TY - JOUR A1 - Pollack, Moritz A1 - Lück, Andrea A1 - Wolf, Mario A1 - Kraft, Eckhard A1 - Völker, Conrad T1 - Energy and Business Synergy: Leveraging Biogenic Resources from Agriculture, Waste, and Wastewater in German Rural Areas JF - Sustainability N2 - The imperative to transform current energy provisions is widely acknowledged. However, scant attention has hitherto been directed toward rural municipalities and their innate resources, notably biogenic resources. In this paper, a methodological framework is developed to interconnect resources from waste, wastewater, and agricultural domains for energy utilization. This entails cataloging existing resources, delineating their potential via quantitative assessments utilizing diverse technologies, and encapsulating them in a conceptual model. The formulated models underwent iterative evaluation with engagement from diverse stakeholders. Consequently, 3 main concepts, complemented by 72 sub-concepts, were delineated, all fostering positive contributions to climate protection and providing heat supply in the rural study area. The outcomes’ replicability is underscored by the study area’s generic structure and the employed methodology. Through these inquiries, a framework for the requisite energy transition, with a pronounced emphasis on the coupling of waste, wastewater, and agriculture sectors in rural environments, is robustly analyzed. KW - Energiewende KW - Energieplanung KW - Abfallwirtschaft KW - organischer Abfall KW - Biomasse KW - Regionalentwicklung KW - biogene Abfallstoffe KW - Abwassermanagement KW - OA-Publikationsfonds2023 Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20231222-65172 UR - https://www.mdpi.com/2071-1050/15/24/16573 VL - 2023 IS - volume 15, issue 24, article 16573 SP - 1 EP - 25 PB - MDPI CY - Basel ER - TY - JOUR A1 - Becher, Lia A1 - Völker, Conrad A1 - Rodehorst, Volker A1 - Kuhne, Michael T1 - Background-oriented schlieren technique for two-dimensional visualization of convective indoor air flows JF - Optics and Lasers in Engineering N2 - This article focuses on further developments of the background-oriented schlieren (BOS) technique to visualize convective indoor air flow, which is usually defined by very small density gradients. Since the light rays deflect when passing through fluids with different densities, BOS can detect the resulting refractive index gradients as integration along a line of sight. In this paper, the BOS technique is used to yield a two-dimensional visualization of small density gradients. The novelty of the described method is the implementation of a highly sensitive BOS setup to visualize the ascending thermal plume from a heated thermal manikin with temperature differences of minimum 1 K. To guarantee steady boundary conditions, the thermal manikin was seated in a climate laboratory. For the experimental investigations, a high-resolution DLSR camera was used capturing a large field of view with sufficient detail accuracy. Several parameters such as various backgrounds, focal lengths, room air temperatures, and distances between the object of investigation, camera, and structured background were tested to find the most suitable parameters to visualize convective indoor air flow. Besides these measurements, this paper presents the analyzing method using cross-correlation algorithms and finally the results of visualizing the convective indoor air flow with BOS. The highly sensitive BOS setup presented in this article complements the commonly used invasive methods that highly influence weak air flows. KW - Raumklima KW - Raumluftströmungen KW - Flow visualization KW - Convective indoor air flow KW - Background-oriented schlieren KW - Human thermal plume KW - Cross-correlation Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220810-46972 N1 - This article is published by Elsevier in Optics and Lasers in Engineering 134 (2020) 106282 and may be found at https://doi.org/10.1016/j.optlaseng.2020.106282 Copyright © 2020 Elsevier Ltd. All rights reserved. This article may be downloaded for personal use only. Any other use requires prior permission of the authors and Elsevier Ltd. VL - 2020 IS - Volume 134, article 106282 ER - TY - CHAP A1 - Hartmann, Maria A1 - Alsaad, Hayder A1 - Völker, Conrad T1 - Das Potential von Fassadenbegrünungen zur Verringerung des Wärmeinseleffekts: Simulation eines Beispielquartiers T2 - Bauphysiktage Kaiserslautern 2022 N2 - Die Auswirkungen einer Fassadenbegrünung auf den Wärmeinseleffekt in Stuttgart wurde für eine Hitzeperiode numerisch simuliert und bewertet. Die Ergebnisse zeigten positive Auswirkungen innerhalb des Simulationsgebiets sowie eine geringe Fernwirkung auf benachbarte Stadtquartiere. Diese Änderungen können zur Verbesserung des thermischen Komforts im Außenraum beitragen. Eine reduzierte Temperatur der Außenoberfläche führt darüber hinaus auch zu einer geringeren Oberflächentemperatur der Wandinnenseite, welche die Innenraumtemperatur beeinflusst. Folglich kann die thermische Behaglichkeit auch im Innenraum erhöht werden. KW - Mikroklima KW - Envi-Met KW - Städtische Wärmeinsel KW - Fassadenbegrünung KW - Living-wall Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220713-46676 SN - 978-3-95974-176-7 SN - 2363-8206 CY - Kaiserslautern ER - TY - CHAP A1 - Alsaad, Hayder A1 - Völker, Conrad T1 - Measuring and visualizing the flow supplied by personalized ventilation T2 - Proceedings Book Roomvent 2020 N2 - This study investigates the flow supplied by personalized ventilation (PV) by means of anemometer measurements and schlieren visualization. The study was conducted using a thermal manikin to simulate a seated occupant facing a PV outlet. Air velocity was measured at multiple points in the flow field; the collected velocity values were used to calculate the turbulence intensity. Results indicated that PV was supplying air with low turbulence intensity that was able to penetrate the convective boundary layer of the manikin to supply clean air for inhalation. The convective boundary layer, however, obstructed the supplied flow and reduced its velocity by a total of 0.26 m/s. The PV flow preserved its value until about 10 cm from the face where velocity started to drop. Further investigations were conducted to test a PV diffuser with a relatively large outlet diameter (18 cm). This diffuser was developed using 3d-modelling and 3d-printing. The diffuser successfully distributed the flow over the larger outlet area. However, the supplied velocity and turbulence fields were not uniform across the section. KW - Belüftung KW - Luftqualität KW - Personalized ventilation KW - Schlieren imaging KW - Air quality KW - Thermal manikin Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220622-46573 CY - Turin, Italy ER - TY - CHAP A1 - Kiesel, Gerd A1 - Engels, Merit A1 - Völker, Conrad ED - Kornadt, Oliver ED - Carrigan, Svenja ED - Hofmann, Markus ED - Völker, Conrad T1 - Energetische Transformation im ländlichen Raum – Aufbau eines prozessorientierten Entwicklungs- und Moderationsmodells T2 - Schriftenreihe des Fachgebiets Bauphysik/Energetische Gebäudeoptimierung N2 - Kleine Kommunen im ländlichen Raum sind aufgrund ihrer oft eingeschränkten personellen und finanziellen Kapazitäten bisher eher sporadisch in den Themenfeldern Energieeffizienz und Erneuerbare Energien aktiv. Immer wieder stellt sich daher Frage, wie die Klimaschutzstrategien des Bundes und der Länder dort mit dem verfügbaren Personal kostengünstig realisierbar sind. Vor diesem Hintergrund wird ein Werkzeug entwickelt, mit dessen Hilfe der aktive Einstieg in diese Thematik mit geringen Aufwand und überwiegend barrierefrei möglich ist. Der Aufbau eines prozessorientierten Entwicklungs- und Moderationsmodells zur Erprobung und Umsetzung bezahlbarer Handlungsoptionen für Energieeinsparungen und effizienten Energieeinsatz im überwiegend ländlichen geprägten Raum ist der Schwerpunkt der Softwarelösung. Kommunen werden mit deren Hilfe in die Lage versetzt, in die notwendigen Prozesse der Energie- und Wärmewende einzusteigen. Dabei soll der modulare Aufbau die regulären Schritte notwendiger (integrierter) Planungsprozesse nicht vollständig ersetzen. Vielmehr können innerhalb der Online-Anwendung - überwiegend automatisiert - konkrete Maßnahmenvorschläge erstellt werden, die ein solides Fundament der künftigen energetischen Entwicklung der Kommunen darstellen. Für eine gezielte Validierung der Ergebnisse und der Ableitung potentieller Maßnahmen werden für die Erprobung Modellkommunen in Thüringen, Bayern und Hessen als Reallabore einbezogen. Das Tool steht bisher zunächst nur den beteiligten Modellkommunen zur Verfügung. Die entwickelte Softwarelösung soll künftig Schritt für Schritt allen interessierten Kommunen mit diversen Hilfsmitteln und einer Vielzahl anderer praktischer Bestandteile zur Verfügung gestellt werden. KW - Modellierung KW - Kommune KW - Energiewende KW - Transformation KW - ländlicher Raum Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220617-46566 SN - 978-3-95974-176-7 SN - 2363-8206 PB - Eigenverlag Technische Universität Kaiserslautern CY - Kaiserslautern ER - TY - CHAP A1 - Geske, Mara A1 - Benz, Alexander A1 - Völker, Conrad ED - Kornadt, Oliver ED - Carrigan, Svenja ED - Hofmann, Markus ED - Völker, Conrad T1 - Anwendung georeferenzierter Bilddaten bei energetischen Quartiersanalysen T2 - Tagungsband Bauphysiktage Kaiserslautern 2022 N2 - Bei Analysen des Gebäudebestands im Quartierskontext werden zu Dokumentationszwecken viele Bilddaten erzeugt. Diese Daten sind im Nachhinein häufig keinen eindeutig genauen Standorten und Blickwinkeln auf das Bauwerk zuzuordnen. Insbesondere gilt dies für Ortsunkundige oder für Detailaufnahmen. Eine zusätzliche Herausforderung stellt die Aufnahme von Wärmebrücken- oder andersartigen Gebäudedetails durch Thermogramme dar. In der Praxis kommen hier oftmals analoge, fehleranfällige Lösungen zum Einsatz. Durch die Nutzung von Georeferenzierung kann diese Lücke geschlossen und eine eindeutige Kommunikation und Auswertung gewährleistet werden. Im Gegensatz zu den üblichen Kameras sind Smartphones nach Stand der Technik ausreichend ausgestattet, um neben Daten zu Standort auch die Orientierungswinkel einer Bildaufnahme zu dokumentieren. Die georefenzierten Bilder können auf Grundlage der in den sogenannten Exif-Daten mitgeschriebenen Informationen händisch in ein bestehendes Quartiersmodell integriert werden. Anhand eines universitären Musterquartiers wird die nutzerfreundliche Realisierung beispielhaft erprobt und auf ihre Potentiale zur Automatisierung in Python untersucht. Hierfür wurde ein bestehendes Quartiersmodell als geometrische Grundlage genutzt und um RGB-Bilder sowie Thermogramme erweitert. Das beschriebene Vorgehen wird im Rahmen der Anwendung auf seinen möglichen Einsatz im Rahmen einer energetischen Quartierserfassung sowie einer Bauschadensdokumentation untersucht. Mit dem vorliegenden Beitrag wird dem Nutzenden ein Werkzeug bereitgestellt, das die hochwertige Dokumentation einer Bestandserfassung, auch im Quartierskontext, ermöglicht. KW - Quartiersanalyse KW - Bilddaten KW - Bauphysik und Sanierung Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220617-46544 SN - 987-3-95974-176-7 SN - 2363-8206 PB - Eigenverlag der Technischen Universität Kaiserslautern CY - Kaiserslautern ER - TY - JOUR A1 - Dokhanchi, Najmeh Sadat A1 - Arnold, Jörg A1 - Vogel, Albert A1 - Völker, Conrad T1 - Measurement of indoor air temperature distribution using acoustic travel-time tomography: Optimization of transducers location and sound-ray coverage of the room JF - Measurement N2 - Acoustic travel-time TOMography (ATOM) allows the measurement and reconstruction of air temperature distributions. Due to limiting factors, such as the challenge of travel-time estimation of the early reflections in the room impulse response, which heavily depends on the position of transducers inside the measurement area, ATOM is applied mainly outdoors. To apply ATOM in buildings, this paper presents a numerical solution to optimize the positions of transducers. This optimization avoids reflection overlaps, leading to distinguishable travel-times in the impulse response reflectogram. To increase the accuracy of the measured temperature within tomographic voxels, an additional function is employed to the proposed numerical method to minimize the number of sound-path-free voxels, ensuring the best sound-ray coverage of the room. Subsequently, an experimental set-up has been performed to verify the proposed numerical method. The results indicate the positive impact of the optimal positions of transducers on the distribution of ATOM-temperatures. KW - Bauphysik KW - Bauklimatik KW - Akustische Laufzeit-Tomographie Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220524-46473 UR - https://www.sciencedirect.com/science/article/abs/pii/S0263224120304723?via%3Dihub VL - 2020 IS - Volume 164, article 107934 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Alsaad, Hayder A1 - Hartmann, Maria A1 - Hilbel, Rebecca A1 - Völker, Conrad T1 - ENVI-met validation data accompanied with simulation data of the impact of facade greening on the urban microclimate JF - Data in Brief N2 - This dataset consists mainly of two subsets. The first subset includes measurements and simulation data conducted to validate the simulation tool ENVI-met. The measurements were conducted at the campus of the Bauhaus-University Weimar in Weimar, Germany and consisted of recording exterior air temperature, globe temperature, relative humidity, and wind velocity at 1.5 m at four points on four different days. After the measurements, the geometry of the campus was modelled and meshed; the simulations were conducted using the weather data of the measurements days with the aim of investigating the accuracy of the model. The second data subset consists of ENVI-met simulation data of the potential of facade greening in improving the outdoor environment and the indoor air temperature during heatwaves in Central European cities. The data consist of the boundary conditions and the simulation output of two simulation models: with and without facade greening. The geometry of the models corresponded to a residential buildings district in Stuttgart, Germany. The simulation output consisted of exterior air temperature, mean radiant temperature, relative humidity, and wind velocity at 12 different probe points in the model in addition to the indoor air temperature of an exemplary building. The dataset presents both vertical profiles of the probed parameters as well as the time series output of the five-day simulation duration. Both data subsets correspond to the investigations presented in the co-submitted article [1]. KW - Messung KW - Measurements KW - Simulations KW - ENVI-met KW - Living wall KW - Green facade KW - Simulation KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220511-46455 UR - https://www.sciencedirect.com/science/article/pii/S2352340922004048#! VL - 2022 IS - Volume 42, article 108200 SP - 1 EP - 13 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Teitelbaum, Eric A1 - Alsaad, Hayder A1 - Aviv, Dorit A1 - Kim, Alexander A1 - Völker, Conrad A1 - Meggers, Forrest A1 - Pantelic, Jovan T1 - Addressing a systematic error correcting for free and mixed convection when measuring mean radiant temperature with globe thermometers JF - Scientific reports N2 - It is widely accepted that most people spend the majority of their lives indoors. Most individuals do not realize that while indoors, roughly half of heat exchange affecting their thermal comfort is in the form of thermal infrared radiation. We show that while researchers have been aware of its thermal comfort significance over the past century, systemic error has crept into the most common evaluation techniques, preventing adequate characterization of the radiant environment. Measuring and characterizing radiant heat transfer is a critical component of both building energy efficiency and occupant thermal comfort and productivity. Globe thermometers are typically used to measure mean radiant temperature (MRT), a commonly used metric for accounting for the radiant effects of an environment at a point in space. In this paper we extend previous field work to a controlled laboratory setting to (1) rigorously demonstrate that existing correction factors used in the American Society of Heating Ventilation and Air-conditioning Engineers (ASHRAE) Standard 55 or ISO7726 for using globe thermometers to quantify MRT are not sufficient; (2) develop a correction to improve the use of globe thermometers to address problems in the current standards; and (3) show that mean radiant temperature measured with ping-pong ball-sized globe thermometers is not reliable due to a stochastic convective bias. We also provide an analysis of the maximum precision of globe sensors themselves, a piece missing from the domain in contemporary literature. KW - Strahlungstemperatur KW - Mean radiant temperature KW - Globe thermometers KW - Indoor environment KW - Thermal comfort KW - Measurements KW - OA-Publikationsfonds2022 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220509-46363 UR - https://www.nature.com/articles/s41598-022-10172-5#citeas VL - 2022 IS - Volume 12, article 6473 PB - Springer Nature CY - London ER - TY - JOUR A1 - Becher, Lia A1 - Gena, Amayu Wakoya A1 - Alsaad, Hayder A1 - Richter, Bernhard A1 - Spahn, Claudia A1 - Völker, Conrad T1 - The spread of breathing air from wind instruments and singers using schlieren techniques JF - Indoor Air N2 - The spread of breathing air when playing wind instruments and singing was investigated and visualized using two methods: (1) schlieren imaging with a schlieren mirror and (2) background-oriented schlieren (BOS). These methods visualize airflow by visualizing density gradients in transparent media. The playing of professional woodwind and brass instrument players, as well as professional classical trained singers were investigated to estimate the spread distances of the breathing air. For a better comparison and consistent measurement series, a single high note, a single low note, and an extract of a musical piece were investigated. Additionally, anemometry was used to determine the velocity of the spreading breathing air and the extent to which it was quantifiable. The results showed that the ejected airflow from the examined instruments and singers did not exceed a spreading range of 1.2 m into the room. However, differences in the various instruments have to be considered to assess properly the spread of the breathing air. The findings discussed below help to estimate the risk of cross-infection for wind instrument players and singers and to develop efficacious safety precautions, which is essential during critical health periods such as the current COVID-19 pandemic. KW - Covid-19 KW - Pandemie KW - Blasinstrument KW - Gesang KW - Schlierenmethode KW - airborne infection KW - background-oriented schlieren KW - schlieren imaging Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220209-45817 UR - https://onlinelibrary.wiley.com/doi/full/10.1111/ina.12869 VL - 2021 IS - volume 31, issue 6 SP - 1798 EP - 1814 PB - Wiley Blackwell CY - Oxford ER -