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Daylighting in Riyadh and Los Angeles: comparison of cultural factors in potential market penetration

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Daylighting in Riyadh and Los Angeles: comparison of cultural factors in potential market penetration

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Content 1

Daylighting in Riyadh and Los Angeles
Comparison of Cultural Factors in Potential Market Penetration

by
Mohammed Aljammaz

May 2016
Presented to the
FACULTY OF THE USC SCHOOL OF ARCHITECTURE
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
MASTER OF BUILDING SCIENCE
2

Committee Chair:

Professor Marc Schiler
School of Architecture
University of Southern California
marcs@usc.edu

Committee Members:

Professor Joon-Ho Choi, Ph.D
School of Architecture
University of Southern California
joonhoch@usc.edu

Professor Goetz Schierle, Ph.D, FAIA
School of Architecture
University of Southern California
schierle@usc.edu

Professor Douglas Noble, FAIA, Ph.D
School of Architecture
University of Southern California
dnoble@usc.edu
3

Table of Contents

ABSTRACT ................................................................................................................................................... 13
Hypothesis .................................................................................................................................................. 13

Chapter 1 : Introduction ............................................................................................................................. 15
1.1. Introduction ......................................................................................................................................... 16
1.1.1. Hypothesis Statement ............................................................................................................... 17
1.2. The Importance of Daylight ................................................................................................................ 17
1.2.1. Daylight is a Relevant Design Factor ......................................................................................... 17
1.2.2. Daylight Can Reduce the Cost of the Building .......................................................................... 18
1.2.3. Daylight Provides a Great Indoor Environmental Quality. ........................................................ 19
1.3. Terms ................................................................................................................................................... 21
1.3.1. Daylighting ................................................................................................................................ 21
1.3.2. Lighting Tube ............................................................................................................................. 21
1.3.3. Hybrid Lighting System ............................................................................................................. 21
1.3.4. Glare .......................................................................................................................................... 21
1.3.5. Illuminance ................................................................................................................................ 21
1.3.6. Luminance ................................................................................................................................. 21
1.3.7. Luminous Intensity .................................................................................................................... 21
1.4. The Context of Saudi Arabia ............................................................................................................... 22
1.4.1. Geographic Position & Natural Resources ................................................................................ 22
1.4.2. Population ................................................................................................................................. 23
1.4.3. Political System and Culture ..................................................................................................... 23
1.5. Riyadh .................................................................................................................................................. 23
1.5.1 The Culture in Riyadh, Saudi Arabia .......................................................................................... 23
4

1.5.2. The Influence of Riyadh Culture on Architecture, and How the Culture of Riyadh Affects the
Buildings and Architecture .................................................................................................................. 24
1.5.3. Riyadh Climate .......................................................................................................................... 26
1.5.4. Riyadh Architecture in Response to the Climate ...................................................................... 28
1.5.5. Saudi People in their Houses. ................................................................................................... 34
1.5.6. Natural Lighting Systems Challenges ........................................................................................ 34
1.6. Los Angeles Climate ............................................................................................................................ 35

Chapter 2: An Overview of Daylighting Systems ....................................................................................... 38
2.1 The Concept of a Daylighting System .................................................................................................. 39
2.2 Anidolic System .................................................................................................................................... 39
2.2.1 Anidolic Ceiling .......................................................................................................................... 41
2.2.2 Integrated Anidolic System ....................................................................................................... 41
2.2.3 Anidolic Solar Blinds .................................................................................................................. 43
2.3 Reflective Tube ..................................................................................................................................... 43
2.3.1. Description of Embodiment Lighting Tube ............................................................................... 44
2.4 Hybrid Daylighting Systems ................................................................................................................. 46
2.4.1. Hybrid Solar Lighting ................................................................................................................. 47
2.4.2. LED Lighting Tube system: ........................................................................................................ 48
2.5 Prismatic System .................................................................................................................................. 49
2.6. Glare .................................................................................................................................................... 49

Chapter 3: Research Methodology ............................................................................................................ 50
3.1. Overview of Methodology .................................................................................................................. 51
3.2. Privacy ................................................................................................................................................. 51
3.3 Climate .................................................................................................................................................. 55
3.4. Site Case Study .................................................................................................................................... 55
3.5. Glare Analysis ...................................................................................................................................... 56
5

3.5.1. Hdrscope ................................................................................................................................... 57
3.6. Illuminance Analysis ............................................................................................................................ 58
3.7. Heat and Energy Analysis .................................................................................................................... 58
3.8. Chapter Summary................................................................................................................................ 58

Chapter 4 .................................................................................................................................................... 60
4.1. Introduction ......................................................................................................................................... 61
4.2. Lighting Tube and the Model .............................................................................................................. 62
4.2.1. Los Angeles Revit Model .......................................................................................................... 63
4.2.2. Riyadh Revit Model ................................................................................................................... 64
4.3. Riyadh Illuminance Tests .................................................................................................................... 65
4.3.1. Riyadh Scenario #1 in Autodesk 360 ......................................................................................... 65
4.3.2. Riyadh Scenario #2 in Autodesk 360 ......................................................................................... 66
4.3.3. Riyadh Scenario #1 in 3ds Max ................................................................................................. 67
4.3.4. Riyadh Scenario #2 in 3ds Max ................................................................................................. 70
4.4. Los Angeles Illuminance Tests ............................................................................................................ 73
4.4.1. Los Angeles Scenario #1 in Autodesk 360 ................................................................................. 73
4.4.2. Los Angeles Scenario #2 in Autodesk 360 ................................................................................ 73
4.4.3. More Data Autodesk 360. ......................................................................................................... 75
4.4.4. 3ds max Los Angeles Plan 4 Lighting Tubes and Curtain Wall .................................................. 76
4.4.5. Los Angeles Scenario #1 in 3ds Max ......................................................................................... 79
4.5. Survey Data......................................................................................................................................... 82
4.5.1. Riyadh Survey Data ................................................................................................................... 82
4.5.2. Los Angeles Survey Data ........................................................................................................... 85
4.6. Heat and Energy .................................................................................................................................. 88
4.6.1. Los Angeles Heat and Energy .................................................................................................... 88
4.6.2. Riyadh Heat and Energy ............................................................................................................ 90
4.7. Glare Tests ........................................................................................................................................... 92
6

4.7.1. Los Angeles Glare Test .............................................................................................................. 92
4.7.2. Riyadh Glare Test ...................................................................................................................... 95
4.8. Chapter Summary................................................................................................................................ 98

Chapter 5 .................................................................................................................................................... 99
5.1. Introduction ....................................................................................................................................... 100
5.2. The Old City Visit Observations ........................................................................................................ 100
5.3. Riyadh Illuminance Analysis ............................................................................................................. 102
5.3.1. Riyadh Scenario #1 in Autodesk 360 ....................................................................................... 102
5.3.2 . Riyadh Scenario #2 in Autodesk 360 ....................................................................................... 103
5.3.3. Riyadh Scenario #1 in 3ds max ................................................................................................ 104
5.3.4. Riyadh Scenario #2 in 3ds max ................................................................................................ 105
5.4. Los Angeles Illuminance Analysis ..................................................................................................... 105
5.4.1. Los Angeles Scenario #1 in Autodesk 360 .............................................................................. 105
5.4.2. Los Angeles Scenario #2 in Autodesk 360 ............................................................................... 106
5.4.3. Los Angeles Scenario #1 in 3ds max ........................................................................................ 107
5.4.4 Los Angeles Scenario #2 in 3ds Max ....................................................................................... 108
5.4.5. Discussion of Survey Results ................................................................................................... 108
5.5. Survey Analyses ................................................................................................................................. 108
5.5.1. Categorizing Participants ........................................................................................................ 108
5.5.2. Window Type Preferences ...................................................................................................... 109
5.5.3. Daily Use of Windows ............................................................................................................. 109
5.5.4. Conclusions Drawn from Survey Results................................................................................. 110
5.6. Energy and Heat ................................................................................................................................ 111
5.6.1. Los Angeles Energy and Heat .................................................................................................. 111
5.6.2. Riyadh Energy and Heat .......................................................................................................... 111
5.7. Glare .................................................................................................................................................. 112
5.7.1. Riyadh and Los Angeles at 9:30am ......................................................................................... 112
7

5.7.2. Riyadh and Los Angeles at 10:30am ....................................................................................... 113
5.7.3. Riyadh and Los Angeles at 11:30am ....................................................................................... 114
5.8. Summary ............................................................................................................................................ 115

Chapter 6 .................................................................................................................................................. 116
6.1. Summary ................................................................................................................................... 117
6.1.1. Research Scope ....................................................................................................................... 118
6.2. Research Obstacles ........................................................................................................................... 118
6.2.1 The Daylighting Tube Model .................................................................................................... 118
6.2.2. Illuminance .............................................................................................................................. 118
6.2.3. Glare ........................................................................................................................................ 118
6.3. Future Work ....................................................................................................................................... 119
6.4. Conclusion .......................................................................................................................................... 119

REFERENCES. ................................................................................................................................. 120

8

Table of figures
Figure 0.1 Latitude of Los Angeles .............................................................................................................. 13
Figure 0.2 Latitude of Riyadh ...................................................................................................................... 13
Figure 0.3 The amount of daylight in living room from a window in Riyadh and Los Angeles. .................. 14
Figure 1.1 Examples of three traditional ways to get daylight into a building ........................................... 16
Figure 1.2 The Karnak daylight system ....................................................................................................... 17
Figure 1.3 The energy percentage for the lighting used in different buildings. ......................................... 18
Figure 1.4 The categories for LEED certification ......................................................................................... 20
Figure 1.5 A section view of a lighting tube ............................................................................................... 21
Figure 1.6 Saudi Arabia map ....................................................................................................................... 22
Figure 1.7 A courtyard space in an apartment building.............................................................................. 25
Figure 1.8 An example of the size and closed condition of windows ......................................................... 25
Figure 1.9 An owner decided that the solid wall around his property was not sufficient, so he added
extra wall above. ......................................................................................................................................... 25
Figure 1.10 Riyadh annual temperature range ........................................................................................... 26
Figure 1.11 Riyadh annual sky cover range ................................................................................................ 26
Figure 1.12 Riyadh monthly diurnal averages ............................................................................................ 27
Figure 1.13 Riyadh time table plot .............................................................................................................. 27
Figure 1.14 Riyadh dry bulb x relative humidity ......................................................................................... 27
Figure 1.15 Riyadh sun shading chart ......................................................................................................... 28
Figure 1.16 Riyadh psychometric chart ...................................................................................................... 28
Figure 1.17 Hijazi style ................................................................................................................................ 29
Figure 1.18 Najdi style ................................................................................................................................ 29
Figure 1.19 Southern style .......................................................................................................................... 29
Figure 1.20 Old Najdy style, the structure of the roof. ............................................................................... 31
Figure 1.21 Old Najdy Style, overhang. ....................................................................................................... 31
Figure 1.22 Old Najdy Style courtyard. ....................................................................................................... 31
Figure 1.23 Urban for old Riyadh and how the different heights create shadows..................................... 32
9

Figure 1.24 Old Najedy streets, very narrow which creates more shadows .............................................. 32
Figure 1.25 Najedy courtyard ..................................................................................................................... 33
Figure 1.26 Some houses built the second floor above the street to create shade. .................................. 33
Figure 1.27 Small windows and thick walls ................................................................................................. 33
Figure 1.28 Los Angeles temperature range ............................................................................................. 35
Figure 1.29 Los Angeles monthly diurnal averages .................................................................................... 35
Figure 1.30 Los Angeles sky cover range .................................................................................................... 36
Figure 1.31 Los Angeles dry bulb x relative humidity ................................................................................. 36
Figure 1.32 Los Angeles sun shading chart ................................................................................................. 36
Figure 1.33 Los Angeles, time table plot ..................................................................................................... 37
Figure 1.34 Los Angeles psychometric chart .............................................................................................. 37
Figure 2.1 The angle for anidolic system .................................................................................................... 39
Figure 2.2 (a) Section details of the device (b) The light directions after it is diffused .............................. 40
Figure 2.3 Detiles of the integrated anidolic system .................................................................................. 42
Figure 2.4 Anidolic ceiling, A duct technique. B section details. ................................................................ 42
Figure 2.5 Anidolic system theory ............................................................................................................... 42
Figure 2.6 3D grid outside and inside ......................................................................................................... 43
Figure 2.7 Anidolic solar blinds model outside, and inside ........................................................................ 43
Figure 2.8 Embodiment lighting tube ......................................................................................................... 45
Figure 2.9 Embodiment lighting tube ......................................................................................................... 45
Figure 2.10 Embodiment lighting tube ....................................................................................................... 45
Figure 2.11 Day lighting tube technique ..................................................................................................... 45
Figure 2.12 Hybrid solar lighting collector .................................................................................................. 47
Figure 2.13 Hybrid solar lighting collector details ...................................................................................... 47
Figure 2.14 Example of the LED daylighting system ................................................................................... 48
Figure 2.15 Prismatic ystem ........................................................................................................................ 49
Figure 3.1 The old town befor rebuild it ..................................................................................................... 55
Figure 3.2 The old town after rebuild it ...................................................................................................... 55
10

Figure 3.3 The tools for the glare test ......................................................................................................... 56
Figure 3.4 Hdrscope .................................................................................................................................... 57
Figure 3.5 Methodology: how the five stages of the research was conducted. ......................................... 59
Figure 4.1 Lighting tube elements modeled in Revit .................................................................................. 62
Figure 4.2 Los Angeles living room floor plan ............................................................................................. 63
Figure 4.3 The assembly of the exterior walls modeled in Revit ................................................................ 63
Figure 4.4 A section view of the Los Angeles living room ........................................................................... 63
Figure 4.5 Section view of the Riyadh living room ...................................................................................... 64
Figure 4.6 The assembly of the exterior walls ............................................................................................ 64
Figure 4.7 Riyadh living room floor plan ..................................................................................................... 64
Figure 4.8 Riyadh scenario #1 at 1:00 pm facing east, tested in Autodesk 360 ......................................... 65
Figure 4.9 Riyadh test (2) at 1:00 pm facing east, Autodesk 360 ............................................................... 66
Figure 4.103ds max illuminance in Riyadh 4 daylighting tubes and 8 windows 3’x3’ 21 June at 1:00pm . 67
Figure 4.11 3ds max illuminance in Riyadh 4 daylighting tubes and 8 windows 3’x3’ 21 September at
1:00pm ........................................................................................................................................................ 68
Figure 4.12 3ds max illuminance Riyadh 4 daylighting tubes and 8 windows 3’x3’ 21 December at 1:00pm
.................................................................................................................................................................... 69
Figure 4.13 3ds max illuminance Riyadh daylighting with 4 daylighting tubes and no windows (June 21)
at 1:00pm .................................................................................................................................................... 70
Figure 4.14 3ds max illuminance Riyadh daylighting with 4 daylighting tubes and no windows 21
September at 1:00pm ................................................................................................................................. 71
Figure 4.15 3ds max illuminance Riyadh daylighting with 4 daylighting tubes and no windows 21
December at1:00pm ................................................................................................................................... 72
Figure 4.16 Los Angeles test (1) at 1:00 pm facing east, Autodesk 360 ..................................................... 73
Figure 4.17 Los Angeles test (2) at 1:00 pm facing east, Autodesk 360 ..................................................... 74
Figure 4.18 Los Angeles test (1) with increasing the scale colors to 1000 foot-candles ............................ 75
Figure 4.19 Los Angeles test (2) with increasing the scale colors to 1000 foot-candles. ........................... 75
Figure 4.20 Riyadh scenario #1 facing west June 21 at 1:00pm ................................................................. 75
Figure 4.21 3ds max Los Angeles plan 4 daylighting tubes and curtain wall 21 June 1:00pm ................... 76
Figure 4.22 3ds max Los Angeles plan 4 daylighting tubes and curtain wall 21 September at 1:00pm ..... 77
11

Figure 4.23 3ds max Los Angeles plan 4 daylighting tubes and curtain wall 21 December at 1:00pm ...... 78
Figure 4.24 3ds max Los Angeles plan with curtain wall and no daylighting tubes 21 June at 1:00pm ..... 79
Figure 4.25 3ds max Los Angeles plan with curtain wall and no daylighting tubes 21 September 1:00pm
.................................................................................................................................................................... 80
Figure 4.26 3ds max Los Angeles plan with curtain wall and no daylighting tube 21 December at 1:00pm
.................................................................................................................................................................... 81
Figure 4.27 Glare analysis in Los Angeles at 9:30am .................................................................................. 92
Figure 4.28 Glare analysis in Los Angeles at 10:30am ................................................................................ 93
Figure 4.29 Glare analysis in Los Angeles at 11:30 am ............................................................................... 94
Figure 4.30 Glare analysis in Riyadh at 9:30am .......................................................................................... 95
Figure 4.31 Glare analysis in Riyadh at 10:30 am ....................................................................................... 96
Figure 4.32 Glare analysis in Riyadh at 11:30am ........................................................................................ 97
Figure 5.1he old Riyadh layout ................................................................................................................. 100
Figure 5.2 Roof constructed from palm leaves ......................................................................................... 101
Figure 5.3 Wshiger “the old city” .............................................................................................................. 102
Figure 5.4 How is the thickness of the wall effect on the direction of the daylight reflect though the
windows. ................................................................................................................................................... 102
Figure 5.5 Lighting zones........................................................................................................................... 104
Figure 5.6 The plot compares the first illuminance horizontal line in #1 3ds max plans. The line is 30 feet
width divided to 13 points, the window on the left of the chart. The numbers in the graph are Fc. ...... 104
Figure 5.7 The plot compares the fourth illuminance horizontal line in #2 3ds max plans. The line is 30
feet width divided to 13 points, the window on the left of the chart. The numbers in the graph are Fc.
.................................................................................................................................................................. 105
Figure 5.8 Los Angeles illuminance analyses, daylighting tubes. .............................................................. 105
Figure 5.9 Los Angeles illuminance analyses, no daylighting tubes. ........................................................ 106
Figure 5.10 the plot compares the first illuminance horizontal line in Los Angeles scenario #1 in 3ds Max
plans. The line is 30 feet width divided to 13 points, the window on the left of the chart. The numbers in
the graph are Fc. ....................................................................................................................................... 107
Figure 5.11 the plot compares the first illuminance horizontal line in Los Angeles scenario #2 in 3ds max
plans. The line is 30 feet width divided to 13 points, the window on the left of the chart. The numbers in
the graph are Fc. ....................................................................................................................................... 108
Figure 5.12 Bar charts show the energy different in Riyadh with windows and without windows. ........ 111
12

Figure 5.13 Riyadh histogram at 9:30 am 10 January 2016 ...................................................................... 112
Figure 5.14 Los Angeles histogram at 9:30am 21 January 2016 ............................................................... 112
Figure 5.15 Riyadh histogram at 10:30am 10 January 2016 ..................................................................... 113
Figure 5.16 Los Angeles at 10:30am histogram 21 January 2016 ............................................................. 113
Figure 5.17 shows the high glare in the yellow Squares .......................................................................... 113
Figure 5.18 Riyadh histogram at 11:30am 13 January 2016 ..................................................................... 114
Figure 5.19 Los Angeles histogram at 11:30am 15 January 2016 ............................................................. 114
Figure 5.20 discomfort glare in the red shape .......................................................................................... 114
Figure 6.1 3ds max Los Angeles plan 4 daylighting tubes and curtain wall 21 June 1:00pm .................. 118

13

ABSTRACT
Choosing an effective daylighting mechanism for a home is a function of its environment: both the
climate and the culture. Two distinct locations, Los Angeles, California and Riyadh, Saudi Arabia, are
used to compare the use of light tubes to improve the amount of daylight penetrating a residential space.
During the daytime in Los Angeles (Latitude 34 N), people receive natural light through the windows of
their homes. As a consequence of this preference, lighting systems such as daylighting tubes are often
unnecessary because the daylighting through the traditional windows exceeds the minimum design level.
In contrast, the residential building interiors in Riyadh (Latitude 24 N) do not achieve the minimum
illuminance from the daylight from the windows due to issues and concerns with glare and privacy.
Because of the discomfort caused by glare and the culturally-founded concerns regarding privacy, the
windows in Riyadh are commonly small and people often keep the curtains closed at all times.
Daylighting tubes would allow the residential interiors to achieve the minimum illuminance from
daylighting, while also addressing the issues of glare and privacy. Although lighting tubes can be used in
any climate and country, certain circumstances make the use of lighting tubes more beneficial. To
determine this, four elements were studied, tested, and compared. The four factors were glare, privacy,
heat gain, and energy. There are multiple computer programs available to test glare. Hdrscope was chosen
because it is one of the best glare programs. A survey was used to analyze and compare the differing
levels of the privacy needs of both cities. Heat and energy were examined by using the energy modeling
program Integrated Environmental Solutions (IES). The objective is to provide an overview of all
common daylighting systems and prove that lighting tubes are more efficient in certain cities and cultures.
The effectiveness of a daylighting system relies on more than just climate and sun exposure; cultural
norms and traditions also play an important role in determining the optimal lighting system, (Alam, n.d.).
Hypothesis
Lighting tubes are more beneficial in achieving the minimum illuminance in residential building in cities
with specific cultural norms and values that affect the size and use of windows. In Los Angeles (at 34 N
Latitude), California, residential buildings often achieve the minimum light levels through large windows.
In Riyadh, (at 24 N Lat) Saudi Arabia, where the windows are culturally smaller or absent, a lighting tube
should be installed to achieve the minimum illuminance of daylighting needed in the residential homes.

Figure 0.2 Latitude of Riyadh

Figure 0.1 Latitude of Los Angeles
14

Figure 0.3 The amount of daylight in living room from a window in Riyadh and Los Angeles.

15

1. Chapter 1 : Introduction

16

1.1. Introduction

Daylight is essential not just for productivity, but also for the human body. If the body does not have
enough exposure to daylight, there is a risk of vitamin D deficiency. Vitamin D deficiency not only
causes generalized muscle weakness, muscle aches, and bone aches and pains, but can also lead to and
exacerbate osteoporosis and osteomalacia (Holick 2002) However, humans cannot live in unprotected
open space; they need to have access to sheltered and controlled environments where air quality,
temperature, and light levels can be managed. Air and light in the homes were first controlled through
walls and windows. Over time, buildings became bigger and the need for artificial lighting increased.
With less exposure to natural light, people started to experience health problems. When energy costs
increased, artificial lighting became more expensive. This led to an increased focus on bringing in more
daylighting into buildings through various techniques. The three most common strategies are sidelights,
skylights, and atriums (Figure 1.1). These strategies were used independently or in conjunction with each
other to maximize daylighting in buildings. The presence of natural light leads to more comfortable, less
stressful, and overall healthier environments for the occupants (Schiler 1992). An additional benefit of
maximizing daylighting in a building is saving energy and, consequently, money. However, daylighting
through traditional sidelights has its limitations as the light cannot penetrate deeply into space, it only
lights the perimeter zones of the building. (Gentile, Dubois, and Laike 2015)

The interest in introducing more daylight and transferring it more deeply into the building sparked many
lighting system ideas, such as single large rotating panels, overhangs, mirrors, louvers, light shelves, and
lenses. All these techniques are used to make the light more controlled and reach more of the floor plan
with less glare. After time and with more technologic advancements, these techniques were developed
further into products like reflective tubes, prismatic systems, lighting shelves, and holographic diffraction
system.

Figure 1.1 Examples of three traditional ways to get daylight into a building (Peng-Chih Wang, August 1993)

17

1.1.1. Hypothesis Statement
Daylighting tubes are more beneficial in achieving minimum illuminance in homes in cities with specific
cultural norms and values that affect the size and use of windows. In Los Angeles (at 34 N Lat),
California, residential buildings often achieve the minimum light level through large windows. In Riyadh,
Saudi Arabia, where the windows are culturally smaller or absent, daylighting tubes should be installed to
achieve the minimum illuminance of daylighting in the residential homes.

1.2. The Importance of Daylight
1. Daylight is a relevant design factor.
2. Daylight can reduce the energy cost of the building.
3. Daylight provides a greater indoor environmental quality than electrical lighting alone.
1.2.1. Daylight is a Relevant Design Factor
The natural light inside the building is a critical factor to consider during design. It improves the interior
aesthetic of the building and the comfort of the occupants. Daylighting must be regarded early in the
design process because of the impact of the site’s location and building’s orientation on its solar access. A
designer must consider the positioning and size of windows in relation to the sun path. This design
mentality dates back thousands of years. For example, the vernacular architecture in Ancient Egypt
oriented temples based on the sun. The Ancient Egyptians so valued the sun, that they worshipped the sun
as one of their gods. These temples were designed so that that the sun’s rays entered the temple at a
particular angle, illuminating the face of the statues inside at the center of their most holy temples at a
specific time in every year. Most of the temples in Egypt were built on the axis (East - West). The
entrance to the temple in the east and the Holy of Holies on the west side so as to allow sunlight to enter
the temple and light the “Sun God” statue in a particular time. One of the temples of the sun god is
Karnak, where each year the sun lights up the center of the temple for one day every year (Figure 0.2).
Most of these temples which were moved, no longer function as originally designed and intended as the
temples no longer align with the sun. This is an example of how architecture was designed with both the
climate and the culture in mind. Not only did this temple introduce light into the interior, it was done so
precisely using the natural daylight.

Figure 1.2 The Karnak daylight system (Peng-Chih Wang1993)
18

1.2.2. Daylight Can Reduce the Cost of the Building

Natural light is free, so why don’t people use it as much as they can? The price of energy is based on the
country’s resources, therefore the countries who belong to the Organization of Petroleum Exporting
Countries (OPEC) have lower costs of electricity than other countries. However, in general, the amount
spent on artificial lighting is between 14% to 45% of the building's total energy costs (Figure 1.4).
Sunlight offers about 10,000 footcandles (10764 lux); indoor spaces only need between )50 to 120 foot-
candles) (538-1291 lux). (Table 1.1). If we can take advantage of the sunlight, we do not need to rely as
heavily on artificial light during the day. With increasing energy costs, the consumer will begin to become
more and more conscious of the amount of energy they are consuming. As a result, it will become even
more important for families to reduce their energy bills at home in any way that they can.

In a building with a large footprint, the windows are not enough because the light through windows do
not fully penetrate into the interior spaces of the building (“Technology | Irts” 2016). As a result, there
are other systems used to get more daylight where there are no windows, such as a skylight if the building
is a single story. Mirror or lensed systems can be usee if the space is huge or some partitions block the
light from going deep into the building, as open space offices where there are big space, and there are
many employee and partitions around them (Harvey 2009).

Figure 1.3 The energy percentage for the lighting used in different buildings.
Daylighting parameters: lumens/watt, solar heat gain, illuminance (Rosenfeld; Selkowitz. Energy and Building, 1977: p.44)

19

Table 1.1 Daylighting parameters: lumens/watt, solar heat gain, illuminance
Direct beam Skylight (incident on vertical window)
1. Lumen/watt
a. Measured, clear
day.
b. Nominal values

106 +.- 2
100

116 +,- 7
120
2. Solar heat gain (btu/ft
2
h)
300

35
3. Illuminance
(footcandles)

9000

1200
Source: Rosenfeld 1977, p.44.

1.2.3. Daylight Provides a Great Indoor Environmental Quality.

Why do people like or dislike a building? If a group of people were taken to multiple buildings and, in the
end, asked the question “which building did you feel most comfortable in?” the results will almost always
be the same. This answer is because the buildings with the greatest indoor environmental qualities will be
the most pleasant and appealing buildings to be in. According to the LEED Green Associate book, to
achieve high indoor environmental quality, the building should have good odor quality, sound quality,
lighting quality, thermal comfort quality, and air quality (figure 1.4). To achieve the desired lighting
quality level, a given building needs sufficient daylight entering the space. Because of the environmental
and health impacts, natural light is required for LEED certification in lighting quality category.

20

Figure 1.4 The categories for LEED certification

21

1.3. Terms
1.3.1. Daylighting
Daylighting is utilizing natural light from the sun to illuminate the interior of a building. There are several
different ways to harness daylight such as windows, skylights, and atriums.

1.3.2. Lighting Tube
“Lighting tube”, “reflective tube”, or “solar tube” are all synonyms for a system that transfers daylight
into a building. It is a cylindrical tube with a very highly reflective material lining inside. The tube
structure is attached to the roof with a dome on the outside to allow the sun to enter the tube and reflect
down to a diffuser in the ceiling of
the room (Figures 8.9). Chapter 2
describes this system in more
detail. (Hoy, Cunagin, and
Hopkins 2003)

1.3.3. Hybrid Lighting System
A “hybrid lighting system” is a
technique that uses natural light
and artificial light together. The
system has a sensor to manage
how much daylight is available. If
the daylight alone is sufficient to
achieve the minimum, the system
will only divert the daylight and
not utilize artificial light. If the
weather conditions are such that
not enough natural light is
accessible, the sensor will turn on
the artificial light until the fixture
achieves the minimum level.

1.3.4. Glare
Glare occurs when there is a difficulty seeing because of the brightness of incoming light, such as direct
sunlight or reflections from the sun. Depending on the level of glare, the consequence can range from
discomfort to visual disability.
1.3.5. Illuminance
Illuminance is the amount of light that hits a surface and is measured in footcandles or lux (Schiler 1992).

1.3.6. Luminance
Luminance is the amount of light that passes through a material or is reflected from a surface. It is
measured in candela per square meter (cd/m
2
) (Schiler 1992).
1.3.7. Luminous Intensity
Luminous intensity is the amount of light from the source in a particular direction and specific angle,
measured in Candela (Schiler 1992).
Figure 1.5 A section view of a lighting tube (“ISKRAMBOL: SOLAR
BOTTLE BULB – TRUELY GREEN” 2014)

22

1.4. The Context of Saudi Arabia
The following overview of the geographic, economic, political, and cultural development of Saudi Arabia
sets the stage to examine the research location of Riyadh, the capital city of Saudi Arabia.
1.4.1. Geographic Position & Natural Resources
The Kingdom of Saudi Arabia is a country in southwest Asia and constitutes the biggest part of the
Arabian Peninsula as an area of about two million square kilometers. Saudi Arabia is bounded on the
north by Iraq, and Jordan, Kuwait from the north-east, and from the east bordered by Qatar and the United
Arab Emirates. Recent geological studies have shown that thousands of years ago, the Arabian Peninsula
was a green oasis with rivers and diverse manifestations of life, which made it a suitable place for human
life since ancient times. Though the large land mass has a diverse topography, large areas of desert now
occupy the region.

Figure 1.6 Saudi Arabia map
(“Introducing Sharat Pani Our Newest SCiPE Member from Riyadh, Saudi Arabia | IADH Edu-Blog” 2015)

23

Saudi Arabia has varied terrains including mountain ranges, valleys, dunes, hills, and plains. It includes
stretches of coast line bordering the Red Sea and the Persian Gulf. The south-eastern portion of the
country hosts the Empty Quarter Desert, the second largest desert in the world, which consists of sand
dunes and mashes. Desert Dahna is a red sand desert in the middle of the Arabian Peninsula, to the north
of the Empty Quarter desert. The Great Start Nafud desert is the largest in Saudi Arabia; it spans from
Zulfi city in the central region through Al-Qassim and Hail to the north. Salt marshes and sand areas
make up the eastern coastal plain of the Arabian Gulf (Saudi Geological Survey).
Currently, Saudi Arabia is predominantly in drought conditions, and there are no permanent rivers or
waterways. Although the dry valleys in most parts flood with water after rainstorms, water cannot be
collected or stored, due to rapid evaporation and leakage into the ground.
The natural resources available in the Arabian Peninsula have afforded the countries within the region a
strong economic significance and role on the international stage. In particular, the discovery of vast oil
reserves in Saudi Arabia has been critical to its economic development.
1.4.2. Population
In 2014, the population of Saudi Arabia was about 30,770,000 with a growth rate of 2.6% and a density of
about 15 people/km^2. The number of Saudi Nationals are 20,700,058 people which are 67% of the total
population, the other 33% (10,070,000 people) are non-Saudi. 65.6% of the population lives in the main
cities such as the Riyadh region and the Mecca and the Eastern region, the rest are distributed to the other
towns and villages. [Central Department of Statistics & Information]. The national language is Arabic.
Islam is the dominant religion in the country. 97% of the total population practices Islam, and 100% of
Saudi citizens are Muslim. The official and dominant character in Saudi Arabia is Sunni Islam. The
majority of workers in Saudi Arabia are Muslims, with a smaller representation of Christians, Hindus, and
Buddhists (only 3%). You have to be Muslim to apply for Saudi citizenship. [Kingdom of Saudi Arabia,
Ministry of Interior, Ministerial Agency of Civil Affairs]

1.4.3. Political System and Culture
The Saudi system of government is a monarchy, deeply tied to the national religion, Islam. The legal
system is defined by Islamic law. The impact of this on the architectural style is discussed in depth in the
following section.
1.5. Riyadh
Riyadh is the capital of Saudi Arabia, it is located in the center of the Arabian Peninsula, and in the center
of the Kingdom of Saudi Arabia on the latitude (38-34) degrees north and longitude (43-46) degrees east,
it is about 600 meters (1968.5 feet’s) above sea level. Riyadh is 900 km (560 miles) away from Mecca
and Medina. It is the largest city in the country, and it is one of the fastest growing cities in the world. It is
the largest Arab city in terms of land, about 1,435 square kilometers. 5.25 million people are living in
Riyadh. Saudis make up 61% of the total population in Riyadh. [Central Department of Statistics &
Information].

1.5.1 The Culture in Riyadh, Saudi Arabia

The Saudi culture has been strengthened and evolved within the framework of legislation and Islamic
teachings. The law is based on the religious scripture, the Qur’an. The prominent religious cities Mecca
and Medina are located within the territory of Saudi Arabia. Everyday throughout the country, there are
five calls to prayer. During this time all of the shops close for 20 minutes, as people are not allowed to
24

buy or sell during prayer time, based on how the Saudi government is interpreting the scripture. Many
people go to pray in the mosques, which can be found all over the country.

The typical dress for men are long, white cotton dresses called “thop,” worn with a red piece of cotton for
the head to protect against the hot sun. Traditional Islamic dress for Saudi women is a black cover for the
entire body called an “abaya,” as accompanied by a head veil. In the public areas such as restaurants and
coffee shops, space is divided into two areas, one for men and one for families. Men and women are not
allowed to go out together if they are not from the same family. Saudi Arabia prohibits drinking alcohol,
according to the vision of Islam, however, many citizens partake in this activity in the privacy of their
homes, further demonstrating the difference in comfort levels in public versus private spaces.

1.5.2. The Influence of Riyadh Culture on Architecture, and How the Culture of Riyadh Affects the
Buildings and Architecture

The role of Islam on how the country functions, both legally and in cultural practices, has a great
influence on how people live. Considerations like how, dictated by Islamic law, non-relatives cannot see
women’s body or hair, are reflected in how buildings are designed with small and infrequent windows.
Because of the restrictions on what people can do, there is typically a solid ten-foot-tall privacy wall
around residential properties, protecting the residents from possible onlookers. Commonly, the windows
on the first floor are bigger than the second floor due to the privacy wall that covers the first story
windows. As a result of the privacy wall feature, the family can gather and play in the front or backyard
with no cover and thus many families have large yards surrounding their homes.
The belief system also shapes the interior floor plan. In every house, there are two main areas: the living
room and the dining hall. This division is created so that when there is a party, the men and women could
be separated in respect of Islamic culture.
There are also many walls and rooms within a Saudi home to create more privacy. The designer of a
Saudi residence should consider the circulation carefully so that men can enter and leave the house
without going through the women’s space in the living room and vice versa.
Anytime that women are in an area that they can remove their coverings, men are not allowed to enter.
This translates to many spaces, residential and commercial, needing to be divided into two separate areas
for men and women including places like wedding and party halls, restaurants, coffee shops, hair salons,
and gyms. In the family restaurants and coffee shops, there are small partitions between the tables which
give more privacy
The building code directs building design and construction to be consistent with cultural values. There
used to be height restrictions on buildings so that people could not see into their neighbor’s backyards
over the tall privacy walls. High-rises are now permitted by law, but there are restrictions on where they
can be located and they cannot be built near residential areas.
Current laws allow to build residencies taller than two stories, however if a neighbor makes a formal
complaint about windows overlooking their backyard and infringing on privacy, the window has to be
removed.
Courtyards are constructed to let light in from the interior of the property rather than the exterior walls for
further privacy (Figure 1-5). Building code states that the building must to be built two meters (about
seven feet) from the neighbor.

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Figure 1.7 A courtyard space in an apartment building
(“Google Image Result for http://3.bp.blogspot.com/-u3EVAo92gzo/Uo5IpEg0vfI/AAAAAAAAAI0/Wr9DaxG0bY0/s400/manour.jpg” 2015)

Figure 1.8 An example of the size and closed condition of windows

Figure 1.9 An owner decided that the solid wall around his property was not sufficient, so he added extra wall above.
26

1.5.3. Riyadh Climate

Riyadh is at Latitude 24.000 North, Longitude 45.000 East. The summer climate in Riyadh is hot and dry,
with average temperatures ranging from 81 - 109 °F (27.2 – 42.7 °C). Frequently there are dust storms in
the summer season due to the dry conditions. The dust is often so thick that visibility is under 10 m (33
ft). The winter climate in Riyadh is cold and dry and the average temperature is 47-68 °F (8.3 – 20 °C).
Rain is rare in Riyadh; the average annual rainfall in the city is 4 inches (100 mm).

Figure 1.10 Riyadh annual temperature range

Figure 1.11 Riyadh annual sky cover range

27

Figure 1.12 Riyadh monthly diurnal averages

Figure 1.13 Riyadh time table plot

Figure 1.14 Riyadh dry bulb x relative humidity

28

Figure 1.15 Riyadh sun shading chart

Figure 1.16 Riyadh psychometric chart
1.5.4. Riyadh Architecture in Response to the Climate
Climate plays an important role in the life of a region. It impacts everything from what types of
vegetation can grow, to which animals will survive, etc. Climate also has a significant effect on the
regional style of building and architecture. Riyadh has not only social, cultural, and economic influences
are seen in its architectural style, but also extreme climate conditions that impact the way in which homes
are constructed in the region.
Most Arab and Islamic countries are found in hot climates located between latitudes 10-30, where the
temperature is on average higher than other areas in the world. The humidity varies between dry air and
humid air, and these extreme temperatures have a direct effect on the life in this region. The climate
requires adaptation and protection in order to inhabit the area comfortably, especially in architecture and
urban planning. Much has been done over the course of history to address these issues and solve problems
through simple solutions for both residential homes and the urban planning of the cities.
In Saudi Arabia, there are three different climates, which resulted in three different vernacular styles.
29

 Hijazi style in west Saudi Arabia

Figure 1.17 Hijazi style
http://saudigazette.com.sa/saudi-arabia/hijazi-houses-of-historic-jeddah/
 Najdi style in the middle of Saudi Arabia.

Figure 1.18 Najdi style
http://www.blueabaya.com/2013/04/al-qaryah-al-najdiya-najdi-village.html
 The Southern style in the south of Saudi Arabia.

Figure 1.19 Southern style
http://www.alsharq.net.sa/lite-post?id=192720

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In Riyadh, the Najdi vernacular style had been used. However, as the economy developed with the
discovery of oil, new construction strayed away from the vernacular style. The resulting buildings use an
unnecessary amount of energy because they do not take advantage of the techniques that responded to the
climate.

The top climatic factors affecting the buildings in Riyadh are:
 Sun exposure
 Temperature
 Wind
 Natural light
 Evaporation and humidity

Sunlight: Architects have been able to take advantage of the sun in residential buildings by using it to
light the interior, but also design in such a way as to protect the inhabitants from the high temperatures by
providing cool, shaded interior spaces.

Sun protection: Architects in this region need to protect occupants from the direct sun. One technique is
enough to reduce the amount of direct and reflected solar radiation on the facades of the buildings. This
technique also increased the privacy in Riyadh very high, especially at home

The sun affects building styles in Riyadh in several ways:
 The massing of the building:
The form of the building and the mass of it has a great importance in controlling the amount of
direct light on the building. Whenever the shape of the building becomes more complex, the
shadows will cast more on the façade of the building, and many shadows created in the courtyard
space. This technique is called "self-shading" (Capeluto 2003).
 Address wall problems:
There is a need to reduce the amount of wall exposed to the sun, which changes throughout the
day. The walls are exposed to the sun less than the roof due to the different exposure to the solar
path during the daytime, and the sun angle changes based on the season. For this reason, the
vertical surfaces gain less sun than the roof. However, it is exposed to solar radiation reflected
especially in desert areas where sand is highly reflective. In Riyadh, they used to use shading
facades by using Tasbil, Louvers, and protrusions in the façade of the building (Figure 1.21).
 Address issues with openings:
The window openings are an important source of heat entry into the building, so controlling the
thermal conditions is a major consideration when designing window openings in Riyadh. Hence
they have a few small windows facing outside and more windows facing the courtyard (Figure
1.22).

 The Orientation of the building:
In Riyadh the building is oriented based on maximizing wind movement and reducing the amount
of solar heat gain to protect against the hot desert climate. From this point of view, the best
guidance and the best windows are in the north, and then south becomes the second best solution
for windows because shading the windows from the south is very easy. The courtyard gives
greater potential to aim them, where there is less solar radiation because of the shading (Figure
1.21), and regulates the heat exchange of the building process. Conversely, West walls are the
worst and East are the second worst. When shifting the axes by 45 degrees, Southwest or
Northwest are probably the worst.
31

 Shape of the building:
It is characteristic of the building forms in Riyadh to be square to maximize the shading in the
courtyard and as a result, achieve internal thermal stability. It is also common to vary the heights
of the façade to create more shadows through more complex shapes/heights in the building.
However, if buildings become rectangular, then large North and South facades with small East
and West facades are best, due to the heat gain on the vertical surfaces. The internal courtyards
are the opposite because a narrow N-S courtyard shades the East facing and the West Facing
facades.
 Building materials
In Riyadh, people use materials with high heat retention capacity such as mud, brick, and stone.
We can increase the thickness of the wall to reduce the amount of heat gained through the wall in
the hot and dry regions.
 Roofing system:
In the desert climate like Riyadh, the air temperature drops at night, so people often sleep on the
roofs, balconies, or open porches which are covered with light roofs of palm leaves. There are
two reasons for this, first as a surface shading device during the daytime, and secondly for
covering at night for sleeping.

Figure 1.21 Old Najdy Style, overhang.

Figure 1.22 Old Najdy Style courtyard.
https://mbasic.facebook.com/notes/
Figure 1.20 Old Najdy style, the
structure of the roof.

32

Figure 1.23 Urban for old Riyadh and how the different heights create shadows

Figure 1.24 Old Najedy streets, very narrow which creates more shadows
33

Figure 1.25 Najedy courtyard

Figure 1.27 Small windows and thick walls

Figure 1.26 Some houses built the second floor
above the street to create shade.

34

1.5.5. Saudi People in their Houses.
People in Riyadh spend the majority of their time in their homes for four main reasons. First, Saudi
Arabia is a religious Islamic country, which means that they cannot do whatever they want in public.
Second, Riyadh is located in the middle of the desert, the temperature is high, and the air is dusty. Third,
the majority of the people live in their homes because real estate prices are low and incomes of Saudi
people are high meaning home ownership is attainable for most Riyadh citizens. Also, the Saudi
government gives every Saudi a parcel of land 2952.76 square feet (274.3 square meters), and $150,000
to build a house. Fourth, Islam and the Saudi culture put great importance on living together as families,
help the parents and not leave them, so the family lives together even if their children are adults. Children
do not move out of their parent’s home until they get married, but even then many stay in the family
home after marriage. Because so much time is spent in the home of family and friends, people make their
home their city. Almost all forms of entertainment occur in the home, and they spend most of the day
indoors where there is cool air conditioning. Because of the desert climate in Riyadh, everything is done
indoors, people try not to spend too much time outside, so all the malls and restaurant and any
entertainment are typically in indoor environments.

1.5.6. Natural Lighting Systems Challenges
The daylighting systems are better than the artificial light for many reasons including a healthier indoor
environment, reduced energy use which results in less greenhouse gas emissions and lower electricity
bills. Even with these benefits, these systems are not widely used due to issues with the cost of the
system and the effectiveness of the system. Often these systems are installed after building construction to
address an issue with the design of the building that is preventing appropriate amounts of daylight from
entering the space. The daylighting elements are used to solve the problem. The result is that they will
confront higher costs, problems with other systems and lower efficiency since these systems are installed
after design and construction are complete. Therefore, if we consider these techniques in the design phase
as a way to get more daylight, many of these problems will be solved. One of the techniques that are more
common is the Reflective tube, as it can transfer natural light deep inside buildings to spaces daylight
from windows does not reach, but it also has many problems. The size of the tube is big, so it needs big
space between the ceiling and the roof for the pipe. This can also create some problems with the HVAC
ducts and beams. Moreover, if the efficiency of the Reflective tube is not high, the more often the light
bounces, the lower the efficiency person will get. Also, as the light goes high and low based on the sun
and time, even the length of the tube will affect the light, so a big room that has more than one tube will
have different illumination in every tube. Also. people now know how these systems are critical to use in
building design, so they are now focusing on improving it more to make it one of the main systems in the
building. We see now how they integrate it with artificial light with smart sensors such as the Hybrid
solar, the Reflective tube with LED, and The heliostat.

35

1.6. Los Angeles Climate
In Latitude 34.0500 N, Longitude 118.2500° W .
The summer climate in Los Angeles is warm to hot, the average Temperature is from 65.6°F – 84.8° F
(18.7 – 29.3 °C), nearly dry. The winter climate in Los Angeles is cool to warm.

Figure 1.28 Los Angeles temperature range

Figure 1.29 Los Angeles monthly diurnal averages

36

Figure 1.30 Los Angeles sky cover range

Figure 1.31 Los Angeles dry bulb x relative humidity

Figure 1.32 Los Angeles sun shading chart
37

(Figure 1-26) Sun Shading Chart
Figure 1.33 Los Angeles, time table plot

Figure 1.34 Los Angeles psychometric chart
38

2. Chapter 2: An Overview of Daylighting Systems

39

2.1 The Concept of a Daylighting System
Humans need daylight in their interiors. However, big windows alone do not solve the problem. Windows
have many advantages including providing good views, but, in some climates and cultures, there are
disadvantages including solar heat gain, less privacy, and glare in the buildings. Therefore, different
systems and techniques were invented to transfer natural light to spaces that light from windows does not
reach. There are many systems on the market, such as anidolic systems, reflective tubes, prismatic
systems, lens systems, lighting shelves, and the holographic diffraction systems. The following section
introduces some of the most common systems.
2.2 Anidolic System
An anidolic system is a non-imaging reflector system. One form is a reflective louver attached above the
view portion of the window, so the louvers will stop the direct sunlight and will redirect the sun. The
reflective material aims the sunlight to the ceiling or the back wall, which then diffuses the light into the
room. This system has been very popular over the last ten years because it is simple and easy to use.
Many manufacturers have improved it through different techniques such as capillary structures (Okalux
1996), specular reflection (reflective lamellae; Koster 1989), total internal reflection (light redirecting
window; Federmann 1996), optical refraction (prismatic panels; Siemens 1996), prismatic films (Wi
thehead et al. 1982) and optical diffraction (holographic panels; Muller 1994).

The amount of light that gets in is based first on the light flux from the outdoor opening that collects the
light and the size of the opening. Secondly, light transmission depends on how many times the light
reflects within the system. Third, when a system is designed for a particular space the angle of the system
must be considered because the angle will determine how far the light will go into the room and how
much light is reflected. Fourth, the length of the anidolic system is crucial, so, during the design, the
distance should be considered for the interior and exterior openings because the distance will have an
effect on the amount of light delivered. (Scartezzini and Courret 2002. Ochoa and Capeluto 2006).

Figure 2.1 The angle for anidolic system
(Scartezzini and Courret 2002)

40

Figure 2.2 (a) Section details of the device (b) The light directions after it is diffused
(Scartezzini and Courret 2002)

Figure 2.2 is an example of the basic anidolic system, and shows the opening is 1.08 ft then decreases in
size and finally increases in size. (Figure 2-2) (a) These angles are chosen to control the light. The system
has many benefits: first it reduces the need for artificial light because by using this system the light will
transfer deeper into the room. Second, anidolic systems can control the light level in space by changing
the angle, size of the opening, and the characteristics of the reflective material. It also protects people
inside the room from the glare, because the light hits the device and then the ceiling, which diffuses the
light into the room. There is direct light coming from the windows, but if the sun is higher than the
louver, it will block the direct light from the window. For people who want to learn more about this
system it is described in detail in (Welford and Winston, 1989); (P. C. Wang 1993), (Courret, 1999),
(Scartezzini and Courret 2002), and (Wittkopf 2007), (wang 1993)

41

There are three different anidolic systems:
 Anidolic ceiling.
 Integrated anidolic systems.
 Anidolic solar binds.
2.2.1 Anidolic Ceiling
The anidolic ceiling system is a duct placed in the ceiling. It has a reflective material and is integrated
with other systems such as the HVAC system, the structural system, and the electrical system powering
artificial lighting. The anidolic ceiling systems are designed to transfer the light deeper into the room. The
anidolic ceiling cannot transfer all the light deep into the room. If the room has a high ceiling, the light
will go deeper (Mckeough 2007), but the level of the light decreases as the parson move further away
with the distance from the window. On the other hand, the anidolic system can transfer much of the light
in the duct into the room until the light finds an opening to go through. There are three advantages of
using this system:
 There are more choices and designs for the façade.
 Better control and interior design.
 Better control for the light, less glare, and better indoor luminescent quality.
There are improved anidolic systems that add an external piece. These versions have two anidolic
elements: the first structural element is placed externally at the entrance to the system. The second
structural aspect is at the end of the duct, through which the flux is guided. One example is basically an
improved anidolic system, so it has a spatial angle using the approach of ‘variable extreme direction’
(Gordon and Rabl, 1992) which means that the angle for the opening for the anidolic collector has an
external edge at 90 degrees and a 55 degree interior edge see (Figure 2-4a) This shows the section details
for the anidolic ceiling system. This system also reduces the size of the collecting system from 1.08 m
(3.5 feet) in the basic system to 0.67 m (2.2 feet). The tube is a rectangular shape and has a reflective
surface inside of anodized aluminum foil 0.5 mm thickness (0.02 inches) and has an insulated double
glazing from the collector and single panel glass from inside (Scartezzini and Courret 2002,Wittkopf
2007).
2.2.2 Integrated Anidolic System
This system has an easier assembly and installation process, so it is favored by those who work on the
façade because it is easier to work with on the exterior. When it is built using this model, the following
should be considered:
 Anidolic reflector should not move, or movement should be minimized to less than 30 cm (11.8
inches).
 The height of the concrete slab from the floor needs to be a minimum of 2.65-2.70m, and the
lowest point of the reflector should be higher than 2m.
Another system: The collector used is similar to the anidolic ceiling system’s ‘variable extreme direction’
method (Gordon and Rabl, 1992) which means the angle of the opening for the anidolic collector has an
external edge of 90-degrees and a 70-degree interior edge. There is another bend for the interior opening
inside that has an angle of 10-37 degrees. See figure 2-5. This system has a second collector, which the
window is a part of, and the glass has micro louvers see (Figure 2-5) to control the light and minimize
solar glare. In this system other systems in the building such as HVAC, beams, and columns. (Scartezzini
and Courret 2002) must be considered, measured and calculated to provide optimal illumination.

42

Figure 2.3 Detiles of the integrated anidolic system

(Scartezzini and Courret 2002)

Figure 2.4 Anidolic ceiling, A duct technique. B section details.
(Scartezzini and Courret 2002)

Figure 2.5 Anidolic system theory
(Peng-Chih Wang, August 1993)

43

2.2.3 Anidolic Solar Blinds
The anidolic solar blind is a non-imaging system which completely blocks the view outside. This system
is made up of a 3D aluminum grid that is highly reflective. The light enters the reflective tube (Figure 2.6)
and the picture on the right shows the 3D grid outside and inside. This system is good if the building’s
location has high glare, and the room needs daylight with no glare. This system can redirect the daylight.
Also, the solar path must be considered, because the solar grids will have different directions and sizes
based on the season and the amount of light needed in the room. In Figure (2-7) the model has 20 pieces.
Each one is 31x35x10cm. The advantages of anidolic solar blinds, as characterized by (Scartezzini and
Courret2002):
 Redirect the natural light and can introduce more daylight into a space than the other systems.
 The system can achieve the best angle to get the maximum sunlight. (Scartezzini and Courret
2002)

2.3
Figure 2.6 3D grid outside and inside (Scartezzini and Courret 2002)

Figure 2.7 Anidolic solar blinds model outside, and inside (Scartezzini and Courret 2002)

44

Reflective Tube
A reflective tube, also known as a light pipe, is a system invented to transfer daylight through a pipe into
a room. This system can contain a heliostat outside to track the sun to optimize daylight transmission.
Before the light goes into the pipe, all of the light needs to be concentrated to one point or aimed to be
parallel, which is accomplished by using a lens or mirrors. Then the light will then travel through a
reflective pipe. There are different materials used for the tube section such as metal. The highest
efficiency achievable is 99.7%. The final part of the system is the diffusers, which attach to the ceiling to
diffuse the light into the room. This system is useful for transferring the light deep into the building. On
the other hand, this system cannot get the same illumination in every tube in the room because the height
of the tube will have an effect on how much light enters. Also, the sky conditions will have an impact on
this. If there is a cloud in the sky the light will hit the cloud and will be diffused, so not as much light will
enter through the tube and the rays will not be parallel. Such a tube can lose much light in the bends, and
the tube needs a big space between the roof and the ceiling.
2.3.1. Description of Embodiment Lighting Tube
(Figures 2-8) and (2-9) show the structure of a lighting tube. (Figure 10), which installs between the roof
of (12) and having the sheeting under the roof of structure (14) is supported and attached to the wood
shingles. These (16) shingles are overlapping other shingles, but (18) are covering the roof. The lighting
tube assembly is (10) and it has a light reflector tube of (20). There is an opener to the outside (22) in
square opening (24) cut with the roof (14) and the roof cover (18). The tube (20) goes vertically through
the attic (30) of the building structure, and it has a lower open (32) continuing through the opening (34) to
the horizontal ceiling. In this case, use a drywall as an example (36) attached to wood shingles (38). The
tube (20) in this case is square, but also, the lighting tube has different shapes, but the most common is
the square and Circular.
As shown (Figure 2-9), the square light reflector tube (20) has four flat faces (40), every face connected
by flexible corners (42). The services (40) made by a high inner reflector (44), the light will hit the
reflector inner surface (44) which is formed by one of many reflector materials in the market such as a
reflector paint, aluminum foil, and other materials which a special treatment like plastic processor (40).
As mentioned above, the lighting tube can be square or rectangular (20), and the flexible corners (42) to
get good attachment and easier for shipping, removal and install as it shows in (Figure 2.10)
The openings (24) and (34) are cut with the roof 14 and the ceiling (36), appropriately, with four wood
strips around the opening (34) Square shape (52) set of screws (53) are attached to the ceiling from the
top (36). The tube (20) is installed with the openings (24) and (34), and the lower open end the tube (20)
is connected to the wood (52) by a good attached such as screws, nails or staples. The same thing occurs
with the upper opening (22). One can use screws, nails or staples of the solar tube (20), trimmed along
(54) in the same line with the roof end with the roof surface. In the top, the extra portion of the tube
should be trimmed (56)
On the upper opening portion (22) of the lighting tube (20), there is the skylight cover (60) which is
preferably vacuum-formed of a plastic sheet material. The panel (60) is attached to the roof (14) by
screws (62) where holes within an outwardly projecting flange (63) of the panel (60). The screws are
covered by the roof covering (18) along the top and sides of the skylight panel. The lower opening end
(32) of the solar tube (20) should be covered by a diffuser or lens (65), and it has double or single plastic
panels (66),and abounded by a plastic frame (67), use a screws (69) to attached it to the ceiling (36), the
screws (69) goes deep into the wood strips (52). The tube (20) should close tightly, so no hot air leaks in
the tube then produce moisture in the services (40) and the panels (66). The model has strips (72) on the
45

frame (67) tight seal with the ceiling (36). The fiberboard (76) is a temporarily installed to the tube while
setting up the system to ensure that the tube has the square or rectangular ship and square corners. When
the tube finish installed the tube the fiberboard (76) should remove. (Hoy, Cunagin, and Hopkins 2003),
(Rillie 2006), (Bracale 2007), (DeBlock, Robinson, and Jr 1999)

Figure 2.8 Embodiment lighting tube
(Hoy, Cunagin, and Hopkins 2003)

Figure 2.9 Embodiment lighting tube
(Hoy, Cunagin, and Hopkins 2003)

Figure 2.10 Embodiment lighting tube
(Hoy, Cunagin, and Hopkins 2003)
Figure 2.11 Day lighting tube technique
(Hoy, Cunagin, and Hopkins 2003)

46

2.4 Hybrid Daylighting Systems
A hybrid daylighting system is a system created to solve a problem that windows cannot solve.
Transferring the daylight deep into a building used to be one of the biggest problems. Therefore, different
systems were created: systems such as a lighting tube, skylight, anidolic system, atrium, and more. These
systems were what could be done based on the tools available at the time. One of the problems that these
daylighting systems have is that the light is not equal in everyday lighting, because the destinations that
needed to transfer the light from the outside to the fixture are not equal, and if the sky is not clear the
level of the light coming from outside will be low.
If we look at these problems from a different point of view and understand that the light source is
variable, the sun gives the earth a dynamic of differing levels and temperatures of light, and that will be
reflected inside as one is using the sun as a resource. Humans understand and accept the changing light
levels with the sun when they are outdoors. However, people do not want to have these light level
changes inside where they live or work. It can be distracting and detrimental to mental health. Also,
when there are different levels of light from every fixture, it gives the feeling of discomfort. As an
example, when you are in a room that has different light levels varying from dark to light, people will
experience differing levels of comfort depending on their location.
The reason people are more sensitive to light changes inside rather than outside has two parts. First,
psychologically, a human outside is connected with nature, and the light moves from darkness in the
morning, to bright throughout the day, and fades to darkness again at night. This is expected by humans.
This is our circadian rhythm. However, inside a building, people are surrounded by furniture, walls,
temperature controls, and lighting that is all made or controlled by them and works for them. Secondly,
outdoor space is lit equally, but when walls or buildings are blocking the light and creating shadows, the
problem will still exist. For example, when a person is in the room and there is a big difference in light
level in every corner of the room. Solar envelope means that every building has the right to have Solar
access to the sun. More information on this topic is available in “The Solar Envelope by Kevin Lynch,
1981”.
Architects and engineers understand that people do not want to let nature control them inside their
residential homes, but at the same time building occupants want to save energy, money, and live in
healthy buildings. As a result, technology is used to achieve this through the hybrid system which solves
many of the problems that previous daylighting system have. It allows for equal light in all of the rooms,
regardless of the sun’s location, and at the same time saves energy and achieves natural lighting benefits
from the sun on human physical and psychological health.
The hybrid system utilizes both daylight and artificial light in a single fixture. Outside, there is a solar
collector and sensor, so if the daylight alone does not achieve the light levels needed, the artificial light
will turn on until the fixture achieves the standard. Therefore, the room will have equal light throughout
the day and save energy at the same time.
There are different types of hybrid systems. The most efficient are:
  Hybrid solar lighting
  LED lighting tube
47

2.4.1. Hybrid Solar Lighting
The Hybrid Solar lighting system is a new technique from Hybrid Solar which uses multiple sources to
get non-intermittent electric power. For example, solar panels and wind turbines produce the energy,
which then goes to the generator, and then the energy will be saved in the battery bank to use in the home.
Recently, this technology has been used for lighting and is called the Hybrid Solar lighting system. At
Oak Ridge National Laboratory in Tennessee in the mid-1990s (“Hybrid Solar Lighting” 2015) they
improved this technology further and released it to the market in 2002. This system has a tracker on the
roof. The tracker has a plastic primary mirror to reflect the sunlight to a second mirror. Then all the light
goes to the receiver module. The tracker uses a GPS receiver to follow the sun path. Then the fiber
transfers the light to the room. Every two fibers can give 60 W, and every piece has about 127 fibers. The
fiber is low cost, but it has low transmission as well and it goes a maximum 30-50 feet (9.1 – 15.24
meters) (“Hybrid Solar Lighting - Hacked Gadgets – IY Tech Blog” 2015).

Figure 2.12 Hybrid solar lighting collector
(“Google Image Result for http://www.daviddarling.info/images/hybrid_solar_lighting_1.gif” 2015)

Figure 2.13 Hybrid solar lighting collector details
(“Google Image Result for http://www.photonics.com/images/spectra/SolarPhotonics/2008/June/Oakridge_Fig2.jpg” 2015)

48

Technology continues to advance and improve the lighting tube systems. The Hybrid Solar system was
not without its issues, one of which is that the fiber optic aspect needs special treatment and high-cost
maintenance. Also, the fiber optics are not very flexible and foldable, so this system has a problem with
dealing with corners, and the installation is complicated.
2.4.2. LED Lighting Tube system:
The LED Solar tube is a system which uses renewable energy sources with the artificial LED light. It has
a dome on the top outside to collect the light. The dome has a lens and tracking sensor to get more solar
light into the tube, and the tube has a very high reflector which ends with the fixture inside. The fixture is
a combination between a daylight fixture and an LED fixture. The tube extends a maximum of 40 feet
(12.2 meters), and in the fixture, there is a sensor which controls the room’s lighting ranging from all
natural daylighting to a combination of daylight and artificial to all artificial light based on how many
lumens are needed in the room and the lumens available in the current weather condition.

Figure 2.14 Example of the LED daylighting system
(“Google Image Result for http://www.solatube.com/sites/default/files/field/images/blog/Image_LED%20dawn_dusk%20use.png” 2015)

49

2.5 Prismatic System
The prismatic system is a glass used to reject or redirect the sunlight. The idea comes from how the
sun’s light is reflected and refracted when it encounters ice. Prismatic systems use the skylight by
diffusing or changing the direction of the light. If there is a building blocking the light this system is a
good solution. Prismatic glass will change the direction of the light to extend it into the room.

2.6. Glare
Glare is a hard, strong light that causes discomfort. Glare is typified by large luminances, which our eyes
are not adapted to accomodate. When direct sunlight or direct artificial light hits your eyes this is glare.
There are two levels of glare: discomfort glare and disability glare. Disability glare is when you lose
visual capabilities due to the level of glare. Discomfort is when a high luminance or contrast makes you
feel discomfort or pain as a result of the excessive light in the field of view. The most important elements
for the glare are how much luminance is coming from the glare source, the contrast between the light
source and the background, how big the glare is, and the position of the glare. There are two mechanisms
of glare, direct and reflected glare. Direct glare is caused from high amounts of light that hit the eye from
the light source directly. Indirect or reflected glare results from the light which hits a reflected material
then the eye (Bole 2015). This is sometimes called veiling reflection.

Figure 2.15 Prismatic ystem
(Peng-Chih Wang, August 1993)

50

3. Chapter 3: Research Methodology

51

3.1. Overview of Methodology
Daylighting systems are techniques to get more daylight into a space, which is difficult to control because
it is coming from a moving source. People until now have not made any system that could transfer the
sun inside the building and diffuse it evenly 100%.
The sun is not the only element that determines if a lighting tube will work or not. Many factors should be
considered, and the most important factors are:

 Privacy
 Glare
 Heat
 Energy

These four factors should be considered and studied to know if this system will work well in a given
location or not.

3.2. Privacy
To quantify the level of privacy in Riyadh in order to compare it with Los Angeles, a survey of 70
Riyadh residents and 70 Los Angeles residents was conducted. The survey consisted of 17 questions
about privacy and four questions about their home type, to address the architectural differences between
Riyadh and Los Angeles. It was important to know what types of windows were in the home, as well as if
there were privacy walls surrounding it.
The survey was distributed electronically via email linked to a website called SurveyMonkey. There were
two surveys, one in Arabic for people in Riyadh and one in English for people in Los Angeles; the
questions were the same but translated into different languages by a native speaker. The data collected is
recorded in Chapter 4 then analyzed in Chapter 5.
The Survey Questions are as follows:
1. What is your gender?
Female
Male
2. What is your age?
20-30
31-40
41-50
51-60
61-70
52

71-80
3. Do you live in a house or in an apartment?
House
Apartment
4. What are the window sizes you prefer?
Small window
Big window
Picture window
Glass wall
5. What do you prefer?
Clear glass
Reflective glass
6. How many hours do you spend during the daytime in front of the window?
I do not stay in front of the window
Less than hour
1 hour - 2 hours
2 hours - 3 hours
4 hours - 5 hours
5 hours or more
7. How often do you leave the curtain closed during the day?
I leave the curtain open all the time.
I close the curtain only when I go to sleep
1-2 hours
2-4 hours
53

4-6 hours
6-8 hours
8-10 hours
10-12 hours
more than 12 hours
8. If the weather is nice outside, do you open the curtain?
Yes
No
9. Do you open the curtain during the night time?
Yes
No
10. Do you prefer to enjoy your time in the
Front yard
Back yard
11. When you open the window to get fresh air do you keep the curtain closed?
Yes
No
12. Do you like to sit in the front yard with your family where people can see you?
Yes
No
I do not care
13. Do you mind if people can see what are you doing in the living room?
Yes
No
14. Do you have garden walls around your property?
54

Yes
No
I live in an apartment
15. Do you prefer?
Open spaces
Closed spaces
16. Would you be willing to pay slightly more for a system that brings daylight into your house,
anywhere you want, without heat or glare?
Yes
No
17. Usually you close the curtains during the day because
privacy
Sunlight
Heat coming in
Thank you for people who helped to collect the data in Riyadh. also, professor Marc Schiler in Los
Angeles, MBS professors and friends who helped and sent the survey to their friends. Further work
would include methods to make sure that the pool of respondents is balanced or more representative in
age, gender and socio-economic terms.
55

3.3 Climate
To design a proper lighting tube for a particular location, the designer needs to investigate:
-Temperature Range, what is recorded high, design high, average high, median, average low, design low,
recorded low, and comfort zone
-Psychometric chart, for the design strategies, and know how many hours the location reaches the comfort
zone every year, sun shading of the windows, internal heat gain, and passive solar direct gain high mass.
- Sky covered range, total cloud cover, recorded high, design high, average high, mean, average low,
design low, recorded low, and clear sky.
- Monthly diurnal averages, Dry bulb mean, wet bulb mean, dry bulb, and comfort zone. Also from the
same chart we can have the Radiation, Global horiz, direct normal, and diffuse.
- Sun shading chart, hot > 75f which mean that need shading, Comfort > 68f which means that shading is
not important but helps, and could < 68f which means that space needs sun.
- Dry bulb, Relative humidity, and dew point.
All this information was collected (See chapter 1) for Riyadh, Saudi Arabia and Los Angeles, California
by using Climate Consultant 6.0. Also the latitude for both sites is given by using Drawsun program.

3.4. Site Case Study
To know more about how the culture and climate affect the building and
the urban planning in Riyadh, in chapter two, find a site visit to an old
restoration town made by the local who lives in the town to make it tourist
place. However, when the restoration finished people went back to live in
their old houses because each element of the traditional buildings had been
designed purposefully to keep the occupants comfortable in the climate
and in respect to the culture.

Figure 3.2 The old town after rebuild it

Figure 3.1 The old town befor rebuild it

56

3.5. Glare Analysis
The case studies were a standard living room in Los Angeles, located at 1600 Vine Street, and a standard
living room at Riyadh. The tools used in this test were a Nikon camera Coolpix 8400, tripod, fish eye
lens, and glare analysis program.

The camera setting:
Use the following settings in the “M” mode:
White balance sunny
Best shot selector off
Image adjustment normal
Saturation control normal
Image quality normal
Image size 8M (3264×2448)
Sensitivity 100 ISO
Image sharpening off
Lens fisheye
Exposure option (AE lock) off
Auto bracketing off
Noise reduction off

Taking pictures:
Took 4 pictures with the focused point in the
same position. One for each of the following settings of
aperture value and exposure time:
Aperture Exposure time
3.8 ½
3.8 1/15
3.8 1/125
3.8 1/1000

 Riyadh:
The author went to Riyadh in January and did a morning study for the standard living room “10:00 am,
11:00 am, and 12 pm.” During that time, just three days had a clear sky.

 Los Angeles:
The author picked a room that has similar conditions with the standed living room model, then took
pictures at “10:00 am, 11:00 am, and 12 pm” for three days.

 Analysis: All the glare programs read just HDR file format, so the photographs needed to be
converted. Phototroph was helpful, but do not forget to change the image to 32 pix, and then
uploaded to Hdrscope:

Figure 3.3 The tools for the glare test

57

3.5.1. Hdrscope
Hdrscope is a software program capable of performing High Dynamic Range (HDR) image processing
and analysis for architectural lighting design. The software builds upon the scene processing and
simulation strengths of existing programs such as Radiance and Evalglare and provides a Graphical User
Interface for manipulating HDR Images” (MS thesis of Viswanathan Kumaragurubaran in collaboration
with Mehlika Inanici at the University of Washington).

Figure 3.4 Hdrscope
Viswanathan Kumaragurubaran Thesis

58

3.6. Illuminance Analysis
In order to know if the daylight in the residential building with the normal windows achieved the
minimum recommended illuminance in each city, it was necessary to perform the following tests:

Using Revit, a model of a standard two-story house found in LA was built for analysis. Four daylighting
tubes were included in the living room space with a small kitchen and dining room tables. The floor area
was 35’x30’ in total. In the first model, there was one big window with no lighting tube. This model was
then exported Autodesk 360, which then simulated 21 June, 21 September, and 21 December at 1:00 PM.
The second model was exactly like the first model, but with four daylighting tubes installed to compare
the illuminance. The model was then exported to 3ds max to analyze the illuminance in the plan.

The next stage was modeling two typical houses found in Riyadh. The first one is a traditional living
room with eight small 3’x3’ windows. This model was then exported to Autodesk 360 to simulate the
same set of dates at 1:00 PM.
The second model had four lighting tubes but no windows. It was exported to Autodesk 360 to conduct
the same analysis. The model was then exported to 3ds max to analyse the illuminance in the plan.
3.7. Heat and Energy Analysis
Heat and energy are elements that need to be addressed in every building design. By using the IESVE
program, four buildings models were built. The first living room was in Riyadh and had eight normal
windows 3’x3’ each. The second living room was in Riyadh had no windows, but had four lighting tubes.
The third model was a living room that had normal windows, commonly seen in Los Angeles. The fourth
model was in Los Angeles and had windows and four daylighting tubes. The simulation was run for all
the four models to see which model uses more energy and had more heat.
3.8. Chapter Summary
This chapter shows the method the author used to test the Hypothesis which compared between the
lighting tube in Riyadh and Los Angeles by doing a survey, that asked people in both cities about privacy.
It then studied the illuminance, heat, and energy in two models in each city with lighting tube, and
without by using Revit for the models, IESVE for heat and energy, Autodesk 360 and 3ds max for
illuminance. Also, the glare in both cities was studied and compared by using Hdrscope program.

59

Figure 3.5 Methodology: how the five stages of the research was conducted.

60

4. Chapter 4

61

4.1. Introduction
This chapter will provide the tests and studies to prove or disprove the hypothesis of this thesis:
“Daylighting tubes are more beneficial in achieving minimum illuminance in residential building in cities
with specific cultural norms and values that affect the size and use of windows. In Los Angeles (at 34 N
Lat) the building often achieves the minimum light level through windows. In Riyadh, (at 24 N Lat)
where the windows are culturally smaller or absent, daylighting tubes should be installed to achieve the
minimum illuminance of daylighting in the residential home.” There are many elements involved in
testing this theory. For this research scope four were tested:

1- Privacy
2- Illuminance
3- Glare
4- Heat and energy

There are inherent complexities in collecting all these data in several months, especially considering the
two cities studied are a 16-hour flight apart. However, programs, such as Climate Consultant, Drawsun,
hdrscope, Revit, 3ds max, Autodesk 360, Green Building Studio Green Building Studio and IES VE,
make it possible to draw comparisions across so many miles. The survey questions were sent via a link in
an email. The survey platform (Survey Monkey) collected the results for further analysis.

The research was conducted in three stages. The first stage addressed the objective of determining the
desire for privacy, which was done by (see chapter 3) asking people questions about the desired level of
privacy in Los Angeles and Riyadh. The data yielded from the 17 questions offered insight into the
differing privacy standards in the two cities.

The second stage encompassed collecting the data for illuminance, heat, and energy. This task could be
accomplished in two ways: either through measuring the illuminance by a light sensor and HOBO data
logger for temperate, RH, heat and energy (do the measurement in a standard living room in Riyadh and
Los Angeles in June, September, and December), or through building a computer model and simulating
the same test. The method chosen for this research was the latter. Autodesk 360 and 3ds max were used to
measure the illuminance, and Autodesk Green Building Studio was used for the heat and energy
measurements.

Lastly, the glare needed to be tested in real site conditions, which presented some obstacles. Glare
programs are neither prevalent nor user friendly, so the glare was tested in Photo LUX, Evalglare, and
hdrscope to see which one yielded the best results. The time period tested was January 1-15
th
for Riyadh
and January 15-30
th
for Los Angeles, the dates were different because the author had to travel from one
location to another. This process was time consuming because of the limitied clear sky days during
January in either city, and the necessity of clear skies to collect comparable data. There were only six
clear days in Riyadh and six in Los Angeles during this month. From this initial trial, hdrscope was
chosen for the subsequent tests because its results most closely compared the real-world data collected.

62

4.2. Lighting Tube and the Model

Figure 4.1 Lighting tube elements modeled in Revit
There is no daylighting tube available
to simulate in any of the available BIM
programs, so to conduct this test the
lighting tube needed to be modeled.
A standard daylighting tube was built
in Revit. It was composed of highly
reflective material, the tube cover, the
dome lenses mounting the tube cover,
and a frame and diffuser connecting to
the room’s ceiling. This model will be
uploaded in the public Autodesk online
library for further use and development
beyond the scope of this research.
63

4.2.1. Los Angeles Revit Model
Figure 4.4 A section view of the Los Angeles living room

Figure 4.2 Los Angeles living room floor plan

Figure 4.3 The assembly of the exterior walls modeled in Revit
64

4.2.2. Riyadh Revit Model

Living room
Figure 4.7 Riyadh living room floor plan

Figure 4.5 Section view of the Riyadh living room

Figure 4.6 The assembly of the exterior walls

65

4.3. Riyadh Illuminance Tests
4.3.1. Riyadh Scenario #1 in Autodesk 360

Figure 4.8 Riyadh scenario #1 at 1:00 pm facing east, tested in Autodesk 360
66

4.3.2. Riyadh Scenario #2 in Autodesk 360

Figure 4.9 Riyadh test (2) at 1:00 pm facing east, Autodesk 360

67

4.3.3. Riyadh Scenario #1 in 3ds Max

4 lighting tubes and 8 windows 3’x3’

Note: the colors do not indicate the level of illuminance

Figure 4.103ds max illuminance in Riyadh 4 daylighting tubes and 8 windows 3’x3’ 21 June at 1:00pm
68

Figure 4.11 3ds max illuminance Riyadh 4 daylighting tubes and 8 windows 3’x3’ 21 September at 1:00pm

Note: the colors do not indicate the level of illuminance

69

Figure 4.12 3ds max illuminance Riyadh 4 daylighting tubes and 8 windows 3’x3’ 21 December at 1:00pm

Note: the colors do not indicate the level of illuminance

70

4.3.4. Riyadh Scenario #2 in 3ds Max

3ds max illuminance Riyadh daylighting with 4 lighting tubes and no windows tests
Note: the colors do not indicate the level of illuminance

Figure 4.13 3ds max illuminance Riyadh daylighting with 4 daylighting tubes and no windows (June 21) at 1:00pm
71

Note: the colors do not indicate the level of illuminance

Figure 4.14 3ds max illuminance Riyadh daylighting with 4 daylighting tubes and no windows 21 September at 1:00pm

72

Note: the colors do not indicate the level of illuminance

Figure 4.15 3ds max illuminance Riyadh daylighting with 4 daylighting tubes and no windows 21 December at1:00pm

73

4.4. Los Angeles Illuminance Tests
4.4.1. Los Angeles Scenario #1 in Autodesk 360

Figure 4.16 Los Angeles test (1) at 1:00 pm facing east, Autodesk 360
74

4.4.2. Los Angeles Scenario #2 in Autodesk 360

Living Room in Los Angeles with curtain
wall, but no daylighting tube
Figure 4.17 Los Angeles test (2) at 1:00 pm facing east, Autodesk 360

75

4.4.3. More Data Autodesk 360.

Figure 4.18 Los Angeles test (1) with increasing the scale colors to 1000 foot-candles

Figure 4.19 Los Angeles test (2) with increasing the scale colors to 1000 foot-candles.

Figure 4.20 Riyadh scenario #1 facing west June 21 at 1:00pm

76

4.4.4. 3ds max Los Angeles Plan 4 Lighting Tubes and Curtain Wall

Note: The numbers are more accurate than the colors.

Figure 4.21 3ds max Los Angeles plan 4 daylighting tubes and curtain wall 21 June 1:00pm

77

Note: The numbers are more accurate than the colors
Figure 4.22 3ds max Los Angeles plan 4 daylighting tubes and curtain wall 21 September at 1:00pm
78

Note: The numbers are more accurate than the colors.

Figure 4.23 3ds max Los Angeles plan 4 daylighting tubes and curtain wall 21 December at 1:00pm
79

4.4.5. Los Angeles Scenario #1 in 3ds Max
3ds max Los Angeles plan with curtain wall and no daylighting tubes.

Note: The numbers are more accurate than the colors.

Figure 4.24 3ds max Los Angeles plan with curtain wall and no daylighting tubes 21 June at 1:00pm
80

Note: The numbers are more accurate than the colors.

Figure 4.25 3ds max Los Angeles plan with curtain wall and no daylighting tubes 21 September 1:00pm

81

7

21
September
Note: The numbers are more accurate than the colors.

Figure 4.26 3ds max Los Angeles plan with curtain wall and no daylighting tube 21 December at 1:00pm

82

4.5. Survey Data
4.5.1. Riyadh Survey Data

83

84

85

4.5.2. Los Angeles Survey Data

86

87

88

4.6. Heat and Energy

4.6.1. Los Angeles Heat and Energy

Los Angeles: windows and no daylighting tube Los Angeles: windows and daylighting tube
89

90

4.6.2. Riyadh Heat and Energy

Riyadh: windows and no daylighting tubes. Riyadh: windows and daylighting tube

91

92

4.7. Glare Tests
4.7.1. Los Angeles Glare Test

Pixels
Cd/m
2

Luminous intensity
Figure 4.27 Glare analysis in Los Angeles at 9:30am

93

Luminous intensity
Pixels
Cd/m
2

Figure 4.28 Glare analysis in Los Angeles at 10:30am

94

Figure 4.29 Glare analysis in Los Angeles at 11:30 am

Luminous intensity
Cd/m
2

Pixels
95

4.7.2. Riyadh Glare Test

Pixels
Luminous intensity
Cd/m
2

Figure 4.30 Glare analysis in Riyadh at 9:30am
96

Luminous intensity
Pixels
Cd/m
2

Figure 4.31 Glare analysis in Riyadh at 10:30 am

97

Luminous intensity
Pixels
Cd/m
2

Figure 4.32 Glare analysis in Riyadh at 11:30am

98

4.8. Chapter Summary
Chapter 4 encompasses the data collected to test the hypothesis. The process began by asking 70 people in
Riyadh and Los Angeles 17 questions about the privacy of their home. Doing a site visit to the old city
(discussed previously in Chapter 1) was important to understanding the culture and, as a consequence,
how the culture affects residents’ perspective on privacy.

The next step was modeling daylighting tubes within a standard living room, which matched with the
Saudi and American cultures respectively. These architectural models were then exported to IES and 3ds
max for lighting analysis to measure how effective including a daylighting tube would be. Energy and
heat simulations were then performed using Autodesk’s Green Building Studio.

The glare study was the final data collection stage. Four pictures were taken with different shutter speeds
(1/2, 1/125,1/250, and 1/1000) for three times in the morning. This process was repeated for three days in
Los Angeles and Riyadh. The images were then upload into Photoshop and converted from JPEG to HDR
to upload into glare program hdrscope.

99

5. Chapter 5

100

5.1. Introduction

This chapter offers the analyses of the glare, privacy, illuminance, heat, and energy data reported in
Chapter 4. To prove or disprove the hypothesis of this thesis “Daylighting tubes are more beneficial in
achieving minimum illuminance in residential in cities with specific cultural norms and values that affect
the size and use of windows. In Los Angeles (at 34 N Lat) the building often achieves the minimum light
level through windows. In Riyadh, (at 24 N Lat) where the windows are culturally smaller or absent,
daylighting tubes should be installed to achieve the minimum illuminance of daylighting in the residential
home”.
5.2. The Old City Visit Observations
The following are observations noted during the site visit of the Old City:
 The air was perceived as cleaner. Cars were not allowed to be driven inside the city, so there was
likely less unburnt hydrocarbons and CO 2 in the air. The primary transit method of people within
the city’s borders is walking or riding bicycles.
 Because there were no cars in the city, everything was designed at a scale appropriate for
walking. The streets were very narrow; some of the streets were 9’ in width to increase shadows
and protect from sun radiation. The stores were smaller than now; some of the residents made
rooms of their home into a store. As a result, some people can work where they live.
 The layout of the city seems to be predominately based on sun direction and air flow (Figure 5.1).
The positions of the buildings facilitate airflow into the heart the city, where the mosque is, from
the east and north. At the same time, the city blocks off the hotter, dust-filled winds that come
from the southwest direction.
 Additionally, because of the
narrow streets, people built
above the streets, creating
tunnels below. The benefits of
this urban design is self-
shading and decreased heat
gain.
 Farms were located out of the
town in part because
agriculture needs a big, open
space, which would translate to
area unprotected from the sun
and thus experience higher
heat gain.
 The temperature was cooler
than the new city because all
the natural and high mass
construction materials used. For example, mud was typical for
the exterior walls, stone for the streets, and wood for roofs.
Figure 5.1he old Riyadh layout

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 Typically, the first floor windows were high, small, and few in number. The second floor
windows tended to be bigger and covered by a wood grid, one to two inches between every line,
in a system called “Mashrabia.” The function of this screen was so people inside could see out,
but people in the street could not see inside through the window, thus offering the occupants air
ventilation with privacy.
 There were no front yards, backyards, or garden walls around the houses. Instead, the buildings
were designed with courtyards. They had more, bigger, and lower windows facing this interior
space.
 Buildings with big hall spaces, like the mosque, were made with three walls with no back wall,
and they used a high tower has opening from the top and other opening in the end attached with
the roof called “Malqaf.” The Malqaf functions to bring in colder air and increase air ventilation.
These special windows are needed because normal windows are not sufficient to have good air
ventilation for large room that accommodates around 300 people.
 There was a basement under the mosque. The tour guide described the purpose of this space as a
room that stayed cooler during the summer and warmer during the winter. People centuries ago
would work from sunrise until noon because of the high temperatures. From 12pm to 2pm the
heat would be so unbearable, they would stop working and take a nap in the basement.
 There was no space between houses; homes were almost sharing the same roof. However, the
heights of the buildings varied to create more shadows.
 For gathering, they had public, semi-open spaces covered by palm leaves that encouraged good
air flow and protected from the solar radiation (Figure 5.1).
Overwhelmingly, it seemed as if every element in the
city was designed to help humans adapt to the natural
climate and be part of the local culture. The techniques
were simple, culturally appropriate, and effective in
responding to the environment. Many of the climate
issues that people in Riyadh currently face were issues
solved in the design of the Old City. This city offers
persuasive evidence that the simple, vernacular
architectural techniques of previous centuries can still
be applicable in modern cities. The strategies of
increasing occupant comfort can be developed and
improved to work with the new systems and be
consistent with recent building codes. The Old City’s
design is so cohesive that it looks like a singular
building (Figure 5.2). In this architectural tradition,
people take advantage of everything around them and the results is a symbiotic relationship between the
buildings and the nature.
Figure 5.2 Roof constructed from palm leaves
http://www.aghnam.com.sa/vb/showthread.php?t=57245&page=2
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Figure 5.3 Wshiger “the old city”
http://www.spa.gov.sa/details.php?id=1303919
5.3. Riyadh Illuminance Analysis
5.3.1. Riyadh Scenario #1 in Autodesk 360
The following simulations were conducted in Autodesk 360 using June 21, September 21, and December
21 at 1pm. The first scenario for Riyadh simulated a living room with 4 daylighting tubes and 8 small
windows. The walls were thick and windows were small (3’ by 3’), which helped reduce the illuminance
levels within the room.
June 21
st
, 1pm
The maximum illuminance on the floor, 400 fc, came from the daylighting tube. The lowest illuminance
level was between 0 to 40 fc and occurred in the corners, between the sofas, and under the furniture. The
exterior wall received mostly between 40 to 80 fc and some spots reached 120 fc. The interior walls got
25% more light than the exterior wall. Because of the thick walls and the high sun at the test time, the
light reflected off of the window sills and the ceiling area closest to the windows received more daylight
than the ceiling regions further into the room. The indirect solar radiation from the sills reflected 240 fc
onto the ceiling. For the rest of the ceiling, the illuminance was closer to 40 fc. The highest illuminance
occurred around the middle of the floor area, ranging from 200-360 fc. This very high illuminance range
demonstrates the possible result of open windows and the daylighting tubes together. However, in
practice, the shades or drapes of these exposed windows would be closed. As a consequence of the
windows being blocked, the daylighting tubes offer the novel value of acquiring daylight while still
respecting the local culture.

Figure 5.4 How is the thickness of the
wall effect on the direction of the
daylight reflect though the windows.
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September 21
st
, 1pm
The illuminance levels on September 21
st
were slightly lower than for the June 21
st
simulation, though in
some areas it is difficult to observe the differences in the images. The maximum illuminance for
September 21
st
was 320 fc. The illuminance on the exterior wall ranged between 0 to 80. The reflected
light from the windows edges decreased sharply to 120 fc. These three observations were the big
differences between the results from the two dates.
December 21
st
, 1pm
The most significant contrast between the September 21
st
and December 21
st
was a result of the sun’s
position and the solar angle. For December, since the sun was lower in the sky, there was less light
reflecting from the window sill onto the ceiling. As a result, there were no big differences at this time
between the area of the ceiling closest to the window and the area further away, which only varied from
120 to 40 fc. Lastly, the corners were a little darker in the December simulation than in September.
5.3.2. Riyadh Scenario #2 in Autodesk 360
The second scenario was a model of a living room with 4 daylighting tubes and no windows.
June 21
st
, 1pm
For the June 21
st
simulation, the highest illuminance level was 320 fc, whereas the lowest was zero. In
this scenario, all the walls received almost the same amount of illuminance. The highest amount of light
on the wall was 120 fc and occurred at the center. Approaching the corners, the light level went down to
10 fc. Because there were no windows, the ceiling did not receive reflected light from the windows. The
ceiling had the most illuminance in the center with 80 fc and decreased to 10 fc around the corners. The
floor got the most illuminance of all, from 320 fc to 80 fc around the furniture.
September 21
st
, 1pm
Because there were no windows and the daylighting tube collected light from the roof, the amount of light
the system collected remained almost the same. In other words, the position of the sun had a smaller
influence on the results because nothing obstructed the daylighting tube’s dome and lenses. The
maximum illuminance within the room only decreased from 320 to 280 fc.
December 21
st
, 1pm
There were no visually discernable differences between the September 21 and December 21. Granted,
there were likely small variances between the two simulations, but because the result of this software is
reported in colors rather than numbers, it is difficult to determine. The simulations in 3ds max, discussed
in the next section, report numeric results.
Summary
In the scenario 1 simulation results, there were high levels of illuminance close to the windows and lower
levels near the wall at the other side of the room. In scenario 2, the amount of light diffused more equally,
with the highest concentration at the center. For scenario 1, the inclusion of the windows meant the time
of year had a bigger influence on how much light entered the room. The illuminance levels changed
clearly from June 21 to September 21, and slightly in December 21, because of the changing sun angle. In
scenario 2, the changes between the three months were very small. An advantage of the daylighting tube
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is that because the tube’s dome collects light from the roof level, the angle of the sun will not affect the
illuminance inside the room.
5.3.3. Riyadh Scenario #1 in 3ds max
The output of the 3ds Max simulations were slightly higher than the data produced through Autodesk 360.
Both programs used the same Revit model; the differences are likely a result of the height the program is
modeling the illuminance sensors. Additionally, in the 3ds Max test the colors which were to identify the
difference of the light levels do not mean anything, there were no colors labelled like Autodesk 360. 3ds
max analyses the illuminance levels only in plan section, meaning that it produced no data for the walls
and ceiling.
3ds Max tested the same scenario 1: a living room with 4 daylighting tube and 8 small windows.
June 21
st
, 1pm
To describe the results, the floor plan was divided into four
zone types (Figure 5.4). The highest amount of light
occurred in Zone Type 1, which was the floor area almost
directly below the daylighting tubes. The second greatest
illuminance zone, Zone Type 2, also received light from the
windows. Zone 2 was where there was direct light from both
systems, windows and tube. Zone Type 3 received indirect
light from both systems. The darkest zone, Zone Type 4, fell
directly under windows, in corners, and close to the walls.
September 21
st
, 1pm
For September 21 and December 21, the illuminance levels
slightly differed and the zones shifted.

Figure 5.6 The plot compares the first illuminance horizontal line in #1 3ds max plans. The line is 30 feet width divided to 13 points, the window
on the left of the chart. The numbers in the graph are Fc.
Figure 5.5 Lighting zones
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The graph shows the first two under the windows, and last two close from the wall got the lowest
numbers, the numbers in the middle were higher because of the daylighting tubes. Also you can see the
numbers are slightly shifted from point to the other.
5.3.4. Riyadh Scenario #2 in 3ds max
Scenario 2 modeled a living room with 4 daylighting tubes and no windows. The 3ds max results of this
scenario was just two zones: the first zone fell directly under the daylighting tubes and second zone
encompassed the area around that.

Figure 5.7 The plot compares the fourth illuminance horizontal line in #2 3ds max plans. The line is 30 feet width divided to 13 points, the
window on the left of the chart. The numbers in the graph are Fc.
5.4. Los Angeles Illuminance Analysis
5.4.1. Los Angeles Scenario #1 in Autodesk 360
- Living room with 4 lighting tubes and curtain wall.
June 21
st
, 1pm
For the June 21
st
simulation, there was a high concentration of light
around the curtain walls, reaching 400 fc. There was also a large
amount of light on the floor, coming from the lighting tubes. The zone
which received direct light from the curtain wall and the daylighting
tube got the highest illuminance, ranging from 360 to 400 fc. The
floor area near the walls and the walls themselves received around
260 fc. 10 feet from the curtain wall, the amount of light in the ceiling
dropped down sharply to 120 fc.
September 21
st
, 1pm
For September 21
st
, there was a significant difference in the amount of light the ceiling received
compared to June 21
st
. The amount of light that reached deep into the room did not change dramatically,
but the amount of illuminance around the window changed. The resulting images look very similar, with
the large yellow regions representing 400 fc. The difference between the three months can be observed at
the ceiling: the luminance levels transition from 400 fc to 120 fc in a shorter distance when the sun’s
position is lower in the winter. The first five feet from the curtain wall, everything was brightly lit; the
Figure 5.8 Los Angeles illuminance
analyses, daylighting tubes.
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floor, walls, and ceiling all received 400 fc. The floor area further from the curtain wall receives slightly
less light.
December 21
st
, 1pm
For the December 21
st
simulation, the light coming from the daylighting tube was either the same or there
was only slightly different from the previous simulation. Because the differences in the angle of the sun
for the three months and its influence on the amount of light entering through the curtain wall, the amount
of light received on the surface of the ceiling changed dramatically. In December, only the first 3 feet
around the curtain wall received 400 fc. The area of the ceiling beyond 5 feet from the window dropped to
120 fc.
5.4.2. Los Angeles Scenario #2 in Autodesk 360
- Living room with curtain wall and no daylighting tube.
June 21
st
, 1pm
In this scenario, the daylight came from just one side of the room, thus there was a big different between
the amount of light around the window and the opposite wall. All the illuminance measurment points
between the curtain wall and a 10-foot distance were 400 fc. The area around the opposite wall received
between 40 to 80 fc. The walls adjacent to the curtainwall received more light compared to floor and
ceiling surfaces. 10 feet from the window, the light level on the adjacent walls reached around 280 fc. On
the other hand, the illuminance on the ceiling and floor was limited to 120 fc.
September 21
st
, 1pm
On September 21
st
, the amount of the light coming through curtain wall is reduced because of the sun
angle. The biggest affect of sun position was the changes in the direct solar radiation on the walls and
ceiling. The amount of light hitting the room’s floor only changed slightly and was difficult to discern just
based on color. Beyond five feet from the window, the light that hit the
walls and ceiling started to reduce to around 360, 320, 280, and 240 fc.
Beyond 10 feet, there is a larger drop (symbolized in green in figure 5.5)
toward the edges of the room, where the light reached around 40 fc.
December 21
st
, 1pm
In the December 21
st
simulation, the light levels were largely lower than
in September. In the Autodesk 360 results, the yellow regions represent
light levels around 400 fc, red indicates 240 fc, green indicates 120 fc,
and blue means 0-40 fc. The amount of yellow was very low, just around
the curtain wall and the three feet region bordering it (Figure 5.6). The
red region goes deep I the walls until 10 feet from the window. Then the
rest between blue and green, the majority was blue. In June and
September, the majority was green.

Figure 5.9 Los Angeles illuminance
analyses, no daylighting tubes.

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5.4.3. Los Angeles Scenario #1 in 3ds max
- Living room with four lighting tubes and curtain wall:
June 21
st
, 1pm
The peak of illuminance was around the window because there was no overhang or thick wall to reduce
the solar radiation in this model, unlike the simulations in Riyadh. As a consequence, there was a spot
where the illuminance level reached around 620 fc. The numbers in 3ds max were higher than the ones
generated in Autodesk 360 because of the majority of the light was above the furniture, five feet from the
ground. The first 10 feet from the window, the illumiance decreases to between 225 and 380, which is the
zone where the direct light from the window and the tube intersect. After the 10-foot distance, there was
another zone, which received direct light from only the lighting tube, resulting in 74-194 fc.
September 21
st
, 1pm
The first five feet from the window, the amount of light incident on the floor was the same as the June
simulation. However, after those first five feet, the illumunance decreased to around 230 fc. In this case,
the angle of the sun has as much of an influence on the amount of the illumination compared to Riyadh
because of the differences between construction of the room. In the LA model, the glazing was covering
all the exterior, but in Riyadh, the windows were 3 feet by 3 feet and wall of 1.2 feet thick.
December 21
st
, 1pm
December 21, there was no change in light level between September and December. However, there were
changing on the directions and level spots. The plot in Figures 5.8 and 5.9 shows that there were slightly
elevated values in the middle where the daylighting tubes were.

Figure 5.10 the plot compares the first illuminance horizontal line in Los Angeles scenario #1 in 3ds Max plans. The line is 30 feet width divided
to 13 points, the window on the left of the chart. The numbers in the graph are Fc.

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5.4.4. Los Angeles Scenario #2 in 3ds Max
- Living room with curtain wall and no daylighting tube.
June 21
st
, 1pm
In this test, all the light came from one source: the curtain wall. The light coming from this glazing
provided almost exactly the same amount as when there was also a lighting tube installed. There was only
a little difference at the center of the floor area where the direct light from the daylighting tube
overlapped.
September 21, December 21, and June 21, they all have very similar data (Figure 5.9)

Figure 5.11 the plot compares the first illuminance horizontal line in Los Angeles scenario #2 in 3ds max plans. The line is 30 feet width divided
to 13 points, the window on the left of the chart. The numbers in the graph are Fc.
5.4.5. Discussion of Survey Results
The results showed that the inclusion of a daylight tube in Los Angeles does not have a significant impact
on the amount of illuminance in a given room.
5.5. Survey Analyses
5.5.1. Categorizing Participants
The purpose of the first and second questions were to determine the gender and age brackets for the
survey participants. 58% of the participants in Riyadh were female and 41 % male, an almost equal
breakdown. On the other hand, 78% of the participants in Los Angeles were female and just 21% were
male. In Riyadh, the highest participating age group was 31- 40 years old (43% of responses). 33% of
participants were between 20-30. 30% fell between 41-50, and the lowest number of responses was
between 50-60 years old (9%). The Los Angeles surveys were in part advertised through college-geared
social media (USC Facebook groups). As a likely consequence, the largest group of participants were
between the ages of 20 and 30 years (60% of responses). The survey was also sent directly to Building
Science faculty at USC, resulting in 12.5% between 61-70 and 7.5% between 51-60. 20% of participants
109

were between 31-40. There were zero participants between 41-50 years old. Future studies should seek a
larger participant pool, but there did not appear to be significant differences between age groups, etc.
The third question asked users to categorize their homes. 86% of the participants from Riyadh reported
living in houses. This is consistent with a cultural preference of houses over apartments. The remaining
14% reported living in apartments. In Los Angeles it was more equally distributed: 57% were living in
apartments and 42% were in houses.
5.5.2. Window Type Preferences
The fourth question asked participants if they preferred larger or smaller windows. 75% preferred larger
windows in Los Angeles and 54% in Riyadh. Also in Riyadh, 6% preferred small windows, compared
with Los Angeles, which was 2%. 15% for the pictures windows and 7.5 for the glass windows in Los
Angeles. Riyadh got 28% glass windows and 10% pictures windows.
The fifth question asked if people prefer reflective glass, which blocks the view from outside to inside.
80% of the people in Los Angeles preferred clear glass rather than reflective glass. In Riyadh, 48% of the
people preferred reflective glass.
5.5.3. Daily Use of Windows
The sixth question was intended to determine if people use their windows just to get daylight or also to
have a good view. In Los Angeles, 32.5% of the people spend 2-3 hours in front of the window, and
22.5% spend between 1-2 hours. There were 20% of the people who spend 5 hours or more in front of the
window which means that they care about having a good view through the window. Also, there were
12.5% spend around 4 hours. Just 12.5% of the total do not stay or they stay less than xxx hour This
means these people do not use the window to look outside. On the other hand, 36% of the people in
Riyadh do not stay in front of the windows at all, and 44.6% of them stay less than hour. 12% between 1
to 2 hours, and 7% of people stay more than two hours. 80% of people spend less than 2 hours in front of
the windows in Riyadh for looking outside. It is big number, so the designer should consider the size and
the height of the window during the design; otherwise the window will be useless functionally and will
increase the cost, and the heat loss.
The seventh question was designed to get a sense of the participants’ behavior in regards to opening and
closing the shades of their windows. The data from Riyadh and Los Angeles survey results were similar.
35% of participants in Los Angeles and 40% in Riyadh reported closing their windows and shades only
when they went to sleep. However, in Los Angeles, 25% of the people reported keeping their windows
and shades open all the day, suggesting that they were not easily bothered by the solar radiation. 12.5% of
LA participants on the other hand, reported keeping it closed more than 12 hours. This suggests that these
residents may keep their windows and blinds closed for a reason besides solar radiation, possibly because
of privacy issues or other concerns. In Riyadh, just 4% of the participants keep the curtains open all day.
However, there were 40% that reported closing their curtains when they went to sleep. A reasoning
behind this behavior may be because the typically used reflective glass of the exterior windows blocks the
view from outside to inside, but at night, if the lights are on, the opposite occurs. People outside can see
into the home, raising a privacy concern.
After determining the participants’ behavior, the eighth and ninth questions developed further, asking if
they keep the curtain closed because of the sun and/or for privacy. The eighth question asked if they open
their curtain if the weather is nice outside. In Los Angeles, 97.5% said yes. In Riyadh, 93% said yes. The
next question asked if they left the curtains closed during the night. 30% in Los Angeles said yes, but in
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Riyadh 72% said yes, which means that the majority of people in Riyadh kept the curtains closed for
privacy.
The tenth question asked where people prefer to stay: in the front yard or backyard. The intention is to
gauge the level of privacy people prefer because in the front yard people on the sidewalk can see the
residents. In Los Angeles, 75% of people prefer backyard. In Riyadh 89% of people like to enjoy their
time in the backyard.
The eleventh question asked when participants opened their windows for fresh air, did they keep their
curtains closed. 82.5% of Los Angeles responses said no, they opened their curtains. Only 17.5% of the
Los Angeles did not open their curtains at all. In Riyadh, there was a dramatic difference: only 13% of
people wanted their curtains open when they wanted fresh air.
The twelfth question was to see how much they cared if people saw them. The question asked: “Do you
like to sit in the front yard with your family where people can see you?” In Los Angeles, 51% said no,
13% people said yes, and 36% said they didn’t care. In Riyadh, 22% more participants than Los Angeles
did not like people outside to see them. 10% said yes and 15% did not care. However, in question
thirteen, when asked if they minded if people outside saw them when they were in their living room, the
majority of both cities minded. Most of people wanted more privacy when they were within their own
home: in Los Angeles, 70% minded and 75% minded in Riyadh.
The fourteenth question asked if the participants had garden walls bordering their property. In Riyadh,
89% of the participants had a garden wall, 2.4% did not, and 9% lived in apartments. In Los Angeles,
42% of them lived in apartments, 30% did not, and just 27.5% had a garden wall.
The fifteenth question was designed to gage whether residents just valued privacy from strangers or
privacy within their home with their family. In Los Angeles, 77.5% liked open spaces in their home,
which has less privacy than closed spaces. In Riyadh, 80% liked open spaces in their home, which may
suggest that both cities do not have problems with privacy between family members. This finding was
surprising for Riyadh because, in Saudi Arabia, it is customary to have two living rooms, separated by
gender. This reported desire to have an open space within the home is contrary to the cultural values.
The sixteenth question asked if people were willing to pay slightly more for a system that brings daylight
into the house, anywhere the person wanted, without heat or glare. 90% of the people in Riyadh said yes
and a similar 87.5% in Los Angeles agreed.
The seventeenth question asked about the reasons participants kept the curtains closed during the day. The
survey had participants choose one or more of the following: privacy, sunlight, and heat. The unexpected
result was that 40% of people in Los Angeles close it because of the privacy, 22.5% sunlight, and 67.5%
for heat coming in. In Riyadh, just 30% chose privacy, 35.8% chose sunlight, and 59% also chose heat
coming in.
5.5.4. Conclusions Drawn from Survey Results
An interesting observation from this research was that although people in Riyadh preferred larger
windows, there was a dilemma: they didn’t want strangers walking by their house to see in. As a
consequence, they preferred reflective glass. Because of this material choice, at night, residents tend to
close their drapes because at night people outside can see into the home.
A finding of the survey was that, in Riyadh, people generally did not use their window for its view.
Likely, this is because of the environment: unlike Los Angeles, where certain areas have beautiful views
111

of mountains or beaches, the topography of Riyadh is desert. Adding onto that is the cultural value of
privacy. In Riyadh, there is both less of a desire for occupants to look out their window and a strong
dislike of strangers looking in. The windows in Riyadh often stay shut to protect the interior space from
the hot, dry air and dust. Ultimately, in Riyadh, the windows commonly stay shut and the drapes stay
closed; people are not using any of the functions of a window. Because of these constraints on the use of
window, both by the climate and the culture, a daylighting tube offers the benefits that a window in
Riyadh cannot.
5.6. Energy and Heat
5.6.1. Los Angeles Energy and Heat
The heat and energy simulations were done in Green Building Studio through Revit. To compare how the
energy use would change when the room has lighting tubes, two simulations were run. One standard
living room, and the other was the same living room but with four lighting tubes (see chapter 4). The
results of both simulations were the same, which means that the daylighting tubes did not reduced the
energy. The light through the windows were enough to achieve the minimum light levels, thus the
daylighting tubes were unnecessary additions.
5.6.2. Riyadh Energy and Heat
The first simulation of a standard living room in Riyadh had typical small windows and daylighting tubes.
The other test was just daylighting tubes, without the windows. The results were that the first used the
most energy in the electricity, and less HVAC because there were no windows, so four lighting tubes in
this case study won't be enough, artificial light is required to achieve the 30-50fc, as recommended by
Title 24. The second test, culturally small windows with daylighting tube, the results were lower lighting
energy because the light though the windows and tubes were enough during the day which make the
electricity lower than the first test, but the HVAC needed more energy than the other test because the heat
goes through windows, so the room needs more energy to cool it.
Riyadh: with windows and daylighting tube Riyadh: with no windows.

Figure 5.12 Bar charts show the energy different in Riyadh with windows and without windows.
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5.7. Glare
In Chapter 4, all the simulations from hdrscope showed that at 9:30am, 10:30am, and 11:30am the
contrast between the light source and the background was significant enough to be considered discomfort
glare on the ground, caused by the direct sunlight from the window. The glare was in the middle of the
room because the height of the window.
The Schiler Glare Method offers a useful rule of thumb to consider the contrast within the image, between
the glare source and background in a histogram. If the ratio of the two measures is less than 2:1, the result
is free of glare, but if the ratio is 3:1 or greater, it can be considered discomfort glare.
5.7.1. Riyadh and Los Angeles at 9:30am

Figure 5.13 Riyadh histogram at 9:30 am 10 January 2016

Figure 5.14 Los Angeles histogram at 9:30am 21 January 2016

As the annotated Riyadh histogram shows (Figure 5.12), the contrast ratio between the glare on the floor,
at the center of the room, and the background of the photo (Chapter 3) was around 1:3. This ratio is
considered discomfort glare.
The Los Angeles histogram displays different levels of light. The difference between these levels were
less than the ratio 1:3.
Luminous intensity
Pixels
Cd/m2
Luminous intensity
Cd/m2

Pixels
113

5.7.2. Riyadh and Los Angeles at 10:30am

Figure 5.15 Riyadh histogram at 10:30am 10 January 2016

Figure 5.17 shows the high glare in the yellow Squares

The Riyadh data from hdrscope shows that there was also glare at 10:30am. Additionally, the histogram
shows that the distance between the glare and the background was more than the first simulation at 9:30
am, which means increased discomfort glare. In contrast, the simulation for Los Angeles at 10:30am
shows that there was no glare inside the room, but there was glare outside on the ground. Further, there
was a high glare region inside the space, called out in figure 5.11 with the yellow rectangles. Although the
LA histogram shows that there was a difference in levels, the ratio was less than 1:3, so the eye can adapt
to the level of contrast. The Los Angeles 10:30am histogram shows bigger contrast than the Los Angeles
9:30am histogram, but still not discomfort glare.

Luminous intensity
Pixels
Cd/m2
Luminous intensity
Pixels
Cd/m2
Figure 5.16 Los Angeles at 10:30am histogram 21 January 2016

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5.7.3. Riyadh and Los Angeles at 11:30am

An anomaly that occurred with the glare results was the color output of the hrdscope program. For the
Riyadh results at 11:30am the glare portion was colored blue. However, the 9:30am and 10:30am glare
results were green. To investigate this question, the professor who developed this program was contacted.
According to Professor Inanici, from the University of Washington, “the colors are random; if you run
the same image multiple times, it might color them differently.”

In this the 11:30am Los Angeles test, the difference between the light sources and the background was the
highest, compared to the other tests. Figure 5.13 shows that there was a dramatic difference in light levels,
but because of the high level of light, which exceeded the 1:3 ratio. the solar radiation was uncomfortable
in some parts in the room. This discomfort glare occurred, even though the whole room was well lit
(Figure 5.13).

Luminous intensity
Luminous intensity Cd/m2
Pixels

Pixels

Cd/m2
Figure 5.18 Riyadh histogram at 11:30am 13 January 2016

Figure 5.19 Los Angeles histogram at 11:30am 15 January 2016
Figure 5.20 discomfort glare in the red
shape

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5.8. Summary
This chapter spanned the analyses of the different types of data collected for this research. Discussing the
results of the survey offers insights into the level of privacy and types of windows people prefer in Los
Angeles and Riyadh. The questions gauged their behavior, in terms of utilizing windows and how heat,
glare, and privacy affected their use. Comparing the two cities, the data shows that people in both cities
were bothered by the heat. People in Riyadh typically preferred privacy from strangers, largely keeping
their curtains closed, even at night. Additionally, the majority of people in Riyadh did not use their
windows to get fresh air. The biggest difference was the view through the windows: people in Los
Angeles used the window to look to the outside view. In Los Angeles, 20% of the people spend more than
five hours in front of the window. On the other hand, 7% of the people in Riyadh spend more than two
hours in front of their window to appreciate a view. This is a significant difference.
Observations were made in Wshiger, the Old City, during the site visit on the building systems,
architectural style, city planning, construction materials, and people’s behavior compared with Riyadh.
There’s an urge in modern cities to create new solutions to climate problems, however, looking to
examples before the industrial revolution offers proven solutions that are more energy efficient. Rather
than fight the climate, architecture in Wshiger responds to it. In Wshiger, the residences contained
courtyards and were designed with small exterior windows and larger windows facing the protected
courtyard space, to increase daylight while protecting occupant privacy. The narrow streets meant spaces
protected from the harsh sun and the entire city was surrounded by trees, so incoming air was naturally
cooled. Thermal mass was achieved through thick walls made from mud. The methods found here are
worth studying and developing and, as urban architecture evolves, should be considered and integrated
with technology. The modern city and its systems should take cues from the techniques of the past.
A major conclusion drawn from the illuminance simulations was that the daylighting tube did not affect
the amount of light in the room with a window wall in Los Angeles or the energy used. On the other hand,
the Riyadh tests demonstrated significant differences in the amount light entering the room, the
distribution of the light, and even the energy use when daylighting tubes were installed. In Los Angeles,
there was sufficient daylight entering the space from the large windows. However, in Riyadh, the typical
small windows were not effective enough and thus the daylighting tubes were helpful in increasing the
daylight amount in the room. Riyadh tests show that when no windows were modeled, the amount of heat
dropped, but the daylighting tubes were not enough to achieve the necessary amount of light, which
meant that the building needed to expend more energy for the artificial light. It is possible that more light
tubes in the same space would be sufficient.
The glare analysis of the photographs shows that the glare in Riyadh was higher than in Los Angeles. All
the Riyadh results included discomfort glare in the room, but only one of the Los Angles tests resulted in
discomfort glare.
All the results show that people in Riyadh with single story buildings, ought to explore options of getting
daylight other than or in addition to windows. The current architecture used in Riyadh does not make
sense for the climate nor the culture. As a consequence, people used a significant amount of energy and
the indoor environmental quality is not as good as it could be with passive strategies.

116

6. Chapter 6

117

6.1. Summary
The building systems that affect human behavior need to be designed with specific climate and cultural
considerations in order to be used effectively. People may ask why sunny cities are not covered in solar
panels, why windy cities are not filled with wind turbines, or why having big windows is not always the
answer to getting more daylight and saving energy. The answer is that these systems need to be adjusted
based on specific contextual elements. For example, solar panels in hot tropical climates would not have
the same efficient as in clear sky or hot dusty climates. Likewise, if occupant behavior is not in line with a
system’s design, it will not fulfill the efficiency intended. To examine the impact of cultural practices on
efficiency, the research modeled daylight through windows and through daylighting tubes in two cities
with similar climates but divergent cultures, Los Angeles and Riyadh.
The research methodology spanned five stages:
1. Site Visit: Observations from visiting an old city in Riyadh offered insight on climate and culture-
sensitive passive strategies.
2. Survey: Residents of Los Angeles and Riyadh answered questions that helped gage occupant
behavior and cultural values.
3. Illuminance Analysis: A standard living room was modeled in both cities and analyzed with two
different scenarios in two programs, Autodesk 360 and 3ds Max. For Riyadh, the Scenario 1
living room included typical, small windows and daylighting tubes. Scenario 2 modeled the same
daylighting tubes but no windows. For Los Angeles, Scenario 1 included a curtain wall and
daylighting tubes. Scenario 2 had the same glazing but no daylighting tube.
4. Heat and Energy Simulation: For all the scenarios, a heat and energy simulation was run in Green
Building Studio.
5. Glare Analysis: Glare was simulated and analyzed in hdrscope.
The urban design of the old city included clever solutions to get more daylight, reduce the heat gain, and
maintain the local culture, yet these techniques are often absent from modern cities. In the old city,
unassisted by building systems, every building element was considered more carefully in its context.
The survey results suggest that people in Riyadh desire big exterior windows, like their American
counterparts. However, the dilemma demonstrated was that, despite this preference, Riyadh residents
largely did not open the drapes of their windows for fresh air, daylight, or to have an outside view.
Further, the Riyadh participants reported that they were also bothered by the intrusion of heat through the
windows, the decreased privacy, and the discomfort glare. The resulting reliance on artificial light
suggests that other avenues for acquiring natural light should be explored, which encouraged the
following research into the possible use of daylighting tubes.
The illuminance tests showed that including the lighting tubes only made a minor difference in Los
Angeles but had a greater impact in Riyadh. In the LA model, the natural light from the curtain wall in the
room was more than enough to satisfy recommended levels. In Riyadh, the first scenario with the small,
culturally-typical windows and daylighting tubes, achieved desirable illuminance levels and diffused
evenly in the room. Riyadh’s Scenario 2 modeled no windows, to mimic the common practice of closing
the windows and the drapes, but included daylighting tubes. The amount of illuminance from the tubes
were not enough to fully eliminate the need for artificial light in this case, but it did supplement it. adding
two more daylighting tubes in this case might have been the solution. According to the heat and energy
simulations, Scenario 2 used less energy than the first scenario, which used more energy for cooling the
room.
Glare was analyzed in hdrscope using real photos taken in Los Angeles and Riyadh during January. In
Los Angeles, the glare was high through the window, but the human eyes can adapt to this amount of
118

glare. The contrast with the background was less than 1:3, but at 11:30am the glare exceeded this ratio,
which suggests more discomfort glare could be expected in the summer. In Riyadh, the glare was higher
and uncomfortable in all morning tests.
6.1.1. Research Scope
The boundary of this research was Los Angeles and Riyadh, chosen for their similar climate conditions
but contrasting cultures. The daylighting tube that was tested in this research was a standard size: 1.6’ in
diameter and 3’ in height. The glare test was conducted in morning winter conditions. The survey
consisted of 17 questions that aimed to categorize the 80 participants’ window type preferences and daily
use of windows.
6.2. Research Obstacles
During data collection, some complexities arose that should be noted before any further research or before
this research is applied in a different culture.
6.2.1 The Daylighting Tube Model
There were no daylighting tubes found in any of the researched simulation programs. A digital model
needed to be built and modeled with a skylight in order to attach to the roof. As a consequence, in order
for Revit to accept it as a roof attachment and have an opening, it was essentially read as a customized
skylight. The interaction of the doom and the lens as a collector, as well as the light bouncing within the
tube, may not be accurate but is still useful for this exercise.
6.2.2. Illuminance
The Autodesk 360 simulations generate image results without numbers. The illuminance levels are
identified by colors, which make discerning small differences difficult. There was no professional
program that measures the daylight illuminance. The best program found for this study was 3ds Max. 3ds
Max does measure the illuminance in plan, walls, roof, and 3d view and reports the result numerically, in
either lux or foot-candles. The results also included
colors, however, as confirmed with the software
developer, these colors had no significance. If the same
simulation was run more than once, the colors might
change. For example, in figure 6.1, the colors show that
the light is coming from the right side and there was
something blocking some of the light (see the circles in
the Figure 6.1) but in fact there was nothing blocking. If
you zoom in and read the numbers, the amount of
illuminance was very close from one area to the other.
Additionally, the calculations of the illuminance in 3ds
Max were not consistent. For example, if the light meter
was moved and then returned to its original position, the
illuminance would change slightly.
6.2.3. Glare
Many difficulties were faced in determining glare. First
and foremost, there was no BIM program that could
simulate glare. The solution used in this research was to
Figure 6.1 3ds max Los Angeles plan 4 daylighting tubes
and curtain wall 21 June 1:00pm

119

test glare in both locations by taking pictures and uploading them to one of the glare analysis programs,
which was other problem.
Neither Revit nor AutoCAD have glare analysis functions. The lighting simulation and analysis programs
did not compute glare. At the time of this research, there were only a few glare programs available in the
market, however, these software programs were still in development rather than fully polished,
professional products. The programs available have many problems, do not run in newer versions of
Microsoft Windows, are not user friendly, and some of them text based programming. Future research
would be greatly improved with more developed glare analysis programs. Typed Manuel input.
6.3. Future Work
Future research could extend beyond residential buildings to include commercial structures. The study of
commercial buildings could be particularly useful in the cases of office spaces where cubical partitions
block the sunlight entering from the windows. Additionally, other spaces where the daylight from the
windows does not reach, such as corridors or area of a large footprint, may benefit from the inclusion of
alternate daylighting solutions like daylighting tubes. This work is mostly applicable to single floor
buildings, which makes it applicable in only certain cases.
This research tested the standard daylighting tube. An interesting development of this research would be
studying the hybrid daylighting tube, which integrates artificial light, and the fiber optic-daylight systems.
These energy-aided options perform in both sunny and overcast climates. It might also better lend itself
to multi-story applications.
Another topic of interest is investigating the ratio between the efficiency and the height of the tube or the
length of the fiber optic. Additionally, in multi-story buildings, which were not considered in this study,
should the tube attach to the roof or the exterior wall?
The methodology could be amended to address other cities and cultures. There is potential for a tool that
could recommend daylighting systems based on both climate and user preferred shading strategies. The
sample size and diversity should be increased.
6.4. Conclusion
In order to improve the energy efficiency of residential buildings, occupants need to understand the
building systems and the personal significance of saving energy. Beyond being beneficial for the
environment, an energy-efficient building system also promotes good indoor environmental quality, saves
money, and can improve occupant health. One of the ways to improve the efficiency is to specify and
adapt the systems for specific locations. Therefore, one of the most important factors to consider during
design beside climate is the culture because of its impact on occupant behavior. The hypothesis of this
thesis tested the daylighting tube in two similar climates but different cultures to prove or disprove the
hypothesis that lighting tubes are more beneficial in achieving the minimum illuminance in residential
building in cities with specific cultural norms and values that affect the size and use of windows. In Los
Angeles (at 34 N Latitude), California, residential buildings often achieve the minimum light levels
through large windows. In Riyadh, (at 24 N Lat) Saudi Arabia, where the windows are culturally smaller
or absent, a lighting tube should be installed to achieve the minimum illuminance of daylighting needed
in the residential homes. The culmination of this research suggests that in social and environmental
climates like Riyadh, where cultural values limit the use of exterior windows, daylighting tubes could be a
useful passive solution.
120

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Abstract (if available)

Abstract Choosing an effective daylighting mechanism for a home is a function of its environment: both the climate and the culture. Two distinct locations, Los Angeles, California and Riyadh, Saudi Arabia, are used to compare the use of light tubes to improve the amount of daylight penetrating a residential space. During the daytime in Los Angeles (Latitude 34 N), people receive natural light through the windows of their homes. As a consequence of this preference, lighting systems such as daylighting tubes are often unnecessary because the daylighting through the traditional windows exceeds the minimum design level. In contrast, the residential building interiors in Riyadh (Latitude 24 N) do not achieve the minimum illuminance from the daylight from the windows due to issues and concerns with glare and privacy. Because of the discomfort caused by glare and the culturally-founded concerns regarding privacy, the windows in Riyadh are commonly small and people often keep the curtains closed at all times. Daylighting tubes would allow the residential interiors to achieve the minimum illuminance from daylighting, while also addressing the issues of glare and privacy. Although lighting tubes can be used in any climate and country, certain circumstances make the use of lighting tubes more beneficial. To determine this, four elements were studied, tested, and compared. The four factors were glare, privacy, heat gain, and energy. There are multiple computer programs available to test glare. Hdrscope was chosen because it is one of the best glare programs. A survey was used to analyze and compare the differing levels of the privacy needs of both cities. Heat and energy were examined by using the energy modeling program Integrated Environmental Solutions (IES). The objective is to provide an overview of all common daylighting systems and prove that lighting tubes are more efficient in certain cities and cultures. The effectiveness of a daylighting system relies on more than just climate and sun exposure

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Asset Metadata

Creator Aljammaz, Mohammed (author)

Core Title Daylighting in Riyadh and Los Angeles: comparison of cultural factors in potential market penetration

School School of Architecture

Degree Master of Building Science

Degree Program Building Science

Publication Date 04/21/2016

Defense Date 03/21/2016

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag daylighting tube,glare,hybrid lighting system,illuminance,luminance,luminous intensity,OAI-PMH Harvest

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Advisor Schiler, Marc (committee chair), Choi, Joon-Ho (committee member), Noble, Douglas (committee member), Schierle, Goetz (committee member)

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