Methodology for the Evaluation of Natural Ventilation in ... - Cham

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Height from Floor (m)The temperatures measured in the heated zone of the ground floor exhibited similar temperaturepatterns, though the smaller the outlet opening sizes the higher the overall temperatures in theheated zone (Figure 52). As seen in Table 33, the air entered through the windows at the groundfloor level in all four cases investigated. The thermocouple locations closest to the heatedaluminum plate had the highest temperatures for each case. There was some amount of radiationat the ceiling, as seen by the slightly increased temperatures at the upper-most thermocouplelocation.At the column measuring locations for the ground level, the temperature pattern for each casewas more linear than was seen in the heated zone (Figure 53). The thermocouple closest to thefloor recorded the lowest temperature for all four cases. As mentioned previously, the mostsignificant heat loss occurred in the atrium, as was evident in the thermocouple reading near thefloor. The cooler air from the atrium was drawn into the edge of the heated zone closest to theatrium at the floor level. The atrium floor and exposed walls also have the largest heat loss,which contributes to the slightly cooler temperatures of the air that is in close proximity. Thetemperature closest to the ceiling for all four cases was the highest and caused by a hot plume ofair from the ceiling of the ground floor. In the stacks closed case, this was slightly moreprominent as all of the incoming air from the ground floor air exited at the first floor level. Thiscaused the hot plume of air from the ground floor zone to exit the ground floor zone at theceiling and then proceeded to enter the first floor zone at the floor level.3.51Stack Open3.02.52Stacks Open3Stacks Open3Stacks Closed2.01.51.00.50.020.0 21.0 22.0 23.0 24.0 25.0 26.0 27.0 28.0Temperature ( C)Figure 53. Two Zone Scaled Temperature Stratification for Full-Scale Building: Ground FloorColumnFor the first floor heated zone (Figure 54), the temperature distribution pattern was similar forthe three cases. Again, as the number of stacks open decreased, the internal temperature128
Height from Floor (m)distribution remained the same, but the overall temperature increased. The thermocouplesclosest to the floor recorded the coolest temperature for all four cases. For the two and threestacks open cases this was due to the incoming ambient air at 13°C. However, for the one stackopen case there was essentially no incoming or outgoing flow through the first floor windows.The temperature stratification was then due to warm, still air at the ceiling level in addition tosome amount of radiation from the heaters. The warm temperatures near the floor were not seenin the first floor case, as the two-heated zone model was carried out before the installation ofaluminum sheets in the upper floor areas. The thermocouples were located 12cm from theheaters, which acted more like large point sources rather than a distributed load in the heatedzone. The thermocouples were therefore not as affected by any radiation from the heaters. Withthe stacks closed case, the air exited the model at the first floor level and the temperature at thelowest thermocouple location in Figure 53 was almost equal to the temperature of the exitingtemperature from the ground floor at the ceiling.3.53.02.51Stack Open2Stacks Open3Stacks Open3Stacks Closed2.01.51.00.50.020.0 21.0 22.0 23.0 24.0 25.0 26.0 27.0 28.0Temperature ( C)Figure 54. Two Zone Scaled Temperature Stratification for Full-Scale Building: First FloorHeated ZoneAs seen in Table 33 and discussed above, for the 2 and 3 stacks open cases the air entered at thefirst floor level. All of the air from the first floor for these cases exited the first floor, mixed withair from the ground floor in the atrium, and was exhausted through the stacks. By the time theair reached the column, it was well mixed for the three stacks open case, and less so for the twostacks open case (Figure 55). Similar to the ground floor, the top thermocouple for the first floorcolumn consistently recorded a higher temperature, due to a hot air plume in the 2 and 3 stacksopen cases. For the 1 stack open and stacks closed cases, the temperature distribution at thecolumn was essentially linear, as there was no inflow at the first floor windows.129
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Thesis Committee:Leon R. Glicksman,
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Table of ContentsTable of Contents
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7.1.3 Full Model Case .............
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Figure 41. Wind Direction Data for
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List of TablesTable 1. Energy End U
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Table 64. Comparison of Dimensionle
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Chapter 1.0IntroductionEnergy consu
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insulated building envelopes with t
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energy usage and efficient design.
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Figure 3. European Patent Office Bu
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selecting boundary conditions) to e
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2.2.1 Buoyancy-Driven VentilationVe
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Figure 7. Neutral Pressure Level fo
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Combined wind-buoyancy flow is more
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design. The depth of natural ventil
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of cooling required by 30 percent o
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considered when determining how the
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environmental conditions are examin
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As natural ventilation is prevalent
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Chapter 3.0Evaluation of Prototype
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Figure 12. Interior Atrium ViewFigu
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Table 8. Prototype Building Window
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Figure 15. HOBO® H8 Series Tempera
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Finally, airflow visualization was
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only is the airflow almost never at
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Table 10. Window Bag Device Measure
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Mon 7-21Tue 7-22Wed 7-23Thu 7-24Fri
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12:00 AM1:00 AM2:00 AM3:00 AM4:00 A
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27-Jul27-Jul28-Jul28-Jul29-Jul30-Ju
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A range of air exchange rates was f
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the windows on the second floor, or
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Total Electric (kWh/m2)Total Gas (k
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movement, Houghton Hall has much le
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Chapter 4.0Modeling and Visualizati
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for future design of similar type b
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lower and upper openings and natura
Page 77 and 78: the acceptable diffusion rate, or
Page 79 and 80: applications involving full-scale b
Page 81 and 82: digital camera with both manually o
Page 83 and 84: Chapter 5.0Dimensional Analysis and
Page 85 and 86: u oHgHT2uocu Hpo1Re Ar1Re Pr(5.7)(5
Page 87 and 88: X HM X HP(5.16)5.3.2 Kinematic Sim
Page 89 and 90: Radiation was found to have an impa
Page 91: height is used for the full-scale b
Page 94 and 95: 6.3 Model Descriptions6.3.1 Physica
Page 96 and 97: Figure 30. Floor Plan of the Protot
Page 98 and 99: Figure 31. North Facade of Model wi
Page 100 and 101: Monitoring data collected from the
Page 102 and 103: By default, there was no accounting
Page 104 and 105: 40-location card inserted into the
Page 106 and 107: 6.5 ExperimentsTo evaluate the mode
Page 108 and 109: modified to determine the impact of
Page 110 and 111: Figure 39. Two Heated Zone ModelWit
Page 112 and 113: minute interval, the model was assu
Page 114 and 115: Figure 42. Cross-Section of Wind-Ge
Page 116 and 117: Table 25. Wind-Assisted Ventilation
Page 118 and 119: Figure 44. Heaters and Zones for a)
Page 120 and 121: Height from Floor (m)Height from Fl
Page 122 and 123: Where V is the outlet velocity, A o
Page 124 and 125: Table 32. Conduction Heat Loss for
Page 126 and 127: a) Air Modelb) Water ModelFigure 50
Page 130 and 131: Height from Floor (m)In the atrium
Page 132 and 133: First NorthUpper Window 0.17 m/s -0
Page 134 and 135: Height from Floor (m)the column at
Page 136 and 137: Height from Floor (m)Height from Fl
Page 138 and 139: Height from Floor (m)3.53.02.52.01.
Page 140 and 141: was less than 12 percent. These val
Page 142 and 143: Table 39. Variation of Outlet Wind
Page 144 and 145: temperature of the air was the same
Page 146 and 147: 3.532.521.55m/s4m/s3m/s2m/s1m/s1.5m
Page 148 and 149: 3.532.521.55m/s4m/s3m/s2m/s1m/s1.5m
Page 150 and 151: The average and exhaust internal bu
Page 152 and 153: Table 43. Calculated Wind and Buoya
Page 154 and 155: In the last two lines, for both the
Page 156 and 157: Figure 80. CFD Simulation of the Te
Page 158 and 159: uoyancy case the air from the groun
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Page 162 and 163: windows of naturally ventilated bui
Page 164 and 165: difficult to select the boundary co
Page 166 and 167: simulations are able to do would al
Page 168 and 169: Bordass, W.T., A.K.R. Bromley and A
Page 170 and 171: Linddament, M. 1996. Why CO2? Air I
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Page 174 and 175: MODEL: K20-8SERIAL: 10047RECORDER_I
Page 176 and 177: 2 Boiler-3 50.00 C1 N1 1.0 ON ON OF
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|PW|DESCRIP |KW |KWH|KVA|KVH|------
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2:5 ;day_ofYr17:P30 ;EOT = 0.000075
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2:3136:P30 ;DUM2 = -0.040891:-4.089
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;7:21 ;input location;8:0 ;mulptipl
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;79:P22 ;EXC w/DELAY (only for dela
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1:45 ;port5 (homeSense)2:31 ;exit l
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13:P95 ;ENDIF14:P95 ;ENDIF15:P3 ;pu
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2:20 ;RH30:P70 ;sample1:12:20 ;RH31
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194
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Five Windows Open: Upper versus Low
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One Window Open: Upper versus Lower
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25 cm / 3 m 24.33 26.62 22.68 22.93
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25 cm / 3 m 24.07 25.26 22.65 22.78
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Two Stacks Open Temperature Stratif
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Stacks Closed Temperature Stratific
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2.3 24.31 24.65 24.781.4 23.35 23.6
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0.6 20.56 20.67 20.94 21.22 21.41 2
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