International Journal of Civil Engineering and Technology (IJCIET)
Volume 10, Issue 04, April 2019, pp. 599–608, Article ID: IJCIET_10_04_062
Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJCIET&VType=10&IType=4
ISSN Print: 0976-6308 and ISSN Online: 0976-6316
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IMPROVING THE DAY LIGHTING OF DEEPPLAN BUILDINGS BY MEANS OF LIGHT
PIPING TECHNIQUE: THE CASE OF
ARCHITECTURAL STUDIOS IN THE
DEPARTMENT OF ARCHITECTURE,
UNIVERSITY OF JORDAN
Dania Abdel-Aziz*
Department of Architectural Engineering, University of Jordan, Amman, Jordan
Esra'a A. Al-Qudah
Department of Architectural Engineering, University of Jordan, Amman, Jordan
Hadeel Y. Yasien
Faculty of Engineering Technology, Department, Al- Balqa' Applied University,
As-Salt, Jordan
Rizeq Hamad
Department of Architectural Engineering, University of Jordan, Amman, Jordan
*Corresponding Author
ABSTRACT
This research discussed the importance of daylight as one of the major factors in
sustainable architectural design and highlights the significant role of daylight in
energy consumption reduction and enhancement of human health and performance
due to the unique characteristics of daylight such as; spectral composition, quality,
and variability which has demonstrated to make it a preferred source of lighting. A
physical 1/20 scale testing model is built in real sky design conditions to evaluate the
feasibility of utilizing light pipes to enhance daylight in deep plan studio and to reduce
the need for electric lighting. Using the model in outdoor day-lighting condition
helped to evaluate the daylight performance of different mirrored light pipe
prototypes. The study provides insight about light pipes parameters and evaluated
them in order to understand the relationship between those parameters and the
amount of illumination delivered. The parameters include cross-section shape, crosssection area, internal angle and collector’s size and inclination angle. The research
proved that the light pipe system is the simplest advanced system that allows daylight
to transport into the interior spaces where windows are restricted. Five horizontal
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pipes are sufficient to illuminate the studio by 750 Lux which are recommended in
design studios.
Key words: Mirrored light pipes, scale model testing, poorly lit spaces, daylight
system, educational buildings.
Cite this Article: Dania Abdel-Aziz, Esra'a A. Al-Qudah, Hadeel Y. Yasien, Rizeq
Hamad, Improving the Day Lighting of Deep-Plan Buildings by Means of Light
Piping Technique: The Case of Architectural Studios in the Department of
Architecture, University of Jordan, International Journal of Civil Engineering and
Technology 10(4), 2019, pp. 599–608.
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=10&IType=4
1. INTRODUCTION
Jordan is a poor country in natural resources (oil and natural gas), with 97% of the country’s
energy imported from neighbouring countries, which created a great load on the national
economy. Thus it becomes a critical and urgent issue for the country to search for other
resources. The use of natural daylight in buildings is one of the easiest and cheapest
solutions. It also, gives psychological and physiological benefits on human health (visual,
nervous, and circadian systems) and its other benefits that proven to produce significant
human productivity. Due to these characteristics, daylight is considered an efficient
sustainable approach that architects trying to provide in buildings (Mohamed, 2008; Edwards
& Torecellini, 2002), Natural daylight is the dynamic tool for expressing the quality of
architectural design. Daylight is a combination of direct sunlight, and skylight. It is an
essential, free and clean, natural inexhaustible resource of light. It offers both aesthetic and
functional benefits to architecture, because it improves the visual appearance and colour of
objects and help occupants to see small details better (Zhang, 2002). It, also, adds depth to
dynamic complex geometries by the effect of shadow results from light (Michael, et al., 2004:
Rockcastle & Andersen, 2014).
Buildings account for approximately 40% of the world’s yearly energy use while most of
the energy is consumed for lighting, heating, cooling, and air conditioning supplies (Alrubaih,
et al., 2013). Lighting and its related cooling costs constitute 30% to 50% of a non-residential
building’s energy use (Mohamed, 2008). The increasing usage of daylight system can provide
better savings in electricity consumption, up to 20-30% of total energy use (Oakley, et al.,
2000). Introducing daylight into deep interior spaces is difficult with side lighting of simple
windows especially for buildings with limited facades while top lighting of roof monitor or
skylights are difficult to implement in multi-storey buildings. New technology, of what is
called Light Pipes, has been developed to harvest daylight and transport it into deep building
interiors.
Educational buildings (schools, colleges and universities), normally have deep plans or
underground areas, thus depend most of the time on electricity for lighting. These buildings
are utilized during daylight hours, resulting in consuming greatest capacities of electricity,
which is opposite to the principles of sustainability and to Jordan’s financial abilities, and
workplace health.
This study highlights the usability issues of light-pipes by discussing their ability to,
transfer light to deep spaces, increasing daylight levels in spaces, contributing in reducing
energy consumption, producing a healthier working environment, provide a connection to the
outside for users and cost-effective solution.
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Improving the Day Lighting of Deep-Plan Buildings by Means of Light Piping Technique: The
Case of Architectural Studios in the Department of Architecture, University of Jordan
1.1. The Climate of Jordan
Jordan is located geographically in Southwest Asia, about 80 km east of the Mediterranean
Sea between 29◦ 11′ to 33◦ 22′ north, and 34◦19′ to 39◦ 18′ east. Altitude ranges from 416 m
below sea level (MSL) at the surface of the Dead Sea up to the 1845m above MSL at Um
Dami Mountain (Ministry of Environment, 2007). The yearly sunshine hours in Amman in
the year are shown in Table. 1. Because of it is location in the earth-sun belt zone which has
high potential solar energy, solar radiation in Jordan is one of the highest values around the
world, therefore, with this high solar radiation and about 330 sunny days annually, Jordan has
high potential in investing solar energy.
Table 1. Data of sunshine period (hours) in Amman. Source: (Amman.climatemps, 2014).
Month January February March April May June July August September October November December
Hour 10.30
11
11.30 13 14 14.5 14.5 13.30
13
11.5
11
10.50
2. LIGHT PIPES SYSTEMS
Delivering Daylight into buildings can be simply done by window openings. They are the
most common devices in buildings. But these devices are not capable of introducing daylight
into deep plan buildings. Thus other systems of delivering daylight are needed. Much research
is being conducted to enhance the performance of light transport systems, focusing on the
collection, transportation and distribution of light. New light transport systems, have the
ability to gather and transport sunlight over large distances within a building. These are called
light pipe systems. By using these devices natural illumination for buildings with depths
greater than 10m from windows can only be practically accomplished (AyersBEng & Carter,
1995). Light pipes consist of the following components that called Light pipe structure:
1. An outside collector: It is composed generally from refracting or reflective systems. The
objective is to catching sunlight and transporting it inside the pipe. Collecting natural light
can be fulfilled by Passive collectors or Active collectors.
2. Light pipe or Light tube itself which is called transporter: It transfers the light to where it is
required, with transportation method dependent on the material chosen for pipe (e.g. lenses,
prismatic pipes, mirrored light pipes and solid core systems).
3. Light pipe Diffuser (which may include extractor tools) that distributes light uniformly
across the interior space. Depending on the light transport device and the scale of the system,
the extractors can be at the end of the tube, at multiple points along the pipe or in a continuous
manner (Garcia-Hansen, 2006).
The majority of light pipe systems depend on direct sunlight as the source of light thus
they are suitable for sunny climates.
3. DESCRIPTION OF THE ARCHITECTURAL DESIGN STUDIO (102)
AT UNIVERSITY OF JORDAN
The architectural design studio (102) is situated in the architectural department at the faculty
of engineering and technology in the University of Jordan (UJ), was chosen to apply the
experiment on. The design studios and lecture halls are situated in the ground and basement
floors of the building, while first and second floors are used for offices. The architectural
design studio (102) is located in the ground floor of the architecture department. The studio is
9.30m wide x 10.80m long x 4.20m height with an area of approximately 100 m2. Figure
(1:a) illustrates the studio plan.
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The studio was selected because it has limited access to natural light; it has just one northfacing wall with windows looking at a 3m-width corridor separating it from central courtyard
with trees inside (figure.1:b). The studio is usually occupied by architectural students from
9:00 am to 5:00 pm which coincide with daylight hours, resulting in achieving greatest
consumption of electricity when there is greatest abundance of daylight for illumination.
Table (2) outlines the variables of the study.
Figure 1.a). Architectural design studio plan (source: Engineering Department of the UJ). (left). b) a
view of the courtyard from the design studio (right).
Table 2 list of research variables
The cross-section shape
Equilateral triangle
rectangle
square
variation:
0.9m
The cross-section area for 1.4m
0.6m
all shapes=0.79m2, and
0.9m
1.2m
the internal angle for all
shapes=45°
The cross-section area
Circle area=0.79m2 Circle area=0.44m2 Circle area=0.2m2
variation:
The internal angle is
75cm
1m
50cm
constant for all areas=45°
Internal angle variation:
Circle area is constant=
0.79m2
45° internal angle
Collector angle variation:
Constant area, shape, and
internal angle
45° collector angle 30° collector angle 60° collector angle
70 cm
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30° internal angle
70 cm
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circle
1m
60° internal angle
70 cm
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Improving the Day Lighting of Deep-Plan Buildings by Means of Light Piping Technique: The
Case of Architectural Studios in the Department of Architecture, University of Jordan
Collector size variation:
Constant collector angle=
60°
small
medium
40 cm
70 cm
large
100 cm
4. EXPERIMENT SET-UP
4.1. Construction of physical scale model
A 1:20 physical scale model of the design studio was constructed to evaluate and study the
performance of horizontal mirrored light pipe. It was built using thick white cardboard paper
sheet covered with black sheet to avoid light leakage. One of the side panels was made
removable to facilitate access to the interior for placing the daylight meter which was used to
measure the daylight factor (DF). The model was placed and leveled on top of table on the
roof for better access and appearance, and was oriented to north-south access to simulate the
orientation of the design studio.
4.2. Light Pipe system: Materials, Design and Construction
There are four different cross-section shapes to be studied, cross-section shape, cross-section
area, internal angle, collector angle. It was important that the materials used were easily
available locally and cheap. The length of the light pipe was 9.35m in order to be located in
the middle of the studio and it was installed at 3m height from the floor (figure 2: a &b).
Figure 2 a) plan shows the location of light pipe (Left). b)section of the light pipe design (right).
The internal angle of the reflective surface facing the inside output aperture was fixed to
45◦ and the internal angle of the other reflective surface which faces the outside input aperture
was varied. The cross-section shape and area also was varied, along with the collector area
and inclination angle.
4.3. Methodology
The experiment had been made in several days in April, 2016 under real sunny conditions
from 9 to 12 am. It is consisted of five phases, within which analysis was performed for 13
light pipe prototypes; Phase one: Comparison was made between 4 prototypes with different
cross-section shapes. The internal angles of the two reflective surfaces in the pipes were 45°
and the cross-section area was 0.79 m2. The cross-section shape with highest performance
was selected for the next phase, Phase Two: In the second phase, the effect of cross-section
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area was studied. The evaluation was conducted between three prototype different in crosssection areas and similar in cross-section shape and internal angles. The best cross-section
area was selected for the third phase, Phase Three: A comparison was conducted between 3
prototypes different in the internal angles (30°, 45° and 60°) of the reflective surface facing
the outside input aperture and Phase Four: The effect of installing collectors with different
inclination angles (30°, 45°, and 60°) was evaluated.
The illuminance was measured using a lux meter device, at the ground level in 3 different
points inside the physical model, one under the light pipe and the other two points are 2m
distance north and west of this point (figure 3). In order to calculate the daylight factor (DF),
the exterior illumination was also measured simultaneously with the interior measurement.
The light sensor of the lux meter shouldn’t be blocked by obstructions or shadows during the
measurement to ensure that measured data giving by the lux meter sensor are precise.
5. RESULTS AND DISCUSSION
The daylight factors (DF) [1] and the uniformity ratios of the light pipe prototypes studied in
the experiment were measured using daylight factor Meter [2]
5.1. Phase1: the effect of cross-section shape
The daylight performance of four light pipes with different in cross-section shapes (triangle,
rectangle, square and circle) under sunny sky conditions was assessed. Figure (3) shows the
measured DF values of the four pipes at three different points inside the scale model. It is
clear that the light pipe with circular cross-section shape has the greatest DF values at the
three points, and the triangular cross-section shape has the lowest values.
Figure 3 Comparison between the DF values of different cross-section shapes
5.2. Phase 2: the effect of cross-section area
The daylight performance of three circular light pipes with different cross-section areas (0.2
m2, 0.44 m2, and 0.79 m2) was evaluated. The measured DF for the prototypes is shown in
Figure (4). It is clear that the light pipe with the largest cross-section area has the highest DF
values at the three points, and the light pipe with the smallest cross-section area has the lowest
values.
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Improving the Day Lighting of Deep-Plan Buildings by Means of Light Piping Technique: The
Case of Architectural Studios in the Department of Architecture, University of Jordan
Figure 4. Comparison between the DF values of different cross-section areas.
5.3. Phase 3: the effect of internal angle
In the third phase, a comparison between the performance of three light pipes with different
internal angles (30°, 45°, and 60°) was conducted. All these pipes have the same circular
cross-section shape and cross-section area of 0.79 m2. The measured DF for the prototypes at
three different points inside the scale model is shown in Figure (5). It is evident that the light
pipe with the internal angle of 60° has the highest DF values at all points, and the light pipe
with the internal angle of 30° has the lowest values.
Figure 5. Comparison between the DF values of different internal angles.
5.4. Phase 4: the effect of using collectors with different angles
In this phase, the effect of installing three collectors with different inclination angles (30°,
45°, and 60°) was evaluated. The measured DF for the prototypes are shown in Figure (6). It
can be seen that the DF values of the prototypes are very close together with the highest DF
values at angle 60° and the lowest values at angle 30°.
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Figure 6. Comparison between the DF values of collectors with different inclination angles.
5.5. Phase 5: the effect of changing the size of the collector
In the final phase, the effect of using three collectors with different sizes was studied. The
measured DF for the prototypes are shown in Figure (7). It can be seen that the DF values of
the prototypes are also very close together with the highest DF values at the large collector
and the lowest values at the small one.
Figure 7. Comparison between the DF values of collectors with different sizes.
It can be seen that the final light pipe has the best daylight performance compared to the
other light pipes. It is a circular light pipe with 0.79m2 cross-section area, 60° internal angle
and large collector with 60° inclination angle. Its DF value at point 2 improved 144 percent
over the DF value of the first triangular light pipe. Figure 8 shows a detailed drawing of the
light pipe.
Figure 8 a detailed drawing of the final light pipe
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Improving the Day Lighting of Deep-Plan Buildings by Means of Light Piping Technique: The
Case of Architectural Studios in the Department of Architecture, University of Jordan
As the recommended DF value is 2%, the studio will need 5 light pipes to provide a good
illumination in the space, since the sky luminance in Amman is 10000 Lux. The illuminance
will be (5*(2/100)*10000)= 1000 Lux. Figure 9 shows the suggested distribution of light
pipes in the studio classroom.
Figure 9 the suggested distribution of light pipes in the studio classroom
As the uniformity ratio of the light pipe is below the recommended ratio, a distribution
system such as glass diffusers or laser cut panels could be used to improve the distribution of
luminance.
6. CONCLUSIONS
The study found that light pipe system is the simplest advanced daylight system that allows
daylight to transport into the interior spaces where windows arc restricted.
It was found that different cross-sectional shapes of light pipe provide good illumination
and the best shape is the circular one. The DF values increases with the increase of the crosssectional area. The best inclination angle of the reflective surface facing the input aperture
was found to be 60°. Installing a passive collector achieved a slight increase in the OF value,
with the highest value achieved by the large collector of 60° inclination angle and the
illuminance in the studio is measured to be 1000 Lux.
The uniformity ratio of the suggested light pipe was below the recommended range, which
means that the light pipe needs a distribution system to diffuse the daylight evenly across the
space.
Using light pipe systems will help in improving visual comfort in classrooms due to the
instruction of natural daylight and distribution to large area. They also assist in saving energy
and could be an effective way to decrease energy consumption in educational buildings in
general. The energy saving using light pipe systems will have a positive effect on the
environment as a result of decreasing co2 emission.
KEYNOTES
1.DF: is the percentage ratio between inside illuminance and outside illuminance.
2.Megatron/UK- name of the manufactory.
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