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

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21-Oct21-Oct22-Oct22-Oct23-Oct24-Oct24-Oct25-Oct25-Oct26-Oct27-Oct27-Oct28-Oct29-Oct29-Oct30-Oct30-Oct31-Oct1-Nov1-Nov2-Nov3-Nov3-Nov4-Nov4-Nov5-Nov6-Nov6-Nov7-Nov8-Nov8-NovTemperature ( C)Temperature ( F)3530South Average TemperatureNorth Average TemperatureOutside Air Temperature928225722015621052542032Figure 20. Fall Average Building Internal Temperature by Orientation: North versus SouthSummer data were collected during the heat wave that occurred during the summer of 2003 inthe UK, which provided data on the performance of this naturally ventilated building duringextreme conditions. Though the external temperature reached over 36 ºC, the average internaltemperature within the building was 30ºC, significantly lower than the outside. It was observedthat when these high temperatures occurred during the workday, occupants wore lighter clothingand used personal fans to generate a breeze to improve their comfort. When comparing theinternal and external temperatures to an adaptive standard for naturally ventilated buildingsbased on ASHRAE Standard 55 (Brager 2000, ASHRAE 2004), the internal temperatures fallwithin the 90 percent acceptability limits. Normally the temperate climate has approximately 30hours when the outside air temperature is at or above 26ºC, whereas in 2003 there were overthree times as many with 98 hours. As for internal conditions, there were 119 hours during thesummer of 2003 when the average building internal temperature was at or above 26ºC; howeverthirty percent of this was during unoccupied hours.60
27-Jul27-Jul28-Jul28-Jul29-Jul30-Jul30-Jul31-Jul1-Aug1-Aug2-Aug2-Aug3-Aug4-Aug4-Aug5-Aug6-Aug6-Aug7-Aug7-Aug8-Aug9-Aug9-Aug10-Aug11-Aug11-Aug12-Aug12-Aug13-Aug14-AugTemperature ( C)Temperature ( F)353025South Average TemperatureNorth Average TemperatureOutside Air Temperature9282722015621052542032Figure 21. North versus South Average Building Temperature: Summer ConditionsThe role of the ceiling soffits as thermal mass, designed to pre-cool the building during thesummer night time was qualitatively assessed. The measured internal temperatures peakedapproximately four hours after the outside temperature reached its maximum for the day (Walker2004). This particular design aspect was not used to its fullest potential; during the nighttimehours, only the smaller, upper level vent windows were open. This does not allow for very highairflow rates needed to cool the concrete soffits. A recommendation was made to turn on the fansin the atrium vents to assist in drawing additional cool nighttime air into the building to furthercool it, particularly during the summer months.3.6.1.2 VentilationThe ability of the naturally ventilated office building to provide adequate cooling and ventilationwas evaluated during summer and fall site visits. A series of air velocity measurements at boththe lower and upper windows for a variety of outside conditions were recorded, and the effectivearea, or percentage of the total vertical window area, for the awning-type window geometry wasdetermined through measurement with a hot-wire anemometer and experiments using the bagdevice. The bag device that was created to determine the effective opening area for the awningtypewindow geometry was used in the late summer/early fall of 2004. With the awning-typewindow there are two triangular sidepieces and a horizontal piece that each can contribute to thevolume of air entering (or leaving) through the window. Air velocity and air volumemeasurements were recorded so that a correlation between the previously recorded air velocitymeasurements and the volume of air entering and leaving the building could be determined. The61
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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
Page 10 and 11: List of TablesTable 1. Energy End U
Page 12 and 13: Table 64. Comparison of Dimensionle
Page 15 and 16: Chapter 1.0IntroductionEnergy consu
Page 17 and 18: insulated building envelopes with t
Page 19 and 20: energy usage and efficient design.
Page 21 and 22: Figure 3. European Patent Office Bu
Page 23: selecting boundary conditions) to e
Page 26 and 27: 2.2.1 Buoyancy-Driven VentilationVe
Page 28 and 29: Figure 7. Neutral Pressure Level fo
Page 30 and 31: Combined wind-buoyancy flow is more
Page 32 and 33: design. The depth of natural ventil
Page 34 and 35: of cooling required by 30 percent o
Page 36 and 37: considered when determining how the
Page 38 and 39: environmental conditions are examin
Page 40 and 41: As natural ventilation is prevalent
Page 43 and 44: Chapter 3.0Evaluation of Prototype
Page 45 and 46: Figure 12. Interior Atrium ViewFigu
Page 47 and 48: Table 8. Prototype Building Window
Page 49 and 50: Figure 15. HOBO® H8 Series Tempera
Page 51 and 52: Finally, airflow visualization was
Page 53 and 54: only is the airflow almost never at
Page 55 and 56: Table 10. Window Bag Device Measure
Page 57 and 58: Mon 7-21Tue 7-22Wed 7-23Thu 7-24Fri
Page 59: 12:00 AM1:00 AM2:00 AM3:00 AM4:00 A
Page 63 and 64: A range of air exchange rates was f
Page 65 and 66: the windows on the second floor, or
Page 67 and 68: Total Electric (kWh/m2)Total Gas (k
Page 69 and 70: movement, Houghton Hall has much le
Page 71 and 72: Chapter 4.0Modeling and Visualizati
Page 73 and 74: for future design of similar type b
Page 75 and 76: 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
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Figure 39. Two Heated Zone ModelWit
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minute interval, the model was assu
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Figure 42. Cross-Section of Wind-Ge
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Table 25. Wind-Assisted Ventilation
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Figure 44. Heaters and Zones for a)
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Height from Floor (m)Height from Fl
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Where V is the outlet velocity, A o
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Table 32. Conduction Heat Loss for
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a) Air Modelb) Water ModelFigure 50
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Height from Floor (m)The temperatur
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Height from Floor (m)In the atrium
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First NorthUpper Window 0.17 m/s -0
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Height from Floor (m)the column at
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Height from Floor (m)Height from Fl
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Height from Floor (m)3.53.02.52.01.
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was less than 12 percent. These val
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Table 39. Variation of Outlet Wind
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temperature of the air was the same
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3.532.521.55m/s4m/s3m/s2m/s1m/s1.5m
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3.532.521.55m/s4m/s3m/s2m/s1m/s1.5m
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The average and exhaust internal bu
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Table 43. Calculated Wind and Buoya
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In the last two lines, for both the
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Figure 80. CFD Simulation of the Te
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uoyancy case the air from the groun
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160
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windows of naturally ventilated bui
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difficult to select the boundary co
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simulations are able to do would al
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Bordass, W.T., A.K.R. Bromley and A
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Linddament, M. 1996. Why CO2? Air I
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172
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MODEL: K20-8SERIAL: 10047RECORDER_I
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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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Methodology for the Evaluation of Natural Ventilation in ... - Cham

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