Alexander Kahnt

Dr. Alexander Kahnt


Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
5 December 2022 in Sustainability
Verified
Journal Article
Open access
PDF file
DADespoina Antypa
Despoina Antypa
FPFotini Petrakli
Fotini Petrakli
AGAnastasia Gkika Anastasia Gkika
Anastasia Gkika Anastasia Gkika
PVPamela Voigt
Pamela Voigt
AKAlexander Kahnt
Alexander Kahnt
Elias KoumoulosElias Koumoulos
Elias Koumoulos
The building sector accounts for 40% of the total energy consumed in Europe at annual basis, together with the relevant Greenhouse Gas (GHG) emissions. In order to mitigate these impacts, the concept and establishment of the Nearly Zero Energy Buildings (NZEBs) is under continuous and intensive research. In fact, as the energy used for buildings’ operation becomes more efficient, impacts resulting from the buildings’ embodied energy become of more importance. Therefore, the selection of building materials and components is of high significance, as these affect the energy performance and potential environmental impacts of the building envelopes. The objective of this study is to perform a preliminary Life Cycle Assessment (LCA) on advanced multifunctional building components, aiming to achieve lower embodied emissions in NZEBs. The advanced components analyzed are composite panels for facade elements of building envelopes, providing thermal efficiency. The design of sustainable building envelope systems is expected to upgrade the overall environmental performance of buildings, including the NZEBs. The findings of this study constitute unambiguous evidence on the need for further research on this topic, as substantial lack of data concerning embodied impacts is presented in literature, adding to the growing discussion on NZEBs at a whole life cycle perspective across Europe. This research has shown that the electricity required from the manufacturing phase of the examined building components is the main contributor to climate change impact and the other environmental categories assessed. Sensitivity analysis that has been performed indicated that the climate change impact is highly depended on the electricity grid energy mix across Europe. Taking into account the current green energy transition by the increase of the renewable energy sources in electricity production, as well as the future upgrade of the manufacturing processes, it is expected that this climate change impact will be mitigated. Finally, the comparison between the CLC thermal insulator and other foam concretes in literature showed that the materials of the building components examined do not present any diversions in terms of environmental impact.

21 February 2022 in Materials
Verified
Journal Article
Open access
PDF file
RKRobert Kraft
Robert Kraft
AKAlexander Kahnt
Alexander Kahnt
Otto GrauerOtto Grauer
Otto Grauer
Mike ThiemeMike Thieme
Mike Thieme
DWDaniel Sebastian Jens Wolz
Daniel Sebastian Jens Wolz
Robert BöhmRobert Böhm
Robert Böhm
The building sector accounts for approx. 40% of total energy consumption and approx. 36% of all greenhouse gas emissions in Europe. As the EU climate targets for 2030 call for a reduction of greenhouse gas emissions by more than half compared to the emissions of 1990 and also aim for climate neutrality by 2050, there is an urgent need to achieve a significant decrease in the energy use in buildings towards Nearly Zero-Energy Buildings (nZEBs). As the energy footprint of buildings includes the energy and greenhouse gas consumption both in the construction phase and during service life, nZEB solutions have to provide energy-efficient and less carbon-intensive building materials, specific thermal insulation solutions, and a corresponding design of the nZEB. Carbon reinforced concrete (CRC) materials have proven to be excellent candidate materials for concrete-based nZEBs since they are characterized by a significantly lower CO2 consumption during component production and much a longer lifecycle. The corresponding CRC technology has been successively implemented in the last two decades and first pure CRC-based buildings are currently being built. This article presents a novel material system that combines CRC technology and suitable multifunctional insulation materials as a sandwich system in order to meet future nZEB requirements. Because of its importance for the life cycle stage of production, cost-efficient carbon fibers (CF) from renewable resources like lignin are used as reinforcing material, and reinforcement systems based on such CF are developed. Cutting edge approaches to produce ultra-thin lightweight CF reinforced concrete panels are discussed with regard to their nZEB relevance. For the life cycle stage of the utilization phase, the thermal insulation properties of core materials are optimized. In this context, novel sandwich composites with thin CRC layers and a cellular lightweight concrete core are proposed as a promising solution for façade elements as the sandwich core can additionally be combined with an aerogel-based insulation. The concepts to realize such sandwich façade elements will be described here along with a fully automated manufacturing process to produce such structures. The findings of this study provide clear evidence on the promising capabilities of the CRC technology for nZEBs on the one hand and on the necessity for further research on optimizing the energy footprint of CRC-based structural elements on the other hand.

22 February 2024 in Actuators
Verified
Journal Article
Open access
PDF file
MSMario Stelzmann
Mario Stelzmann
FZFelix Zakner
Felix Zakner
ISIñaki Navarro de Sosa
Iñaki Navarro de Sosa
ANAmir Nemati
Amir Nemati
AKAlexander Kahnt
Alexander Kahnt
WDWelf-Guntram Drossel
Welf-Guntram Drossel
In the field of adaptive building technologies, this research introduces the development of a self-regulating solar shading actuator that utilizes the thermal shape memory effect. The study focuses on addressing the actuator’s performance under diverse environmental conditions. Thermal simulations were carried out during the development of the individual components of the actuator and for the prediction of specific switching temperatures. The investigation includes an analysis of the sunshade’s response to varying environmental conditions, emphasizing its effectiveness on clear summer days and identifying challenges during overcast periods. The critical coordination between the solar collector and the shape memory alloy (SMA) wire is examined, shedding light on the impact of SMA temperature dynamics on the actuation performance. Through the integration of simulation data and real-world measurements, the study validates the thermal model for the solar collector, establishing the robustness of the system’s operation. This research work contributes significantly to the development of intelligent actuators and outlines the importance of validation of SMA-based applications under real conditions.

18 January 2024 in Preprints.org
Verified
Preprint
Open access
PDF file
MSMario Stelzmann
Mario Stelzmann
FZFelix Zakner
Felix Zakner
ISIñaki Navarro de Sosa
Iñaki Navarro de Sosa
ANAmir Nemati
Amir Nemati
AKAlexander Kahnt
Alexander Kahnt
WDWelf-Guntram Drossel
Welf-Guntram Drossel
In the field of adaptive building technologies, this research introduces the development of a self-regulating solar shading actuator, that utilizes the thermal shape memory effect. The study places its focus on addressing the actuator’s performance under diverse environmental conditions. Thermal simulations were carried out during the development of the individual components of the actuator and for the prediction of specific switching temperatures. The investigation includes an analysis of the sunshade’s response to varying environmental conditions, emphasizing its effectiveness on clear summer days and identifying challenges during overcast periods. The critical coordination between the solar collector and the shape memory alloy (SMA) wire is examined, shedding light on the impact of SMA temperature dynamics on the actuation performance. Through the integration of simulation data and real-world measurements, the study validates the thermal model for the solar collector, establishing the robustness of the system’s operation. This research work contributes significantly to the development of intelligent actuators and outlines the importance of validation of SMA-based applications under real conditions.

1 April 2022 in Beton- und Stahlbetonbau
Verified
Journal Article
Closed access
MSMario Stelzmann
Mario Stelzmann
MKMarén Kupke
Marén Kupke
AKAlexander Kahnt
Alexander Kahnt

1 April 2023 in Beton- und Stahlbetonbau
Verified
Journal Article
Closed access
MSMario Stelzmann
Mario Stelzmann
ELEmanuel Lägel
Emanuel Lägel
AKAlexander Kahnt
Alexander Kahnt
Klaus HolschemacherKlaus Holschemacher
Klaus Holschemacher