Traditional House - Desa - Copie

8/6/2019 Traditional House - Desa - Copie

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A Case Study of a Traditional HouseModel in the Medina of Rabat

Thermal Comfort in

Courtyard Housing inMorocco


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#S

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RABAT

Temara

SkhirateTifelt

KhemissetAin El Aouda

Rommani

REGION DE RABAT-SALE-

ZEMMOUR-ZAER

ETAGES BIOCLIMATIQUES

Province de Knitra

Province de Sidi Kacem

Province deKhnifra

WilayadeMknes

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Source : Atlas des Ressources Naturelles0 10 Kilometers

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Province de

Khouribga

Province deBenslimane

Etages bioclimatiquesArideSub-humide et humide

Semi-aride hiver tempr et chaudSemi-aride hiver froid et frais

Cour d'eau permanentCour d'eau temporaire

#S Principales villes


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Problem

The buildings in Morocco are often designedwithout taking the climate into consideration.Consequently a great part of the builtenvironment has a poor climate.

One of the most frequent complains among thefamilies living in the Moroccan traditionalhouses, regardless of the age of the house,involves moisture. The moisture that causes

condensation and creates musty odours inbasement wall, the ceiling and other coldsurfaces affects approximately 46% of thetraditional houses.


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Problem

There is also the problem of the too high and lowtemperatures. These thermal discomfort problems areprimarily due to the following factors:

- The climatic conditions

- The thermal quality of the building materials

- The ventilation and the renewal of the air - The orientation of the frontages

- The lack of sun shining in the patio during the winterseason.

The inquire housing confirms this observation for thetraditional houses. Those that have the problems of toohigh temperature are localised in the following regions:the Meknes-Tafilalet region (73%), the Rabat-Sal region(62%), the Casablanca region (58%) and the Tangier-Tetouan region (56%).


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Problem

Concerning the problems of the too low temperatures,among the housing types that have this thermaldiscomfort, there are the traditional houses in the Rabat-Sal region (77%), the Tangier-Tetouan region (56%) andthe Fez region (31%).

In Rabat-Sal region, the moisture in more than 30% ofthe traditional houses affects the interior basement wallsand the ceiling.

We note that the discomfort thermal problem in winterseason in term of the humidity and the too lowtemperatures is posed with acuity in some traditionalhouses of the Medinas (Rabat, Sal, Tangier, Fez,).


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The aim of the study is to analyse the climatic behaviour ofthe rooms surrounding the courtyard in the Medina ofRabat.

The internal courtyard can then affect the indoor climate.Unfortunately, this space is not studied because of thelimitation of the computer program (DEROB-LTH), whichcannot simulate an open space, a courtyard for example.

Secondly, due to the lack of the courtyard climaticmeasurements during the summer and winter seasons,including the temperature, the humidity and the windvelocity, the main hypothesis of the present study is toconsider the courtyard as an open space and treated asoutdoor.

Third, the DEROB-LTH program does not take into accountthe humidity of the air, which can be the principal sourceof the discomfort in the Rabat region.

Hypothesis


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Givoni bio climatic diagram and Mahoneys tables havebeen used in this study. There are still useful tools to givegeneral considerations of the comfort zone with somerecommendations for passive design of building.

According to the Givoni climatic diagram, there is a

possibility to extend the comfort zone for the cold monthsby internal gains and in some severe cases by heating. Atthe other side, the requirement for the hot months isventilation.

Based on a diagnosis of some climatic indicators, the

Mahoney tables give the performance specifications andthe sketch design recommendation for the region of Rabat:

yThe layout has to have an orientation North South

yPermanent air movement

yMedium openings

yLight, low thermal capacity walls and floors

yLight, well insulated roof

Method: Traditional tools


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Givoni Bio ClimaticDiagram


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Program

DEROB-LTH , which is an acronym for Dynamic EnergyResponse of Buildings LTH, is a MS Windows based flexiblesimulation tool using a RC-network for thermal modeldesign. The program consists of 8 modules. Six of themodules are used to calculate values for temperatures,heating and cooling loads. The calculations are performedin a dynamic way for each hour during a specified period ofsimulation. The calculations are influenced by climaticfactors such as outdoor temperature, solar radiation andthe sky temperature. Properties for the indoor climate ofthe building can be calculated based on these simulatedresults.

DEROB was originally developed at the NumericalSimulation Laboratory of the School of Architecture of theUniversity of Texas at Austin. The DEROB-LTH modulesare further developed to suit the local needs at the

Department of Building Science at Lund Institute ofTechnology.

Method: Parametric modelling


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Different thermal simulations by DEROB-LTH were carriedout using different parameters to improve the indoorclimate. The variants during winter are:

y The faade orientation: The orientation for solar access isimportant, especially in the winter. The four orientation

cases, the faade facing to South (Case 0), East (Case 1),North (Case 2) and West (Case 3) were analyzedseparately. Next, the parameters were studied incombination in order to improve the indoor climate.

y The shading devices: The gallery in the traditional houseis a covered space of the circulation and the transition

between the courtyard or patio and the rooms. In winter,the galleries make it possible to circulate when it is raining.In summer, the galleries create shade and become anobstacle for the intense sun rays access. The shadingdevice in the courtyard has a width of L=0.7 m in thebaseline case. In Cases 4, 5, 6 and 7, the shading device is

out in the courtyard.



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y The ceiling height: The traditional house rooms have

generally a high ceiling height (more than 3.0 m). In thebaseline case, the ceiling height H=3.5 m, which is reducedto H=3.0 m in Cases 8, 9, 10 and 11.

y The surroundings: The site layout in terms of the widthstreet and the surroundings height were analyzed incombination with the orientation. The variation of thesurrounding facing building height (H=3.5 m and H=7.0m) and the small width street (1.5 m) are examined in theCase 12.

y The roof/ceiling and walls insulation: Thermal insulationof the roof and the walls is also important for bettercomfort. Composite insulating panels (woodwool /mineralwool) for walls and woodwool slabs for roof wereused (Cases 13 and 14).

y The air infiltration: The ventilation is an important factorfor comfort, especially the night and day ventilations. Theair change hour is reduced during evening (between 19

and 24), and night (between 01 and 07). This correspondsto the Case 15.



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The variants during summer are:

y The ceiling height: The ceiling height is increasing fromH=3.0 m to H=3.5 m in the Case 17.

y The shading devices: In the Case 18, the shading device

in the courtyard has a width of 1.0 m instead of 0.7 m.

y The air infiltration: day ventilation (Case 19) and nightventilation (Case 20).



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ResultsWi

Vo l u m e T e m pe r a t u r e ( W i nt e r b a se c a se )

5

5

2

25

2 3 4 5 6 7 8 9

2

3

4

5

6

7

8

9 2

2

22 23 24

T i m e ( ho ur )

_

V

_

V

2_

V 3_

V

4_

V

5_

Figure 11: Temperature in the volumes during December (Case0)


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ResultsWi

O p e r a t i v e T e m p e r a t r e ( Vo l . 2 & V ol . 3 )

0

10

1

0

1

10 11 1

1 1

1 1 1 1 1

0

1

T i me ( h ou r )

! p T # $ p E

! p T # $ p

E

! p T # $ p

N

! p T # $ p N

! u%

d T # $ p

Figure 17: Operative temperature in volumes 2 - 3 and orientation during December (Case10)


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ResultsWi

O p e r a t i v e T e m p e r a t u r e ( Vo l . 2 & V ol . 3 ) ( H = c e i l i n g h e i g h t )

0

&

10

1 &

'

0

'

&

1'

(

)

& 0 1 2 3 10 11 1'

1 ( 1)

1 & 1 0 1 1 1 2 1 3'

0'

1' ' '

(

' )

T i me ( h ou r )

4 p T 6 7 p'

(H = ( 0 7 )

4 p T 6 7 p ( (H = ( 0 7 )

4 p T 6 7 p'

(H = ( 8 & 7 )

4 p T 6 7 p ( (H = ( 8 & 7 )

4 u9

d T 6 7 p

Figure 18: Operative temperature in volumes 2 - 3 and ceiling height during December (Case10)


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ResultsWi

O p e r a t i v e T e m p e r a t u r e i n Vo l u m e 3

0

@

10

1 @

A

0

A

@

B 0

1A

B

C

@ D E F G 10 11 1A

1 B 1C

1 @ 1 D 1 E 1 F 1 GA

0A

1A A A

B

A C

T i me ( h ou r )

H p T P Q p (I R su laS

P d R o o Q )

H p T P Q p (I R su laS

P d Wa l l s )

H p T P Q p ( c as P @A

)

H uS

d T P Q p

Figure 21: Operative temperature in volume 3 and walls/ceiling roof insulation during December (Case14)


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ResultsWi

Figure 22: Operative temperature in volume 3 and air changes hour reduction during December (Case15)

O p e r a t i v e T e m p e r a t u r e i n V o l . 3

c a s e 9 : 0 1- 0 7 A C H = 3 & 19 - 2 4 A C H = 4

c a s e 1 0 : 0 1 - 0 7 A C H = 1 & 1 9 - 2 4 A C H = 2

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

T i me ( h o ur )

Op_Temp3 (case9)

Op_Temp3 (case10)

Outd_T emp


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ResultsSummer

Figure 24: Operative temperature in volumes 2 - 3 and ceiling height during August (Case17)

O p e r a t i v e T e m p e r a t u r e a n d C e i l i n g H e i g h t

0

5

10

15

20

25

30

35

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

T i m e ( h ou r )

Op T eU

p2 (H =3.0 m)

Op T emp3 (H =3.0 m)



OuV

d T emp


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ResultsSummer

O p e r t i v e T e m pe r t re i l . n d l .

S d i n g D e v i c e s f t h e rt y a r d

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 13 1 4 1 5 1 6 17 1 8 1 9 2 0 2 1 2 2 2 3 2 4

T i me ( h o

W

r )

O p _ T e m p 2 (LX

1 . 0m )

O p _ T e m p 3 (LX

1 . 0m )

O p _ T e m p 3 (LX

0 . 7m )

O p _ T e m p 2 (LX

0 . 7m )

O u t d _ T e m p

Figure 25: Operative temperature in volumes 2 - 3 and shading devices dimension of the courtyard duringAugust (Case18)


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ResultsSummer

O p e ra t i v e T e m p e ra t re i n o l m e

D a y a n d N i g h t e n t i l a t i o n s

0

5

10

15

20

25

30

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

T i me ( ho Y r )

Op_T emp( ia

b

t V en t . )

Op_T emp(D cd

V en t . )

Ou td _ T e m p

Figure 26: Operative temperature in volume 2 and ventilation during August (Cases 19 and 20)


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Conclusions

Thr u h llsimul ti s, we lu ethati

r ert keeptraditi al urt ardhousei Rabatbei thermall omfortableduri bothseasons,somemodifi ationsshouldbemade.

In winter:

-To redu ethe eilingheight

-Toadoptaninsulated roofand wallsbuttheinsulation wallsmightbebadinsummer.

-To redu etheair hangeshourduringe eningandnight. owe er, forhealth reasons,this ratemustnotbetoolow.

Insummer: -Toincreasetheceilingheightasmuchas

possible.

-Toincreasethedimensionsoftheshadingde icesofthecourt ard.

-Toincreasethenight ventilationasmuchaspossible. uringdaytime,alow airchanges rateisrecommended.

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