TY  - CHAP
A1  - Mesenhöller, Eva
A1  - Jacobs, Steffen
A1  - Vennemann, Peter
A1  - Hussong, Jeanette
T1  - Unsteady Ventilation in a Scaled Room Model with Swirl Ceiling Diffusers
T2  - CLIMA 2022 conference
N2  - Mechanical ventilation of buildings is generally based on steadily operating systems. This field is well known and established. But, an approach based on time-varied supply flow rates might improve indoor air quality, comfort, and energy consumption. Typical time-scales of the variation are in the order of seconds or minutes. Until now, the effects of unsteady ventilation scenarios are not fully described and so, reliable dimensioning rules are missing. Hence, with a better understanding of the flow in unsteady ventilation, systems can be calculated and optimised. To understand the effective mechanisms and derive functional relations between the flow field and variation parameters, full-field optical flow measurements are executed with a particle image velocimetry (PIV) system. Experiments are conducted under isothermal conditions in water in a small-scale room model (1.00 m × 0.67 m × 0.46 m) with two swirl ceiling diffusers, Reynolds-scaling assures similarity. In a series of experiments, the effects of different unsteady ventilation strategies on the flow fields are investigated and compared to steady conditions with the same mean exchange rate. Mean exchange rates, signal types, periods, and amplitudes are varied. Time-averaged normalised velocity fields already indicate notable differences between steady and unsteady cases especially for lower exchange rates: the distribution is more homogeneous in unsteady scenarios compared to steady conditions, and low-velocity areas are reduced while the mean velocity of the room increases. So, unsteady ventilation might be beneficial in terms of improved ventilation and energy savings in partial-load operation. Fast Fourier Transformation (FFT) analyses of the mean velocity for each field over the whole series detect the main frequency of the volume flow variation. By dividing the velocity field into smaller areas, this main frequency is still detected especially in the upper part of the room, but side frequencies play a role in the room as well.
KW  - unsteady ventilation
KW  - PIV
KW  - room airflow
KW  - mixing ventilation
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-151811
UR  - https://proceedings.open.tudelft.nl/clima2022/article/view/200
PB  - TU Delft OPEN
CY  - Delft
ER  - 
TY  - GEN
A1  - Mesenhöller, Eva
A1  - Vennemann, Peter
T1  - Raumströmungsmessung mit Particle Image Velocimetry - Instationärer Betrieb von RLT-Anlagen
N2  - Überblick über Methodik, Hintergründe und Ziele des Projekts zu instationärer Raumlüftung sowie bisherige Untersuchungsschwerpunkte auf diesem Gebiet.
KW  - instationäre Lüftung
KW  - PIV
KW  - Lüftungstechnik
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-178587
ER  - 
TY  - GEN
A1  - Mesenhöller, Eva
A1  - Vennemann, Peter
A1  - Hussong, Jeanette
T1  - Raumströmungsmessung mit Particle Image Velocimetry (PIV) - Instationärer Betrieb von RLT-Anlagen
N2  - Posterzusammenfassung der Hintergründe, Ziele, Messprinzipien, Messungen und des Versuchsstandes im Projekt zur Untersuchung instationärer Raumlüftung.
KW  - PIV
KW  - instationäre Lüftung
KW  - Lüftungstechnik
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-178597
ER  - 
TY  - GEN
A1  - Mesenhöller, Eva
A1  - Jacobs, Steffen
A1  - Vennemann, Peter
T1  - Raumströmung bei instationärem Betrieb von RLT-Anlagen - Experimentelle und numerische Untersuchungen mit PIV und CFD
N2  - Posterzusammenfassung der Hintergründe, Ziele, Methoden (messtechnisch und numerisch) und Ergebnisse im Projekt zu instationärer Lüftung.
KW  - instationäre Lüftung
KW  - PIV
KW  - CFD
KW  - Lüftungstechnik
KW  - OpenFOAM
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-178605
ER  -