Alexander Hollberg


Last Name

Hollberg

First Name

Alexander

ORCID

0000-0002-9756-2362

Organisational unit

Filters

2016 - 2019222020 - 202420
Reset filters

Search Results

Publications 1 - 10 of 42
  • Bio-based materials as a robust and optimal solution for building renovation
    Item type: Conference Paper
    Rodionova, Alina; Moustapha, Maliki; Hollberg, Alexander; et al. (2021)
    Building energy renovation is urgent in order to lower green house gas (GHG) emissions and achieve carbon neutrality by 2050. Building energy renovation can be achieved by more efficient thermal insulation and replacing the fossil heating system in a building. Currently, conventional building insulation materials dominate the market. However, to drastically reduce GHG emissions, bio-based materials are a valuable asset. These can be applied not only to reduce the operational energy but also to temporarily store carbon in the building stock. To evaluate the environmental and cost performance of such insulation, life cycle cost analysis (LCCA) and environmental life cycle assessment (LCA) can be used. However, as buildings are long lasting systems, many parameters in these analyses are uncertain. Such parameters include the future climate, future inflation rates, point in time when materials are replaced, future energy policies, and so on. In this paper, we apply bio-based insulation materials for building renovation and define the optimal solution for building energy-related renovation using a novel methodology, which combines non-dominated sorting genetic algorithm (NSGA-II) with surrogate modeling. We use materials such as straw, hemp, and wood fibre along with conventional materials such as EPS. At the same time, we account for the uncertainties associated with these materials’ production and replacement as well as those associated with the future building operation. In this analysis, we also include the carbon storage calculation. The results show that bio-based materials provide a robust solution for building renovation and have high potential to store carbon in building components in comparison with conventional insulation materials. The results also show that to achieve the highest GHG emissions reduction, building energy-efficient measures should be combined with the replacement of the existing fossil heating system. The approach presented here allows the identification of the robust and optimal building renovation solution performed with bio-based materials and the comparison of such renovation with conventional materials.
  • Design-integrated LCA using early BIM
    Item type: Conference Paper
    Hollberg, Alexander; Tschetwertak, Julia; Schneider, Sven; et al. (2017)
  • Do we need a saw? Carbon-based analysis of facade BIPV performance under partial shading from nearby trees
    Item type: Conference Paper
    McCarty, Justin; Waibel, Christoph; Galimshina, Alina; et al. (2023)
    Journal of Physics: Conference Series ~ CISBAT International Conference 2023: Renewable Energy
    Building integrated photovoltaics (BIPV) are becoming more common in urban spaces. The impact of shading from nearby trees on BIPV performance and the potential conflict between the carbon sequestration benefits of trees and the carbon mitigation benefits of BIPV is not well documented in research. Therefore, this paper investigates the cost-benefit relationship of the carbon storage potential of trees vs. their shading effects on a nearby BIPV facade from the perspective of a life cycle assessment (LCA) using a high-resolution BIPV model and temporally sensitive tree growth model. The study is based on a typical Swiss residential building with adjacent vegetation and includes various BIPV facade permutations with different cell types, module orientations, inverter types, facade azimuths, grid emissions profiles, and tree planting scenarios. The results indicate that the removal of trees does not necessarily influence the overall carbon balance when considering LCA to the same degree as other features of the model space such as the grid carbon intensity or the configuration of the BIPV array. Furthermore the parametric-based analysis enables reporting on which BIPV configurations operate with the highest system efficiency under partial shading.
  • Environmental benchmarks for buildings: needs, challenges and solutions—71st LCA forum, Swiss Federal Institute of Technology, Zürich, 18 June 2019
    Item type: Journal Article
    Frischknecht, Rolf; Balouktsi, Maria; Lützkendorf, Thomas; et al. (2019)
    The International Journal of Life Cycle Assessment
  • Earth Plastered Wall Heating as a Low-Emitting, Cost-Effective and Robust Energy System for Building Renovation
    Item type: Conference Paper
    Rodionova, Alina; Moustapha, Maliki; Hollberg, Alexander; et al. (2022)
    Construction Technologies and Architecture ~ Bio-Based Building Materials
    Renovation of the building stock in Europe is urgent to decrease the environmental impact from the building sector and meet the United Nations climate action goals. However, it is often hard to define a robust scenario for a renovation due to numerous uncertainties, which occur during the production, operation and end-of-life stage. One can cite the loss of performance of insulation and heating systems, the replacement time of installation or the future energy prices as well as the future climate. The replacement of oil boilers with heat pumps has shown a good performance regarding costs and greenhouse gas emissions. However, due to the flow and return temperature differences, often the current heat distribution system needs to be replaced as well, which is normally done with conventional radiators or floor heating. In this paper, we analyse a new possibility of a heat distribution system with earth plastered wall. We develop a methodology on the integrated assessment of life cycle assessment (LCA) and life cycle cost analysis (LCCA) for the renovation scenarios and adapt the analysis of the heat pump renovation solution with conventional radiators system and the earth plastered wall for two typical residential buildings located in Switzerland. Through rigorous statistical treatment, we then propagate the possible sources of uncertainty and perform the uncertainty quantification using polynomial chaos expansion to compare the distributions of two outcomes. The results show that the solution with the earth plaster has lower overall environmental impacts and costs. It has also been noticed that the solution with the earth plaster is more robust in investment cost and embodied emissions compared to the solution with the conventional radiators.
  • Environmental design
    Item type: Conference Paper
    Hollberg, Alexander; Hildebrand, Linda; Habert, Guillaume (2018)
    Proceedings of the 6th eCAADe Regional International Symposium
  • Statistical method to identify robust building renovation choices for environmental and economic performance
    Item type: Journal Article
    Galimshina, Alina; Moustapha, Maliki; Hollberg, Alexander; et al. (2020)
    Building and Environment
    Building renovation is urgently required to decrease the energy consumption of the existing building stock and reduce greenhouse gas emissions coming from the building sector. Selecting an appropriate renovation strategy is challenging due to the long building service life and consequent uncertainties. In this paper, we propose a new framework for the robust assessment of renovation strategies in terms of environmental and economic performance of the building's life cycle. First, we identify the possible renovation strategies and define the probability distributions for 74 uncertain parameters. Second, we create an integrated workflow for Life Cycle Assessment (LCA) and Life Cycle Cost analysis (LCC) and make use of Sobol’ indices to identify a prioritization strategy for the renovation. Finally, the selected renovation scenario is assessed by metamodeling techniques to calculate its robustness. The results of three case studies of residential buildings from different construction periods show that the priority in renovation should be given to the heating system replacement, which is followed by the exterior wall insulation and windows. This result is not in agreement with common renovation practices and this discrepancy is discussed at the end of the paper.
  • Review of existing service lives’ values for building elements and their sensitivity on building LCA and LCC results
    Item type: Conference Paper
    Lasvaux, Sébastien; Giorgi, M.; Favre, Didier; et al. (2018)
    Life-Cycle of Civil Engineering Systems ~ Life Cycle Analysis and Assessment in Civil Engineering: Towards an Integrated Vision
  • Design-integrated Environmental Performance Feedback based on Early-BIM
    Item type: Conference Paper
    Hollberg, Alexander; Agustí-Juan, Isolda; Lichtenheld, Thomas; et al. (2018)
    Life-Cycle of Civil Engineering Systems ~ Life Cycle Analysis and Assessment in Civil Engineering: Towards an Integrated Vision
  • Using a budget approach for decision-support in the design process
    Item type: Conference Paper
    Hollberg, Alexander; Lützkendorf, Thomas; Habert, Guillaume (2019)
    Proceedings of the 2019 Sustainable Built Environment Conference (SBE19)
    The use of Life Cycle Assessment (LCA) during the design phase can help to improve the environmental performance of buildings. However, designers and clients find it difficult to set environmental performance targets and interpret the results obtained through LCA in order to improve the building design. Therefore, performance levels or benchmarks are needed that provide design guidance towards reducing the environmental impacts of buildings in the life cycle. This paper uses a dual benchmark approach. The main concept consists in combining building-related top-down targets with building component-related bottom-up benchmarks. The overall top-down targets per capita and year are derived from the capacity of the global eco system. The bottom-up benchmarks for building elements are calculated following a best-in-class (top 5%) approach. A workflow of applying these benchmarks is proposed. It provides guidance on how to optimize the environmental performance of a building and its components efficiently by differentiating between material and design-related options. The approach is exemplified by means of a case study of a multi-family house.
Publications 1 - 10 of 42