Refine
Has Fulltext
- yes (53) (remove)
Document Type
- Article (23)
- Conference Proceeding (8)
- Bachelor Thesis (6)
- Master's Thesis (5)
- Doctoral Thesis (4)
- Preprint (3)
- Report (2)
- Study Thesis (2)
Institute
- Professur Bauphysik (53) (remove)
Keywords
- Bauphysik (10)
- Raumklima (8)
- Bauklimatik (5)
- computational fluid dynamics (5)
- Acoustic Travel-Time Tomography (4)
- Simulation (4)
- Strömungsmechanik (4)
- Akustische Laufzeit-Tomographie (3)
- BIM (3)
- Belüftung (3)
- Living wall (3)
- Mikroklima (3)
- OA-Publikationsfonds2022 (3)
- OA-Publikationsfonds2023 (3)
- Wärmeübertragung (3)
- schlieren imaging (3)
- thermal comfort (3)
- Behaglichkeit (2)
- Building Information Modeling (2)
- CFD (2)
- Delphin (2)
- Dissipation (2)
- ENVI-Met (2)
- Energiebedarf (2)
- Energiewende (2)
- Ermüdung (2)
- Feuchteleitung (2)
- Gebäude (2)
- Gebäudehülle (2)
- Gebäudesimulation (2)
- Heat transport (2)
- IFC-basierte Gebäudesimulation (2)
- Latentwärmespeicher (2)
- Lernspiel (2)
- Luftqualität (2)
- Measurements (2)
- Messung (2)
- Moisture transport (2)
- PCM (2)
- Personalized ventilation (2)
- Raumakustik (2)
- Schlieren imaging (2)
- Schnittstelle (2)
- building simulation (2)
- cyclic load (2)
- ductless personalized ventilation (2)
- heat transfer coefficient (2)
- indoor air quality (2)
- personalized ventilation (2)
- phase change materials (2)
- thermische Gebäudehülle (2)
- Abfallwirtschaft (1)
- Absorber (1)
- Absorberelement (1)
- Absorption (1)
- Absorptionskoeffizient (1)
- Abwassermanagement (1)
- Air quality (1)
- Akustik (1)
- Akustik im Barock (1)
- Akustische Tomographie (1)
- Arbeitsplatz (1)
- Architektur <Informatik> (1)
- Aufwindkraftwerk (1)
- Axial fan (1)
- Background-oriented schlieren (1)
- Bauakustik (1)
- Bauphysik und Sanierung (1)
- Baustoff Quartett (1)
- Benutzung (1)
- Beton (1)
- Bilddaten (1)
- Bildverarbeitung (1)
- Biomasse (1)
- Blasinstrument (1)
- BuildVille (1)
- CAD (1)
- Computersimulation (1)
- Computerunterstütztes Lernen (1)
- Computerunterstütztes Verfahren (1)
- Convective indoor air flow (1)
- Covid-19 (1)
- Cross-correlation (1)
- Crowdsourcing (1)
- Deutlichkeit (1)
- Diffusionswärme (1)
- Diffusität (1)
- Digital Game Based Learning (1)
- Digital Games Based Learning (1)
- Digital image correlation (1)
- Dissipationsenergie (1)
- ENVI-met (1)
- Energieplanung (1)
- Energietransport (1)
- Envi-Met (1)
- Ergänzungsbaustoffe (1)
- Facebook (1)
- Fahrradergometer (1)
- Fassadenbegrünung (1)
- Feuchtepufferung (1)
- Finite-Volumen-Methode (1)
- Fliplife (1)
- Fliplife Mitarbeiterrekrutierung (1)
- Flow visualization (1)
- Fluid (1)
- Gebäudesimulation ESP-r (1)
- Gesang (1)
- Gesellschaftsspiel (1)
- Globe thermometers (1)
- Green facade (1)
- Human thermal plume (1)
- IAQ (1)
- Indoor environment (1)
- Intensivstation (1)
- Kirchenbau (1)
- Klarheitsmaß (1)
- Kommune (1)
- Kontamination (1)
- Konvektion (1)
- Kupplung (1)
- Körperschall (1)
- Lautstärke (1)
- Leitung (1)
- Lernen nach Gagné (1)
- Lernspiele (1)
- Living-wall (1)
- Lärm (1)
- Lüftung (1)
- Lüftungsanlage (1)
- Mathematisches Modell (1)
- Mean radiant temperature (1)
- Minecraft (1)
- Missionsmanager (1)
- Modellierung (1)
- Multiplayer (1)
- Musik im Barock (1)
- Nachhall (1)
- Nachhallzeit (1)
- Numerische Strömungsmechanik (1)
- Numerische Strömungssimulation (1)
- Nutzerorientierte Bausanierung (1)
- PCM-Putz (1)
- PCM-plaster (1)
- Pandemie (1)
- Paraffin (1)
- Phase Change Materials (1)
- Phasenumwandlung (1)
- Phasenübergangsmaterialien (1)
- Photothermische Methode (1)
- Post Occupancy Evaluation (1)
- Probekörpererwärmung (1)
- Probleme (1)
- Quartett (1)
- Quartiersanalyse (1)
- Raumakustische Rekonstruktion (1)
- Raumeindruck (1)
- Raumluftströmungen (1)
- Raumlufttemperatur (1)
- Regionalentwicklung (1)
- Rekonstruktion (1)
- Schall (1)
- Schlierenmethode (1)
- Schlierenspiegel (1)
- Simulations (1)
- Singleplayer (1)
- Skill (1)
- Skillmanager (1)
- Skillsystem (1)
- Social Game (1)
- Social Games (1)
- Sonnenenergie (1)
- Sonnenkollektor (1)
- Spieler (1)
- Spielermodell (1)
- Sport (1)
- Strahlung (1)
- Strahlungstemperatur (1)
- Strömung (1)
- Strömungsfeld (1)
- Städtische Wärmeinsel (1)
- Temperatur (1)
- Temperaturfeld (1)
- Thermal comfort (1)
- Thermal manikin (1)
- Thermodynamik (1)
- Thermography (1)
- Training (1)
- Transformation (1)
- Transportgleichung (1)
- UCB model (1)
- Umfrage (1)
- Validierung (1)
- Ventilation (1)
- Verglasung (1)
- Visualisierung (1)
- Visualization (1)
- Weimar / Schloss Wilhelmsburg / Schlosskapelle Himmelsburg (1)
- Wärmeempfindung (1)
- Wärmeverlust (1)
- Wärmeübergang (1)
- Wärmeübergangskoeffizient (1)
- Wärmeübergangskoeffizient an Zylinder (1)
- Wärmeübergangszahl (1)
- Zyklische Beanspruchung (1)
- acoustical measurement (1)
- airborne infection (1)
- background-oriented schlieren (1)
- bauphysikalische Methoden (1)
- biogene Abfallstoffe (1)
- building acoustics (1)
- climate chamber (1)
- computer simulation (1)
- conduction (1)
- convection (1)
- coupling (1)
- cross-contamination (1)
- cycle ergometer (1)
- desk fan (1)
- fatigue (1)
- game mechanic (1)
- heat storage (1)
- heat transfer coefficient for cylinders (1)
- historic church (1)
- historic palace (1)
- housing (1)
- human thermal plume (1)
- intensive care unit (1)
- k-Wert (1)
- latent heat storage (1)
- ländlicher Raum (1)
- mathematical model (1)
- mathematical modelling (1)
- micro climate (1)
- microclimate (1)
- noise (1)
- numerical simulation (1)
- occupant requirements (1)
- occupant satisfaction (1)
- organischer Abfall (1)
- particles concentration (1)
- personalisierte Lüftung (1)
- questionnaire (1)
- radiation (1)
- residential buildings (1)
- room acoustics (1)
- salt hydrate (1)
- schlieren velocimetry (1)
- social game (1)
- solar energy (1)
- sommerlicher Wärmeschutz (1)
- sound pressure level prediction (1)
- sport (1)
- structure-borne sound (1)
- structure-borne sound sources (1)
- summer overheating in buildings (1)
- thermal building simulation (1)
- thermal glazings (1)
- thermal manikin (1)
- thermal protection (1)
- thermal sensation (1)
- thermisches Empfinden (1)
- thermodynamics (1)
- thermography (1)
- tracer gas (1)
- training (1)
- transport of energy (1)
- upwind power plant (1)
- validation (1)
- zerstörungsfreie Prüfung (1)
- zyklische Beanspruchung (1)
- Überhitzung (1)
- äquivalente Temperatur (1)
This study aims to develop an approach to couple a computational fluid dynamics (CFD) solver to the University of California, Berkeley (UCB) thermal comfort model to accurately evaluate thermal comfort. The coupling was made using an iterative JavaScript to automatically transfer data for each individual segment of the human body back and forth between the CFD solver and the UCB model until reaching convergence defined by a stopping criterion. The location from which data are transferred to the UCB model was determined using a new approach based on the temperature difference between subsequent points on the temperature profile curve in the vicinity of the body surface. This approach was used because the microclimate surrounding the human body differs in thickness depending on the body segment and the surrounding environment. To accurately simulate the thermal environment, the numerical model was validated beforehand using experimental data collected in a climate chamber equipped with a thermal manikin. Furthermore, an example of the practical implementations of this coupling is reported in this paper through radiant floor cooling simulation cases, in which overall and local thermal sensation and comfort were investigated using the coupled UCB model.
Reconstruction of the indoor air temperature distribution using acoustic travel-time tomography
(2021)
Acoustic travel-time tomography (ATOM) is being increasingly considered recently as a remote sensing methodology to determine the indoor air temperatures distribution. It employs the relationship between the sound velocities along sound-paths and their related travel-times through measured room-impulse-response (RIR). Thus, the precise travel-time estimation is of critical importance which can be performed by applying an analysis time-window method. In this study, multiple analysis time-windows with different lengths are proposed to overcome the challenge of accurate detection of the travel-times at RIR. Hence, the ATOM-temperatures distribution has been measured at the climate chamber lab of the Bauhaus-University Weimar. As a benchmark, the temperatures of NTC thermistors are compared to the reconstructed temperatures derived from the ATOM technique illustrating this technique can be a reliable substitute for traditional thermal sensors. The numerical results indicate that the selection of an appropriate analysis time-window significantly enhances the accuracy of the reconstructed temperatures distribution.
In dieser Arbeit wird eine umfassende Untersuchung der raumakustischen Qualität der Schlosskapelle des Weimarer Residenzschlosses für den Zustand, wie sie zwischen 1658 und 1774 existierte, durchgeführt. Die Schlosskapelle als sakraler Raum innerhalb der Schlossanlage diente der Ausübung religiöser Handlungen und war fester Bestandteil des kulturellen Lebens am Weimarer Hof. Eine wesentliche Bedeutung erlangte sie in diesem Zusammenhang als musikalische Wirkungsstätte Johann Sebastian Bachs. Mit ihrer akustischen Qualität hatte sie einen erheblichen Einfluss auf sein musikalisches Schaffen. Die Untersuchung der raumakustischen Situation stellt damit eine notwendige Grundlage für eine musikwissenschaftliche Einordnung der Schlosskapelle als Aufführungsstätte geistlicher Kompositionen dar. Der raumakustische Zustand der Weimarer Schlosskapelle ist eng mit der baulichen Entwicklung der gesamten Schlossanlage verbunden, die infolge äußerer Einflüsse einem steten Wandel unterlag. Die Umgestaltung der Schlosskapelle zu Beginn des 17. Jahrhunderts erfolgte nach barocken Raumvorstellungen. Einen wesentlichen Einfluss auf die Gestaltung des Innenraumes übte zudem die reformierte Kirche mit ihren liturgischen Anforderungen aus. Die historische Entwicklung der architektonischen Stilepoche sowie der protestantischen Kirche wird in Bezug zu dem akustischen Erscheinungsbild der Schlosskapelle näher untersucht. Ausgehend von der architektonischen Rekonstruktion wird die Raumstruktur der historischen Schlosskapelle in ein Computermodell übertragen, mit dem die Berechnung akustischer Bewertungskriterien möglich ist. Eine ausgiebige Recherche nach verwendeten Materialien und der Ausbildung baulicher Konstruktionen ist dabei die Grundvoraussetzung für aussagekräftige Simulationsergebnisse. Die Wahl der Materialparameter sowie der Einfluss der geometrischen Besonderheiten der Weimarer Schlosskapelle auf die simulierten Schallfeldparameter werden durch die Untersuchung eines Referenzobjektes verifiziert. Dafür werden die akustischen Bewertungskriterien mit einer raumakustischen Messung ermittelt und mit Simulationsergebnissen verglichen. Ein besonderes Interesse bei der Simulation der Schlosskapelle gilt der Nachhallzeit als Charakteristikum der Halligkeit, die in sakralen Gebäuden die auffälligste akustische Raumeigenschaft darstellt. Mit der rekonstruierten Nachhallzeit wird die Schlosskapelle mit barocken Kirchen verglichen und bezüglich ihrer Lage im baustiltypischen Bereich beurteilt. Der Direktschall und die im zeitig folgenden Reflexionen sind bei der raumakustischen Simulation maßgeblicher Gegenstand der Betrachtung. Während der Nachhall das Verschmelzen einzelner Töne zu einem Gesamtklang fördert, ist der Direktschall für die Deutlichkeit von Sprache und der klanglichen Durchsichtigkeit von musikalischen Strukturen verantwortlich. Der Einfluss des Direktschalls wird mit speziellen Energiekriterien beurteilt, mit denen gezielte Aussagen über die akustische Qualität einzelner Platzbereiche möglich sind. Die unterschiedlichen akustischen Anforderungen an die Schlosskapelle bei der jeweiligen Nutzung des Raumes werden mit den Energiekriterien differenziert untersucht und bewertet.
Personalized ventilation (PV) is a mean of delivering conditioned outdoor air into the breathing zone of the occupants. This study aims to qualitatively investigate the personalized flows using two methods of visualization: (1) schlieren imaging using a large schlieren mirror and (2) thermography using an infrared camera. While the schlieren imaging was used to render the velocity and mass transport of the supplied flow, thermography was implemented to visualize the air temperature distribution induced by the PV. Both studies were conducted using a thermal manikin to simulate an occupant facing a PV outlet. As a reference, the flow supplied by an axial fan and a cased axial fan was visualized with the schlieren system as well and compared to the flow supplied by PV. Schlieren visualization results indicate that the steady, low-turbulence flow supplied by PV was able to penetrate the thermal convective boundary layer encasing the manikin's body, providing clean air for inhalation. Contrarily, the axial fan diffused the supplied air over a large target area with high turbulence intensity; it only disturbed the convective boundary layer rather than destroying it. The cased fan supplied a flow with a reduced target area which allowed supplying more air into the breathing zone compared to the fan. The results of thermography visualization showed that the supplied cool air from PV penetrated the corona-shaped thermal boundary layer. Furthermore, the supplied air cooled the surface temperature of the face, which indicates the large impact of PV on local thermal sensation and comfort.
A new large‐field, high‐sensitivity, single‐mirror coincident schlieren optical instrument has been installed at the Bauhaus‐Universität Weimar for the purpose of indoor air research. Its performance is assessed by the non‐intrusive measurement of the thermal plume of a heated manikin. The schlieren system produces excellent qualitative images of the manikin's thermal plume and also quantitative data, especially schlieren velocimetry of the plume's velocity field that is derived from the digital cross‐correlation analysis of a large time sequence of schlieren images. The quantitative results are compared with thermistor and hot‐wire anemometer data obtained at discrete points in the plume. Good agreement is obtained, once the differences between path‐averaged schlieren data and planar anemometry data are reconciled.
Summer overheating in buildings is a common problem, especially in office buildings with large glazed facades, high internal loads and low thermal mass. Phase change materials (PCM) that undergo a phase transition in the temperature range of thermal comfort can add thermal mass without increasing the structural load of the building. The investigated PCM were micro-encapsulated and mixed into gypsum plaster. The experiments showed a reduction of indoor-temperature of up to 4 K when using a 3 cm layer of PCM-plaster with micro-encapsulated paraffin. The measurement results could validate a numerical model that is based on a temperature dependent function for heat capacity. Thermal building simulation showed that a 3 cm layer of PCM-plaster can help to fulfil German regulations concerning heat protection of buildings in summer for most office rooms.
The performance of ductless personalized ventilation (DPV) was compared to the performance of a typical desk fan since they are both stand-alone systems that allow the users to personalize their indoor environment. The two systems were evaluated using a validated computational fluid dynamics (CFD) model of an office room occupied by two users. To investigate the impact of DPV and the fan on the inhaled air quality, two types of contamination sources were modelled in the domain: an active source and a passive source. Additionally, the influence of the compared systems on thermal comfort was assessed using the coupling of CFD with the comfort model developed by the University of California, Berkeley (UCB model). Results indicated that DPV performed generally better than the desk fan. It provided better thermal comfort and showed a superior performance in removing the exhaled contaminants. However, the desk fan performed better in removing the contaminants emitted from a passive source near the floor level. This indicates that the performance of DPV and desk fans depends highly on the location of the contamination source. Moreover, the simulations showed that both systems increased the spread of exhaled contamination when used by the source occupant.
Performance assessment of a ductless personalized ventilation system using a validated CFD model
(2018)
The aim of this study is twofold: to validate a computational fluid dynamics (CFD) model, and then to use the validated model to evaluate the performance of a ductless personalized ventilation (DPV) system. To validate the numerical model, a series of measurements was conducted in a climate chamber equipped with a thermal manikin. Various turbulence models, settings, and options were tested; simulation results were compared to the measured data to determine the turbulence model and solver settings that achieve the best agreement between the measured and simulated values. Subsequently, the validated CFD model was then used to evaluate the thermal environment and indoor air quality in a room equipped with a DPV system combined with displacement ventilation. Results from the numerical model were then used to quantify thermal sensation and comfort using the UC Berkeley thermal comfort model.