Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Experimental evaluation of air distribution in mechanically ventilated residential rooms: Thermal comfort and ventilation effectiveness
Highlights ► High levels of thermal comfort were reached for all the winter cases. ► No effects on thermal comfort due to extract air terminal position in summer. ► Risk of ventilation short circuit when warm outdoor air was used in summer. ► Ventilation effectiveness indices (ɛ a P and CRE) gave opposite information.
Abstract The effect of low ventilation rates (1 or 0.5 air change per hour) on thermal comfort and ventilation effectiveness was experimentally studied in a simulated residential room equipped with radiant floor heating/cooling and mixing ventilation systems. The tests were performed for various positions of supply and extract air terminals and different winter and summer boundary conditions. Vertical air temperature, operative temperature and air velocity profiles were measured in different positions in the room, and equivalent temperatures were derived, in order to characterize thermal comfort. Contaminant removal effectiveness (CRE) and local air change index was measured in order to characterize ventilation effectiveness in the occupied zone. Acceptable thermal comfort was found in most experiments; however, air temperature differences higher than 3°C occurred when floor cooling was combined with unconditioned outdoor air supply, i.e. at the supply air temperatures higher than the room air temperature. Moreover, low floor temperatures were needed to maintain the desired reference temperature in the stratified thermal environment. Mainly in cooling conditions the ventilation effectiveness depended on the positions of supply and extract air terminals and on the difference between the supply and the room air temperature, and it could be as low as 0.5, where 1 is complete mixing.
Experimental evaluation of air distribution in mechanically ventilated residential rooms: Thermal comfort and ventilation effectiveness
Highlights ► High levels of thermal comfort were reached for all the winter cases. ► No effects on thermal comfort due to extract air terminal position in summer. ► Risk of ventilation short circuit when warm outdoor air was used in summer. ► Ventilation effectiveness indices (ɛ a P and CRE) gave opposite information.
Abstract The effect of low ventilation rates (1 or 0.5 air change per hour) on thermal comfort and ventilation effectiveness was experimentally studied in a simulated residential room equipped with radiant floor heating/cooling and mixing ventilation systems. The tests were performed for various positions of supply and extract air terminals and different winter and summer boundary conditions. Vertical air temperature, operative temperature and air velocity profiles were measured in different positions in the room, and equivalent temperatures were derived, in order to characterize thermal comfort. Contaminant removal effectiveness (CRE) and local air change index was measured in order to characterize ventilation effectiveness in the occupied zone. Acceptable thermal comfort was found in most experiments; however, air temperature differences higher than 3°C occurred when floor cooling was combined with unconditioned outdoor air supply, i.e. at the supply air temperatures higher than the room air temperature. Moreover, low floor temperatures were needed to maintain the desired reference temperature in the stratified thermal environment. Mainly in cooling conditions the ventilation effectiveness depended on the positions of supply and extract air terminals and on the difference between the supply and the room air temperature, and it could be as low as 0.5, where 1 is complete mixing.
Experimental evaluation of air distribution in mechanically ventilated residential rooms: Thermal comfort and ventilation effectiveness
Tomasi, R. (Autor:in) / Krajčík, M. (Autor:in) / Simone, A. (Autor:in) / Olesen, B.W. (Autor:in)
Energy and Buildings ; 60 ; 28-37
07.01.2013
10 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Ventilation Parameters and Thermal Comfort of Naturally and Mechanically Ventilated Offices
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Determination of the ventilation effectiveness in mechanically ventilated spaces
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