traditional influence

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International Journal of Earth Sciences and Engineering 1ISSN 0974-5904, Vol. 03, No. 01, February 2010, pp. 1-5

#02030101 Copyright 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.

The influence of internal courtyard of Kerala

traditional residential buildings in providing acomfortable indoor environment

DILI A. S.*, NASEER M. A.**, ZACHARIA VARGHESE T.*

*Department of Civil Engineering, National Institute of Technology Calicut, Kerala, India**Department of Architecture, National Institute of Technology Calicut, Kerala, India

Email: [email protected], [email protected], [email protected]

Abstract: Traditionally, the built form of any region is derived for the beneficial aspectof the climate and to reduce the impact of unfavorable conditions. Kerala, the land on

the southwest coast of India, has a characteristic Warm-Humid climate because of itsgeographic settings. The presence of high amount of moisture in the atmosphere for

major part of the year causes thermal discomfort as there is less evaporation, resulting

in perspiration. This becomes more acute in summer when the air temperature is closeto or higher than the body temperature. In the traditional buildings of Kerala, whichevolved through ages, the influence of internal courtyards is found to be highly effectivein providing a comfortable indoor environment. The authors have conducted a smoke

study to understand the influence of internal courtyard in inducing a constant andcontinuous air flow in traditional buildings of Kerala. This paper illustrates briefly the

need for climate responsive design of buildings, the effect of internal courtyards intraditional buildings of Kerala and an investigation in a selected traditional building basedon smoke study to analyze the flow of air through the interiors to achieve better thermalcomfort.

Key words:Kerala, Traditional architecture, climate, thermal comfort, courtyard, smoke

study

Introduction

Climate responsive design is the one thatwould provide a comfortable indoor

environment in response to the seasonalvariations of the climate at a particular

place. Irrespective of the extreme climaticconditions that prevail outside, the buildingindoors should keep its occupants

physiologically comfortable. This isachieved by means of passive controlsystems used in the building design. Themodern architecture does not give due

respect to passive and naturalenvironment control measures as it goes

along with modern materials, trends andtechnology which often cause high energyconsumption. On the other hand, thetraditional architecture at any place hasevolved through ages by consistent and

continuous effort to achieve more efficientand perfect solutions that are

environmental friendly.

Kerala, a strip of land on the southwestcoast of India lying between Arabian Seaon the west and Western Ghats on theeast, has a warm-humid climate. The

presence of high amount of moisture in theatmosphere along with higher air

temperature for major part of the year isthe characteristic of warm-humid climate.Under such climatic conditions, the

physiological comfort can only be achievedby providing a constant and continuousflow of air through the interior of thebuilding. The traditional architecture of

Kerala is well known for its use of naturaland passive methods in providing a perfectclimate responsive design. The authorshave been conducting experimentalinvestigations to analyze the passivecontrol methods of Kerala traditionalbuildings [Dili A. S. et al, 2009, 5 papers].

The internal courtyard provided in suchtraditional buildings is found to have a

prime role in providing the required airmovement through the building. Thus, in


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The influence of internal courtyard of Kerala traditional residentialBuildings in providing a comfortable indoor environment

International Journal of Earth Sciences and Engineering 1ISSN 0974-5904, Vol. 03, No. 01, February 2010, pp. 1-5

addition to the air flow measurementrecorded with electronic sensors, a smokestudy was conducted to analyze theinternal air movement especially the airmovement that is induced in the interiors

of traditional buildings when there is still

condition outdoors.

The outcome of the study proves theefficiency of internal courtyard in climateresponsive design of Kerala traditionalarchitecture.

Study of traditional buildings thepresent status

The modern practice in architecture lacksconscious effort in using passive methods

of controlling the indoor environment.Excessive use of modern materialsirrespective of their efficiency in regulatingthe indoor environment has often resultedin high energy consumption, leading tomany environmental problems. There is a

close connection between the energy usein buildings and the resultedenvironmental damage. This is because ofenergy intensive solutions that arerequired in buildings to attain comfortconditions in terms of mechanical cooling

and ventilation and artificial lighting. Thishas caused severe depletion of non-

renewable energy resources andenvironmental degradation.

Studies on passive environment controlsystems in buildings providing thermalcomfort are in progress in the form ofassessment of thermal comfort parametersof traditional buildings, in various part ofthe world [Youngryel Ryu et al, 2009,

Mujgan Serefhanoglu Sozen et al, 2007,

Do-Kyoung Kim et al, 2005, Lin Borong, etal, 2003 and Ryozo Ooka, 2000]. Thesetypes of studies were originated in Koreaand Zambia in 1996 [Kyung-Hoi Lee et al,Steve Sharples et al, 1996, Albert Malamaet al, 1997]. It was then attempted in

different countries such as Japan, China,etc. within a short period. In other parts of

India, the results of such studies havepublished recently in the context of N-Eregion [Manoj Kumar Singh et al., 2009].The majority of these studies have preciseaims to find out methods to adopt inmodern buildings. The results of such

studies have been used recently in modernbuildings in Korea [T.J. Kim et al, 2009].

Kerala traditional architecture, evolvedbased on the principles of climate

responsive design, has now emerged as an

important area among the researchers inthis field. Efforts are made by researchersin this field for a comprehensive andquantitative analysis of traditionalarchitecture of Kerala [Dili et al, 2009].These studies undertaken in the context ofKerala have already started providing

valuable results regarding the passiveenvironment control systems. It is believedthat the outcome of the research willprovide the present day architects andengineers with energy efficient and

sustainable design even while utilizing themodern materials and constructionmethods.

The Effect of Internal Courtyards inTraditional Buildings of Kerala

The basic module of a traditional Keralaresidential building is nalukettu with fourblocks generally rectangular or square inplan, built around an open courtyard. The

blocks are topped with a sloping roof on

four sides while the courtyard is open tosky for letting air and light inside (Fig.1).There is an internal verandah around thecourtyard for protection from rain and sun.A typical layout of a traditional Keralahouse is shown elsewhere [Dili et al,2009].

Fig.1: A typical courtyard of a Keralatraditional residential building

Courtyard and patio are quite common inwarm humid climate where the building


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International Journal of Earth Sciences and EngineeringISSN 0974-5904, Vol. 03, No. 01, February 2010, pp. 1-5

encloses an open space fully or partly[Krishnan et al]. Such spaces arecommonly referred to as microclimate

modifiers. They enjoy better microclimaticconditions than the surrounding openareas, and are supposed to have a positive

effect on the indoor comfort conditions ofthe enclosing building volume. In acourtyard, a pool of cool air is retained asthis is heavier than the surrounding warm

air [Koenigsberger et al]. The top layer ofthe air in the courtyard gets warmer in day

time and becomes lighter, causing the airto move upwards. Thus a low pressuredevelops in the courtyard and it induces anair movement from outside, through thesurrounding spaces (Fig.2). In addition tothis thermal induction, the internal

courtyard helps to induce air movementdue to pressure effect in the event of highvelocity external wind that flow above thebuilding. The wind flow reduces thepressure at the top layer of the air columnand creates a suction effect above thesmall courtyard. This produces an upwardmovement in the top layer of air in thecourtyard, pulling the air towards the courtthrough the surrounding spaces resulting

in circulation of air in those spaces.

Fig.2: Concept of air movement throughcourtyard

Smoke study

The residential building selected for thesmoke study is located in the northern partof Kerala at Nilambur in the Malappuramdistrict. The building (Puthiya Kovilakam)is nearly 300 years old.

The building has three courtyards ofrectangular shape in which one courtyard

is surrounded by a double storeyedstructure. The other two courtyards aresurrounded by single storeyed structures.

The internal space taken for the study is

around the courtyard of 6 ft x 12 ft. Thecourtyard has an inward looking verandah

of 3.5 ft width. The two sides of thecourtyard are semi open spaces used forliving and prayer. The other two sides are

adjoined with rooms having windowsopening to the courtyard. A plan andsection with the selected area marked isgiven elsewhere [Dili et al, 2009].

The authors have devised and installed aninstrumentation setup called ArchitecturalEvaluation System (AES) in the building tomonitor various climatic parameterscontinuously over a period of time. Theinferences drawn from the fieldobservations have already been published

[Dili et al, 2009]. It was proved that thereexists a continuous internal air movementirrespective of the flow of external wind.

In order to understand the internal airmovement better, especially under still-aircondition, a smoke study was conducted.The smoke generated outside was allowedto pass through the building. The

movement of smoke through variousinternal spaces of the building and thecourtyard was then observed. These

movements were then captured using highresolution cameras set at differentlocations within the building. It wasobserved that the smoke entered fromoutside to the internal spaces through thewindow openings and moved towards the

courtyard to ultimately escape through thecourtyard (Fig.3&4). Interestingly, it wasalso observed that when the smoke wasput off, it disappeared from the buildingwithin seconds.

Fig.3: Smoke enters the building


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The influence of internal courtyard of Kerala traditional residentialBuildings in providing a comfortable indoor environment

International Journal of Earth Sciences and Engineering 1

ISSN 0974-5904, Vol. 03, No. 01, February 2010, pp. 1-5

The study was conducted in the presenceof external wind and also in the absence,i.e., when a still condition prevailed. The

pattern of smoke captured clearly indicatesthat the movement is faster and the flow isturbulent in the presence of external wind

due to the wind effect. The movement ofsmoke was slow but steady and thepattern of flow was laminar during the stillcondition. This clearly establishes that

there exists a continuous convective flowthrough the building at all times as

explained in the previous section.

Fig.4: Smoke moves upwards from the

courtyard

Discussion

A continuous and constant air movementexists through the internal spaces and theinternal courtyard of a traditional building

irrespective of the external wind [Dili et al,2009]. The smoke study conducted in thetraditional building confirms this especiallyunder still condition of external wind. Thisstudy establishes the influence of internalcourtyard in inducing a continuous internal

air movement thereby an effective passivecontrol system for the thermal comfort ofoccupants in traditional buildings of Kerala.

Arithmetical and experimental studieshave reported that the airflow throughwindows drops down and then flows alongthe floor [Per Heiselberg, et al, 2001].Since the windows are placed at a lowerlevel (1 ft from floor) in traditional

buildings of Kerala, this phenomenon helpsthe warm air from outside to interact with

the cool air settled near the floor during itsflow. This again makes the indoors cooler.

Conclusion

Natural and passive control of the indoorenvironment is an important aspect of

traditional architecture of Kerala. Thepresence of internal courtyards has a

prime role in achieving this comfortcondition.

The present study clearly establishes theinfluence of internal courtyard in inducinga continuous internal air movement to

achieve thermal comfort in warm-humidclimate even when still-air condition

prevails outdoors.

It is hoped that the methods andtechniques thus adopted in the Kerala

traditional architecture can be applied tothe contemporary architecture of warm humid regions.

Acknowledgements

The authors extend sincere gratitude toMr. Ravi Varma of Nilamboor Kovilakamfor his kind cooperation for the conduct ofthe investigation.

References

[1] Dili A S, Naseer M A, ZachariaVarghese T, The passive environmentcontrol system of Kerala vernacularresidential architecture: Anexperimental investigation on wind flowand thermal comfort, International

Journal of Earth Science & Engineering,2, 2009, 264 271.

[2] Dili A S, Naseer M A, Zacharia

Varghese T, Passive Environment

Control System for a Healthy andComfortable Indoor Environment: AStudy of Kerala Vernacular ResidentialBuildings, Healthy Buildings 2009International Conference, 14th-17thSeptember 2009, Syracuse, NY, USA,paper no. 947.

[3] Dili A S, Naseer M A, ZachariaVarghese T,Investigation on indoor airtemperature control of vernacularresidential buildings of Kerala inSummer, Journal of Institution of

Engineers India (AR), Accepted.


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DILI A. S, NASEER M. A and ZACHARIA VARGHESE T.

International Journal of Earth Sciences and EngineeringISSN 0974-5904, Vol. 03, No. 01, February 2010, pp. 1-5

[4] Dili A S, Naseer M A, PassiveEnvironment Control System forComfortable Living: The need for a

comprehensive and quantitativeinvestigation of Kerala VernacularArchitecture, 25th National Convention

of Architectural Engineers,20th-21stNov2009 at Calicut, Kerala, India, 69-71.


Varghese T, The Passive EnvironmentControl System for Tropical Climate:An Investigation of Kerala VernacularArchitecture, Building Science andEngineering 2009 InternationalConference, 14th-15th December 2009,Johor, Malaysia, BSE03/002, 78.


Varghese T, Passive control methods ofKerala traditional architecture for a

comfortable indoor environment: Acomparative investigation during winter

and summer, Building and Environment(Elsevier), 45, 2010, 1134-1143.

[7]Dili A S, Naseer M A, Zacharia VargheseT, Passive environment control system

of Kerala vernacular residentialarchitecture for a comfortable indoorenvironment: A qualitative andquantitative analyses, Energy and

Buildings (2010),doi:10.1016/j.enbuild.2010.01.002, article in press.

[8]Youngryel Ryu, Seogcheol Kim, DowonLee, The influence of wind flows onthermal comfort in the Daechung of atraditional Korean house, Building andEnvironment, 44 (2009) 1826.

[9] Mujgan Serefhanoglu Sozen, GulayZorer Gedk, Evaluation of traditionalarchitecture in terms of buildingphysics: Old Diyarbakr houses,

Building and Environment 42 (2007)18101816.

[10] Do-Kyoung Kim, The naturalenvironment control system of Koreantraditional architecture: Comparisonwith Korean contemporary

architecture, Building and Environment41 (2005) 19051912.

[11] Lin Borong, et. al., Study on thethermal performance of the Chinese

traditional vernacular dwellings in

Summer, Energy and Buildings, 36,2003, 7379.

[12] Ryozo Ooka, Field study on

sustainable indoor climate design of aJapanese traditional folk house in

cold climate area, Building andEnvironment, 37, 2000, 319329.

[13] Kyung-Hoi Lee, Dong-Wook Han, Ho-Jin Lim, Passive design principles and

techniques for folk houses in ChejuIsland and Ull ng Island of Korea,

Energy and Buildings, 23, 1996, 207-216.

[14] Steve Sharples, Albert Malama:

Thermal Performance of TraditionalHousing in the Cool Season inZambia, Renewable Energy, 8, 1996,190-193.

[15] Albert Malama, Steve Sharples:Thermal Performance of Traditionaland Contemporary Housing in theCool Season of Zambia, Building andEnvironment,32, 1997, 69-78.

[16] Manoj Kumar Singh, SadhanMahapatra, S.K. Atreya, Bioclimatismand vernacular architecture of north-east India, Building and Environment,44, 2009, 878888.

[17] Manoj Kumar Singh, SadhanMahapatra , S.K. Atreya, Thermal

performance study and evaluation ofcomfort temperatures in vernacularbuildings of North-East India,Building and Environment, 45, 2010,

320329, available online.

[18] T.J. Kim, J.S. Park, Naturalventilation with traditional Koreanopening in contemporary house,Building and Environment, 45, 2010,

5157, available online.

[19] Krishnan, A., et al.,.Climate

Responsive Architecture- A designhandbook for energy efficient

buildings. New Delhi:Tata Mcgraw Hill Publishing Co. Ltd., 2001.

[20] Koenigsberger, et al, Manual oftropical Housing and building

Climatic design, Orient LongmanPrivate Limited, 1975.

[21] Per Heiselberg, Kjeld Svidt, Peter V.

Nielsen, Characteristics of airflowfrom open windows, Building and

Environment, 36, 2001, 85969.

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