Comparisons of ventilation performance of different air supply devicesin in an office environment
(English)Manuscript (preprint) (Other academic)
The aim of this study was to compare ventilation performance of four different air supply devices in an office environment with respect to thermal comfort, ventilation efficiency and energy-saving potential, by performing numerical simulations. The devices have the acronyms: Mixing supply device (MSD), Wall confluent jets supply device (WCJSD), Impinging jet supply device (IJSD) and Displacement supply device (DSD). Comparisons were made under identical set-up conditions, as well as at the same occupied zone temperature of about 24.2°C achieved by adding different heat loads and using different air-flow rates. Energy-saving potential was addressed based on the air-flow rate and the related fan power required for obtaining a similar occupied zone temperature for each device.
Results showed that the IJSD could provide an acceptable thermal environment while removing excess heat more efficiently than the MSD, as it combined the positive effects of both mixing and stratification principles. This benefit also meant that this device required less fan power than the MSD for obtaining equivalent occupant zone temperature. The WCJSD studied in this paper behaved somewhat like the MSD, but caused higher draught discomfort at ankle level because of very high supply velocities, which was might due to small nozzle diameter of the supply device. Further studies are required for the WCJSD to make these conclusions applicable for general conditions. The DSD showed a superior performance on heat removal, air exchange efficiency and energy saving to all other devices, but it had difficulties in providing acceptable vertical temperature gradient between the ankle and head levels for a standing person.
Ventilation performance, air supply devices, thermal comfort, energy-saving
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-106491OAI: oai:DiVA.org:liu-106491DiVA: diva2:716386