MAXIMIZING NATURAL VENTILATION BY DESIGN IN LOW RISE RESIDENTIAL BUILDINGS USING WIND CATCHERS IN THE HOT ARID CLIMATE OF UAE by Rashed Khalifa Al-Shaali A Thesis Presented to the FACULTY OF THE SCHOOL OF ARCHITECTURE UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements of the Degree MASTER OF BUILDING SCIENCE August 2002 Copyright 2002 Rashed Khalifa Al-Shaali
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MAXIMIZING NATURAL VENTILATION BY DESIGN IN LOW RISE RESIDENTIAL BUILDINGS USING WIND CATCHERS IN THE HOT
ARID CLIMATE OF UAE
by
Rashed Khalifa Al-Shaali
A Thesis Presented to the FACULTY OF THE SCHOOL OF ARCHITECTURE
UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements of the Degree
MASTER OF BUILDING SCIENCE
August 2002
Copyright 2002 Rashed Khalifa Al-Shaali
UNIVERSITY OF SOUTHERN CALIFORNIA
The Graduate School
University Park
LOS ANGELES, CALIFORNIA 90089-1695
This thesis, written by
…………………………………………………..
Under the direction of h…………….. Thesis
Committee, and approved by all its members,
Has been presented to and accepted by The
Graduate School, in particular fulfillment of
requirements for the degree of
……………………………………………….
……………………………………………….
Dean of Graduate Studies
Date ……………………..
THESIS COMMITTEE
………………………………………………..
Chairperson
………………………………………………..
………………………………………………..
ii
Acknowledgements
First of all, I would like to thank Allah (God) for granting me patience that
carried me through all the difficult times. Second, I would like to thank my father
and mother, the most wonderful friends I have ever had and loved, for all the
sacrifices, caring and guidance and for giving me such a wonderful sister and
brothers. The list of people whom I want to thank is very long. However, I would
like to value the following people for their indispensable help:
Professor Pierre Koenig, my chief advisor, for his ultimate and important
support, direction, encouragement and patience.
Professor Marc Schiler, for his guidance, support and forbearance through
out all the study period and for opening the doors of opportunities when I thought
that all of them are closed.
Professor Ralph L. Knowles, for his assistance, kindness and for always
reminding me of the spiritual side of Architecture.
Professor Murray Milne, for providing me with all the necessary computer
documents and his immediate and positive responses to my questions.
I would also like to especially thank my friend Ahmad Al Awar for his
incessant help, as well as Nasser Al-Shaali, Khalid Al Hammadi, Zainab A. Al-
Rustamani and Dr. D. E. Ordway for their assist and kindness.
Last but not least, I would like to thank my wife Amal for her support and
love that carried me smoothly through a lot of difficult time and for giving me the
best gifts I have ever had, our children Khalifa and Reem.
1 UAE _______________________________________________________________ 1 1.1 Physical features _________________________________________________ 1 1.2 Climatic conditions _______________________________________________ 2 1.3 Housing ________________________________________________________ 2 1.4 Social needs and demands__________________________________________ 3 1.5 Environmental and cultural issues ___________________________________ 3
1.5.1 Vernacular architecture styles_____________________________________ 4 1.5.2 Environmental sense and consideration _____________________________ 4
1.6 Wind and wind catchers ___________________________________________ 5 REFERENCES: _________________________________________________________ 6
2 Climatic Data and Analysis ____________________________________________ 7 2.1 Writing TMY2 Data Format ________________________________________ 7
2.1.1 What is TMY2 Data ____________________________________________ 7 2.1.2 TMY2 Data Format ____________________________________________ 7 2.1.3 Calculating the Missing Data _____________________________________ 8
2.1.3.1 Direct Beam Solar Radiation __________________________________ 8 2.1.3.2 Total Horizontal (diffused) Solar Radiation_______________________ 9 2.1.3.3 Dew point outdoor air temperature_____________________________ 10
2.2 SCRAM _______________________________________________________ 10 2.2.1 What is SCRAM Data _________________________________________ 10 2.2.2 SCRAM Data Format__________________________________________ 11
2.3 Climatic Data Charts ____________________________________________ 13 2.3.1 City of Abu Dhabi ____________________________________________ 13
2.3.1.1 Temperature Range ________________________________________ 13 2.3.1.2 Temperature + Relative Humidity _____________________________ 14 2.3.1.3 Wind Velocity Range_______________________________________ 15 2.3.1.4 Bioclimatic Timetable ______________________________________ 16 2.3.1.5 Psychrometric Chart________________________________________ 17
2.3.2 City of Al-Ain________________________________________________ 18 2.3.2.1 Temperature Range ________________________________________ 18 2.3.2.2 Temperature + Relative Humidity _____________________________ 19 2.3.2.3 Wind Velocity Range_______________________________________ 20 2.3.2.4 Bioclimatic Timetable ______________________________________ 21 2.3.2.5 Psychrometric Chart________________________________________ 22
2.4 Wind Roses ____________________________________________________ 23 2.4.1 City of Abu Dhabi ____________________________________________ 23 2.4.2 City of Al-Ain________________________________________________ 25
3 Wind and Ventilation ________________________________________________ 28 3.1 Wind Characteristics_____________________________________________ 28
3.1.1 Wind near the Ground _________________________________________ 28 3.1.2 Wind in an Urban Environment __________________________________ 30 3.1.3 Wind Flow __________________________________________________ 30
3.2 Natural Ventilation for Thermal Comfort _____________________________ 31 3.2.1 Removal of Excess Heat________________________________________ 32 3.2.2 Cooling Effect over the Human Body _____________________________ 32 3.2.3 Cooling the Structure __________________________________________ 33
5 Setting the Variables_________________________________________________ 60 5.1 Hypothesis_____________________________________________________ 60 5.2 When to use Natural Ventilation ____________________________________ 60
5.2.1 City of Abu Dhabi ____________________________________________ 61 5.2.2 City of Al-Ain________________________________________________ 78
5.3 Model Drawings and Testing Environment____________________________ 96 5.3.1 Helium Bubble Generator_______________________________________ 96 5.3.2 Drawings ___________________________________________________ 96
6 Wind Catcher with Different Sizes and Outlets__________________________ 103 6.1 1/3 Wind Catcher ______________________________________________ 104
6.4 Additional Tests________________________________________________ 163 6.4.1 Wind catcher with Smaller Opening______________________________ 163 6.4.2 Wind Catcher in the Middle of the Windward Façade ________________ 166
Figure 1-1 United Arab Emirates Map .............................................................................................. 1 Figure 2-1 Scram Data Format........................................................................................................ 11 Figure 2-2 Abu Dhabi 1997 Temperature Range ............................................................................. 13 Figure 2-3 Abu Dhabi 1997 Temperature + Relative Humidity........................................................ 14 Figure 2-4 Abu Dhabi 1997 Wind Velocity Range .......................................................................... 15 Figure 2-5 Abu Dhabi 1997 Bioclimatic Timetable ......................................................................... 16 Figure 2-6 Abu Dhabi 1997 Psychrometric Chart............................................................................ 17 Figure 2-7 Al-Ain 1997 Temperature Range ................................................................................... 18 Figure 2-8 Al-Ain 1997 Temperature + Humidity ........................................................................... 19 Figure 2-9 Al-Ain 1997 Wind Velocity Range ................................................................................ 20 Figure 2-10 Al-Ain 1997 Bioclimatic Timetable ............................................................................. 21 Figure 2-11 Al-Ain 1997 Psychrometric Chart ................................................................................ 22 Figure 2-12 Abu Dhabi 1997 Wind Rose ........................................................................................ 23 Figure 2-13 Abu Dhabi 1991, 92, 93, 94, 95, 97, 98 and 99 Wind Rose ........................................... 24 Figure 2-14 Al-Ain 1997 Wind Rose .............................................................................................. 25 Figure 2-15 Al-Ain 1995, 96, 97, 98 and 99 Wind Rose .................................................................. 26 Figure 3-1 Typical Record of the Wind Velocity near the Ground .................................................. 28 Figure 3-2 Wind Patterns (a) Constricted by Topography. (b) Above and Below Tall Buildings. (c)
Around large Buildings. ........................................................................................................ 29 Figure 3-3 Effect of Terrain on Wind Velocity Profiles ................................................................... 30 Figure 3-4 Wind Pressure around Building ..................................................................................... 31 Figure 3-5 Wind Pressure Drives Cross Ventilation......................................................................... 31 Figure 3-6 Heat Generated and lost (approximate) by a person at rest (rh fixed at 45%)................... 33 Figure 3-7 Isocomfort Curve........................................................................................................... 34 Figure 3-8 Isocomfort Curve Parametrized as a Function of the air velocity..................................... 34 Figure 4-1 Wind Tower in the Middle East ..................................................................................... 36 Figure 4-2 Catching Efficiency for Different Wind Catcher Designs................................................ 37 Figure 4-3 Roof plan of the Fu'ad Riyad house in Cairo, showing the malqaf with sectional details.. 38 Figure 4-4 Section of the Fu'ad Riyad house showing the malqaf..................................................... 39 Figure 4-5 Section of a modern villa designed for Saudi Arabia showing the use of malqaf.............. 39 Figure 4-6 Section through the hall of Muhib Ad-Din Ash-Shaf'i Al-Muwaqqi showing the malqaf
and central location of the hall............................................................................................... 40 Figure 4-7 Arrows indicate the direction of airflow; arrow length corresponds to airspeed. The
measurements where made on 2 April 1973 by scholars from the Architectural Association School of Architecture in London. All wind and airspeeds are given in meters per second. ..... 40
Figure 4-8 Malqaf with wetted baffles and a wind-escape. Design by Hassan Fathy ........................ 41 Figure 4-9 Details of the malqaf with wetted baffles........................................................................ 42 Figure 4-10 Barjeel details.............................................................................................................. 43 Figure 4-11 Mohamed Sharif house, first floor................................................................................ 44 Figure 4-12 Wooden doors and opening.......................................................................................... 45 Figure 4-13 Interior view of the Wooden doors and openings.......................................................... 45 Figure 4-14 Shaikh Saeed house (North Elevation) ......................................................................... 46 Figure 4-15 Shaikh Saeed house (East Elevation)............................................................................ 46 Figure 4-16 Shaikh Saeed house (Courtyard view) .......................................................................... 46 Figure 4-17 Traditional Square Barjeel ........................................................................................... 47 Figure 4-18 Unusual cylindrical Barjeel.......................................................................................... 47 Figure 4-19 The Barjeel Closed to Block Undesirable Wind............................................................ 48 Figure 4-20 A fort in the City of Ajman uses the Barjeel for Natural Ventilation ............................. 48 Figure 4-21 Wind scoop, Hyderabad, Sind, Pakistan ....................................................................... 49 Figure 4-22 Wind Scoops facing the prevailing wind ...................................................................... 49 Figure 4-23 Scoops in Pakistan at different levels ........................................................................... 50
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Figure 4-24 A picture from the roof ................................................................................................ 51 Figure 4-25 Section/Elevation of Humanities Faculty Modules ....................................................... 51 Figure 4-26 An External Picture of the Wind Catchers .................................................................... 52 Figure 4-27 A picture from the courtyard........................................................................................ 52 Figure 4-28 Qatar University (Phase 1), Kamal El-Kafrawi ............................................................. 53 Figure 4-29 Ariel View of Qatar University .................................................................................... 53 Figure 4-30 From above: Wind tower; monodirectional wind tower and scoop; multidirectional wind
tower and scoop; combined wind tower and scoop ................................................................. 54 Figure 4-31 Day and Night reverse wind directions......................................................................... 55 Figure 4-32 Concept Drawings for rotating wind scoops ................................................................. 56 Figure 5-1 Hours to Block Natural Ventilation in Abu Dhabi .......................................................... 61 Figure 5-2 January Wind Rose........................................................................................................ 62 Figure 5-3 February Wind Rose...................................................................................................... 63 Figure 5-4 March Wind Rose.......................................................................................................... 64 Figure 5-5 April Wind Rose ........................................................................................................... 65 Figure 5-6 May Wind Rose............................................................................................................. 66 Figure 5-7 June from Midnight to 7am Wind Rose.......................................................................... 67 Figure 5-8 June from 15pm until Midnight Wind Rose.................................................................... 68 Figure 5-9 July from Midnight to 7am Wind Rose .......................................................................... 69 Figure 5-10 July from 3pm to Midnight Wind Rose ........................................................................ 70 Figure 5-11 August from Midnight to 7am Wind Rose.................................................................... 71 Figure 5-12 August from 2pm to Midnight Wind Rose.................................................................... 72 Figure 5-13 September from Midnight to 7am Wind Rose............................................................... 73 Figure 5-14 September from 2pm to Midnight Wind Rose .............................................................. 74 Figure 5-15 October Wind Rose ..................................................................................................... 75 Figure 5-16 November Wind Rose.................................................................................................. 76 Figure 5-17 December Wind Rose .................................................................................................. 77 Figure 5-18 Hours to Block Natural Ventilation in Al-Ain .............................................................. 78 Figure 5-19 January Wind Rose...................................................................................................... 79 Figure 5-20 February Wind Rose.................................................................................................... 80 Figure 5-21 March Wind Rose........................................................................................................ 81 Figure 5-22 April Wind Rose.......................................................................................................... 82 Figure 5-23 May from Midnight to 8am Wind Rose........................................................................ 83 Figure 5-24 May from 3pm to Midnight Wind Rose........................................................................ 84 Figure 5-25 June from Midnight to 7am Wind Rose........................................................................ 85 Figure 5-26 June from 5pm to Midnight Wind Rose........................................................................ 86 Figure 5-27 July from Midnight to 7pm Wind Rose ........................................................................ 87 Figure 5-28 July from 5pm to Midnight Wind Rose ........................................................................ 88 Figure 5-29 August from Midnight to 7am Wind Rose.................................................................... 89 Figure 5-30 August from 5pm to Midnight Wind Rose.................................................................... 90 Figure 5-31 September from Midnight to 7am Wind Rose............................................................... 91 Figure 5-32 September from 4pm to Midnight Wind Rose .............................................................. 92 Figure 5-33 October Wind Rose ..................................................................................................... 93 Figure 5-34 November Wind Rose.................................................................................................. 94 Figure 5-35 December Wind Rose .................................................................................................. 95 Figure 5-36 Helium Bubble Generator ............................................................................................ 96 Figure 5-37 Side and Top View of the Model.................................................................................. 97 Figure 5-38 1/3 Wind Catcher, Top View, Section and Front View ................................................. 98 Figure 5-39 2/3 Wind Catcher, Top View, Section and Front View ................................................. 99 Figure 5-40 Full Length Wind Catcher, Top View, Section and Front View .................................. 100 Figure 5-41 Leeward Elevation with different Apertures ............................................................... 101 Figure 5-42 General Setup of the Experiments .............................................................................. 102 Figure 6-1 Model Position in respect to the Wind Catcher ............................................................. 103 Figure 6-2 1/3 Wind Catcher Front Axonometric View ................................................................. 104
viii
Figure 6-3 Case 0 Back Axonometric View .................................................................................. 104 Figure 6-4 Six Frames Combined ................................................................................................. 105 Figure 6-5 Four Frames Combined ............................................................................................... 105 Figure 6-6 Five Frames Combined................................................................................................ 106 Figure 6-7 Two Frames Combined................................................................................................ 106 Figure 6-8 Five Frames Combined................................................................................................ 107 Figure 6-9 Case 0 3D Drawing ..................................................................................................... 107 Figure 6-10 Case 0 Side View ...................................................................................................... 108 Figure 6-11 Speed Vs Location..................................................................................................... 108 Figure 6-12 Case 1 Back Axonometric View ................................................................................ 109 Figure 6-19 Six Frames Combined................................................................................................ 109 Figure 6-27 Seven Frames Combined ........................................................................................... 110 Figure 6-33 Five Frames Combined.............................................................................................. 110 Figure 6-40 Six Frames Combined................................................................................................ 111 Figure 6-46 Five Frames Combined.............................................................................................. 111 Figure 6-47 Case 1 3D Drawing ................................................................................................... 112 Figure 6-48 Case 1 Side View ...................................................................................................... 112 Figure 6-49 Speed Vs Location..................................................................................................... 113 Figure 6-50 Case 2 Axonometric Back View ................................................................................ 114 Figure 6-58 Eight Frames Combined ............................................................................................ 114 Figure 6-63 Five Frames Combined.............................................................................................. 115 Figure 6-73 Nine Frames Combined ............................................................................................. 115 Figure 6-81 Five Frames Combined.............................................................................................. 116 Figure 6-88 Five Frames Combined.............................................................................................. 116 Figure 6-89 Case 2 3D Drawing ................................................................................................... 117 Figure 6-90 Case 2 Side View ...................................................................................................... 117 Figure 6-91 Speed Vs Location..................................................................................................... 118 Figure 6-92 Case 3 Axonometric Back View ................................................................................ 119 Figure 6-98 Five Frames Combined.............................................................................................. 119 Figure 6-101 Two Frames Combined............................................................................................ 120 Figure 6-108 Five Frames Combined............................................................................................ 120 Figure 6-114 Six Frames Combined.............................................................................................. 121 Figure 6-115 Case 3 3D Drawing.................................................................................................. 121 Figure 6-116 Case 3 Side View..................................................................................................... 122 Figure 6-117 Speed Vs Location................................................................................................... 122 Figure 6-118 Speed Vs Cases ....................................................................................................... 123 Figure 6-119 Speed Vs Cases ....................................................................................................... 124 Figure 6-120 Speed Vs Cases ....................................................................................................... 124 Figure 6-1211/2 Wind Catcher Front Axonometric View .............................................................. 125 Figure 6-122 Case 0 Back Axonometric View............................................................................... 126 Figure 6-128 Five Frames Combined............................................................................................ 126 Figure 6-134 Six Frames Combined.............................................................................................. 127 Figure 6-139 Four Frames Combined............................................................................................ 127 Figure 6-140 Case 0 3D Drawing.................................................................................................. 128 Figure 6-141 Case 0 Side View..................................................................................................... 128 Figure 6-142 Speed Vs Location................................................................................................... 129 Figure 6-143 Case 1 Axonometric Back View............................................................................... 130 Figure 6-150 Seven Frames Combined ......................................................................................... 130 Figure 6-159 Eight Frames Combined........................................................................................... 131 Figure 6-164 Bubble Speed 0.95 m/s ............................................................................................ 131 Figure 6-165 The Bubble Exiting from the Bottom Opening and other Bubbles following the same
Path .................................................................................................................................... 132 Figure 6-166 Some Bubbles Exit using the Bottom Opening and some Bubbles head Upwards...... 132 Figure 6-167 Bubbles headed Upward creating a Vortex ............................................................... 133
ix
Figure 6-168 Nine Frames Combined ........................................................................................... 133 Figure 6-173 Four Frames Combined............................................................................................ 134 Figure 6-174 Case 1 3D Drawing.................................................................................................. 134 Figure 6-175 Case 1 Side View..................................................................................................... 135 Figure 6-176 Speed Vs Location................................................................................................... 135 Figure 6-177 Case 2 Axonometric Back View............................................................................... 136 Figure 6-184 Six Frames Combined.............................................................................................. 136 Figure 6-191 Six Frames Combined.............................................................................................. 137 Figure 6-197 Five Frames Combined............................................................................................ 137 Figure 6-206 Eight Frames Combined........................................................................................... 138 Figure 6-207 Case 2 3D Drawing.................................................................................................. 138 Figure 6-208 Case 2 Side View..................................................................................................... 139 Figure 6-209 Speed Vs Location................................................................................................... 139 Figure 6-210 Case 3 Axonometric Back View............................................................................... 140 Figure 6-216 Six Frames Combined.............................................................................................. 141 Figure 6-222 Five Frames Combined............................................................................................ 141 Figure 6-228 Six Frames Combined.............................................................................................. 142 Figure 6-229 Case 3 3D Drawing.................................................................................................. 142 Figure 6-230 Case 3 Side View..................................................................................................... 143 Figure 6-231 Speed Vs Location................................................................................................... 143 Figure 6-232 Speed Vs Cases ....................................................................................................... 144 Figure 6-233 Speed Vs Cases ....................................................................................................... 144 Figure 6-234 Speed Vs Cases ....................................................................................................... 145 Figure 6-235Full Length Wind Catcher Front Axonometric View ................................................. 145 Figure 6-236 Case 0 Axonometric Back View............................................................................... 146 Figure 6-241 Five Frames Combined............................................................................................ 146 Figure 6-246 Five Frame Combined ............................................................................................. 147 Figure 6-250 Three Frame Combined ........................................................................................... 147 Figure 6-251 Case 0 3D Drawing.................................................................................................. 148 Figure 6-252 Case 0 Side View..................................................................................................... 148 Figure 6-253 Speed Vs Location................................................................................................... 149 Figure 6-254 Case 1 Axonometric Back View............................................................................... 150 Figure 6-260 Five Frame Combined ............................................................................................. 150 Figure 6-266 Five Frame Combined ............................................................................................. 151 Figure 6-271 Six Frame Combined ............................................................................................... 151 Figure 6-272 Case 1 3D Drawing.................................................................................................. 152 Figure 6-273 Case 1 Side View..................................................................................................... 152 Figure 6-274 Speed Vs Location................................................................................................... 153 Figure 6-275 Case 2 Axonometric Back View............................................................................... 153 Figure 6-281 Five Frame Combined ............................................................................................. 154 Figure 6-287 Other Bubbles taking a Different Path ...................................................................... 154 Figure 6-288 Bubbles Exiting the Model....................................................................................... 155 Figure 6-289 Seven Frame Combined........................................................................................... 155 Figure 6-294 Bubbles Grouping together to Exit ........................................................................... 156 Figure 6-295 Six Frame Combined ............................................................................................... 156 Figure 6-296 Case 2 3D Drawing.................................................................................................. 157 Figure 6-297 Case 2 Side View..................................................................................................... 157 Figure 6-298 Speed Vs Location................................................................................................... 158 Figure 6-299 Case 3 Axonometric Back View............................................................................... 158 Figure 6-306 Six Frame Combined ............................................................................................... 159 Figure 6-311 Five Frame Combined ............................................................................................. 159 Figure 6-315 Three Frame Combined ........................................................................................... 160 Figure 6-316 Case 3 3D Drawing.................................................................................................. 160 Figure 6-317 Case 3 Side View..................................................................................................... 161
x
Figure 6-318 Speed Vs Location................................................................................................... 161 Figure 6-319 Speed Vs Cases ....................................................................................................... 162 Figure 6-320 Speed Vs Cases ....................................................................................................... 162 Figure 6-321 Speed Vs Cases ....................................................................................................... 163 Figure 6-322 1/3 Wind Catcher with Smaller Intake Opening........................................................ 164 Figure 6-323 Eighteen Frames Combined with Fan Speed No.1 .................................................... 164 Figure 6-324 Six Frames Combined with Fan Speed No.2............................................................. 165 Figure 6-325 Six Frames Combined with Fan Speed No.3............................................................. 165 Figure 6-326 1/3 Wind Catcher in the Middle of the Windward Façade......................................... 166 Figure 6-327 Front View .............................................................................................................. 166 Figure 6-328 3D Drawing............................................................................................................. 167 Figure 7-1 Curved Wind Catcher .................................................................................................. 170 Figure 7-2 Openings on the Opposite Wall.................................................................................... 170
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Abstract
This research studies natural ventilation in a residential building using
different wind catcher sizes and exhausts to maintain a comfortable environment that
would reduce energy consumption in a hot arid zone.
All the simulated airflow tests were performed on a 1:48 scale model of a
building 14’ wide, 28’ long and 10’ high. A wind catcher with three different sizes
was built and tested. All three sizes had the same section but varying lengths, which
represented 1/3, 1/2 and all of the windward façade. The leeward façade was used as
an exhaust in two general configurations: the first configuration used the entire
façade as an outlet (10' X 14'), while the second used an opening of 4' X 14' placed at
varying locations. A Helium Bubble Generator was used to investigate the air speed
and pattern inside the model. The device produces neutrally buoyant bubbles filled
with helium. The bubbles follow the air flow streamlines. The tests were recorded
using a Digital camcorder.
All the wind catcher sizes showed an acceptable air speed inside the model.
The major distinction was in the plan exposure area, where it becomes narrower as
smaller wind catcher is used. On the other hand, this type of wind catcher can not
provide sufficient air flow for cooling the ceiling. In addition, if the same exhaust
was used with different fan speeds the air pattern will remain the same.
1
1 UAE
1.1 Physical features
Established on 2nd of December, 1971, the United Arab Emirates is a
federation of seven emirates: Abu Dhabi, Dubai, Sharjah, Ajman, Umm al-Qaiwain,
Ras al-Khaimah and Fujairah.
Comprising an area of 83,600 square kilometers, the country lies between
latitudes 22°–26.5°N and longitudes 51°–56.5°E. It is bordered to the north by the
Arabian Gulf, to the east by the Gulf of Oman and Sultanate of Oman, to the south
by the Sultanate of Oman and Saudi Arabia, and to the west by Qatar and Saudi
Arabia.
The UAE has 700 kilometers of coastline, including 100 kilometers on the
Gulf of Oman. Along the Arabian Gulf coast are offshore islands, coral reefs and salt
marshes, whilst stretches of gravel plain and barren desert characterize the inland
region.1
Figure 1-1 United Arab Emirates Map2
2
1.2 Climatic conditions
The UAE lies in the arid tropical zone extending across Asia and North
Africa. Climatic conditions in the area are strongly influenced by the Indian Ocean.
This explains why high temperatures in summer are always accompanied by high
humidity along the coast. There are noticeable variations in climate between the
coastal regions, the deserts of the interior and mountainous areas. Prevailing winds,
which are influenced by the monsoons, vary between south or southeast, to west or
north to northwest, depending upon the season and location. Average rainfall is low
at less than 6.5 centimeters annually, more than half of which falls in December and
January. 1
1.3 Housing
In 1985 Government spending on housing stood at 20.1% of total
government expenditure. By 1993 this had climbed to almost 30%. There has been a
noticeable improvement in overall housing standards within the UAE.
The Abu Dhabi Department of Social Services and Commercial Buildings
had 504 buildings and villas under construction in Abu Dhabi and Al Ain in mid
1995 and was studying 417 new projects.
The Department has constructed 40,000 housing units since its inception in
1976. The Department's investments rose from Dh 79 million in 1976 to Dh 11
billion in 1993.
All the Municipal authorities in the UAE have provided important housing
schemes and government funding has been substantial. In addition a number of
3
schemes funded by personal contributions have been undertaken. Among these is the
scheme for construction of 2,000 houses for UAE nationals, financed by the
President Sheikh Zayed bin Sultan Al Nahyan.3
1.4 Social needs and demands
One of the major UAE Government projects is the Housing Ministry's
building of neighborhoods for citizens. The Ministry established the project in
fulfillment of a personal order from the president of the UAE.
Natural ventilation and day-lighting is neglected in the design of these houses
because of two main reasons:
• The Energy (mainly electricity) is very cheap at 8.97 fils/kwh (0.02
US$) because of government support for the prices of Gas.4
• There is modest (almost none) awareness of environmental issues.
Nearly all the new neighborhoods and houses ignored the cumulative
knowledge that shaped the form and style of old houses. Old houses had a lot of
respect for Natural Forces, mainly Sun and Wind, which underpinned two major
traditional elements, the courtyards and cooling towers.
1.5 Environmental and cultural issues
UAE is a unique case when it comes to the mix of ethnic groups living on its
soil. According to CIA publications (1982), Citizens form only 19% of the
population, Iranian and other Arabs 23%, South Asian 50%, other expatriates 8%.
These percentages have been more or less sustained up to this year.5
4
The unbalanced structure of the population, along with relaxed environmental
laws, caused setbacks in two major and notably related topics:
1.5.1 Vernacular architecture styles
This style is drawing its last breath, mostly for aesthetic reasons, but more
importantly because of no understanding of natural forces that was the key factor to
building in that style. The deterioration of Vernacular styles is due mainly to the
implementation of designs from other cultures that are not suitable for climatic
conditions in the UAE, which gives rise to the second topic.
1.5.2 Environmental sense and consideration
More than half of the population is transient, living in the UAE for a short
period of time, which makes them less interested in environmental and power
savings issues. This and slack laws make it the perfect combination to produce the
following for a country with only 3 million inhabitants (Based on International
Energy Agency (IEA) and (EIA) International Energy Annual 1999):
• Total Energy Consumption (1999E):
1.9 Quadrillion Btu* (0.5% of world total energy consumption)
• Energy-Related Carbon Emissions (1999E):
32.2 million Metric tons of carbon (0.5% of world total carbon
emissions)
• Per Capita Energy Consumption (1999E):
652.7 million Btu (vs. U.S. value of 355.8 million Btu)
5
• Per Capita Carbon Emissions (1999E):
11.2 metric tons of carbon (vs. U.S. value of 5.5 metric tons of
carbon)
• Renewable Energy Consumption (1998E):
0.71 Trillion Btu* (0% increase from 1997)6
1.6 Wind and wind catchers
Through recent history, generally two groups of people lived in two very
different divisions in UAE. These two dominions searched for possible survival
methods; one colonized in the desert area and became cattle breeders (Bedouin),
forcing them to move from an oasis to another looking for plants and water for them
and their animals. The other group became fishermen and the sea became their major
source of life, either by going into long fishing trips or traveling to other countries
for trading purposes.
Understanding the wind was a major survival tool for Bedouin as it was for
fishermen. The Bedouin predicted the rare seasons of rain that was very much
dictated by wind movement. They were also warned by the warm winds that dried
their bodies of valuable and scarce water. The direction and time of wind was a
matter of life and death for the fishermen and their starving families also. This very
careful trial-and- error process gave a jump-start in building wind towers and
orienting them in the right direction.
6
REFERENCES:
1 United Arab Emirate. The official site for the Ministry of Information and Culture in the UAE. The Country. 29 Jan. 2002 <http://www.uaeinteract.com/uaeint_main/yearbook/yr_country/002country03.asp >. 2 The University of Texas library Online. United Arab Emirates Map. 15 Jan. 2002 <http://www.lib.utexas.edu/maps/middle_east_and_asia/unitedarabemirates.jpg> 3 The Emirates Center For Strategic Studies and Research. Housing. 5 Jan. 2002 <http://www.ecssr.ac.ae/00uae.socialhousing.htm>. 4 United Arab Emirate. The official site for the Ministry of Information and Culture in the UAE. CMS Energy Signs Taweelah A2 Deal 3 Jun. 2002 <http://www.uaeinteract.com/uaeint_main/newsreport/19981004.htm>. 5 Central Intelligence Agency. United Arab Emirates. 20 Dec. 2001 <http://www.odci.gov/cia/publications/factbook/geos/tc.html>. 6 Energy Information Administiration. United Arab Emirates. 22 Dec. 2001 <http://www.eia.doe.gov/emeu/cabs/uae.html>.
7
2 Climatic Data and Analysis
2.1 Writing TMY2 Data Format
2.1.1 What is TMY2 Data
The TMY2s (Typical Meteorological Year) are data sets of hourly values of
solar radiation and meteorological elements for a 1-year period. Their intended use is
for computer simulations of solar energy conversion systems and building systems to
facilitate performance comparisons of different system types, configurations, and
locations in the United States and its territories. Because they represent typical rather
than extreme conditions, they are not suited for designing systems to meet the worst-
case conditions occurring at a location. Yet, it can be a good tool for architects to
understand the weather they are trying to design for.1
2.1.2 TMY2 Data Format
CLIMATE CONSULTANT is a computer program. It only reads weather
data if it is in the following format:
MMDDHHBBBBBHHHHHTTTTKKKKWWWWCCZZZ
MM Month 01 to 12
DD Day 01 to 31
HH Hour 01 to 24
BBBBB Direct Beam Solar Radiation in kilojoules per square meter
HHHHH Total Horizontal Solar Radiation in kJ/sq m
TTTT Dry-bulb outdoor air temperature in degrees C times 10
8
KKKK Dew point outdoor air temperature in degrees C times 10
WWWW Wind speed in meters per second times 10
CC Sky cover in tenths (00 to 10)
ZZZ Wind direction in degrees from north
Every line represents an hour, which will result in an 8760 lines of data that
represent the TMY2 year.
2.1.3 Calculating the Missing Data
The weather data I obtained from the United Arab Emirates was missing
some major components such as:
• Direct Beam Solar Radiation
• Total Horizontal Solar Radiation
• Dew point outdoor air temperature
2.1.3.1 Direct Beam Solar Radiation
Direct radiation is rays that we get directly from the sun and is capable of
casting shadow.2 The sun's radiation for a day is represented by a sine curve. The
area under the curve is the sum of the direct beam radiation of the day which is the
radiation data format I got from the UAE. In order to change it to an hourly data I did
the following calculation:
A = M t1 ∫ t2
(sin π t / ∆ t) dt3
Where, A is Area under the curve
M is the Maximum amplitude
9
t1 ،t2 is time of start and end of radiation.
t is the time in hours with t = 0 representing midnight.
∆ t is the overall time of sun-shine (t2-t1).
From this equation and knowing the area under the curve (the sum of the direct beam
radiation of the day) we can obtain M (Maximum amplitude)
M = A / t1 ∫ t2 (sin π t / ∆ t) dt
= A * π / N * 2
Where, N is the number of sun exposure hours, which of course differ each day of
the year. Therefore, I considered the 21st as a typical day for the month.
After obtaining the Maximum amplitude we can get the amplitude at any
given hour using the following equation:
Y = M sin (π t / ∆ t)
Y is the amplitude at any given hour.
t is the time in hours with t = 0 representing midnight.
∆ t is the overall time of the sun-shine (t2-t1).
2.1.3.2 Total Horizontal (diffused) Solar Radiation
As solar radiation passes through the earth's atmosphere, part of the radiation
is intercepted by dust particles and dry air while other parts may be absorbed by the
ozone on the upper levels and by water vapor in the surface near the ground. The
result would be a scattered radiation in all directions4, which is most noticed in a
cloudy day, where the clouds block all the direct beams of the sun and there is no
obvious or well-defined shadow.
10
We can obtain the total horizontal radiation from direct radiation using the
following equation:
Global horizontal Gh = Direct normal x Cos (zenith angle) + scattered radiation
Also Gh= Direct normal x Sin (horizontal angle) + scattered radiation
2.1.3.3 Dew point outdoor air temperature
Dewpoint calculated from Dry Bulb Temperature and Relative Humidity
T = Air Temperature (Dry Bulb) in Centigrade (C) degrees
RH = Relative Humidity in percent(%)
B = intermediate value (no units)
D = Dewpoint in Centigrade (C) degrees5
2.2 SCRAM
2.2.1 What is SCRAM Data
The SCRAM (MET144) format is essentially a reduced version of the
traditional CD-144 format. CD-144 refers to the "Card Deck 144 format". The
SCRAM (MET 144) format consists of fewer weather variables. The file is
composed of one record per hour, with all weather elements reported in a 28-column
card image.6
11
2.2.2 SCRAM Data Format
1-5 Surface Station Number
6-7 Year
8-9 Month
10-11 Day
12-13 Hour
14-16 Ceiling Height (Hundreds of Feet)
17-18 Wind Direction (Tens of Degrees)
19-21 Wind Speed (Knots)
22-24 Dry Bulb Temperature (Degrees Fahrenheit)
25-26 Total Cloud Cover
27-28 Opaque Cloud Cover
Figure 2-1 Scram Data Format5
Surface Station Number - The WBAN number identifying the NWS surface
observation station for which hourly meteorological data are input to the met
processing program .
Year, Month and Day of Record - Identifies the year, month and day during which
the meteorological data were observed. Only the last two digits of the year are
reported .
12
Hour - Identifies the hour of the meteorological data observation. Hour is based on
the 24-hour clock and is recorded as 00 through 23. Times are Local Standard Time
(LST) and are adjusted in PCRAMMET to the 01 - 24 clock in which hour 24 is the
same as hour 00 of the next day .
Ceiling Height - The height of the cloud base above local terrain and is coded in
hundreds of feet .
Wind Direction - The direction from which the wind is blowing, based on the 36
point compass, e.g. 09=East ،18= South, 27=West, 36=North, 00=Calm .
Wind Speed - The wind speed measured in knots (00=Calm) .
Dry Bulb Temperature - The ambient temperature measured in whole degrees
Fahrenheit .
Cloud Cover - There are two cloud cover parameters, opaque cloud cover and total
cloud cover in the SCRAM meteorological data files.5
13
2.3 Climatic Data Charts
2.3.1 City of Abu Dhabi
2.3.1.1 Temperature Range
The temperature range for Abu Dhabi can be plotted using Climate
Consultant. (See Figures 2-2 through 2-10)
In summary, the year can be classified into three main groups:
• Group 1: The hottest months, May, June, July, August and September where
the temperature mean value exceeded the comfort zone range.
• Group 2: The Moderate months from November through March that showed
moderate temperatures plotted around the human comfort zone.
• Group 3: April and October, which were the transmission months to and
from the hot 5 months mentioned in group 1.
Figure 2-2 Abu Dhabi 1997 Temperature Range
14
2.3.1.2 Temperature + Relative Humidity
A typical day for Abu Dhabi with dry-bulb temperature and relative humidity
level can be plotted using Climate Consultant. (See figures 2-11 through 2-19)
The same three temperature groups (discussed in section 2.3.1.1) can be
noticed here also with a high humidity level all through the year with a RH
difference that can reach 40% sometimes between day and night.
Figure 2-3 Abu Dhabi 1997 Temperature + Relative Humidity
15
2.3.1.3 Wind Velocity Range
The wind velocity range for Abu Dhabi can be plotted using Climate
Consultant. (See Figures 2-20 through 2-28)
The wind low and high average velocities for all the years showed a very
similar pattern that ranged from 2.5 to 15 mph. In addition, there was an irregular
pattern of the record high speeds which is most probably caused by occasional
storms.
Figure 2-4 Abu Dhabi 1997 Wind Velocity Range
16
2.3.1.4 Bioclimatic Timetable
The bioclimatic timetable for Abu Dhabi can be plotted using Climate
Consultant. (See Figures 2-29 through 2-37)
According to the following charts, there are three categories of months:
• 1st Category from October 15 through March 15: The day and night is in
the comfortable temperature range.
• 2nd Category from March 15 through June 15 and from September 15
through November 15: The nigh only is in the comfortable
temperature range.
• 3rd Category from June 15 through September 15: The overheated period
lasts 24 hour.
Figure 2-5 Abu Dhabi 1997 Bioclimatic Timetable
17
2.3.1.5 Psychrometric Chart
The Psychrometric chart for Abu Dhabi can be plotted using Climate
Consultant. (See Figures 2-38 through 2-46)
There is almost a 20'F difference in dry-bulb temperature between day and
night. In summer, the change in absolute humidity values was greater than the other
seasons while in winter only a change in relative humidity appeared with a constant
absolute humidity value.
The charts suggest that the effective strategy would be ventilation (zone 6)
coupled with high mass and night ventilation (zone 7&8), all under sun shading
(zone 5). Furthermore, there are some months (like July and August) that are too hot
and humid for such strategies to work successfully
Figure 2-6 Abu Dhabi 1997 Psychrometric Chart
18
2.3.2 City of Al-Ain
2.3.2.1 Temperature Range
The temperature range for Al-Ain can be plotted using Climate Consultant.
(See Figures 2-47 through 2-52)
In summary, the year can be classified into three main groups:
• Group 1: The hottest months, May, June, July, August and September where
the temperature mean value exceeded the comfort zone range.
• Group 2: The Moderate months from November through March that showed
moderate temperatures plotted around the human comfort zone.
• Group 3: April and October, which were the transmission months to and
from the hot 5 months mentioned in group 1.
Figure 2-7 Al-Ain 1997 Temperature Range
19
2.3.2.2 Temperature + Relative Humidity
A typical day for Al-Ain with dry-bulb temperature and relative humidity
level can be plotted using Climate Consultant. (See figures 2-52 through 2-56)
The same three temperature groups (discussed in section 2.3.2.1) can be
noticed here also with a high humidity level (sometimes 80%) from November
through May. On the contrary, the relative humidity percentages drop to 20% in
April through October during the night and about 45% during the day.
Figure 2-8 Al-Ain 1997 Temperature + Humidity
20
2.3.2.3 Wind Velocity Range
The wind velocity range for Al-Ain can be plotted using Climate Consultant.
(See Figures 2-57 through 2-61)
The wind low and high average velocities for all the years showed a very
similar pattern that ranged from 2.5 to 18 mph. In addition, there was an irregular
pattern of the record high speeds which is most probably caused by storms that is
more frequently appearing in the city of Al-Ain.
Figure 2-9 Al-Ain 1997 Wind Velocity Range
21
2.3.2.4 Bioclimatic Timetable
The bioclimatic timetable for Al-Ain can be plotted using Climate
Consultant. (See Figures 2-62 through 2-66)
According to the following charts, there are three categories of months:
• 1st Category from October 15 through March 15: The day and night is in
the comfortable temperature range.
• 2nd Category from March 15 through June 15 and from September 15
through November 15: The nigh only is in the comfortable
temperature range.
• 3rd Category from June 15 through September 15: The overheated period
lasts 24 hour.
Figure 2-10 Al-Ain 1997 Bioclimatic Timetable
22
2.3.2.5 Psychrometric Chart
The Psychrometric chart for Al-Ain can be plotted using Climate Consultant.
(See Figures 2-67 through 2-71)
There is almost a 25'F difference in dry-bulb temperature between day and
night. In summer, the relative humidity values decreases although the absolute
humidity value increases.
The charts suggest that the effective strategy would be ventilation (zone 6)
coupled with high mass and night ventilation (zone 7&8), all under sun shading
(zone 5). Moreover, there are some days that are too hot and dry for such strategies
to work successfully.
Figure 2-11 Al-Ain 1997 Psychrometric Chart
23
2.4 Wind Roses
2.4.1 City of Abu Dhabi
The wind rose can be plotted using WR Plot. (See Figures 2-72 through 2-80)
The prevailing wind for Abu Dhabi is northwest. However, there are some
years that had two prevailing wind direction, northeast, south and southeast.
WIND ROSE PLOT
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WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 2-12 Abu Dhabi 1997 Wind Rose
24
WIND ROSE PLOT
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CALM WINDS
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COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 2-13 Abu Dhabi 1991, 92, 93, 94, 95, 97, 98 and 99 Wind Rose
25
2.4.2 City of Al-Ain
The wind rose can be plotted using WR Plot. (See Figures 2-80 through 2-86)
The prevailing wind for Al-Ain is northwest. However, there are some years
that had two prevailing wind direction, northeast, south and southeast.
WIND ROSE PLOT
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DISPLAY
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WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 2-14 Al-Ain 1997 Wind Rose
26
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1995 1996 1997 1998 1999 Jan 1 - Dec 31Midnight - 11 PM
DISPLAY
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COMMENTS
ORIENTATION
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WRPLOT View 3.5 by Lakes Environmental Software - www .lakes-environmental.com
Figure 2-15 Al-Ain 1995, 96, 97, 98 and 99 Wind Rose
27
REFERENCES:
1 The Renewable Resource Data Center . TMY2 User's Manual. 5 Mar. 2002 <http://rredc.nrel.gov/solar/old_data/nsrdb/tmy2/> 2 Kreider, Jan F, and Kreith, Frank. Solar Heating and Cooling: Engineering, Practical Design, and Economics. Washington, D.C.: Hemisphere, 1975, pp 5. 3 Larson, Roland E., and Hostetler, Robert P. Calculus with analytical geometry. Toronto: Heath and Company, 1986, pp 278. 4 Threlkeld, James L., Thermal Environmental Engineering, New Jersey: Englewood Cliffs, 1970, pp 294. 5The University of Arizona. Dewpoint Formulas. 2 Jan. 2002 <http://ag.arizona.edu/azmet/dewpoint.html> 6 The Meteorological Resource Center. Met Data Guide. 4 Jan. 2002. <http://www.webmet.com/MetGuide/SCRAMSurface.html>
28
3 Wind and Ventilation
3.1 Wind Characteristics
Wind is a key design factor for Architects. It can increase the occupant
satisfaction level in a space and make them thermally comfortable. Therefore,
understanding the nature of wind is crucial if the building is to be environmentally
useful.
3.1.1 Wind near the Ground
Wind is a very irregular phenomenon. In the lower layer of the atmosphere,
various obstacles and objects as well as landforms and vegetation cause turbulence.
Turbulence slow the speed of wind in general where obstacles change wind patterns
inducing increasing velocity in some areas, while protects other areas.1
Figure 3-1 Typical Record of the Wind Velocity near the Ground 1
29
Figure 3-2 Wind Patterns (a) Constricted by Topography. (b) Above and Below Tall Buildings. (c)
Around large Buildings.2
30
3.1.2 Wind in an Urban Environment
The friction caused by numerous obstacles that increase the roughness of the
ground affects the wind velocity.
In an urban environment, a reduction of 20% to 30% in the average wind
speed and an increase of 50% to 100% in the turbulence intensity are noticed when
moving from the countryside in addition to the more frequent weak winds.3
Figure 3-3 Effect of Terrain on Wind Velocity Profiles4
3.1.3 Wind Flow
Wind is a direct result of low and high pressure. The sun radiation heats the
equatorial zone which raises the air causing low pressure that invites wind from other
areas with higher pressure. Similarly, flow in a building is mainly introduced by the
different pressures in and around the building.
Wind flow is produced when an inlet is positioned in an area of positive
pressures and outlets are placed in areas of negative pressures. The pressure
differences between the inlet and outlets induce the air to move through a building.5
Natural ventilation is the movement of air into and out of a space through
openings intentionally provided for this purpose or it is simply the use of outside
cool breezes when possible. The main purpose of natural ventilation is to provide
fresh air and a cooling effect either by replacing the hot interior air or by the motion
itself.7
32
3.2.1 Removal of Excess Heat
Heat is mainly gained in a space by solar radiation and conduction through
the building envelope; it is also generated in the space by different means such as
people, lights, mechanical and electrical systems. As the air temperature increases
the air rises to the top of the space and increases the temperature of the ceiling,
which radiates heat into the space. The removal of this excess heat can decrease the
overall cooling load of the space and move the temperature more towards the
comfort zone.
3.2.2 Cooling Effect over the Human Body
When the body core temperature increases the hypothalamus calls for
changes in our blood distribution system. Because blood carries heat, the blood flow
toward the skin increases which will result in an increase of the sweat glands and
eventually evaporation. When the air molecules pass by the skin it absorbs heat and
will decrease the temperature of the body. Once air and surface temperature
approach the human body temperature (37 'C or 98.6 'F) evaporation becomes more
important and most effective.8
33
Figure 3-6 Heat Generated and lost (approximate) by a person at rest (rh fixed at 45%)8
3.2.3 Cooling the Structure
The air movement over the different surfaces of the interior decreases the
heat gain through convection and long-wave radiation. The faster the air velocity
over the surface, the cooler it becomes. This happens mainly in a strategy termed
nocturnal ventilation or night time flushing, when the day time ventilation is not
possible due to the high day time temperatures of the region. Nocturnal ventilation is
used with high mass building envelope.
The high mass envelope basically stores the heat during the day-time and
delays the heat transfer to the interiors. When the night falls and the wall becomes
ready to transfer heat into the space, wind is driven into the space in order to carry
the heat outside the building. This process decreases the surface temperature of the
interior and makes the space ready for the next day.
34
Figure 3-7 Isocomfort Curve9
Figure 3-8 Isocomfort Curve Parametrized as a Function of the air velocity. 9
Figures 3-7 and 3-8 show Isocomfort graphs with some of the possible
combinations achieved with a ventilation strategy. All the points appearing on the
Isocomfort curve has the same comfort conditions9. Furthermore, the wind becomes
less effective as the temperature reaches 33'C, which means that faster wind velocity
is needed with higher temperatures.
35
REFERENCES:
1 Allard, Francis. Natural Ventilation in Buildings: A design handbook. London: James & James, 1998, pp 11. 2 Bradshaw, Vaughn. Building Control Systems. New York: John Wiley & Sons. 1993, pp 71. 3 Allard, Francis. Natural Ventilation in Buildings: A design handbook. London: James & James, 1998, pp 22. 4 Brown, G. Z., and Dekay, Mark. Sun, Wind and light: Architectural Design Strategies. New York: John Wiley & Sons. 2001, pp17 5 "Wind Towers: Detail in Building". Battle McCarthy Consulting Engineers. 1999: 6, pp 17 6 "Wind Towers: Detail in Building". Battle McCarthy Consulting Engineers. 1999: 6 pp 16 7 Bradshaw, Vaughn. Building Control Systems. New York: John Wiley & Sons. 1993, pp 246 8 Stein, Benjamin, and Reynolds, John S. Mechanical and Electrical Equipment for Building. New York: John Wiley & Sons, 2000, pp 39 9 Allard, Francis. Natural Ventilation in Buildings: A design handbook. London: James & James, 1998, pp 45
36
4 Historical Precedents
4.1 Hot and Arid Zones
Before the industrial revolution, residents of hot arid zones were encouraged
to figure out natural ways to cool their houses and keep them as comfortable as
possible during hot days. In the Middle East, different approaches had been
attempted by dwellers according to different cultural and climate conditions (besides
material availability).
Figure 4-1 Wind Tower in the Middle East1
37
Figure 4-2 Catching Efficiency for Different Wind Catcher Designs2
38
4.1.1 The Malqaf
This wind catcher device is widely used in Egypt. It is mainly a scoop rising
above the building to collect stronger and cooler prevailing wind. Wind is
predominantly driven into large spaces below the Malqaf and then forced out
through openings in the top of a central hall. In addition to the cooling effect over the
body as a result of wind flow, it also removes excess heat that is generated from
occupants. The disadvantages of the Malqaf are that it can only catch the wind from
one direction and it would only have an effect over limited rooms when forced
through the top of the central hall.
Figure 4-3 Roof plan of the Fu'ad Riyad house in Cairo, showing the malqaf with sectional details3
39
Figure 4-4 Section of the Fu'ad Riyad house showing the malqaf4.
Figure 4-5 Section of a modern villa designed for Saudi Arabia showing the use of malqaf5
40
Figure 4-6 Section through the hall of Muhib Ad-Din Ash-Shaf'i Al-Muwaqqi showing the malqaf
and central location of the hall6
Figure 4-7 Arrows indicate the direction of airflow; arrow length corresponds to airspeed. The
measurements where made on 2 April 1973 by scholars from the Architectural Association School of Architecture in London. All wind and airspeeds are given in meters per second.7
41
In dryer conditions, Architect Hassan Fathy suggested wetted baffles which
can help reduce the air temperature by evaporation. Air is mainly directed over a
fountain or a basin of still water, to increase air humidity. He also mentioned that
baffles can reduce air flow which can be overcome by increasing the size of the
Malqaf and suspending the wetted matting in its interior.8
Figure 4-8 Malqaf with wetted baffles and a wind-escape. Design by Hassan Fathy 9
42
Figure 4-9 Details of the malqaf with wetted baffles10
43
4.1.2 The Badgir (Barjeel)
This type of wind catcher was developed in Iran around 900 AD11. It is
principally a shaft that rises 3 meters above the building with two partitions placed
diagonally with openings on all four sides.
Figure 4-10 Barjeel details12
The Badgir (Barjeel) would work both as an intake and exhaust at the same
time. Wind is sucked out by the negative pressure that is created in the leeward side
of the tower. When there is no air movement in the region, stack effect would
remove hot air that is generated inside the space below the Barjeel. The Barjeel is
44
mostly positioned in the corner of the building and directly over the place where
people either gather or sleep. The room or space that is ventilated by the Barjeel is
always being situated near the courtyard of the house and uses it as a major exhaust.
The air that is channeled through the barjeel is transferred to other rooms through
wooden doors or openings on the top of the room. These wooden doors will be
closed if the wind reached uncomfortable velocities. (Figure 4-11 and 4-12)
Figure 4-11 Mohamed Sharif house, first floor13
45
Figure 4-12 Wooden doors and opening14
Figure 4-13 Interior view of the Wooden doors and openings15
46
Figure 4-14 Shaikh Saeed house (North Elevation)16
Figure 4-15 Shaikh Saeed house (East Elevation)
Figure 4-16 Shaikh Saeed house (Courtyard view)
47
Figure 4-17 Traditional Square Barjeel
Figure 4-18 Unusual cylindrical Barjeel
48
Figure 4-19 The Barjeel Closed to Block Undesirable Wind17
Figure 4-20 A fort in the City of Ajman uses the Barjeel for Natural Ventilation18
49
4.1.3 Wind Scoops
In high density cities multi-storey buildings are likely to appear which
decreases the wind velocity near the ground. Windows wouldn't be efficient to
provide the necessary air flow for cooling the inhabitants. The only way around this
problem is to reach for the higher wind velocities by rising above the city skyline.
That is exactly what happened in Hyderabad in Pakistan, where the wind
scoops peak over the roofs of the buildings direct air into spaces below multi-storey
houses. Subsequently, the windows act as an exhaust and guide the wind to the
exterior.
Figure 4-21 Wind scoop, Hyderabad, Sind, Pakistan19
Figure 4-22 Wind Scoops facing the prevailing wind20
50
Figure 4-23 Scoops in Pakistan at different levels21
51
4.2 Design Examples of Wind Catchers
4.2.1 Qatar University in Doha
The university was built in the Arabian Gulf area, for this reason the design
came in favor of natural ventilation. The wind catcher that rose above the octagonal
shaped building was the dominating view from every side of the university. Besides
the astonishing view from the courtyards that surrounds these beautiful traditional
elements, the Barjeels give the impression of being guards protecting the adjacent
spaces from harsh environment.
Figure 4-24 A picture from the roof22
Figure 4-25 Section/Elevation of Humanities Faculty Modules23
52
Figure 4-26 An External Picture of the Wind Catchers24
Figure 4-27 A picture from the courtyard25
53
Figure 4-28 Qatar University (Phase 1), Kamal El-Kafrawi26
Figure 4-29 Ariel View of Qatar University27
54
4.2.2 Concept drawings
The effectiveness of the wind tower and wind catcher depends first and
foremost on how much the device can make use of pressure differences created in
and around the building. Furthermore, the microclimate of the region has to be
examined with awareness of other factors that can influence the direction in which
the wind blows from. For example, sites near the sea are subject to reverse wind
direction from day to night as a result of differences in thermal inertia between land
and water. Similarly, sites located in mountain areas would have the same changing
direction of prevailing wind.
Figure 4-30 From above: Wind tower; monodirectional wind tower and scoop; multidirectional wind
tower and scoop; combined wind tower and scoop28
55
Figure 4-31 Day and Night reverse wind directions29
56
Therefore, designers suggested a new breed of wind scoops that can face the
wind and maximize ventilation without any need of a mechanical system, yet, the
new scoop needs a lot of structural balance low friction bearings and a good centre of
gravity in order to rotate easily with weak low velocity wind.30
Figure 4-32 Concept Drawings for rotating wind scoops31
57
REFERENCES:
1 "Wind Towers: Detail in Building". Battle McCarthy Consulting Engineers. 1999: 6, pp25 2 Brown, G. Z., and Dekay, Mark. Sun, Wind and light: Architectural Design Strategies. New York: John Wiley & Sons. 2001, pp 189 3 Fathy, Hassan. Natural Energy and Vernacular Architecture: Principles and Examples with Reference to Hot Arid Climates. Chicago: University of Chicago. 1986, pp 131 4 Fathy, Hassan. Natural Energy and Vernacular Architecture: Principles and Examples with Reference to Hot Arid Climates. Chicago: University of Chicago. 1986, pp 130 5 Fathy, Hassan. Natural Energy and Vernacular Architecture: Principles and Examples with Reference to Hot Arid Climates. Chicago: University of Chicago. 1986, pp 128 6 Fathy, Hassan. Natural Energy and Vernacular Architecture: Principles and Examples with Reference to Hot Arid Climates. Chicago: University of Chicago. 1986, pp 116 7 Fathy, Hassan. Natural Energy and Vernacular Architecture: Principles and Examples with Reference to Hot Arid Climates. Chicago: University of Chicago. 1986, pp 117 8 Fathy, Hassan. Natural Energy and Vernacular Architecture: Principles and Examples with Reference to Hot Arid Climates. Chicago: University of Chicago. 1986, pp59 9 Fathy, Hassan. Natural Energy and Vernacular Architecture: Principles and Examples with Reference to Hot Arid Climates. Chicago: University of Chicago. 1986, pp 124 10 Fathy, Hassan. Natural Energy and Vernacular Architecture: Principles and Examples with Reference to Hot Arid Climates. Chicago: University of Chicago. 1986, pp 125 11 Allard, Francis. Natural Ventilation in Buildings: A design handbook. London: James & James, 1998, pp237
58
12 UAE. Dubai Municipality: the Historical Building Section. Elements of Traditional Architecture in Dubai. Dubai: Dubai Municipality, 2000, pp C-(1). 13 UAE. Dubai Municipality: the Historical Building Section. Elements of Traditional Architecture in Dubai. Dubai: Dubai Municipality, 2000, pp A-(8-1). 14 Forman, Werner, Phoenix Rising: The United Arab Emirates Past, present and future. London: The Harvill. 1996, pp 183. 15 Prakash Subbarao, Sheikh Saeed Al Maktoum House. 12 Dec. 2001 <http://www.datadubai.com/saeedh.htm> 16 UAE. Dubai Municipality: the Historical Building Section. Elements of Traditional Architecture in Dubai. Dubai: Dubai Municipality, 2000, pp B-(1-1). 17 Forman, Werner, Phoenix Rising: The United Arab Emirates Past, Present and Future. London: The Harvill. 1996, pp 13. 18 Vine, Peter. UAE in Focus: A photographic history of the United Arab Emirates. London: Trident. 1998, pp 134. 19 "Wind Towers: Detail in Building". Battle McCarthy Consulting Engineers. 1999: 6, pp 26 20 "Wind Towers: Detail in Building". Battle McCarthy Consulting Engineers. 1999: 6, pp 27 21 Fathy, Hassan. Natural Energy and Vernacular Architecture: Principles and Examples with Reference to Hot Arid Climates. Chicago: University of Chicago. 1986, pp 114 22 Roger Williams University. Qatar University. 2 May. 2002 <http://faculty.rwu.edu/~huk/Kahncaseweb/University%20of%20Qatar/Q1.gif> 23 Brown, G. Z., and Dekay, Mark. Sun, Wind and light: Architectural Design Strategies. New York: John Wiley & Sons. 2001, pp 188. 24 Roger Williams University. Qatar University. 2 May. 2002 <http://faculty.rwu.edu/~huk/Kahncaseweb/University%20of%20Qatar/Q16a.gif> 25 Roger Williams University. Qatar University. 2 May. 2002 <http://faculty.rwu.edu/~huk/Kahncaseweb/University%20of%20Qatar/Q6p.gif>
59
26 Brown, G. Z., and Dekay, Mark. Sun, Wind and light: Architectural Design Strategies. New York: John Wiley & Sons. 2001, pp 188 27 Roger Williams University. Qatar University. 2 May. 2002 <http://faculty.rwu.edu/~huk/Kahncaseweb/University%20of%20Qatar/Q14a.gif> 28 "Wind Towers: Detail in Building". Battle McCarthy Consulting Engineers. 1999: 6, pp 30 29 "Wind Towers: Detail in Building". Battle McCarthy Consulting Engineers. 1999: 6, pp 14 30 "Wind Towers: Detail in Building". Battle McCarthy Consulting Engineers. 1999: 6, pp 34 31 "Wind Towers: Detail in Building". Battle McCarthy Consulting Engineers. 1999: 6, pp 35
60
5 Setting the Variables
5.1 Hypothesis
Wind catchers can be adapted to provide comfort without overly constraining
either development or design possibilities for new housing in hot-arid climates.
5.2 When to use Natural Ventilation
As discussed in section 3.2.2, when the air temperature approaches human
body temperature (37 'C or 98.6 'F), all the cooling effect is credited to evaporation.
Furthermore, heat loss via convection and radiation decreases to a minimum and
eventually becomes nil. In addition, if the temperature rises above 37 'C and the
evaporation rate decreases, the human body will start gaining heat via convection
from warmer air moving around the body.
When air moves over a wet skin, it will without doubt give a cooling
sensation even if the temperature was amazingly high. On the other hand, there was
no scientific way to prove it. Accordingly, the human body temperature was used as
a reference point for ventilation and the assumption that natural ventilation would be
effective only when temperatures are lower than 37 'C was made for this thesis.
Above that temperature, the human body could gain heat from wind.
Year 1997 was chosen as a typical year for both cities to find the optimum
orientation for the wind catcher; an orientation that will collect wind at the right
times (below 37'C) in order to have a positive effect over the comfort zone.
61
5.2.1 City of Abu Dhabi
Figure 5-1 Hours to Block Natural Ventilation in Abu Dhabi
Hours to block wind would be as follows:
June from 7:00 to 15:00
July from 7:00 to 15:00
August from 7:00 to 14:00
September from 7:00 to 14:00
62
The prevailing wind for Abu Dhabi is northwest which is also the case in the
afternoon period; however, the wind had almost a reverse direction from midnight
through the early morning hours where the wind blows from the south, southeast and
southwest.
WIND ROSE PLOT
Station # 11111 - ,
NORTH
SOUTH
WEST EAST
3%
6%
9%
12%
15%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME1997 Jan 1 - Jan 31Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
1.48%AVG. WIND SPEED
1.64 m/s
COMMENTS
ORIENTATIONDirection(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-2 January Wind Rose
63
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
6%
12%
18%
24%
30%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Feb 1 - Feb 29Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
1.04%AVG. WIND SPEED
2.12 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-3 February Wind Rose
64
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
3%
6%
9%
12%
15%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Mar 1 - Mar 31Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
1.21%AVG. WIND SPEED
2.24 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-4 March Wind Rose
65
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
4%
8%
12%
16%
20%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Apr 1 - Apr 30Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
1.53%AVG. WIND SPEED
2.00 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-5 April Wind Rose
66
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
4%
8%
12%
16%
20%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 May 1 - May 31Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
0.67%AVG. WIND SPEED
1.77 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-6 May Wind Rose
67
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
4%
8%
12%
16%
20%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Jun 1 - Jun 30Midnight - 7 AM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
2.50%AVG. WIND SPEED
1.52 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-7 June from Midnight to 7am Wind Rose
68
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
3%
6%
9%
12%
15%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Jun 1 - Jun 303 PM - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
1.85%AVG. WIND SPEED
1.61 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-8 June from 15pm until Midnight Wind Rose
69
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
5%
10%
15%
20%
25%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Jul 1 - Jul 31Midnight - 7 AM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
2.02%AVG. WIND SPEED
1.61 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-9 July from Midnight to 7am Wind Rose
70
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
5%
10%
15%
20%
25%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Jul 1 - Jul 313 PM - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
2.87%AVG. WIND SPEED
1.65 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-10 July from 3pm to Midnight Wind Rose
71
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
3%
6%
9%
12%
15%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Aug 1 - Aug 31Midnight - 7 AM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
3.63%AVG. WIND SPEED
1.34 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-11 August from Midnight to 7am Wind Rose
72
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
3%
6%
9%
12%
15%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Aug 1 - Aug 312 PM - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
2.26%AVG. WIND SPEED
1.83 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-12 August from 2pm to Midnight Wind Rose
73
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
4%
8%
12%
16%
20%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Sep 1 - Sep 30Midnight - 7 AM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
5.83%AVG. WIND SPEED
1.39 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-13 September from Midnight to 7am Wind Rose
74
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
4%
8%
12%
16%
20%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Sep 1 - Sep 302 PM - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
8.33%AVG. WIND SPEED
1.60 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-14 September from 2pm to Midnight Wind Rose
75
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
3%
6%
9%
12%
15%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Oct 1 - Oct 31Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
4.57%AVG. WIND SPEED
1.78 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-15 October Wind Rose
76
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
3%
6%
9%
12%
15%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Nov 1 - Nov 30Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
1.94%AVG. WIND SPEED
1.64 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-16 November Wind Rose
77
WIND ROSE PLOT
Station #11111 - ,
NORTH
SOUTH
WEST EAST
4%
8%
12%
16%
20%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Dec 1 - Dec 31Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
2.02%AVG. WIND SPEED
1.63 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-17 December Wind Rose
78
5.2.2 City of Al-Ain
Figure 5-18 Hours to Block Natural Ventilation in Al-Ain
Hours to block wind would be as follows:
May from 8:00 to 15:00
June from 7:00 to 17:00
July from 7:00 to 17:00
August from 7:00 to 17:00
September from 7:00 to 14:00
79
The prevailing wind for Al-Ain is northwest which is also the case in the
afternoon period; however, the wind had almost a reverse direction from midnight
through the early morning hours where the wind blows from the south, southeast and
southwest and occasionally east.
WIND ROSE PLOT
Station # 22222 - ,
NORTH
SOUTH
WEST EAST
3%
6%
9%
12%
15%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Jan 1 - Jan 31Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
0.81%AVG. WIND SPEED
1.82 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-19 January Wind Rose
80
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
5%
10%
15%
20%
25%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Feb 1 - Feb 29Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
0.15%AVG. WIND SPEED
2.14 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-20 February Wind Rose
81
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
3%
6%
9%
12%
15%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Mar 1 - Mar 31Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
1.61%AVG. WIND SPEED
2.30 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-21 March Wind Rose
82
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
3%
6%
9%
12%
15%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Apr 1 - Apr 30Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
0.56%AVG. WIND SPEED
2.19 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-22 April Wind Rose
83
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
3%
6%
9%
12%
15%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 May 1 - May 31Midnight - 8 AM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
1.43%AVG. WIND SPEED
1.91 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes -environmental.com Figure 5-23 May from Midnight to 8am Wind Rose
84
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
4%
8%
12%
16%
20%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 May 1 - May 313 PM - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
2.15%AVG. WIND SPEED
1.62 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-24 May from 3pm to Midnight Wind Rose
85
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
5%
10%
15%
20%
25%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Jun 1 - Jun 30Midnight - 7 AM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
3.33%AVG. WIND SPEED
2.14 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-25 June from Midnight to 7am Wind Rose
86
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
4%
8%
12%
16%
20%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Jun 1 - Jun 305 PM - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
1.90%AVG. WIND SPEED
1.65 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-26 June from 5pm to Midnight Wind Rose
87
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
6%
12%
18%
24%
30%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
PLOT YEAR-DATE-TIME
1997 Jul 1 - Jul 31Midnight - 7 AM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
2.02%AVG. WIND SPEED
1.71 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-27 July from Midnight to 7pm Wind Rose
88
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
5%
10%
15%
20%
25%
Wind Speed (m/s)
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PLOT YEAR-DATE-TIME
1997 Jul 1 - Jul 315 PM - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
3.69%AVG. WIND SPEED
1.43 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-28 July from 5pm to Midnight Wind Rose
89
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
4%
8%
12%
16%
20%
Wind Speed (m/s)
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PLOT YEAR-DATE-TIME
1997 Aug 1 - Aug 31Midnight - 7 AM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
1.61%AVG. WIND SPEED
1.59 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-29 August from Midnight to 7am Wind Rose
90
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
5%
10%
15%
20%
25%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
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PLOT YEAR-DATE-TIME
1997 Aug 1 - Aug 315 PM - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
4.15%AVG. WIND SPEED
1.67 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-30 August from 5pm to Midnight Wind Rose
91
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
6%
12%
18%
24%
30%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
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PLOT YEAR-DATE-TIME
1997 Sep 1 - Sep 30Midnight - 7 AM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
1.67%AVG. WIND SPEED
2.07 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-31 September from Midnight to 7am Wind Rose
92
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
4%
8%
12%
16%
20%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
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PLOT YEAR-DATE-TIME
1997 Sep 1 - Sep 304 PM - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
1.25%AVG. WIND SPEED
1.64 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-32 September from 4pm to Midnight Wind Rose
93
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
3%
6%
9%
12%
15%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
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PLOT YEAR-DATE-TIME
1997 Oct 1 - Oct 31Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
0.40%AVG. WIND SPEED
2.04 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-33 October Wind Rose
94
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
3%
6%
9%
12%
15%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
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PLOT YEAR-DATE-TIME
1997 Nov 1 - Nov 30Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
1.53%AVG. WIND SPEED
1.88 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-34 November Wind Rose
95
WIND ROSE PLOT
Station #22222 - ,
NORTH
SOUTH
WEST EAST
4%
8%
12%
16%
20%
Wind Speed (m/s)
> ��.��
�.�� - ��.��
�.�� - �.��
�.�� - �.��
�.�� - �.��
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PLOT YEAR-DATE-TIME
1997 Dec 1 - Dec 31Midnight - 11 PM
DISPLAY
Wind SpeedUNIT
m/s
CALM WINDS
2.02%AVG. WIND SPEED
1.68 m/s
COMMENTS
ORIENTATION
Direction(blowing from)
WRPLOT View 3.5 by Lakes Environmental Software - www.lakes-environmental.com Figure 5-35 December Wind Rose
96
5.3 Model Drawings and Testing Environment
5.3.1 Helium Bubble Generator
The Helium Bubble Generator is a device that produces neutrally buoyant
bubbles filled with helium. The bubbles follow the air flow streamlines and rarely
collide with objects. Additionally, the bubbles will follow laminar and turbulent
airflows.
Figure 5-36 Helium Bubble Generator
5.3.2 Drawings
All the simulated airflow tests were preformed on a 1:48 scale model of a
building 14’ wide, 28’ long and 10’ high.
97
Top View
Side View
Figure 5-37 Side and Top View of the Model
A wind catcher with three different sizes was built and tested. All three sizes
had the same section but varying lengths, which represented 1/3, 1/2 and all of the
windward façade.
98
aa
Top View
Section a-a
Front View
Figure 5-38 1/3 Wind Catcher, Top View, Section and Front View
99
aa
Front View
Section a-a
Top View
Figure 5-39 2/3 Wind Catcher, Top View, Section and Front View
100
aa
Front View
Section a-a
Top View
Figure 5-40 Full Length Wind Catcher, Top View, Section and Front View
101
The leeward façade was used as an exhaust in two general configurations: the
first configuration used the entire façade as an outlet (10' X 14'), while the second
used an opening of 4' X 14' placed at varying locations.
Full Opening (CASE 0)
2' X 2' X 14' (CASE 1)
Top Opening 4' X 14' (CASE 2)
Bottom Opening 4' X 14' (CASE 3)
Figure 5-41 Leeward Elevation with different Apertures
102
Fan
ModelLight Projector
Table
Bubble Output
FanLight Projector
ModelBubble Output
Wall
Side View
Top View
Figure 5-42 General Setup of the Experiments
103
6 Wind Catcher with Different Sizes and Outlets
All the tests were performed with the wind blowing perpendicular to the wind
catcher's façade.
Wind
WindwardLeeward
WindSide View
Top View
Figure 6-1 Model Position in respect to the Wind Catcher
The tests were recorded using a digital camcorder with a 30 frame per second
rate. The duration of each frame is 0.033 second. In short, every 1 inch in the picture
represents 60 inch per second or 0.76 meters per seconds.
The fan had three speeds, as follows:
• Fan Speed 1 = 5 ft/s = 1.5 m/s = 3.4 mph
• Fan Speed 2 = 7.5 ft/s = 2.3 m/s = 5.1 mph
• Fan Speed 3 = 10 ft/s = 3.1 m/s = 6.8 mph
104
6.1 1/3 Wind Catcher
Figure 6-2 1/3 Wind Catcher Front Axonometric View
environmental.com/lakewrpl.html> Larson, Roland E., and Hostetler, Robert P. Calculus with analytical geometry.
Toronto: Heath and Company, 1986 Milne, Murray. Climate Consultant, University of California, Los Angeles, 1991. The Renewable Resource Data Center . TMY2 User's Manual. 5 Mar. 2002
<http://rredc.nrel.gov/solar/old_data/nsrdb/tmy2/> Stein, Benjamin, and Reynolds, John S. Mechanical and Electrical Equipment for
Building. New York: John Wiley & Sons, 2000 Threlkeld, James L., Thermal Environmental Engineering, New Jersey: Englewood
Cliffs, 1970 UAE. Dubai Municipality: the Historical Building Section. Elements of Traditional
Architecture in Dubai. Dubai: Dubai Municipality, 2000 Vine, Peter. UAE in Focus: A photographic history of the United Arab Emirates.