Methodology for the Evaluation of Natural Ventilation in ... - Cham
Methodology for the Evaluation of Natural Ventilation in ... - Cham
Methodology for the Evaluation of Natural Ventilation in ... - Cham
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7.1 Buoyancy-Driven <strong>Ventilation</strong> ResultsThe results <strong>for</strong> <strong>the</strong> three buoyancy-driven ventilation experiments, s<strong>in</strong>gle zone, two zone and fullmodel, are presented along with <strong>the</strong> comparisons to <strong>the</strong> numerical simulations.7.1.1 S<strong>in</strong>gle Heated Zone CaseThe simplified model with a s<strong>in</strong>gle heated zone connected to <strong>the</strong> atrium was <strong>in</strong>vestigated us<strong>in</strong>gonly <strong>the</strong> lower w<strong>in</strong>dows <strong>in</strong>itially, and <strong>the</strong>n us<strong>in</strong>g only <strong>the</strong> upper w<strong>in</strong>dows. This allowed view<strong>in</strong>g<strong>the</strong> effect <strong>of</strong> w<strong>in</strong>dow location on <strong>the</strong> flow patterns and result<strong>in</strong>g temperature distribution with<strong>in</strong><strong>the</strong> heated zone. The physical model was <strong>the</strong>n created as a CFD simulation us<strong>in</strong>g PHOENICS.The s<strong>in</strong>gle heated zone model was evaluated <strong>for</strong> temperature distribution, air flow rate through<strong>the</strong> model, and heat loss through <strong>the</strong> envelope. The temperature distribution was evaluated <strong>in</strong>both <strong>the</strong> heated zone and with<strong>in</strong> <strong>the</strong> atrium space. Additional temperature measurements wererecorded at <strong>the</strong> <strong>in</strong>let and outlet conditions.The measured temperature data with<strong>in</strong> <strong>the</strong> physical model provided <strong>in</strong>sight <strong>in</strong>to <strong>the</strong> <strong>in</strong>fluence <strong>of</strong>w<strong>in</strong>dow location on <strong>the</strong> <strong>in</strong>ternal temperature distribution. The data <strong>for</strong> <strong>the</strong> upper w<strong>in</strong>dows opencase and lower w<strong>in</strong>dows open case were compared us<strong>in</strong>g <strong>the</strong> situation with seven w<strong>in</strong>dows andthree stacks open <strong>for</strong> each case <strong>in</strong> Figure 45 through 47 below. The data recorded from <strong>the</strong>physical model were non-dimensionalized and scaled <strong>for</strong> use <strong>in</strong> predict<strong>in</strong>g <strong>the</strong> full build<strong>in</strong>gtemperatures. The full build<strong>in</strong>g temperatures and correspond<strong>in</strong>g height with<strong>in</strong> <strong>the</strong> space arepresented, us<strong>in</strong>g 20°C as <strong>the</strong> ambient conditions <strong>for</strong> <strong>the</strong> full build<strong>in</strong>g case. At <strong>the</strong> column,located at <strong>the</strong> edge <strong>of</strong> <strong>the</strong> heated zone where it connects to <strong>the</strong> atrium, <strong>the</strong> temperaturedistribution was similar <strong>for</strong> both <strong>the</strong> upper and lower w<strong>in</strong>dow case (Figure 45). This was similarto <strong>the</strong> atrium temperature distribution, shown <strong>in</strong> Figure 47, where <strong>the</strong> location <strong>of</strong> <strong>in</strong>let w<strong>in</strong>dowsdid not significantly affect <strong>the</strong> temperature stratification. The maximum temperature differencebetween <strong>the</strong> upper and lower w<strong>in</strong>dow measurements <strong>for</strong> both <strong>the</strong> scaled column and atriummeasurements was 0.13°C.In <strong>the</strong> heated zone, <strong>the</strong> temperature patterns were somewhat different between <strong>the</strong> upper andlower w<strong>in</strong>dow locations. When <strong>the</strong> upper w<strong>in</strong>dows were used, <strong>the</strong> temperature measurementclosest to <strong>the</strong> floor and ceil<strong>in</strong>g were higher than <strong>for</strong> <strong>the</strong> lower w<strong>in</strong>dow case at <strong>the</strong> mid-po<strong>in</strong>t <strong>of</strong><strong>the</strong> heated zone, where <strong>the</strong> vertical temperature measurements were taken. For <strong>the</strong> lowerw<strong>in</strong>dow experiments, <strong>the</strong> temperatures with<strong>in</strong> <strong>the</strong> heated zone were very similar <strong>for</strong> <strong>the</strong> upperfour po<strong>in</strong>ts, and <strong>the</strong>n <strong>in</strong>creased closer to <strong>the</strong> floor, which was located 3 cm above <strong>the</strong> heatedalum<strong>in</strong>um plate. The maximum temperature difference <strong>of</strong> 0.45°C occurred at a height <strong>of</strong> 1.1m(9.5cm as measured <strong>in</strong> <strong>the</strong> model) from <strong>the</strong> floor.119