate to set planetary sustainability targets, and propose a novel approach for sectorial allocation based on sufficientarianism and “decent living” scenarios. Finally, challenges related to the assessment of these targets are highlighted. In particular, the paper draws attention to differences in system boundaries between the LCA and the targets.
Mitigating carbon emissions of single-family houses: Assessing the need for a limit value
Authors: Tozan B , Nielsen L H , Hoxha E , Birgisdóttir H 
Published: December 2023

Abstract
Reducing carbon emissions in the global building and construction sector is a crucial part of achieving climate targets. Laws that aim to limit the carbon emissions of new buildings have yet to be implemented on a larger scale, although some nations already have thresholds. These thresholds may not be sufficient to mitigate carbon emissions, and not all types of buildings are obliged to comply with them. In the case of Denmark, single-family houses (SFH) are not required to not comply with a limit, although they represented approximately 17% of all newly built areas from 2010 to 2022, indicating significant resource use and associated carbon emissions. This study aims to establish sufficient background data to support the need for implementing a limit value for SFHs in building regulations to ensure necessary reductions in carbon emissions. The study finds that the life cycle carbon emissions of Danish SFHs vary between 5.6 and 13.2 kg CO2e/m2/year, showing that compliance with the current limit value of larger buildings is possible and that a reduction of more than 50% in carbon emissions is possible. However, currently, there is no intentional investigation or achievement of potential carbon emissions in the construction industry. The study’s findings inform policymakers that a limit value for SFHs must be introduced no later than 2025 to initiate the necessary reduction of carbon emissions.
Turning dynamic LCA principles into practice
Authors: Andersen C E , Sørensen C G , Jensen O M , Hoxha E , Rasmussen F N , Birgisdóttir H 
Published: December 2023

Abstract
The building and construction sector quantifies the environmental impacts of buildings using the Life Cycle Assessment (LCA) method. To put LCA into practice often simplified application of the LCA method is used, without considering timely aspects. Instead, the method dynamic LCA includes timely aspects, which are more complex in the modeling and thus difficult to apply. To investigate the consequences of using the dynamic LCA method, this study develops a tool that takes data available in a simple LCA tool that follows the standardized LCA method and calculates dynamic LCA results. The tool reimplements the calculation engine from the simple LCA tool and adds the more complex aspects of dynamic LCA afterward. Doing so makes it possible to add other complex methods to the original calculation engine to help investigate more complex methodological aspects in the future.
The potential of agricultural residual waste as building material in South Sweden
Authors: Kanters Jouri , Kulsomboon Montanun , Bruijn Paulien Strandberg-de 
Published: December 2023

Abstract
A literature review and statistical analysis of the potential of agricultural residual waste as building materials in South Sweden was carried out. This data showed that there is a clear capacity for the use of mainly straw-generating crops as building materials in the region.
The Urban-Industrial metabolism: contribution of waste recycling to the circular economy objectives within the construction sector
Authors: Komkova A , Habert G 
Published: December 2023

Abstract
The construction and buildings sector is facing an urgent need to reduce GHG emissions and ensure efficient resource utilization while minimizing waste in order to comply with climate change policies and circular economy initiatives. Alkali-activated materials, as an alternative binder to CO2-intensive conventional cement, show potential in utilizing waste streams from urban environments in their production technology, thereby reducing CO2 emissions. This study examines two waste streams generated in Switzerland: incineration ashes from municipal solid waste treatment facilities and mineral wool waste from building stock renovation and demolition activities. Geospatial analysis is combined with LCA methods to assess optimal scenarios for waste recycling, utilizing a multi-objective optimization framework based on mixed integer linear programming. The objectives are to minimize the environmental impacts and costs associated with alternative supply chain networks, thereby identifying optimal locations for waste pre-treatment and concrete manufacturing. The proposed scenarios demonstrate reductions of 56% in global warming potential and 29% in costs when compared to the business-as-usual scenario of conventional cement concrete use and waste landfilling. Results show that recycling of urban waste streams in alternative concrete can reduce GHG emissions of industry and heavy transportation sectors by 0.46 mt. CO2 eq. by year 2030, equivalent to 23% and 4% of the Swiss carbon budget reduction targets for these sectors.
A Danish model of building macro-components to promote circularity
Authors: Francart N , Gummidi S R B , Hoxha E , Birgisdottir H 
Published: December 2023

Abstract
A better understanding of the material composition of the existing building stock is important for the development of circular economy strategies in the building sector. This paper presents a recently developed model to map the types and amounts of various materials in existing buildings in Denmark, with a high level of detail at the level of components rather than just material types. The model is meant to enable a detailed description of the building stock and a consideration of how components could be reused. Building properties are imported from the Danish national building registry (BBR) and processed into a relational database. Properties are combined with information on past construction techniques from architecture handbooks to estimate the most likely macro-components (types of wall, roof, etc) used in each building, and dimension these components. Material amount estimates from the model are compared with previous estimates as well as with material inventories from case study buildings. While the open-source model currently lacks accuracy, it is intended to be easily modifiable, and can support continuous improvements of the estimates based e.g. on new information from material passports, waste treatment facilities or remote sensing data. The paper discusses future opportunities to improve the model’s accuracy and use it to help develop circularity strategies and complement on-site inspections to overcome barriers to circularity.
PixelFrame: A reconfigurable, precast, post-tensioned concrete structural system for a circular building economy
Authors: Donovan I , Schnitzler J , Lee KJ , Wongsittikan P , Liu Y , Mueller CT 
Published: December 2023

Abstract
The demand to build for a growing urban population conflicts with the need to reduce the AEC (Architecture, Engineering and Construction) sector’s contributions to global CO2 emissions. Structural systems are a key factor in this challenge, as they contribute substantially to a building’s mass and are typically overdesigned. In this paper, we present PixelFrame, a new precast concrete structural system that is algorithmically designed to use less carbon upfront and be reused across multiple lifecycles. We achieve a high reuse potential for structural elements through building load demand analysis, a segmental externally post-tensioned design, and an integrated optimal assignment strategy. In addition to improving reuse potential, a segmental optimization strategy also yields higher efficiency in comparison to traditional prismatic concrete structural elements. The detailing of concrete mixes is informed by a statistical analysis of anticipated building load demands and a custom clustering asymmetric distance function and clustering algorithm. Compared to previous work in this area, our contribution is original in its bidirectional algorithmic approach; both the target building structure and the circular material inventory are computationally generated to achieve versatility while minimizing emissions.
Projected energy savings of a 3D printed selective heat transfer facade
Authors: Seshadri B , Morroni D , Hischier I , Masania K , Schlueter A 
Published: December 2023

Abstract
Dynamic building facades offer untapped potential for reducing building energy consumption and emissions. However, there is currently a lack of suitable technologies for bespoke components for new and retrofit applications. In previous work, we developed a 3D printed polymer facade component that selectively acts as a thermal conductor or insulator depending on outdoor and indoor conditions. Our experiments demonstrate that the element can achieve effective thermal conductivities as low as 0.03 W/mK and as high as 28 W/mK in insulating and conducting modes. In this work, we assess the potential impact of this technology on reducing heating and cooling energy demand. We conducted a parametric analysis of ten physical characteristics of the facade component. Then, we simulated the façade component employed in 270 building typologies and climate combinations. Our results indicate annual energy reduction of up to 80 kWh/m2 (heating) and 15 kWh/m2 (cooling) for building typology-climate combinations that can benefit the most from this technology.
A benchmark for the simulation of meshed district heating networks based on anonymised monitoring data
Authors: Boghetti R , Kämpf Jérôme H. 
Published: December 2023

Abstract
With the increasing interest in District Heating Networks (DHNs) as a potential solution to decarbonize heating, new simulation tools are being developed, raising the need for standardized benchmarks to validate their performance. Currently, the main benchmark used for DHN simulation models is the DESTEST, which consists in an inter-model comparison on the simulation of a toy radial network. However, no common benchmarks based on monitoring data from a meshed network exist at the moment, which would be needed to complement the DESTEST. To address this issue, this paper presents aggregated monitoring data from a medium-sized meshed DHN and proposes a benchmark based on this data. While aggregating the data and assuming steady-state conditions is not a suitable strategy for representing locally high dynamic behaviours, applying the benchmark to an existing simulation tool showed that the simulation results are coherent with the published monitoring data, as a low difference in temperature across most available sensors is found. The published data and the proposed benchmark aim to encourage the development of more accurate models for DHNs and to facilitate the evaluation of the performance of different simulation tools and enable their optimization, which will ultimately lead to more efficient and reliable DHNs.
Digitisation and analysis of energy data at municipal scale: an application to the municipality of Mendrisio
Authors: Belliardi Marco , Cereghetti Nerio , Bettini Albedo , Fusine Katia Dalle , Vismara Francesco , Sormani Michela , Briccola Mario , Martinenghi Gabriele , Muntaner Martin , Camponovo Paolo , Gottardi Filippo De , Pusterla Moreno , Gianolli Gabriele 
Published: December 2023

Abstract
The concept of Smart Cities has gained significant attention in recent years due to the increasing need for efficient energy management in urban areas. This paper describes a digital platform for the management of energy databases that aims to synchronize, update, and analyze different energy installations and uses in the municipality of Mendrisio 1according to the Smart City concept. The platform interweaves and compares various energy databases to ensure better efficiency in the use of thermal and electrical energy, as well as optimize the consumption and production of renewable energies. The geodigital platform created is capable of conducting energy assessments for the development of new district heating projects in the municipality and the creation of local energy communities. This paper presents the design and functionalities of the proposed digital platform, highlighting its potential for improving energy management in Smart Cities and facilitating the transition to more sustainable energy practices. The results of this study, financed by Swiss Energy together with Canton Ticino and AIM (Aziende Industriali Mendrisio), contribute to the growing body of research on digital technologies for energy management in urban areas and provide insights for policymakers and urban planners seeking innovative solutions for sustainable energy development.
“rubber band” - a practical support tool for integrated and resource-efficient early design in construction
Authors: Jenny David , Graser Konrad , Baldini Luca 
Published: December 2023

Abstract
The planning and construction sector is one of the world’s largest greenhouse gas emitters and has shown the lowest increase in productivity among economic sectors over the last century. Increasing complexity and performance requirements in building projects require the collaboration of ever more interdisciplinary project teams, but conventional planning tools often do not facilitate a tangible knowledge exchange between project stakeholders from different fields of expertise. This is most notable in early project phases when fundamental design decisions are made. To address this challenge, we introduce a flexible and expandable digital workflow using a single 3D-model to integrate and moderate expertise from multiple project stakeholders such as architects, structural engineers, energy planners, contractors, and future users. This workflow creates a “rubber band” between different interdependent design goals and constraints, offering an opportunity to negotiate and optimize design parameters early-on. The framework is an addition to conventional planning tools whose complexity and costs often prevent stakeholders in the building industry from embracing the potentials of the digital transformation.
Energetic performance of a smart neighborhood of existing multifamily buildings with heat pumps, PV and CHP focusing on energy balance and CO2 emissions
Authors: Kropp M , Metz J , Lämmle M 
Published: December 2023

Abstract
A smart energy concept was designed and implemented for a cluster of 5 existing multi-family houses, which combines heat pumps, photovoltaic (PV) modules and combined heat and power units (CHP) to achieve energy- and cost-efficient operation. Measurement results of the first year of operation show that the local power generation by PV modules and CHP unit has a positive effect on the electrical self-sufficiency by reducing electricity import from the grid. In winter, when the CHP unit operates continuously for long periods, the entire electricity for the heat pump and 91 % of the total electricity demand of the neighborhood are supplied locally. In summer, only 53 % is generated within the neighborhood. The use of a specifically developed energy management system EMS is intended to further increase this share. CO2 emissions for heating and electricity of the neighborhood are evaluated and amount to 18.4 kg/(m2a). Compared to the previous energy system consisting of gas boilers (29.1 kg/(m2a)), savings of 37 % are achieved with electricity consumption from the grid being reduced by 65 %. In the second construction stage, an additional heat pump, CHP unit and PV modules will be added. The measurement results indicate that the final district energy system is likely to achieve the ambitious CO2 reduction goal of -50% and further increase the self-sufficiency of the district.
National building stock model for evaluating the impact of different retrofit measures
Authors: Vulic N , Eggimann S , Sulzer M , Orehounig K 
Published: December 2023

Abstract
In this study, a methodology was developed to evaluate different retrofit strategies, which allows an estimation of the current and future thermal space heating demand of the approximately 1.8 million residential buildings in Switzerland. The approach is based on a building stock dynamics model that considers new buildings, replacement buildings, demolitions, as well as past and current rates of energy-related retrofits. Different potential retrofit strategies are applied to evaluate their impact on reducing space heating demand. The results show the effectiveness of the distinct retrofit strategies in reaching the target reduction and emphasize the differences in the resulting annual retrofit rates. The simulated specific retrofit rates can serve as a basis for developing building retrofit measures at the national level, as well as for informing the next generation of regulations.