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Qualitative evaluation of the flow supplied by personalized ventilation using schlieren imaging and thermography

  • 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 massPersonalized 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.show moreshow less

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Metadaten
Document Type:Article
Author:Dr.-Ing. Hayder AlsaadORCiDGND, Prof. Conrad VoelkerORCiDGND
DOI (Cite-Link):https://doi.org/10.25643/bauhaus-universitaet.4511Cite-Link
URN (Cite-Link):https://nbn-resolving.org/urn:nbn:de:gbv:wim2-20211008-45117Cite-Link
URL:https://www.sciencedirect.com/science/article/abs/pii/S0360132319306602?via%3Dihub
Parent Title (English):Building and Environment
Publisher:Elsevier
Place of publication:New York
Language:English
Date of Publication (online):2021/10/02
Date of first Publication:2021/10/02
Release Date:2021/10/08
Publishing Institution:Bauhaus-Universität Weimar
Institutes and partner institutions:Fakultät Bauingenieurwesen / Professur Bauphysik
Volume:2020
Issue:Volume 167, article 106450
Pagenumber:11
Tag:Axial fan; Personalized ventilation; Schlieren imaging; Thermography; Visualization
GND Keyword:Bildverarbeitung; Photothermische Methode; Visualisierung; Belüftung; Lüftungsanlage
Dewey Decimal Classification:500 Naturwissenschaften und Mathematik / 530 Physik / 535 Licht, Infrarot- und Ultraviolettphänomene
BKL-Classification:56 Bauwesen / 56.55 Bauphysik, Bautenschutz
Licence (German):License Logo Creative Commons 4.0 - Namensnennung-Nicht kommerziell-Keine Bearbeitung (CC BY-NC-ND 4.0)
Note:
This is the accepted manuscript of the article published by Elsevier in Building and Environment 167 (2020) 106450, which can be found at https://doi.org/10.1016/j.buildenv.2019.106450.