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

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Height from Floor (m)3.53.02.52.01.51.03 Stacks Open1 Stack OpenStacks Closed0.50.020.0 21.0 22.0 23.0 24.0 25.0 26.0Temperature ( C)Figure 65. Full Model Scaled Temperature Stratification for Full-Scale Building: Second FloorHeated ZoneFigure 66. Temperature Distribution for Buoyancy Case: Full Model with Stacks Open138
Figure 67. Airflow Patterns for the Buoyancy Case: Full Model with Stacks Open7.2 Wind-Driven Ventilation ResultsThe experiments on the physical and CFD models were carried out for a range of wind speeds,both with and without the use of the heaters for the internal loads. The wind-only cases arepresented first for the full-model configuration with either all of the stacks open or all closed.The inlet velocities and outlet velocities were measured and airflow balance calculated.7.2.1 Wind-Only CaseConducting the wind-only cases before the addition of internal heat loads assisted in theunderstanding the air velocities caused by wind alone. Experiments were carried out using avariety of fan speeds, simulating external wind conditions. The stacks were set to either all openor all closed for each of the fan speeds to determine how much wind exited through the stackvents when they were open.The focus of the wind-only experiments was determining the inlet velocity at the windows on thesouth façade and the resulting outlet velocities on the north façade and at the stacks for the stacksopen scenarios. Using the wind device described in Chapter 6, the model was evaluated at fivedifferent wind speeds. The inlet velocities were recorded at 5 m/s at fan setting 3, 4 m/s at fansetting 2, and 3 m/s at fan setting one. Further experiments were carried out at lower fan settingsusing a Variac® that reduced the voltage provided to the fans. Measurements were recorded attwo additional points, at fan setting 1 with the Variac® at 83% and at fan setting 1 and theVariac ® set at 57%. This provided air velocities of 2 m/s and 1 m/s respectively. The inletvelocities were uniform across the south façade of the model as measured at the face of thewindow, and at all of the inlet windows. The measurements between windows deviated by±0.1m/s, which was the measurement error of the hot-wire anemometer used. The airflowbalance was determined by calculating the inflow volume of air, minus the outflow volume ofair, divided by the inflow volume of air. The maximum percentage error in the airflow balance139
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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
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the acceptable diffusion rate, or
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applications involving full-scale b
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digital camera with both manually o
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Chapter 5.0Dimensional Analysis and
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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 128 and 129: Height from Floor (m)The temperatur
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 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
Page 178 and 179: |PW|DESCRIP |KW |KWH|KVA|KVH|------
Page 180 and 181: 2:5 ;day_ofYr17:P30 ;EOT = 0.000075
Page 182 and 183: 2:3136:P30 ;DUM2 = -0.040891:-4.089
Page 184 and 185: ;7:21 ;input location;8:0 ;mulptipl
Page 186 and 187: ;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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Methodology for the Evaluation of Natural Ventilation in ... - Cham

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