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A platform for research: civil engineering, architecture and urbanism
Comparison of airflow and contaminant distributions in rooms with traditional displacement ventilation and under-floor air distribution systems
This study compared the airflow, air temperature, and contaminant or air distribution effectiveness distributions in indoor spaces between the TDV (traditional displacement ventilation) and UFAD (under-floor air distribution) systems using both experimental and numerical approaches. The experimental approach gave the most realistic data to describe the ventilation performances of the systems but had low data resolution. The numerical simulations, well calibrated by the experiment, can provide detailed information on the ventilation performance and can easily show different sizes of indoor spaces, such as an office, a classroom, and a workshop. The results obtained with the CFD program are in good agreement with the experimental data. The experimental results show that the perforated-corner TDV diffuser, swirl diffuser, and perforated-floor-panel diffuser created low air velocity in the occupied zone. However, the perforated-corner TDV and perforated-floor-panel diffusers could generate a high temperature difference between the head and ankle level of an occupant. The linear diffuser created the highest velocity in the occupied zone, making the potential draft risk high. The TDV and UFAD systems had better ventilation performance than the mixing ventilation system in cooling mode. For heating mode, the TDV and UFAD system created mixing conditions except in the vicinity of the floor. The results from the numerical simulations for an office, a classroom, and a workshop confirm the findings from the experiment. The three systems created higher air distribution effectiveness than did the mixing ventilation system. The effectiveness for TDV and L-UFAD systems was similar but higher than that for the H-UFAD system. The air distribution effectiveness seems in proportion to the ceiling height. In addition, the H-UFAD systems using linear diffusers had a high draft risk.
Comparison of airflow and contaminant distributions in rooms with traditional displacement ventilation and under-floor air distribution systems
This study compared the airflow, air temperature, and contaminant or air distribution effectiveness distributions in indoor spaces between the TDV (traditional displacement ventilation) and UFAD (under-floor air distribution) systems using both experimental and numerical approaches. The experimental approach gave the most realistic data to describe the ventilation performances of the systems but had low data resolution. The numerical simulations, well calibrated by the experiment, can provide detailed information on the ventilation performance and can easily show different sizes of indoor spaces, such as an office, a classroom, and a workshop. The results obtained with the CFD program are in good agreement with the experimental data. The experimental results show that the perforated-corner TDV diffuser, swirl diffuser, and perforated-floor-panel diffuser created low air velocity in the occupied zone. However, the perforated-corner TDV and perforated-floor-panel diffusers could generate a high temperature difference between the head and ankle level of an occupant. The linear diffuser created the highest velocity in the occupied zone, making the potential draft risk high. The TDV and UFAD systems had better ventilation performance than the mixing ventilation system in cooling mode. For heating mode, the TDV and UFAD system created mixing conditions except in the vicinity of the floor. The results from the numerical simulations for an office, a classroom, and a workshop confirm the findings from the experiment. The three systems created higher air distribution effectiveness than did the mixing ventilation system. The effectiveness for TDV and L-UFAD systems was similar but higher than that for the H-UFAD system. The air distribution effectiveness seems in proportion to the ceiling height. In addition, the H-UFAD systems using linear diffusers had a high draft risk.
Comparison of airflow and contaminant distributions in rooms with traditional displacement ventilation and under-floor air distribution systems
Vergleich der Luftströmungs- und Schadstoffverteilung in Räumen mit herkömmlicher Quelllüftung und Fußbodenluftverteilungssystemen
Lee, Kisup (author) / Zhang, Tengfei (author) / Jiang, Zheng (author) / Chen, Qingyan (author)
2009
16 Seiten, 12 Bilder, 9 Tabellen, 21 Quellen
Conference paper
English
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