JOURNAL OF ENGINEERING AND APPLIED SCIENCE, VOL. 66, NO. 6, DEC. 2019, PP.

679-701
FACULTY OF ENGINEERING, CAIRO UNIVERSITY

ANALYSIS OF THERMAL COMFORT ENHANCEMENT USING

VERNACULAR ARCHITECTURE IN SIWA OASIS, EGYPT

H. SAMEH1, A. El ZAFRANY2 AND D. N. ATTIYA3

ABSTRACT

Siwa Oasis has a unique vernacular architecture, built with walls of an earth
martial called (Kerchief), and roofs of palm tree trunks. The uniqueness of Siwa’s
cultural heritage is accentuated by its natural heritage. However, modernization
reached this exotic place. Concrete and multi-story buildings started to appear
changing the original vernacular atmosphere, and local residents started to adopt new
building technologies to suit a modern lifestyle, threatening the integrity of the cultural
heritage. Vernacular Kerchief buildings are known to be cooler than conventional
modern concrete; specially in hot daytime, but Kerchief walls are extremely vulnerable
to water (scarce rain destroys the buildings and sanitary water used inside threatens the
safety of the bearing walls). But, locals often prefer the modern (hot) buildings to the
traditional cool yet vulnerable buildings. This paper aims at analyzing the thermal
behavior of vernacular Kerchief buildings, compared to modern buildings, to define
what exactly makes them perform better thermally (the material, the mass or the
design). Simulation of ten parameters and combinations of a model building in Siwa
was conducted, using EnergyPlus and Design Builder software to determine the
parameters that affect thermal comfort.

KEYWORDS: Vernacular architecture, thermal comfort, thermal mass, kerchief

bearing walls, adobe, simulation.

1. INRODUCTION

Shali Castle in Siwa Oasis has a unique style in construction [1]. It is now just
ruins and houses on the verge of falling apart, whose traditional form can be

1
Prof. of Architecture Design, Architecture Dept., Faculty of Eng., Cairo Univ., Egypt
2
Prof. of Environmental Design, Urban Design Dept., Faculty of Urban Planning, Cairo Univ., Egypt
3
PhD Student, Architecture Dept., Faculty of Eng., Cairo Univ., Egypt. dinanoureldeen@gmail.com
 H. SAMEH ET AL

distinguished by walls and windows. These ruins have a special morphology,

distinguishing it as a landmark of Siwa Oasis [2].
In summer, thermal comfort is a major concern in Egypt arid climate [2].
Climate is an important element in determining the basis for the design of buildings;
distances between buildings, building shapes, their orientation, and the outer envelope
of the building [3]. Heat transfer is an important factor in the determination of the
building design parameters; windows, wall thickness, and wall materials that improve
thermal comfort [3]. It is claimed that the use of traditional building materials of Siwa;
Kerchief bearing walls and palm trunk roofs, result in buildings with better thermal
performance than that of the new building techniques and materials; concrete skeleton
and brick walls. In new housing, i.e. concrete skeleton and masonry walls architecture
does not fit the desert climate. Kerchief as a wall building material is known to have
superior thermal properties compared to common brick walls. The wooden roof is also
proven to have better insulation than the concrete roof. Using the traditional way in
building houses by Kerchief requires the windows to be small–which formulates an
important attribute in the traditional building that makes it always in good
performance. The benefit of traditional building depends on using local materials
[4-6]. Traditional architecture is always defined as a type of architecture that depends
on materials available on site. This type of architecture reflects the traditions that
match the climate and needs of Siwa’s society‫۔‬
The current housing in Siwa is considered unsatisfactory to the community of
the oasis, accordingly, the people are moving towards the use of contemporary
building materials and techniques, despite the environmental sustainability of the
traditional buildings. This community began to leave their traditional homes and
demolish them for socioeconomic goals. Accordingly, new housing has been built with
artificial modern materials. As a result of these movements, the Oasis started to lose its
identity and its heritage buildings. In areas with hot, dry climate, especially in urban
areas, the amount of energy and loads increase in summer. In Egypt, due to high
temperatures, people have relied on the use of mechanical cooling systems to improve
the indoor thermal performance of space. Currently, the economic need has increased
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which led to a change in the perception of the concept of indoor comfort [7]. Previous
studies have shown that dry hot areas use 70% to 80% mechanical cooling systems [8].
Now people use mechanical cooling systems to improve the indoor thermal comfort,
instead of creating new solutions through traditional architecture techniques.
Recently, building performance simulation tools played an important role
during early stages of design [3]. This could help design decisions related to wall
thickness and materials, hence, improving the indoor thermal comfort. The building
envelope is the most influential parameter to indoor thermal comfort [9]. The
manipulation of windows, wall thickness, insulation, and color is used to reach indoor
thermal comfort. Thus, the traditional thickness of walls is an important element to
minimize heat transfer through walls [10]. This research focuses on the study of
traditional architecture in Siwa Oasis and the mechanisms for improving the existing
houses within the climate conditions, by examining the techniques and methods
required to reach a satisfying life for the society of Siwa in contemporary times.
It is important to conserve the distinctive architecture and urban character of
Siwa Oasis and to utilize the advantages of local and traditional materials and
techniques, while achieving good quality of life including thermal comfort, with low
energy consumption.

2. LITERETURE REVIEW
2.1 Location

Siwa Oasis is the northernmost of the Egyptian Oases of the Sahara, it is

situated 12 km east of the Libyan border [11] and 300 km south of the Mediterranean
coast. The Oasis extends in east-west direction in a depression 17 m below the sea
level [2]. long., 25.5°E lat., 29.2°N [12].

2.2 Climate

Siwa Oasis has a hot dry climate; it has high temperature most of the year
exceeding comfort zone shown in Fig. 1, the mean maximum temperature exceeds
40°C in summer months (June till August) and the minimum temperature barely
reaches the comfort limits during summer nights. In spring and autumn, the daytime

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temperature is hot 32°C to 39°C), with cold nights. The diurnal range is high (20°C)
which opens way to utilizing thermal storage as a passive cooling technique which is
needed nine months of the year, air movement is very weak in summer but high in
winter, between (0.25 m/s to 4 m/s). In addition to that, the humidity is very low due to
the desert climate.

Fig. 1. Temperature of Siwa Oasis.

2.3 Traditional Building Materials

People in Siwa build their houses using Kerchief bearing walls and palm trunk
roofs called (Fatimi) [13, 14] as shown in Figs. 2-4. Kerchief is a (concrete– like)
building material composed of rock-salt blocks cemented by a mixture of salt, clay and
sand; which exists naturally around salty lakes in Siwa.

Fig. 2. Structure system in Siwa Oasis

(Kerchief bearing walls and palm trunks called Fatimi) [15].

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Fig. 3. Structure system in Siwa Oasis Kerchief bearing

walls and palm trunks called (Fatimi).

Fig. 4. Traditional Kerchief houses.

The Kerchief material is considered suitable for the climate conditions, due to
its bearing capacity it is usually built with thickness exceeding 2 feet [16]. It varies
from 0.5 m to 1.00 m, so it has high thermal mass that help keep the building cool in
summer and warm in winter [17].
The house located in Siwa Oasis beside El Babenshal hotel as shown in Fig. 5.
The house consists of several rooms on two floors (ground floor and first floor).

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Fig. 5. A Sample traditional Kerchief house.

Kerchief is a (concrete– like) building material composed of rock-salt blocks

cemented by a mixture of salt, clay and sand; which exists naturally around salty
lakes[18, 19], the material is mainly NaCl salt crystals with impurities of clay and sand
as shown in Fig. 4. Halite is commonly known as salt, chemically is known as a
sodium chloride (NaCl) as shown in Fig. 6 and Fig. 7. In geology, it is defined as rock
composed primarily of halite, known as “rock salt” [20]. The NaCl composes more
than half of the Kerchief walls as shown in Table 1 [2]. It is widely accepted in
architecture that traditional natural materials have thermal properties better than
artificial materials [16, 21, 22]. Kerchief consists of seven salt rocks and mud [2, 11]
one of the salt rocks is called halite and it’s about 86% of Kerchief as shown in Table
1, the halite conductivity is between 1.6 and 6 W/m2.K [23], but the measured thermal
properties for the Kerchief as shown in Table 2. Based on a lab test for sample
material [21] proves a different fact; thermal conductivity is between 1.6 W/m.K and
2.35 W/m.K which is much higher than adobe (0.4 W/m.K) [24] or even fired brick
(0.6-0.7W/m.K) [25-27], this seemed strange and surprising. A confusion often
happens considering Kerchief and adobe as one material while they are not, Kerchief
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consists of salt rocks and mud and adobe is a mix of clay and sand with some organic
fibers (reeds) that are added to reduce cracking.
A mixture of sand, clay and halite can have conductivity higher than adobe
(sand, clay and organic fibers). Further section of this paper explains why Kerchief
construction has good thermal performance in spite of its high conductivity.

Fig. 6. Salt around the lake at Siwa Oasis. Fig. 7. Halite (rock salt) [28].

Table 1. Kerchief material properties based on a lab test for sample material [2].
Material Halite NaCl% Quartz%
Kerchief 86 4

Table 2. Kerchief material properties based on a lab test for sample material [21].
Material Thermal conductivity W/m.K Density kg/m3
Kerchief 1.65-2.35 2185-2400

2.4 Current Building Materials

In modern time, different materials and structure systems are used, (listed in
Table 3). The most dominant building is bearing wall masonry structures followed by
Kerchief buildings. Adobe and concrete skeleton types are both familiar.
Table 3. Structure Systems in Siwa Oasis [24].
Structure system Area (Fadden) Ratio%
Bearing wall 101.47 29
Kerchief 91.40 26.1
Adobe 74.40 21.3
Skelton 73.80 21.1
Stone 5.49 1.6
Metal 3.20 0.9
Wood 0.04 0.0
Total 349.80 100

Although vernacular architecture contributes to Siwa’s image as a tourism

attraction, a lot of Siwan people replaced the traditional Kerchief houses with modern

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buildings using materials such as concrete, fired brick or limestone, both bearing walls
and skeleton type are used as shown in Fig. 8.

Fig. 8. Mixed structure models of houses at Siwa Oasis.

By interviewing Siwan people in 2012 [29] to investigate why local residents

started to adopt new building technologies, threatening the integrity of the cultural
heritage site, it was found that there were many reasons that led them to the use of
modern techniques, among them:
• Saving construction time.
• Seeking more spaces by multi-story building.
• Suit new modernized lifestyle with better quality of life.
• Protecting them from natural hazards that could damage their houses like rain and
termites.
• Allowing modern showers and sanitary systems (which is a threat to earth material
especially salty Kerchief).
Some hybrid buildings exist as well, for example; an American woman who
lives permanently in Siwa built a house using concrete and brick, and covered it with
adobe, that gave her a wall that looks, that look like Kerchief traditional house but
enabled her to overcome wet facilities problem and to use modern bathroom and
kitchen in her (semi-vernacular) house.
When the government tried to enforce using Kerchief only buildings, locals
covered their modern building with a Kerchief coating, a spontaneous Facadism
conservation approach.

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2.5 Comparing Thermal Performance of Traditional and Modern Buildings

Measurements were conducted in 2012 comparing between internal

temperatures in main rooms of a traditional Kerchief house and a modern skeleton
type house [29], it was found that temperature in the traditional house was closer to
thermal comfort compared to skeleton type buildings Fig. 9. In spite of the fact that
temperature was out of comfort in both houses, skeleton houses residents suffered
from high temperature to the extent that they were not able to stay indoor during
daytime. In contrast to Kerchief houses, residents were able to stay during daytime at
home, but at night, indoor temperature became too high and they had to sleep on the
roof.
That raised the question: why do traditional buildings perform better? and
which elements affect thermal comfort? Is it possible to develop buildings that
achieve modern quality, thermal comfort, and preserve culture heritage as well?
36
34
32
30
28
26
men room women room living room bed room
out temp. 34 34 35.5 34.8
traditional house 31 30 30 30
modern house 33.5 33.5 34.1 34.5

Fig. 9. The temperature between the traditional Siwan house and skeleton
Siwan house [29].

3. RESERCH PROBLEM AND PAPER OBJECTIVE

Modernization is threatening the unique cultural heritage of Siwa, in spite of the

fact that traditional buildings have lower daytime temperatures compared to modern
buildings, locals prefer to use modern building techniques to have a better quality of
life, but face uncomfortable thermal conditions in the modern buildings, or use air
conditioning, hence increasing energy use and cost which is hard to compensate in a
remote community facing poverty.

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This paper aims at analyzing the thermal behavior of vernacular Kerchief

buildings, compared to modern buildings, to define what exactly makes them perform
thermally better (the material, the mass or the window wall ratio).

4. METHODOLOGY

In order to answer the question, it is necessary to analyze elements of the outer

envelope of the building (walls, windows, ceiling) that affect building thermal
performance, to define which element and its properties that have the most significant
positive effect.
Simulation using Energyplus and DesignBuilder was used to assess the indoor
temperature of a simplified model of a room resembling the house, with different
combinations of wall material and thickness, roof type, and window sizes. After
defining the best performing elements, new combinations of modern and traditional
elements are tested.

4.1 Location and Case Study

The case study will be a simplified single room building of (4 x 3 m 2) used as a

bedroom located on upper floor (exposed roof) as shown in Fig. 10.

Fig. 10. DesignBuilder case study.

4.2 Simulation Parameters

The study will focus on the wall combinations; a sensitivity room having one
window (1.0 x 1.0) m2 area and roof will be traditional Siwan roof.
This study adopts “simulation study” as the main investigatory method by
energy simulation software – namely Design Builder version 2011 which uses Siwa
Oasis weather file (epw) to assess the thermal performance of the model. The
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experimental process began in January and continued until December. The thermal
analysis of the room will be examined by several wall thicknesses as shown in Tables
4-8, windows as shown in Table 9, roofs as shown in Table 10. And floors as shown in
Table 11.
Our experimental study will focus on the wall thickness and materials; their
behavior with the outer and inner temperature.
The main material that we use is Kerchief, which is as a traditional material in
Siwa Oasis, as well as brick and adobe because those are the most used materials in
Siwa Oasis. We added the thermal properties of each material in DesignBuilder as
shown in the Table 12 below and will simulate the variables to see the thermal
behavior of the walls around the year especially in July.

Table 4. Kerchief walls [30]. Table 5. Brick walls [30].

All walls have a Kerchief plaster All walls have a cement plaster
internally and externally 2cm thick, internally and externally 2cm thick,
with conductivity 1.5 (W/m.K). with conductivity 0.72 (W/m.K).
Thickness(m) U-value (W/m2.K) Thickness(m) U-value (W/m2.K)
1.00 1.43 1.00 0.61
0.75 1.74 0.75 0.78
0.50 2.23 0.50 1.08
0.38 2.58 0.38 1.32
0.25 3.10 0.25 1.74
0.12 3.89 0.25 2.55
U-value calculated by DesignBuilder U-value calculated by DesignBuilder

Table 6. Adobe walls [30]. Table 7. Limestone walls [30].

All walls have an adobe plaster All walls have a cement plaster
internally and externally 2cm thick, internally and externally 2cm thick,
with conductivity 1.5 (W/m.K ). with conductivity 0.72 (W/m.K).
Thickness(m) U-value (W/m2.K) Thickness(m) U-value (W/m2.K)
1.00 0.38 0.25 2.55
0.75 0.50 0.20 2.78
0.50 0.72 0.12 3.27
0.38 0.90 U-value calculated by DesignBuilder
0.25 1.26
0.12 2.07
U-value calculated by DesignBuilder

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Table 8. Another wall variables [30]. Table 9. Windows variables [30].

Identification W1 W2 W3

Conductivity (W/m.K)

Specifications
U-value (W/m2.K)

No window
2.0 x 1.3m2

1.0 x 1.0m2
Windows
Thick. (m)
Type (cm)

Material
Wall

Glaze Clear Clear -

martial 3mm 3mm
Glazing (%) 26% 11.1% -
Clay 0.02 1.5 Window 2.0 1.0 -
Kerchief + Brick

Kerchief [21] 0.25 2.00

1.46
width
50

Brick 0.25 0.72

Window 1.3 1.0 -

Window layout
Cement 0.02 0.72 height
Clay or silt 0.02 1.5
Sill height 1.0 1.0 -
Kerchief [21] 0.12 2.00
2.28
25

Brick 0.12 0.72 Window 0.1 1.0 -

Cement 0.02 0.72 spacing
Cement 0.02 0.72 Vent spacing 0.1 0.1 -
Brick 0.25 0.72 Frame width 0.040 0.040 -
0.54

expanded Divider 0.020 0.020 -

0.05 0.04 width
polystyrene
Cement 0.02 0.72 frame Painted Painted -
Cement 0.02 0.72 wooden wooden
Brick 0.25 0.72 Material Oak Oak -
0.32

Expanded (radial) (radial)

0.10 0.04
polystyrene Thickness 0.002 0.002 -
Cement 0.02 0.72
Numbers of 15 10 -
Brick + Insulation

Cement 0.02 0.72

blades
Louvers

Brick 0.12 0.72

Vertical 0.1 0.1 -
expanded
0.55

0.05 0.04 spacing

25

polystyrene
Brick 0.12 0.72 angle 15 15 -
Cement 0.02 0.72 Distance 0.05 0.05 -
Cement 0.02 0.72 from
Brick 0.12 0.72 window
expanded Blade depth 0.05 0.05 -
0.32

0.10 0.04
polystyrene
Brick 0.12 0.72
Cement 0.02 0.72
Cement 0.02 0.72
expanded
0.10 0.04
0.32

polystyrene
Brick 0.12 0.72
Cement 0.02 0.72
U-value calculated by DesignBuilder

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Table 10. Roofs variables [30]. Table 11. Floors variables [30].

U-value( Wm-2K-1)
U- value (Wm-2K-1)

Identification

Conductivity
Thickness (m)
Identification

Conductivity

materials

(W/m.K)
Thick. (m)
materials

(W/m.K)

name
name

Kerchief [21] 0.02 2.00

Kerchief
Floor 1

ground

0.464
Kerchief ]21] 0.02 2.00 Clay 0.02 1.5
Palm roof
Roof 1

Clay or silt 0.02 1.5

0.025
Earth, gravel 1.00 0.52

Fatimi palm [13] 0.20 0.005 Ceramic 0.02 1.3

Original ground
Plaster 0.02 0.72
Concrete tiles Sand 0.10 0.25

Floor 2
0.02 1.5

0.831
(roofing)
expanded 0.02 0.04
Cement/plaster 0.02 0.72 polystyrene
Isolated concrete roof

Sand 0.06 0.25 Sand and 0.10 2.00

expended gravel
0.10 0.04
Roof 2

0.280

polystyrene Kerchief[21] 0.02 2.00

Kerchief
Floor 3

Bitumen 0.002 0.17

0.025
internal
Clay 0.02 1.5
Concrete /cast- Fatimi palm 0.2 0.00
0.12 1.9
dense, reinforced ]13] 5
Cement/plaster 0.02 0.72 Ceramic 0.02 1.3
Original internal

Plaster (light Plaster 0.02 0.72

0.02 0.16
weight)
Floor 4

0.884
Concrete 0.12 0.16
Concrete 0.02 1.5
Non-isolated concrete roof

roofing slab
tiles(roofing)
Plaster 0.02 0.72
Cement/plaster 0.02 0.72 Acrylic 0.02 0.02
Sand 0.06 0.25
Roof 3

U-value calculated by DesignBuilder

1.014

Bitumen, pure 0.02 0.17

Concrete, cast- 0.12 1.9
dense, reinforced
Cement/plaster 0.02 0.72
plaster 0.02 0.16
U-value calculated by DesignBuilder

Table 12. Thermal properties of materials used in simulation.

Density conductivity Thermal storage capacity
material
kg/m3 W/m.K J/kg.K
Kerchief [21] 2293 2.00 900
Adobe [24] 2400 0.42 840
Brick [30] 1920 0.72 840

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5. RESULTS

The simulation takes place in July that represents a typical hot summer day, at which
average air temperature is 43°C in Siwa. Simulation demonstrates the influence of material
type and thickness on the air temperature inside the occupied space. The graph below shows
assembled results for the comparative analysis of different variables used during the study.
The highest air temperature is recorded when applying Kerchief wall with thickness
12 cm, as shown in Fig.11.
44

42

40

38

36

34

32

30

28
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0

Fig. 11. Walls temperatures in July.

5.1 Existing Situation in Siwa

Two main construction methods are used in Siwa nowadays, the traditional method
(75 cm Kerchief wall, with 1.0 m x1.0 m window, Fatimi palm roof) and modern method
(25 cm brick wall, with (2.0 x 1.3) m2 window, Nonconcrete roof).

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By comparing the insulated existing situations, the analysis shows that the Kerchief wall is
better than brick wall as shown in Fig. 12.

Fig. 12. Simulation the existing (traditional-modern) situation in Siwa.

5.2 Assessing Different Material Types

When considering the comparative analysis for the results, as shown in the below
graphs, the thermal results show divergence in the air temperature when applying different
materials.

5.2.1 12 cm Thickness

The analysis is held using different material types; Kerchief, adobe, brick and
limestone at 2:00 p.m. The Kerchief wall recorded the highest temperature at 39°C, adobe
wall was 39.26°C, and the brick wall was 38.36°C, while the limestone showed the lowest
degrees at 37.49° C. A remarkable divergence in temperature is recorded during the whole
day when using small wall thickness. The fluctuation between high and low temperature
occurs as shown in Fig. 13.

5.2.2 25 cm Thickness

When comparing indoor temperatures using brick wall of 25 cm thickness, with

using Kerchief wall of 25 cm thickness, better results are recorded for the brick wall at
35.90°C, as shown in Fig. 14.

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Fig. 13. (12 cm Thickness). Fig. 14. (25 cm Thickness).

5.2.3 75 cm Thickness

When increasing the wall thickness to 75 cm, the Kerchief wall shows the highest air
temperature when compared to other materials used as shown in Fig. 15.

Fig. 15. (75 cm Thickness).

5.3 Assessing Different Material Thickness

5.3.1 Using kerchief wall

A comparative analysis is carried on a Kerchief wall type with different thickness,

(100cm -75cm - 50cm - 38cm - 25cm - 12cm). The results show the higher wall thickness
has better impact as it shows lower temperature at 36.33°C, as shown in Fig. 16.

5.3.2 Using Adobe Wall

The results show that the increase in thickness has a better influence on decreasing
the air temperature when using adobe wall material. The 100 cm wall thickness is the best
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as it shows low air temperature, while the 12 cm thickness is the highest air temperature. A
great similarity between the 38 cm and 75 cm is recorded, as Fig. 17 shows.

5.3.3 Using brick wall

By comparing the wall thicknesses (100 cm – 75 cm – 50 cm – 38 cm – 25 cm –

12 cm) when implementing brick material, the 100 cm brick wall has a better influence in
decreasing the temperature when compared to other thicknesses as shown in Fig. 18.
Increasing the wall thickness increases the thermal conductivity of the material which
results in decreasing the fluctuation and divergence in the temperature during the day. This
is shown in the linearity that occurs in the curve at the below graph, Figs. 16-18.

Fig. 16. Kerchief walls. Fig. 17. Adobe walls.

Fig. 18. Brick walls.

5.4 Assessing Variation in Material and Thickness

A lower temperature degree is achieved when using a smaller thickness (50 cm) of
adobe material when comparing it to Kerchief material with greater thickness (75 cm). The

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temperature of the occupied space reached 36.5°C when applying the adobe material of 50
cm thickness, while one degree higher in temperature, 37°C, is recorded with Kerchief
material of 75 cm thickness as shown in Fig. 19.
The brick material shows improvement on the air temperature when comparing it
with adobe material of the same thickness (25 cm), and Kerchief of greater thickness (38
cm) as shown in Fig. 20.

Fig. 19. 75 cm Kerchief wall, 50 cm Adobe Fig. 20. 38 cm Kerchief wall , 25 cm Brick
wall. wall, 25 cm Adobe wall.

• A remarkable decrease in temperature counts for one and half degrees is realized,
when comparing between (50cm brick+ Kerchief) wall and (25 cm Brick + Kerchief)
wall, Fig. 21.
• The brick wall (25 cm) thickness and adobe wall (25 cm) thickness shows
improvement on the air temperature when comparing it with Kerchief material
(50 cm), Fig. 22.

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Fig. 21. Compined Brick and Kerchief wall Fig. 22. 50 cm Adobe, 25 cm Kerchief,
in two thikness (50 cm – 25 cm). 25 cm Brick walls.

6. ANALYSIS AND DISCUSSION

Nowadays, traditional architecture proved to be more convenient to our climate. A

better thermal performance is achieved while using traditional material in the residential
units when compared with modern materials. Although traditional materials show
improvement in the thermal performance inside the occupied space, the residents prefer the
modern approach in construction material to avoid other problems that may occur like bugs,
rain and outdated lifestyle. Enthusiasm for improving the weak points of the traditional
materials is rising, as the resistance to it is increasing. More studies are required to
ameliorate the construction method keeping the thermal properties of the material. The
study proposes integration between the traditional and the modern materials to benefit from
the properties of each of them. Diversity in parameters is used for analyzing the thermal
performance inside the occupied space. Wall material and thickness together with the
window size and the roof material and insulation are the parameters used for simulating the
residential space. If we change the thermal properties for the roof and make the roof
insulated it will make a difference and that means the uninsulated roof problem is solved.
When the window area increases the heat that inter the space increases. when controlling for
the roof insulation and window size, and changing the materials of the wall using adobe,
brick or Kerchief, and when increasing the wall thickness between different material it is
found that the Kerchief makes a considerable difference, from that it is found that the wall
thickness is the parameter that is the most effective on thermal performance of the wall, not
the thermal properties of the materials.

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7. CONCLUSION

The parameters affecting the indoor thermal comfort that were considered in this
study are wall thickness and material, roof insulation, and window size. The simulation
proved that the traditional house shows better thermal performance than the modern house.
In Siwa, Traditional buildings are built by massive bearing walls of Kerchief
material, which is an earth material consisting of rock salt aggregate cemented by clay,
sand, and organic fibers, it is usually confused with adobe which does not have rock salt
(Halite). Kerchief has higher thermal conductivity than adobe or even brick due to high
conductivity of Halite. In spite of that, thick Kerchief walls assisted in improving indoor air
temperature. Thermal mass of thick walls is more significant than their conductivity. Adobe
and brick thick walls showed slightly better indoor thermal performance than Kerchief walls
but comparing thin walls; Kerchief walls have worse thermal performance. Wall thickness
proved to be a more effective parameter in indoor thermal performance than wall material.
When it comes to window size and roofs, small size windows paired with insulated roofs
proved to result in the best indoor thermal performance.
In the modern house, brick walls, and insulated roof, with small windows, resulted in
the same indoor thermal comfort as the traditional building, and better in some cases. From
the analysis, 25 cm brick wall with 1.0 × 1.0 m2 window and insulated roof have the best
thermal performance in the modern house.
The urban conservation of the heritage of Siwa is a major goal, as well as satisfying
user demand for modern quality of life, integrating modern and traditional building
materials and techniques could be the answer, while improving thermal performance of the
building. In urban conservation sites; the study recommends the use of hybrid buildings
with small windows and insulated concrete roof and a composite wall with an Internal brick
layer of 25 cm, and an outer 25 cm Kerchief layer, to increase thermal mass and give a
heritage- compatible façade.

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‫تحليل األداء الحرارى للعمارة التقليدية فى واحة سيوة‬

‫يهدف البحث الى تحليل االداء الحرارى لمادة الكرشيف مقارنة بالمواد الحديثة لتحديد ما الذى يؤثر على‬
‫االداء الحرارى للمبنى هل هى المادة ام الكتلة وذلك من خالل عمل محاكاة رقمية باستخدام برنامج‬
‫)‪ )Designbuilder‬للمواد التى يبنى بها فى واحة سيوة (الكرشيف – الطوب االحمر – الطين – الحجر‬
‫الجيرى) وظهر ان سمك المادة الحائط هو المؤثر على االداء الحرارى للفراغ بصرف النظر عن نوع المادة وان‬
‫مادة الكرشيف ادائها الحرارى جيد فى سمك الحائط الكبير على عكس ادائها فى السمك الصغير بالرغم من انها‬
‫مادة طبيعية وذلك يرجع الى ان خصائصها الح اررية سيئة الحتوائها على الملح الصخرى‪.‬‬

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