Conference Agenda

Life Cycle Assessment (LCA) serves as a crucial methodology for evaluating the environmental impacts of building wall structures throughout their entire lifespan, from raw material extraction to end-of-life disposal. This study presents a comprehensive analysis of various wall construction systems, examining their environmental performance across production, construction, use, and end-of-life phases. The assessment utilizes a functional unit of one square meter of wall structure over a 50-year service life, considering equivalent thermal resistance and load-bearing requirements. This study also analysis the implementation of circular economy principles in building construction, focusing on material flows, design strategies, and systemic changes required for circular building practices. The assessment of wall compositions shows that the largest contributors to GHG are the load-bearing structures of the wall, namely burnt brick or aerated concrete. Perforated burnt brick contribute to GWP by value of 144 kg CO2e/m3, aerated concrete brick 9.56 kg CO2e/m3, sand-lime brick 301.71 kg CO2e/m3. All the bricks used achieve a 25% circularity score because of 100% virgin materials are used and 100% of the waste is moved to downcycling. The highest emissions are achieved by EPS thermal insulation, and of the plasters it is silicone plaster. The circularity score of plasters when placed in landfill at the end of their life is 0%, however if we recycled the plaster its circularity score would be 50%. Circularity scores for the perimeter wall compositions ranged from 20% to 77%. Changing the end-of-life phase increased the lowest circularity score composition by 9% and reduced emissions by 1.4%. The highest costs are quantified for the B6 energy consumption phase for all perimeter wall compositions. Other factors such as aesthetics, maintenance requirements and local climatic conditions may also need to be considered when selecting the appropriate vegetated roof composition for a particular building or site. This research concludes that achieving building circularity requires a coordinated transformation of the construction industry, encompassing technical, economic, and social innovations to enable closed-loop material cycles and sustainable resource management in the built environment.

The operational energy efficiency of new buildings in the EU should be at the level of ultra-low or near-zero energy buildings. It is therefore relatively difficult to achieve further energy savings. The pre-commissioning phase represents a valuable opportunity to further reduce energy input and greenhouse gas emissions. This period can be characterized by the embodied or grey energy required to construct the building and the resulting emissions. Unlike operational energy, no standard or legislative criteria have yet been established for embodied energy. The paper therefore explores the possibility of using PENRT (Primary Energy Non-Renewable Total) and GWP (Global Warming Potential) indicators, related to 1 m² of heated building area, as criteria for assessing the environmental quality of buildings. It may be beneficial to consider the calculation of PENRT/m² and GWP/m² in the context of energy certification, with benchmarks possibly dependent on the shape factor, in a manner analogous to the assessment of heating demand. Shape factor is the ratio of the heat exchange surface of the building envelope to the heated volume of the building. The results show that relating PENRT/m2 or GWP/m2 to the shape factor is a fairer way of assessing building quality than a single numerical value for any geometry.

Global fossil fuel resources continue to deplete and population growth drives in-creasing energy demand, the efficient use of energy has become a critical focus in sustainable development. In the building sector, thermal insulation plays a crucial role in carbon emissions and energy consumption reduction while minimizing re-liance on natural resources. Moreover, thermal insulation can significantly impact life cycle costs (LCC) that account for all expenses incurred throughout the life of a building. Therefore, this study presents a comparative LCC analysis of two widely used thermal insulation materials: expanded polystyrene (EPS) and miner-al wool (MW). For both materials, purchase prices, installation costs, maintenance requirements, and end-of-life costs, including removal, transport, and disposal are evaluated. Calculated costs were adjusted to net present value using dis-count rates recommended by the European Commission, allowing for an accurate comparison over the operational life of 35 years. Results indicate that the total life cycle cost for EPS is €107.30/m², with approximately 70% attributed to installation costs. Similarly, the results for MW show that installation costs account for more than 70% of a total life cycle cost of €127.85/m². Key distinctions in materi-al properties, including thermal conductivity, durability, and ease of installation, are also discussed, providing insight into the trade-offs between these insulation options. This comparative analysis underscores the importance of incorporating LCC assessments into material selection processes for energy-efficient building design. By providing a comprehensive understanding of economic and environ-mental impacts, the study aids stakeholders in making informed decisions to optimize energy savings and sustainability outcomes.

Reducing the energy consumption of buildings effectively is a key challenge in building physics. Conventional methods such as simulations and physical calculations provide valuable insights but often fall short in addressing the complex interplay of influencing factors and evaluating alternative scenarios. This study explores the application of Fault-Tree Analysis (FTA), a method originally developed for aerospace systems, to identify and assess energy-saving measures in the building sector. FTA enables a systematic analysis of vulnerabilities (primary events) and their impact on overarching goals (top events), such as reducing energy demand. By structuring relevant influencing factors hierarchically within a fault tree, individual components of building physics systems can be analyzed, and their interdependencies can be made transparent. This structured approach allows planners to identify measures with the greatest impact on the top event while simultaneously evaluating equivalent alternatives. A key focus of the study is the integration of FTA into the planning process. This method not only evaluates the effectiveness of specific measures but also relates them to associated costs. Given rising construction costs driven by increasing interest rates, labor shortages, and material scarcity, this capability is particularly valuable. FTA provides planners with alternative solutions that meet both ecological and economic criteria. The study includes practical examples of common vulnerabilities in building physics systems and their impact on energy efficiency. Scenarios are developed to evaluate alternative measures based on different influencing factors. Results demonstrate that FTA offers a structured foundation for decision-making and enhances communication between building physicists, planners, and stakeholders. This contribution highlights that FTA, as a complement to established methods like simulations and physical calculations, can significantly enhance the optimization of energy efficiency in buildings. Particularly for complex projects, FTA provides new perspectives for planning and implementing energy-saving measures in a holistic and cost-conscious manner. By identifying critical factors and their interactions, FTA not only supports the selection of effective measures but also fosters a transparent and systematic approach to addressing energy efficiency challenges. The findings underline the potential of FTA to contribute meaningfully to sustainable building practices in the context of contemporary economic and environmental constraints.

The study considers a long-time assessment of total annual carbon savings through on-site energy generation in a historic religious development. The overarching research goal is to investigate and determine the total monthly and yearly carbon savings through on-site energy production, usage, and banked rates in the development for four years (2017 – 2021). The research novelty is the assessment of the monthly and annual carbon savings in the historic development over several years. The case study is a Mid-Century Modern/Neo-Expressionist building used for multiple purposes, including religious activities, communal, offices, educational, recreational, etc. The development was completed in 1964, and it is in the northeast region of the United States. It is one of the state’s historic buildings with an estimated floor area of 2,508.4m2 (i.e., 27,000ft2). The principal source of on-site energy generation is photovoltaic (PV) systems with a wattage capacity of over 35,000. The estimated U-values of the building components varied from 1.8-3.0W/m2K. The investigation considered the actual data collection of on-site energy production, utilization, and savings in the development for six years (2016 – 2021). The current study focuses on years with the complete energy data for 12 months (i.e., 2017 – 2020) and considers data analysis for these years. The total annual carbon savings in the development using the kgCO2ekWh benchmark for solar panels ranged from -0.91 tonnes to 7.23 tonnes. The research showed the highest quarterly carbon savings are noted in the second and third quarters of each year, while July is the month with the highest monthly carbon savings. The average annual carbon savings from 2017 - 2020 is estimated to be 2.04 tonnes, while the average yearly cost per kWh ($/kWh) is less than one US dollar. The research demonstrated that historic developments can be sustainable if appropriate retrofit strategies or interventions are considered for their operations. The study implies that historic buildings do not require sophisticated interventions to be resilient and retrofitting of historic buildings can contribute to lowering the overall annual carbon emissions in various regions. The research outcomes can encourage owners of historic buildings to consider various cost-effective strategies for improving their building performance.

Many studies have been conducted to detect and attempt to mitigate the collateral harm caused by the building sector, with a primary focus on the usage stage for greater energy efficiency. It has become clear, nonetheless, that research must concentrate on the whole life cycle of buildings.

In this paper, life cycle assessment for 9 different wall systems that are com-monly used in Hungary is carried out to compare their environmental impact. The contribution of the life cycle stages and materials to the carbon footprint is as-sessed in absolute and relative terms. We also explain the reasons behind these differences and relating them to the natural characteristics of these materials.

Calculations show that the stage with the highest contribution is the produc-tion (A1-A3), reaching 88% for reinforced concrete while it ranges for other walls from 16.5%-83.7%. The wall with the highest carbon footprint was rein-forced concrete and aerated concrete wall (with 123.3 CO2-eq and 94.9 CO2-eq respectively).

By addressing the methodologies in the analysis, we can offer more in-depth information about how well building materials (like concrete, steel, and timber …etc.) perform.