shade and cooling effect of colonnade in low...
TRANSCRIPT
SHADE AND COOLING EFFECT OF COLONNADE
IN LOW-RISE STREET CANYON IN TROPICAL CLIMATE
LAM JIIH KUI
A thesis submitted in fulfilment of the
requirements for the award of the degree of
Master of Architecture
Faculty of Built Environment
Universiti Teknologi Malaysia
MARCH 2012
iii
To my beloved parents, brothers, sisters and friends
for their support and encouragement.
iv
ACKNOWLEDGEMENT
I would like to firstly express my thankfulness to Dr Dilshan Remaz Ossen,
my main thesis supervisor, who is always willing to offer help and guidance
throughout the whole process of this thesis. I am also very thankful to Assoc. Prof.
Dr. Mohamed Rashid Embi, the Deputy Dean (Postgraduates & Research) of my
faculty and his administrative staffs. Without their continued support and interest,
this design thesis would not have been the same as presented here.
My sincere appreciation also extends to all my brothers and sisters in Hope
Church Johor Bahru, my fellow colleagues and others who have provided assistance
at various occasions such as supplying the relevant literatures and giving
encouragements. Thank you to all my friends and all whose name are not mentioned
for your supports and sacrifices.
I am grateful to all my family members, especially my parents for their
unconditional love and support throughout my study and my life.
v
ABSTRACT
The shophouse buildings in Malaysia, which flank commercial streets, are of
low-rise planning. The building height is controlled according to council’s plot ratio,
but is always built on the development needs. Colonnade has been a part of the
shophouse design regulations to provide overhead rain shelter and for sun shading.
Provision of 7.5 feet (2.25 m) is the minimum depth. The main aim of this study is to
investigate the potential of colonnade depth to lower the overall air temperature in
the urban street microclimate. At the same time, fundamental climatic criteria of
overhead shading elements and provision of enough space as a pedestrian
thoroughfare in the urban must be fulfilled. Ecotect is used to run the shading
analysis. Envelope Ratio and CTTC model are used for air temperature reduction
simulations. In a H/W 0.25 street, adequate overhead shading from 1100 to 1600 can
only be achieved with Dc/Hc 1.5 and above. This translates to 6 meters of colonnade
depth. Colonnade in H/W 2 street with Dc/Hc 1 and above provides comfortable
shades throughout the day. To lower the air temperature, the optimum colonnade
depth to street width ratio is C/W 0.6. Deeper colonnade will give no significant
microclimate improvement. It is found that the ideal colonnade ratio is C/W 0.2 to
0.6. Existing urban code requires Dc/Hc 0.75. In a north-south street, it is only able to
offer adequate shade of 2 meter from 1230 to 1400. In a east-west street, it is only
able to give 1 to 1.5 meter of shade, during the extreme case of summer and winter
solstice. Existing colonnade depth of 2.25 meter and street width of 15 meter will
give C/W 0.15. In both shallow and deep canyons, the effect in reducing the air
temperature is limited.
vi
ABSTRAK
Rumah kedai, bangunan yang biasa didapati di jalan-jalan komersial di Malaysia,
dikategorikan dalam pembangunan bertingkat rendah. Ketinggian bangunan dikawal
mengikut nisbah plot majlis, tetapi lebih biasa dibina mengikut keperluan. Ruang kaki
lima telah menjadi sebahagian daripada rumah kedai untuk menyediakan tempat
perlindungan hujan dan untuk teduhan matahari. Mengikut peraturan, kedalaman ruang
ini sekurang-kurangnya 7.5 kaki (2.25 m). Tujuan utama kajian ini adalah untuk
mengkaji potensi kedalaman ruang kaki lima dalam merendahkan suhu udara
keseluruhan iklim mikro jalan bandar. Pada masa yang sama, asas tujuan reka bentuk
teduhan atas kepala dan penyediaan ruang yang cukup sebagai ruang pejalan kaki perlu
dipenuhi. Perisian Ecotect digunakan untuk menjalankan analisis teduhan. Model
Envelope Ratio dan CTTC digunakan untuk menjalankan simulasi pengurangan suhu
udara. Bagi jalan H/W 0.25, teduhan atas kepala yang mencukupi dari jam 11 hingga
jam 16 jam hanya boleh dicapai dengan Dc/Hc 1.5 dan ke atas. Ini akan menterjemahkan
ruang kaki lima sedalam 6 meter. Ruang kaki lima di jalan H/W 2 dengan Dc/Hc 1 ke
atas menyediakan teduhan yang selesa sepanjang hari. Nisbah C/W 0.6 adalah nisbah
optimum bagi pengurangan suhu. Kedalaman yang selebihnya tidak akan memberikan
peningkatan yang ketara. Nisbah kaki lima yang optimum ialah C/W 0.2 hingga 0.6.
Peraturan perancangan bandar sedia ada memerlukan Dc/Hc 0.75. Bagi jalan yang
berorientasi utara-selatan, ia hanya mampu untuk menawarkan tempat teduh yang
mencukupi (2 meter) dari 1230 hingga 1400. Bagi jalan yang berorientasi timur-barat, ia
hanya dapat memberikan 1 hingga 1.5 meter tempat teduh, semasa solstis musim panas
dan musim sejuk. Ruang kaki lima sedia ada yang sedalam 2.25 meter dan lebar jalan 15
meter akan memberikan C/W 0.15. Keupayaan nisbah ini dalam mengurangkan suhu
udara adalah terhad.
vii
TABLE OF CONTENTS
CHAPTER TITLE PAGE
THESIS TITLE i
DECLARATION ii
DEDICATION iii
ACKNOWLEDGEMENTS iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF TABLES xii
LIST OF FIGURES xiv
LIST OF ABBREVIATIONS xviii
LIST OF SYMBOLS xix
1 GENERAL INTRODUCTION 1
1.1 Introduction 1
1.2 The Problem Statement 4
1.3 Research Hypothesis 5
1.4 Research Questions 6
1.5 Research Gap 6
1.6 Research Objectives 8
1.7 Scope and Limitations 9
1.8 Importance of the Research 12
viii
1.9 Thesis Organization 13
2 URBAN PLANNING CODES, COLONNADE AND
LOW-RISE STREET CANYON MICROCLIMATE 16
2.1 Urban Canopy Layer Microclimate 17
2.1.1 Energy Balance of an Urban Canyon Layer 19
2.1.2 Effects of Urban Features to the Energy
Balance 22
2.1.3 Strategies to Improve Microclimate of
Tropical Urban Canopy Layer 26
2.2 Low-Rise Street Canyon Microclimate 28
2.2.1 Air Temperature 28
2.2.2 Relative Humidity 30
2.2.3 Thermal Comfort 30
2.2.4 Wind Flow 31
2.2.5 Urban Heat Island 31
2.3 Low-Rise Street Canyon Design Strategies 32
2.3.1 Street Orientation 33
2.3.2 Overhead Shading 33
2.3.2.1 Overhangs 34
2.3.3 Urban Form 36
2.3.3.1 Solar Angle Induced Models 37
2.3.3.2 Courtyard 39
2.3.4 Ventilative Cooling 40
2.3.5 Vegetation and Green Area 41
2.3.6 Solar Reflectivity (Albedo) 41
2.4 Colonnade 42
2.4.1 Rationale of Strategy 43
2.4.2 Envelope Ratio 44
2.4.3 Thermal Performance 46
2.4.4 Overhead Shading 47
2.5 Urban Canyon Layer of Commercial Street in
Johor Bahru 48
ix
2.5.1 Urban Planning Codes 51
2.5.2 Colonnade 54
2.6 Summary 55
3 METHODOLOGY 57
3.1 The Need for the Experiment 58
3.2 Qualitative Analysis of Current Urban Planning
Codes 58
3.3 Development of Colonnade and Street Configurations 59
3.3.1 Street Aspect Ratio 60
3.3.2 Street Orientation 60
3.3.3 Colonnade Depth to Height Ratio 60
3.3.4 Colonnade to Street Width Ratio 61
3.3.5 Envelope Ratio 62
3.4 Shading Analysis 63
3.4.1 Methods of Shading Analysis 64
3.4.1.1 Manual Calculation Method 64
3.4.1.2 Computer Simulation 65
3.4.2 Selection of Shading Simulation Software 66
3.4.3 Ecotect Simulation Procedure 67
3.4.3.1 Step I: Data Requirement 68
3.4.3.2 Step II: Preparation of the Models 69
3.4.3.3 Step III: Detailed Interface – Selecting
Simulation Parameters and Perform
Simulation 70
3.4.3.4 Step IV: Review Simulation Results 72
3.4.4 Simulation Limitations 73
3.5 Urban Canyon Layer Air Temperature Prediction 73
3.5.1 Methods of Air Temperature Prediction 74
3.5.1.1 Field Experiment 74
3.5.1.2 Physical Model Method 75
3.5.1.3 CFD 76
3.5.1.4 Statistical Model 76
x
3.5.1.5 Digital Elevation Models 77
3.5.1.6 Computer Simulation 77
3.5.1.7 Calculation Method 78
3.5.2 Selection of Air Temperature Prediction Model 78
3.5.3 The Cluster Thermal Time Constant (CTTC)
Model 78
3.6 Envelope Ratio 88
3.6.1 Calculation Procedure 91
3.6.1.1 Step I: Data Requirement 91
3.6.1.2 Step II: Preparation of the Models 93
3.6.1.3 Step III: Calculation 93
3.6.1.4 Step IV: Review Simulation Results 94
3.6.2 Simulation Assumptions & Limitations 94
3.7 Simulation Analysis Criteria 95
3.8 Conclusion 98
4 RESULTS, ANALYSIS AND FINDINGS 99
4.1 Shading Analysis on Colonnade 100
4.1.1 North-South Oriented Street 100
4.1.2 East-West Oriented Street 105
4.1.3 Influence of Colonnade Depth to Height on
Shade Percentage 109
4.1.4 Influence of Street Aspect Ratio on
Shade Percentage 110
4.1.5 Influence of Street Orientation on Shade
Percentage 111
4.1.6 Impact of Current Urban Planning Codes on
Shade Percentage 112
4.1.7 Summary of Colonnade Depth to Colonnade
Height Ratio (Dc/Hc) 114
4.2 Solar Radiation Absorption, ∆𝑇!"#$% (K) 115
4.2.1 Influence of Envelope Ration to the Solar
Radiation Absorption 118
xi
4.2.2 Impact of Current Urban Planning Codes on
Solar Irradiation Absorption 120
4.3 Net Long-Wave Radiation, ∆𝑇!"#$ 121
4.3.1 Influence of Sky View Factor in Heat Release 123
4.4 Air Temperature 125
4.4.1 Envelope Ratio Effect 127
4.5 Summary of Colonnade Depth to Street Width Ratio
(C/W) 129
4.6 Summary 130
5 SUMMARY AND RECOMMENDATION 132
5.1 Review of Thesis Objectives and Research Questions 132
5.2 Thesis Conclusion 134
5.2.1 Colonnade and Shading 135
5.2.2 Colonnade Depth and Envelope Ratio 135
5.2.3 Envelope Ratio and Air Temperature 136
5.2.4 Sky View Factor and Air Temperature 137
5.2.5 Influence of Existing Urban Planning Codes 138
5.3 Envelope Ratio and CTTC 138
5.4 Suggestions for Further Research 139
REFERENCE 140
APPENDIX 150
A Example of CTTC Calculation Spreadsheet 150
A1. Solar radiation absorption, ∆𝑇!"#$% calculation 151
A2. Net long-wave radiation loss, ∆𝑇!"#$ calculation 152
B Conference Paper: Effect of Urban Geometry on Solar Insolation
Threat In JSNAC (Pilot Study) 153
C Conference Poster: Colonnade in Cooling Urban Canopy Layer 154
xii
LIST OF TABLES
TABLE NO. TITLE PAGE
1.1 Summary of previous research related to tropical urban street design, colonnade and urban canopy layer microclimate 7
2.1 Climatic scales in an urban area 17 2.2 Thermal properties of materials 21 2.3 Radiative properties of materials 24 2.4 Effects of urban features to the energy balance 26 2.5 Simulated colonnade effects in canyon streets and closed
courtyards at 15:00, July data, Tel Aviv 45 2.6 Roles and functions of authorities in different level
regarding town and country planning in Malaysia 51 2.7 Town and country planning regulations in Johor Bahru
City Centre 53 2.8 Commercial Projects in Johor Bahru and the Built-up
Geometry Analysis. Average H/W= 0.51 54
2.9 Microclimate of low-rise street canyon 55 3.1 Colonnade depth to height ratio (D/H) and colonnade depth To street width ratio (C/W) 59 3.2 Envelope ratio for the research 62 3.3 Design variables for shading analysis 66
xiii
3.4 The variables and parameters which are included in the
CTTC model 79
3.5 Cluster Thermal Time Constant (CTTC) values 84 3.6 Comparison of sky view factor by using calculation method
and Ecotect simulation 87 3.7 Climatological element and their relation to urban features 88 3.8 Temperature and solar insolation on 18 August 2009 91 3.9 Urban variables and input parameters to the CTTC model 92 3.10 Independent variables, dependent variables and constants
of the CTTC model 94 3.11 Data analysis indicators and their interpretation 96
4.1 Depth of shaded area, x on colonnade ground of east facing
facade (H/W= 0.25, colonnade height = 4m) 110 4.2 Difference between north-south oriented street and east
-west oriented street 112 4.3 Simulated colonnade effect at 14:00, 18 August 127 4.4 Colonnade depths (in meter) in various street aspect ratios 130 4.5 Colonnade depths (in meter) in various colonnade heights 131
xiv
LIST OF FIGURES FIGURE NO. TITLE PAGE 1.1 Sectional diagram of a typical commercial street in
Malaysia 5 1.2 Main variables for heat stress reduction analysis – Street
aspect ratio (H/W) and Colonnade depth to street width ratio (C/W) 11
1.3 Main variables for shading analysis – Colonnade depth
to colonnade height ratio (Dc/Hc) 11 1.4 Requirement of colonnade design chart 12 1.5 The flow of research process and thesis structure 15 2.1 Climatic scales in urban areas: meso, local and
micro-scale 18 2.2 The urban street canyon and the energy balance in
equation 2.1 20 2.3 Sky view factor. Source: Sebastian Wypych 25 2.4 Overhang in a street canyon 34 2.5 Adjustable vertical and horizontal shading device 35 2.6 Building types: (a) pavilions (b) courts 36 2.7 Urban block design using shadow umbrella theory 37 2.8 Self-shading building by Capeluto 38 2.9 Courtyards in various ratios 39 2.10 The relationship between the surface-air temperature
difference (∆T) and the albedo of selected paints and roofing materials facing the sun 42
2.11 Colonnades at both sides of the street 42
xv
2.12 Map of Johor Bahru city 49 2.13 Air Temperature and Solar Radiation of Johor Bahru
on a Typical Clear Day (18 August 2009) 50 2.14 Illustration of shophouse and urban planning codes in
Malaysia 52 3.1 Investigated colonnade depth to its height ratios 61 3.2 Investigated colonnade depth to the street width ratios 62 3.3 The calculation of shadow points on a flat ground given
the azimuth and altitude of the sun 65 3.4 Colonnade shading simulation procedures in Ecotect 68 3.5 Formulated 3D simulation models in Sketchup 69 3.6 Simulated plane line (in orange) representing the 2D
section of the ground for infinite canyon length simulation 70 3.7 Site location and time zone input in Ecotect 71 3.8 Overshadowing percentage simulation under sun-path
diagram window 71 3.9 Shading simulation results 72 3.10 Selection of desired simulation date 73 3.11 Variables in net solar 𝑇!"#$% exchanges 81 3.12 Variables in Partial Shaded Area (PSA) equation 82 3.13 Typical vertical cross-section of a symmetrical urban
street canyon showing open space area external wall area and plot area 83
3.14 Site obstructions projected back onto an imaginary
hemisphere centred at the point of interest 86 3.15 Projected site obstructions shown in a sun-path diagram
centred at the point of interest 86 3.16 Envelope ratio 89 3.17 Overall simulation procedures with design variables and
performance variables 97
xvi
4.1 Shading percentage on colonnade ground for east-facing façade in (a) H/W 0.25, (b) H/W 0.5, (c) H/W 1, (d) H/W 2 streets on 21 June. 101
4.2 Shading type: (a) overhead shading on a colonnade with
D/H 0.5 (colonnade depth = 2m, height = 4m), (b) mutual shading effect on a colonnade with Dc/Hc 0.5, (c) overhead shading on a colonnade with Dc/Hc 0.5 (colonnade depth = 2m, height = 4m) 102
4.3 Shading percentage for west-facing façade in (a) H/W 0.25,
(b) H/W 0.5, (c) H/W 1, (d) H/W 2 streets on 21 June 104 4.4 Shading percentage for north-facing façade in (a) H/W 0.25,
(b) H/W 0.5, (c) H/W 1, (d) H/W 2 streets on 21 June 105 4.5 Monthly shading percentage on colonnade ground of north
facing façade in east-west oriented street in H/W 0.25 street 107 4.6 Shading percentage for south-facing façade in (a) H/W
0.25, (b) H/W 0.5, (c) H/W 1, (d) H/W 2 streets on 21 December 108
4.7 Shading percentage on colonnade ground of (a) D/H 0.5
and (b) D/H 2.5 in various street aspect ratios from 17:30 to 14:00 on 21 June 111
4.8 Overhead shading from 11:00 to 16:00 in various D/H ratios
for north-south oriented street 113 4.9 Overhead shading from 11:00 to 16:00 in various D/H ratios
for east-west oriented street 113 4.10 Simulated solar radiation absorption in various colonnade
depth to street width ratios, in (a) H/W0.25, (b) H/W 0.5, (c) H/W 1, (d) H/W 2 streets on 18 August 115
4.11 The effect of colonnade depth to street width ratio (C/W)
and aspect ratio on absorbed solar radiation (K) on 14:00, 18 August 117
4.12 Envelope ratio of various colonnade depth to street width
ratio (C/W) in low-rise street aspect ratio 118 4.13 Envelope ratio and colonnade effect on solar radiation
absorption at 14:00, 18 August 119 4.14 Current urban planning code (C/W0.15) and the solar
radiation absorption reduction (K) 120
xvii
4.15 Simulated net long-wave radiation on (a) H/W 0.25, (b) H/W 0.5, (c) H/W 1, (d) H/W 2 street by various SVF 121
4.16 Sky view factor of various colonnade depth to street
width ratio (C/W) in low-rise street aspect ratio 123 4.17 Effect of SVF in net long-wave radiation loss in (a) 15:00,
(b) 20:00 124 4.18 Simulated air temperature by various colonnade depth to
street width ratio in (a) H/W 0.25, (b) H/W 0.5, (c) H/W 1, (d) H/W 2 streets on 18 August 125
4.19 Simulated air temperature reduction (K) 128 5.1 Colonnade depth and various variables 134 5.2 Simulated air temperature rise by colonnade depth in
various street aspect ratio 137
xviii
LIST OF ABBREVIATIONS
2D - Two-dimensional
3D - Three-dimensional
CBD - Central business district
CFD - Computational fluid dynamic
CTTC - Cluster Thermal Time Constant
DEM - Digital elevation model
E - East
GIS - Geographic information system
H/W - Aspect ratio
HSA - Horizontal shading angle
N - North
NE - North-east
NLWR Net long-wave radiation loss
NW - North-west
PET - Physiological Equivalent Temperature
RH - Relative humidity
RMT - Radiant mean temperature
S - South
SE - South-east
SVF - Sky view factor
SW - South-west
UCL - Urban canopy layer
UHI - Urban heat island
VSA - Vertical shading angle
W - West
xix
LIST OF SYMBOLS
∝ - Reflectivity of short-wave radiation
𝛼 - Albedo
𝛽! - Sun altitude angle (°) at time 𝑡
Br - Brunt number
C - Heat capacity (J m-3 K-1 x 106)
C/W - Colonnade depth to street width ratio
D - Diffuse-beam radiation (W/m2)
D - Depth of building (m)
Dc/Hc - Colonnade depth to colonnade height ratio
dx - Offset from the shading point
dy - The depth of the shade
𝑒! - Solar azimuth angle (°) measured from the south, at
time 𝑡
𝜀 - Emissivity for long-wave radiation at the surface
FA - Plan area of building roofs in cluster (m2)
GA - Ground area (m2)
h - Overall heat transfer coefficient at surface (W/m2 K)
H - Building height
h roof - Overall heat transfer coefficient at roof surface (W/m2
K)
𝐼!"#$%# !"#(𝑡) - Solar radiation intensity on rooftop (W/m2)
𝐼! - Solar radiation intensity on the ground (W/m2)
𝐼!"# - The total absorbed solar irradiation on surface (W/m2)
𝐼!"#$ - Net long wave radiation loss from an unobstructed
xx
black surface
𝐼𝑣! - Solar radiation intensity on the sunny part of the ith
wall (W/m2)
K - Temperature degree Kelvin
k - Thermal conductivity (W m-1 K-1)
𝐾 ∗ - Incoming short-wave radiation (W/m2)
𝐾 ↑ - Reflected radiation (W/m2)
𝐾 ↓ - Incoming global radiation (W/m2)
𝐿 ∗ - Incoming long-wave radiation (W/m2)
𝐿 ↑ - Outgoing long-wave radiation (W/m2)
𝐿 ↓ - Incoming long-wave radiation (W/m2)
m - Surface solar radiation absorptivity
mg - Ground surface solar radiation absorptivity
mH - Wall surface solar radiation absorptivity
𝜎 - Stefan-Boltzmann constant
PSA! - Walls’ partial shaded areas on the ground
PSA - Partial shaded area
𝜌 - Density (in kg m-3 x 103)
∆𝑄! - Net advection through the sides of the volume
∆𝑄! - Net heat storage
𝑄! - Latent heat
𝑄! - Anthropogenic heat
𝑄! - Sensible heat
S - Direct-beam radiation (W/m2)
S - Total investigated area (m2)
SVF roof - Sky view factor of the roof surfaces
t - Time (h)
t min - Minimum value a time t
𝑇! - Base temperature (°C)
𝑇! - Air temperature variation (K)
𝑇!"# - Ambient air temperature (K)
𝑇!"#$ - Contribution of net long-wave radiation exchange to air
temperature (K)
xxi
𝑇!"#$% - Contribution of solar radiation absorption to air
temperature (K)
Ts - Temperature of the surface
𝑢 - mean wind speed (m/s)
𝜇 - Thermal admittance (J m-2 S-1/2 K-1)
V - Envelope ratio
V - Envelope ratio
WA - Wall area (m2)
X! - Shaded strip width (m) at time 𝑡
λ - Time (h) of indexing
CHAPTER 1
GENERAL INTRODUCTION
1.1 Introduction
Optimization can be done in our existing urban design to unleash the fullest
potential. Evaluation on the current urban planning regulations and a profound
understanding on climate-sensitive design theories will lead to a revisit on the
common practices of urban planning and design.
One of the possible potential in Malaysian context, is the use of colonnade
(commonly known as five-foot-way locally) to reduce the thermal heat stress in the
urban canopy layer. Colonnade has been a part of the shophouse design regulations
to provide overhead rain shelter and for sun shading in the commercial street since
1822, by Sir Stamford Raffles (Governor of Singapore). It was set to be 7.5 feet
(2.25 m) minimum in depth.
The street’s size and geometry are governed by a set of urban planning codes
(refer chapter 2.5.1 for detailed descriptions). Among all these constraints,
colonnade depth has the potential to be explored to achieve urban cooling effect.
2
There are a few infant theories explaining this phenomenon and they point to
a promising environmental advantage of such design element to the canyon street
microclimate. Hanna Swaid (1993) confirmed the use of colonnade would offer
reduced heat stress round the clock. Johansson (2006) found out that colonnades
provide more efficient shading than trees. Ali-Toudert’s (2007) research observed
shorter period of high streets in the street which was caused by the colonnade. B
Taylor (2008) explained the role of colonnade in minimizing diffuse as well as direct
solar gain. It was further affirmed that the colonnade makes maximum use of shaded
thermal mass which is able to reduce the radiant temperature field to below the air
temperature.
In another finding, Shashua-bar (2006) suggested that the cooling effect is
proportionate to the envelope ratio (ratio of ground area to total surface area in the
site, ( !"#$%& !"#$!"#$%& !"#$!!"## !"#$
) (refer figure 3.16 for illustration). The depth of the five-
foot-way will add the total wall area in the envelope. Therefore, as a rule of thumb,
in the street envelope area, the more wall area added, the more cooling effect it will
bring to the urban canopy layer.
Malaysia, an under developing nation, is experiencing rapid urbanization as
well. In accommodating the growth, the solution is by increasing row houses or
structures to accommodate the growth. Developments of new dwelling areas are
always accompanied by paved surfaces, parking lots, roofs and wall surfaces and etc.
Construction materials like tarmac, concrete and steel are large heat storage in the
urban, which absorb heat in the morning and radiate into the surrounding at night. It
is predicted to cause 10oC or more temperature rise in city centers than suburban
green areas (Ahmed, 2003).
Drainage and Irrigation Department (2000) carried out the rainfall analysis
for Kuala Lumpur after the CBD was observed and reported to be too hot in the
3
daytime hours. It was found that the increasing trend in flash floods was related to
the increased frequencies of extreme rainfall events and increased total annual
rainfalls.
Most developing nations and cities are located in the tropical region. These
nations are experiencing unprecedented rate of growth. There are influxes of
population into the urban areas in seeking of opportunities. In year 2000, the
proportion of the world’s population living in the tropical climate zone was
estimated at about 40% (Landsberg, 1984). World Bank (2002) projected the urban
population in the developing world is expected to increase by about 25–45% except
in Latin America and the Caribbean where the urban population already exceeds
70%) from 1990 to 2020. By 2020, the urban population is expected to be greater
than the rural population in all parts of the world.
Construction is unavoidable in solving the constant increase of population. In
the world most populated nation, China, the housing sector accounted for 40% of
global new building volume in year 2007 (Fernandez, 2007).
Urban areas act as climate modifiers. Climate elements, such as solar
radiation, air temperature, humidity and wind are affected by the urban fabric. These
caused the nocturnal urban-rural temperature differences of 6°C or more in the
centres of major cities (Oke, 1987). The average diurnal temperature rise due to
urbanization is projected to be greater than the estimated 1–3.5°C rise in temperature
due to global climate change over the next 100 years (IPCC, 2001).
Physical environmental issues are also reported as the results of rapid
urbanization. These include air (air pollution), water (floods and storms) and climate
quality (heat waves) (Campbell-Lendrum and Corvalan, 2007).
4
Plagued by financial resources, political will and professional input, rapid
urbanization in developing countries is often negative. It causes poor housing
conditions, poverty, environmental problems, health problems and social issues.
Thus, there is an urge for the urban built-environment planning approaches
which ameliorate the urban climate change. Researchers and urban planners should
therefore take up the challenge to offer their expertise, to help ensure the life quality
of the urban dwellers.
According to Emmanuel (2006), the current trend of emphasis for urban heat
island mitigation has been on ventilation. In his suggestion, the basis for possible
mitigatory approach in tropical cities lies in the provision of urban shade by utilizing
buit-up areas. Not only shade offers further enhancement to the ventilation
mitigation approach, the happy by-product of shade by utilizing urban geometry
approach is the possibility of accommodating very hight density urban living.
1.2 The Problem Statement
The current urban street geometry is mostly governed by various urban
design and planning codes, manuals and standards. The shophouse buildings, which
flank a commercial street, are of low-rise planning. Often, they are not more than 4
stories high. There is no front set back. The building height is controlled according
to council’s plot ratio, but is always built on the development needs. The street width
is planned to accommodate the driveway, parking lots and sometimes landscape
features, which made it between 15 m to 25m. The backlane, if built in minimum
distance, is only 6 m apart (refer table 2.7 for the regulations and codes).
5
When translated to the urban climatic design terms, the current urban design
and planning codes will give a shallow canyon to the entire fabric. There is also no
street orientation consideration as well.
Thus, despite a set of constrained planning rules on the street width and
building height, the most possible variable to be adjusted and utilized is the
colonnade depth. Hence, the focus of this study is to find out the influence of
colonnade depth to the overall microclimate of the urban canopy layer.
Figure 1.1 : Sectional diagram of a typical commercial street in Malaysia
1.3 Research Hypothesis
The hypothesis of this study is that an optimum depth of a colonnade will
achieve the following:
i. Provide adequate shade as an overhead shading shelter.
ii. Reduction of the thermal heat stress of the street.
iii. Thus, creating cooling effect to the street canopy layer.
6
1.4 Research Questions
The following questions will be addressed in this thesis:-
i. What is the depth of the colonnade to provide adequate overhead shading
in different street aspect ratio and orientation?
ii. What is the influence of colonnade depth to the envelope ratio?
iii. What is the influence of envelope ratio in reducing solar radiation
absorption?
iv. What is the influence of colonnade depth in SVF and heat release?
v. Does existing colonnade requirement favour or hinder climate-conscious
urban design?
1.5 Research Gap
Previous reseaches on street design and colonnade were reviewed in order to
get a clear understanding of the shading and thermal heat stress reduction knowledge
and identify the areas which had not been covered in the past. It reviewed that
research on tropical urban street design had been focusing mainly on: solar shading
strategies on urban canopy street, thermal balance and microclimate in urban canopy
layer, and human comfort and perception.
7
Some researches were done in temperate climate and were in the summer
period. They covered both shallow and deep canyon street strategies. Thus, literature
materials can be extracted to review the microclimate on low-rise street canyon.
There are research on the influence and impact of colonnade, but they are
limited to only conventional depth / width. Hence, exploration into various depths
can be carried out.
Table 1.1 : Summary of previous research related to tropical urban street design,
colonnade and urban canopy layer microclimate
Research M
ethodology
Clim
ate
Design Variables Performance Variables H
/W – Shallow
Canyon
H/W
– Deep C
anyon
Orientation
SVF
Envelope R
atio
Colonnade D
epth
Projection Ratio*
Shade
Direct Solar R
adiation
Diffuse Solar R
adiation
Tem
perature
Hum
an Com
fort (PET
)
Morad (1979)
S T √ √ √ √ √ √
H Swaid (1992)
S T √ √ √ √ √ √
H Swaid (1993)
S T √ √ √ √ L √
E Johansson (2006)
S HH √ √ √ L √ √
Shashua Bar (2006)
S T √ √ √ √ L √
R Emannuel (2007)
S HH √ √ √ √ √ √
Ali Toudert (2007)
S HA √ √ √ L √ √
B. Taylor (2008)
S T L √
Present Study (2011)
S HH √ √ √ √ √ √ √ √
* Projection ratio of shading device, adjustable louvers or any kind of overhang
HA Hot Arid HH Hot Humid L Limited depth S Simulation T Temperate
8
1.6 Research Objectives
The main purpose of this study is to study the potential use of colonnade
depth in current shophouse design to lower the overall air temperature in the urban
street microclimate. Other fundamental climatic criterions of the colonnade design
must be fulfilled for hot and humid climate context: overhead shading and provide
enough space as a pedestrian thoroughfare in the urban. It is envisioned that the next
generations of shophouse façade design will be revolutionized. It not just merely
fulfils the basic urban planning and design codes, but incorporates climate-sensitive
principles.
In achieving the above goals, a few objectives are derived.
i. To define the colonnade and street design in Malaysia urban by looking
into the urban planning codes.
ii. To evaluate the climatic impacts of colonnade in current shophouse and
street design in terms of the shade percentage in the colonnade and
contribution to the urban street air temperature.
iii. To determine the depth of the colonnade based on the performance of
shading and street cooling effect.
iv. To determine the influence of aspect ratio (building height to street width
ratio) on the shade and cooling performance of the colonnade.
9
1.7 Scope and Limitations
The study and analysis of the research are limited by the microclimate
evaluation model used. The overall microclimate evaluation concept is built upon the
Cluster Thermal Time Constant model. It is a simple evaluation calculation model to
calculate the air temperature in the urban canopy layer. Envelope Ratio concept is a
further development of CTTC model, which quantifies that the ratio of the ground
surfaces to the overall street envelope surfaces main influence to the heat gain of the
canopy layer. It is, however, limited to the calculation of a symmetrical street.
Further, Ecotect building simulation software is used to run the shading analysis and
solar insolation on facades.
This research concentrates on how colonnade depth impacts the thermal heat
stress in the urban microclimate. The scopes of the research are discussed as
follows:-
(i) The configurations of the colonnade and street will be formulated to
represent the low rise aspect ratio found in Malaysia cities. The street
canyons are made up with aspect ratio of 0.25, 0.50, 1, 2, for both north-
south and east-west oriented street. Street canyons are treated as terraced
building in infinity length. Back lane is not considered. Only street front
with colonnade is considered.
(ii) The study is limited to hot humid climate. Johor Bahru climate data is
selected as input such as base temperature and solar radiation. Data were
obtained from Senai Airport station.
(iii) Dry or wet season is not important in this research. Ground cover and
wall materials are set constant throughout the simulations.
10
(iv) Shading analyses are done on the colonnade facing cardinal directions.
For east and west facing facades, solar angles of 21 June are used.
Whereas for north and south facing facades, solar angles of extreme cases
during summer and winter solstices.
(v) The thermal heat reduction analysis is limited to the microclimate at
street level, i.e. the urban canopy layer, roughly the space between the
ground and the roof tops.
(vi) The main variable in the colonnade is the colonnade depth, which will
influence also the envelope ratio of the street.
(vii) Thermal heat stress reduction will be analysed through absorbed solar
irradiation and net long-wave release on the envelope surfaces. Only
direct beam solar radiation is considered. Anthropogenic heat and all
other types of heat are not considered.
(viii) Solar radiation absorption simulation is based on data on 18 August,
which represents a typical fine and clear day which shows high and
consistent solar radiation through the day. Time period of simulation is
based on the local standard time. Simulated hours will start from 07:00 to
23:00. Diurnal effect applies from 07:00 to 20:00 when the canyon
receives solar radiation. Nocturnal effect applies from 21:00 to 23:00.
11
Figure 1.2 : Main variables for heat stress reduction analysis – Street aspect ratio
(H/W) and Colonnade depth to street width ratio (C/W)
Figure 1.3 : Main variables for shading analysis – Colonnade depth to colonnade
height ratio (Dc/Hc)
12
1.8 Importance of The Research
This research aims to study a possible optimization of existing colonnade to
reduce heat stress in the street canyon. The outcome will be helpful in reducing the
heat island effect and to enhance the usability of the urban outdoor spaces.
The basic function of a colonnade, which is as an overhead shading shelter
(shading between 11:00 to 16:00), will be evaluated. Further, the depth of the
colonnade and its climatic influence will be studied. To the occupants, reduce in
thermal heat stress would mean reduce in cooling load of buildings. So,
improvements on urban microclimate would lead to energy savings. To the
developers and architects, this study opens up new possibilities in architectural
facade design and colonnade design with consideration of climatic design principles.
Figure 1.4 : Requirement of colonnade design chart
Requirement of Colonnade Design
Overhead Shading
shade from 11:00 to 16:00
Pedestrian Thoroughfare
minimum depth of 2.25m
Reducing Heat Stress
Envelope Ratio
13
1.9 Thesis Organization
This thesis report is structured into five chapters as summarized below.
Chapter one is the introductory of this thesis. It tells the background of this
research, the main issues, proposed hypothesis of the study, research questions and
the objectives of the research. Further, research gap, scope and limitations of the
study are further highlighted. The overall thesis structure is presented at the end of
the chapter.
Chapter two reviews the energy balance within the urban canopy layer and
especially the low-rise street canyon. Strategies in improving the urban
microclimate are discussed. The rationale of colonnade design is presented. Johor
Bahru is taken as the study area for this research. A few shophouse developments are
chosen as samples to evaluate the street aspect ratios (as results of existing planning
rules) and colonnades.
Chapter three discusses the methodology implemented in this research.
Available urban canopy layer microclimate evaluation models are reviewed
Experimental needs are determined and appropriate model is then formulated, which
are based on the CTTC (Cluster Thermal Time Constant) mathematical calculation
and Envelope Ratio concept. Further, the mathematical simulation procedure,
assumptions and limitations are described. Validation is done by using Ecotect
simulation software. Finally, the data analysis criterions are discussed, which is used
to analyse the results of the experiment.
Chapter four presents the results and analysis of shading, absorbed solar
radiation, net long-wave radiation loss and cooling effect for the simulated models.
14
The role of urban planning codes is also discussed. The results of the simulations are
analysed based on the following principles:
a. Colonnade depth and shade.
b. Influence of colonnade depth on envelope ratio.
c. Impact of sky view factor on shading on radiation loss.
d. Impact of envelope ratio on canyon cooling effect.
e. Assess the relationship between aspect ratio, orientation and envelope
ratio.
Chapter five sums up the overall thesis, through reviews of the thesis
objectives and research questions. It is followed by the conclusion remarks of the
major findings of the experiment. Envelope Ratio concept and CTTC are reviewed
as well. Finally, other possible areas to be further studied are suggested.
15
Figure 1.5 : The flow of research process and thesis structure
Issues and Problems
Literature Review
Urban Planning Codes, Colonnades and Low-rise
Street Canyon Microclimate
Chapter 2
Methodology (Shading and air
temperature simulations)
Chapter 3
Results and Analysis
Chapter 4
Conclusion
Chapter 5
REFERENCE
Ahmed, K. S. (2003). Comfort in Urban spaces: Defining the Boundaries of Outdoor
Thermal Comfort for the Tropical Urban Environments. Energy and
Buildings, 35 (1), 103-110.
Aida, M. & Gotoh, K. (1982). Urban Albedo as a Function of the Urban Structure —
A Two-Dimensional Numerical Simulation. Boundary-Layer Meteorology,
23(4), 415-424.
Aizenberg, A. (1992). Development of Climatic Urban Design Guidelines Based on
the Analytical CTTC Model for Prediction of Air Temperature Variations.
M.Sc. Thesis (in Hebrew, English summary). Technion, Haifa, Israel.
Akbari, H. (2003). Measured Energy Savings from the Application of Reflective
Roofs in Two Small Non-Residential Buildings. Energy, 28(9), 953–967.
Akbari, H., Levinson, R., Rainer L. (2005). Monitoring the Energy-Use Effects of
Cool Roofs on California Commercial Buildings. Energy and Buildings.
37(10), 1007–1016.
Ali-Toudert, F., and Mayer, H. (2006). Numerical Study on the Effects of Aspect
Ratio and Orientation of An Urban Street Canyon on Outdoor Thermal
Comfort in Hot and Dry Climate. Building and Environment, 41(2006), 94–
108.
141
Ali-Toudert, F., and Mayer, H. (2007). Effects of Asymmetry, Galleries,
Overhanging Facades and Vegetation on Thermal Comfort in Urban Street
Canyons. Solar Energy, 81(6), 742-754.
Arnfield, A.J. (1990a). Street Design and Urban Canyon Solar Access. Energy and
Buildings, 14(2), 117-131.
Arnfield A.J. (1990b). Canyon Geometry, The Urban Fabric and Nocturnal Cooling:
A Simulation Approach. Physical Geography, 11, 220–239.
Arnfield, A.J. (2003). Two Decades of Urban Climate Research: A Review of
Turbulence, Exchanges of Energy and Water, and the Urban Heat Island.
International Journal of Climatology, 23(1), 1-26.
Arnfield, A.J. & Grimmond, C.S.B. (1998). An Urban Canyon Energy Budget
Model and Its Application to Urban Storage Heat Flux Modeling. Energy and
Buildings, 27(1), 61–68.
Aynsley, R. and Gulson, L. (1999). Microclimate and Urban Planning in the Humid
Tropics. In: Planning in the hothouse – 27th National Congress of the Royal
Australian Planning Institute.
Baruch and Givoni (1992). Climatic Aspects of Urban Design in Tropical Regions.
Atmospheric Environment. Part B. Urban Atmosphere, 26(3), 397-406.
Bourbia, F. and Awbi, H. (2004). Building Cluster and Shading in Urban Canyon for
Hot Dry Climate: Part 1: Air and Surface Temperature Measurements.
Renewable energy, 29(2), 249-262.
Campbell-Lendrum, D. & Corvalan, C. (2007). Climate Change and Developing-
Country Cities: Implications for Environmental Health and Equity. Journal
of Urban Health, 84, 109-117.
142
Capeluto, I. (2003). Energy Performance of the Self-Shading Building Envelope.
Energy and Buildings, 35(3), 327-336.
Chan, A. T., Au, W. T. W., So, E. P., (2003). Strategic Guidelines for Street Canyon
Geometry to Achieve Sustainable Street Air Quality—Part II: Multiple
Canopies And Canyons. Atmospheric Environment, 37(20), 2761–2772.
Chia, S. L., Ahmad, M. and Ossen, D. (2007). The Effect of Geometric Shape and
Building Orientation on Minimizing Solar Insolation on High-Rise Buildings
in Hot Humid Climate. Journal of Construction in Developing Countries,
12(1), 27-38.
Corbella OD, Magalhes MAA. (2008). Conceptual Differences Between the
Bioclimatic Urbanism for Europe and for the Tropical Humid Climate.
Renewable Energy, 33(5), 1019-1023.
Coronel, J. F. & Alvarez, S. (2001). Experimental Work and Analysis of Confined
Urban Spaces. Solar Energy, 70(3), 263–273.
Dimoudi, A., Nikopoulou, M. (2003). Vegetation in the Urban Environment:
Microclimatic Analysis and Benefits. Energy and Buildings, 35(1), 69-76.
Drainage and Irrigation Department (2000). Malaysian Urban Stormwater
Management Manual. Kuala Lumpur: Percetakan Nasional Malaysia Berhad.
Eliason, I. (1996). Urban Nocturnal Temperatures, Street Geometry and Land Use.
Atmospheric Environment, 30(3), 379-392.
Elnahas, M. M., and Williamson, T. J. (1997). An Improvement of the CTTC Model
for Predicting Urban Air Temperatures. Energy and Buildings, 25(1), 41-49.
Embi, A. F. B. (2005). What Will It Take to Bring Our Rivers Back to Life?
International Journal of River Basin Management, 3(3), 185-190.
143
Emmanuel, R. (2005). An Urban Approach to Climate-Sensitive Design. Abingdon:
Spon Press.
Emmanuel, R. (2006) Influence of Urban Morphology and Sea Breeze on Hot
Humid Climate. Climate Research, 30, 189–200.
Emmanuel, R., Rosenlund, H., and Johansson, E. (2007). Urban Shading – A Design
Option for the Tropics? A Study in Colombo, Sri Lanka. International
Journal of Climatology, 27(14), 1995-2004.
Erell, E. and Williamson T. (2006). Comments on the Correct Specification of the
Analytical CTTC Model for Predicting the Urban Canopy Layer Temperature.
Energy and Buildings, 38(8), 1015-1021.
Fernández, John E. (2007). Resource Consumption of New Urban Construction in
China. Journal of Industrial Ecology, 11(2), 99–115.
Givoni, B. (1998). Climate Considerations in Building and Urban Design. New
York: Wiley.
Grimmond, C. S. B., Potter, S. K., Zutter, H. N. & Souch, C. (2001). Rapid Methods
to Estimate Sky-View Factors Applied to Urban Areas. International Journal
of Climatology, 21(7), 903–913.
Intergovermental Panel on Climate Change (2001). Climate Change 2001. Web:
GRID-Arendal.
Johansson, E. (2006). Urban Design and Outdoor Thermal Comfort in Warm
Climates. Unpublished Doctoral Dissertation, Lund University.
Khandaker, S. A. (2003). Comfort in Urban Spaces: Defining The Boundaries of
Outdoor Thermal Comfort for the Tropical Urban Environments. Energy and
Buildings, 35(1), 103-110.
144
Knowles, R. (1981). Sun Rhythm Form. MIT Press.
Kubota, T. and Ossen, D. R. (2009). Spatial Characteristics of Urban Heat Island in
Johor Bahru City, Malaysia. Proceedings of the 3rd SEATUC Symposium
(South East Asian Technical Universities Consortium).
Kubota, T. and Supian, A. (2006). Wind Environment Evaluation of Neighborhood
Areas in Major Towns of Malaysia. Journal of Asian Architecture and
Building Engineering, 5(1), 199-206.
Jo, H. K., McPherson, E. G. (2001). Indirect Carbon Reduction by Residential
Vegetation and Planting Strategies in Chicago, USA. Journal of
Environmental Management, 61( 2), 165-177.
Kastner-Klein, P., Plate, E. J. (1999). Wind-Tunnel Study of Concentration Fields in
Street Canyons. Atmospheric Environment, 33(24–25), 3973–3979.
Lam, J. K., Ossen, D. R. and Ahmad, M. (2008). Effect of Urban Geometry on Solar
Insolation Threat in JSNAC (Pilot Study). Proceedings of the 2008 9th
International Seminar in Sustainable Environment & Architecture (SENVAR).
1-3 December. Shah Alam, Selangor: SENVAR + ISESEE 2008: Humanity
+ Technology, 293 – 206.
Landsberg, P.T. (1984). Non-Equilibrium Concepts in Solar Energy Conversion,
Proceedings of the NATO Advanced Study Institute on Energy Transfer
Processes in Condensed Matter, June 16-30, 1983, 537-592.
Lechner, N. (1991). Heating, Cooling, Lighting. Design Methods for Architects. New
York: Wiley Interscience Publication.
Lin, T. (2009). Thermal Perception, Adaptation and Attendance in A Public Square
in Hot and Humid Regions. Building and Environment, 44(10), 2017-2026.
145
Lin, T., Matzarakis, A. and Hwang, R. (2010). Shading Effect on Long-term
Outdoor Thermal Comfort. Building and Environment, 45(1), 213-221.
Littlefair P. (2001). Daylight, Sunlight and Solar Gain in the Urban Environment.
Solar Energy, 70(3), 177-185.
Lu, J., Arya, S. P., Snyder, W. H. & Lawson, R. B. Jr. (1997). A Laboratory Study of
the Urban Heat Island in a Calm and Stably Stratified Environment. Part II:
Velocity Field. Journal of Applied Meteorology, 36(10).
McPherson, E. G., Herrington, L. P. and Heisher, G. (1998). Impacts of Vegetation
on Residential Heating and Cooling. Energy and Buildings, 12, 41-51.
Mills, G. (1997). An Urban Canopy-Layer Climate Model. Theoretical and Applied
Climatology, 57(3-4), 229-244.
Mohsen, M. (1979). Solar Radiation and Courtyard House Forms II: Application of
the Model. Buildings and Environment, 14(3), 185-201.
Moseri, A. (1990). The Inner Courtyard as a Climatic Component in a Residential
Area. Msc. Thesis. Technion, Haifa , Israel .
Muhaisen, A. S. (2006). Shading Simulation of the Courtyard Form in Different
Climatic Regions. Building and Environment, 41(12), 1731–1741.
Nicol, J. and Wong, M. (1996). Mapping and Modeling of Urban Environmental
Quality in Hong Kong. The Department of Land Surveying and Geo-
Informatics, The Hong Kong Polytechnic University.
Offerle B., P. Jonsson, I. Eliasson and Grimmond, C.B.S. (2005). Urban
Modification of The Surface Energy Balance in the West African Sahel:
Ouagadougou, Burkina Faso. Journal of Climate, 18, 3983-3995.
Oke, T. R. (1981). Canyon Geometry and The Nocturnal Heat Island. Comparison of
Scale Model and Field Observations, Journal of Climatology, 1, 237-254.
146
Oke, T. R. (1987). Boundary Layer Climates. Quarterly Journal of the Royal
Meteorological Society, 114(484), 1568.
Oke, T. R. (1988). Street Design and Urban Canopy Layer Climate. Energy
Buildings, 11(1-3): 103 – 113.
Oke, T. R. (1989). The Micrometeorology of the Urban Forest. Philosophical
Transactions of the Royal Society of London. Series B, Biological Sciences,
324, 335-349.
Oke, T. R., G. T. Johnson, D. G. Steyn and I. D. Watson (1991). Simulation of
Surface Urban Heat Islands Under 'Ideal'conditions at Night, Part 2:
Diagnosis of Causation. Earth and Environmental Science. 56(4), 339-358.
Oke, T. R. (2004). Initial Guidance to Obtain Representative Meteorological
Observations at Urban Sites. World Meteorological Organization.
Olgyay, V. (1967). Bioclimatic Orientation Method for Buildings. International
Journal of Biometeorology, 11(2), 163-174.
Pearlmutter, D., Berliner, P. and Shaviv, E. (2007). Integrated Modeling of
Pedestrial Energy Exchange and Thermal Comfort in Urban Street Canyons.
Building and Environment, 42(6), 2396-2409.
Pearlmutter, D., Bitan, A., Berliner, P. (1999). Microclimate Analysis of “Compact”
Urban Canyon s in an Arid Zone. Atmospheric Environment, 33(24–25),
4143–4150.
Ratti, C., Raydan, D. and Steemers, K. (2003). Building Form and Environmental
Performance: Archetypes, Analysis and An Arid Climate. Energy and
Buildings, 35(1), 49-59.
147
Rosenfeld, A. H., Akbari, H., Bretz, S., Fishman, B. L., Kurn, D. M., Sailor, D.,
Taha, H. (1995). Mitigation of Urban Heat Islands: Materials, Utility
Programs, Updates. Journal of Energy and Buildings, 22(1995). 255–265.
Schillers, S. and Evans, J. (1998). Sustainable Urban Development: Design
Guidelines for Warm Humid Cities. Urban Design International, 3(4), 165-
184.
Sharlin, N. and Hoffman, M. E. (1984). The Urban Complex as a Factor in the Air-
temperature Pattern in a Mediterranean Coastal Region. Energy and
Buildings, 7(2), 149-158.
Shashua-Bar, L., Hoffman, M. E. (2000). Vegetation as A Climatic Component in
The Design of An Urban Street. An Empirical Model for Predicting The
Cooling Effect of Urban Green Area With Trees. Energy and Buildings, 31,
221–235.
Shashua-Bar, L., Hoffman, M. E. (2002). The Green CTTC model for predicting the
air temperature in small urban wooded sites. Building and Environment,
37(12), 1279-1288.
Shashua-Bar, L., Hoffman, M. E. and Tzamir, Y. (2004). Thermal Effects of
Building Geometry and Spacing on the Urban Canopy Layer Microclimate in
A Hot-Humid Climate in Summer. International Journal of Climatology,
24(13), 1729-1742.
Shashua-Bar, L., Hoffman, M. E. and Tzamir, Y. (2006). Integrated Thermal Stress
Effects of Generic Built Forms and Vegetation on the UCL Microclimate.
Building and Environment, 41(3), 343-354.
Steemers, K., Baker, N., Crowther, D., Dubiel, J. & Nikolopoulou, M. (1998).
Radiation Absorption and Urban Texture. Building Research & Information,
26(2), 1998.
148
Swaid, H. (1992). Intelligent Urban Forms (IUF): A New Climate-concerned Urban
Planning Strategy. Theoretical and Applied Climatology, 46(2), 179-191.
Swaid, H. Bar-El, M. and Hoffman, M. E. (1993). A Bioclimatic Design
Methodology for Urban Outdoor Spaces. Theoretical and Applied
Climatology, 48(1), 49-61.
Swaid, H., Hoffman, M. E. (1990a). Prediction of Urban Air Temperature Variations
Using the Analytical CTTC Model. Journal of Energy and Buildings, 14(4),
313-324.
Swaid, H., Hoffman, M. E. (1990b). Climatic Impacts of Urban Design Features for
High and Mid-latitude cities. Journal of Energy and Buildings, 14(4), 325-
336.
Taylor, B. and Guthrie, P. (2008). The First Line of Defence: Passive Design at an
Urban Scale. Proceedings of Air Conditioning and the Low Carbon Cooling
Challenge, Widsor.
Todhunter, P. E. (1990). The Response of Urban Canyon Energy Budgets to
Variable Synoptic Weather Types – A Simulation Approach. Atmospheric
Environment. Part B. Urban Atmosphere. 24(1), 35–42.
Voogt, J. A. & Oke, T. R. (1990).Validation of an Urban Canyon Radiation Model
for Nocturnal Long-Wave Fluxes. Boundary-Layer Meteorology, 54(4), 347-
36.
Wong, N. H. (2005). Study of Green Areas and Urban Heat Island in a Tropical City.
Habitat International, 29(3), 547-558.
World Bank (2002). World Development Report 2002: Building Institutions for
Markets. USA: Oxford University Press.
149
Xie, X., Huang, Z., Wang, J., Xie, Z., (2005). The Impact of Solar Radiation And
Street Layout on Pollutant Dispersion in Street Canyon. Building and
Environment, 40, 201-212.
Yezioro, A., Shaviv, E. (1994). Shading: A Design Tool for Analyzing Mutual
Shading between Buildings. Solar Energy, 52(1), 27–37.
Yezioro, A., Capeluto, I. G. and Shaviv, E. (2006). Design Guidelines for
Appropriate Insolation of Urban Squares. Renewable Energy, 31(7), 1011-
1023.