Thermal Comfort Comparative Analysis of Houses in Kituiarchitecture.uonbi.ac.ke/sites/default/files/cae/builtenviron... · i “...Although I believe that the appearance of a building

Thermal Comfort Comparative Analysis of Houses in Kitui

University of Nairobi

College of Architecture and Engineering

School of the Built Environment

Department of Architecture & Building Science

BAR 613: Research Thesis

Ghati Charles Mwita

B02/0807/2011

2016/2017

Tutor: Arch. James Kimanzi

i

“...Although I believe that the appearance of a building has the most profound effect upon its

inhabitants, yet one cannot house men in the Parthenon. One’s beautiful designs must serve

the humble everyday needs of men; indeed, if these designs are true to their materials, their

environment, and their daily job, they must necessarily be beautiful.”

Hassan Fathy (1973)

ii

This Thesis is my original work and has not been presented in any other University or Institution for the purpose of awarding a degree to

the best of my knowledge. This thesis is submitted in partial fulfilment of the examination requirements for the award of the Bachelor of

Architecture degree, in the Department of Architecture and Building Science at the University of Nairobi.

DECLARATION

Author: ....................................................................... Date........................................................... Ghati Charles Mwita

Tutor: .......................................................................... Date........................................................... Arch. James Kimanzi

Year Master: .............................................................. Date........................................................... Arch. Erastus Abonyo

Chairman: ................................................................. Date........................................................... Arch. Musau Kimeu

iii

To The Almighty God.

To My Family, For The Support.

DEDICATION

iv

v

TABLE OF CONTENTSCHAPTER ONE: INTRODUCTION

1.1 Background of Study .................................................................................................................. 01

1.2 Problem Statement ..................................................................................................................... 02

1.3 Research Objectives .................................................................................................................. 03

1.4 Research Questions .................................................................................................................... 03

1.5 Justification of Study ................................................................................................................... 04

1.6 Significance of Study .................................................................................................................. 04

1.7 Research Scope & Limitations ................................................................................................... 05

1.8 Research Organisation ............................................................................................................... 06

CHAPTER TWO: LITERATURE REVIEW

2.1 Introduction ................................................................................................................................. 08

2.1.1 Brief History of Kitui ...................................................................................................... 09

2.1.2 The Savanna Climatic Zone in Kenya ...................................................................... 10

2.1.3 Climatic Conditions of Kitui ....................................................................................... 11

2.1.4 Comfort Analysis ......................................................................................................... 12

2.2 Thermal comfort .......................................................................................................................... 13

2.2.1 Comfort Zone & Thermal Stress ................................................................................. 13

2.2.2 Heat Exchanges Between Man and the Environment .......................................... 14

2.2.3 Factors Influencing Human Thermal Comfort ......................................................... 15

2.3 Bioclimatic Design Guidelines for the Savanna Climate ........................................................ 18

2.3.1 Site Planning ................................................................................................................ 19

2.3.2 House Plans & Courtyard Plan Types ....................................................................... 19

2.3.3 Internal Planning ......................................................................................................... 20

vi

2.3.4 Structure & Materials .................................................................................................. 20

2.3.5 Orientation .................................................................................................................. 21

2.3.6 Openings & Ventilation .............................................................................................. 22

2.3.7 Outdoor Spaces - Landscaping ............................................................................... 24

2.4 Thermo-Physical Properties of Building Materials .................................................................... 25

2.4.1 Thermal Conductivity, Resistance and Transmittance .......................................... 25

2.4.2 Surface Characteristics with Respect to Radiation ............................................... 26

2.4.3 Surface Convective Coefficient .............................................................................. 26

2.4.4 Heat Capacity ............................................................................................................ 26

2.5 Summary ..................................................................................................................................... 27

CHAPTER THREE: RESEARCH METHODOLOGY

3.1 Introduction ................................................................................................................................. 30

3.2 Research Purpose ....................................................................................................................... 30

3.3 Research Strategy ....................................................................................................................... 30

3.4 Time Horizon ................................................................................................................................. 30

3.5 Population, Element & Population Frame ................................................................................ 31

3.6 Sampling Method ....................................................................................................................... 31

3.7 Data Collection Methods .......................................................................................................... 31

3.8 Data Analysis ............................................................................................................................... 33

3.9 Data Presentation ....................................................................................................................... 34

CHAPTER FOUR: THE HOUSES IN KITUI

4.1 Introduction ................................................................................................................................. 36

4.2 Architectural Development of Kitui Town ................................................................................ 37

4.3 Common Building Materials in Kitui ........................................................................................... 39

4.4 The Akamba Traditional Architecture ....................................................................................... 41

vii

4.4.1 Settlement Pattern ..................................................................................................... 41

4.4.2 Homestead Layout ..................................................................................................... 41

4.4.3 Typology ...................................................................................................................... 42

4.4.4 Form, Technology and Materials .............................................................................. 42

4.4.5 The Free Standing Traditional Unit ............................................................................ 43

4.5 The Swahili Courtyard Houses .................................................................................................... 44



4.6 The Contemporary Houses ........................................................................................................ 46



4.7 Comparative Summary of the House Typologies ................................................................... 48

CHAPTER FIVE: RESEARCH FINDINGS

5.1 Introduction ................................................................................................................................. 50

5.2 Case Studies ................................................................................................................................ 51

5.2.1 Bi. Mwikali’s House (‘Musonge’) ............................................................................... 52

5.2.2 Bwana Katabu’s House ............................................................................................. 57

5.2.3 Bwana Khatibu’s Courtyard House .......................................................................... 62

5.2.4 Mama Arianna’s house ............................................................................................. 68

5.3 Comparative Analysis of the Houses Investigated ................................................................. 74

CHAPTER SIX: CONCLUSIONS AND RECOMMENDATIONS

6.1 Introduction ................................................................................................................................. 81

6.2 Summary of Findings and Conclusions ..................................................................................... 81

6.3 Recommendations ..................................................................................................................... 85

6.4 Recommendations For Future Research .................................................................................. 86

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LIST OF FIGURES

CHAPTER ONE

CHAPTER TWO

Fig. 1.1: An Akamba traditional house (Musonge). ..............................................01

Fig. 1.2: A Swahili house. ...........................................................................................01

Fig. 1.3: A contemporary house. .............................................................................01

Fig. 1.4: Contemporary housing units. ....................................................................01

Fig. 1.5: Mulleys Shopping Centre in Kitui Town CBD. ............................................02

Fig. 1.6: A Swahili courtyard house in Kitui Town, Mjini Settlement. .....................02

Fig. 1.7: The Vitruvian Model of Environment. ........................................................03

Fig. 1.8: View Park Towers in Nairobi, Kenya. A non-responsive building to the local climate. .............................................................................................................04

Fig. 1.9: A Section of the Eastgate Building in Harare, Zimbabwe. An environmentally responsive building. .....................................................................04

Fig. 1.10: A satellite image showing the Kitui Township Area and locations of the selected cases for this study. ...................................................................................05

Fig. 2.11: A typical comfort diagram scientifically referred to as a psychometric chart. ..........................................................................................................................13

Fig. 2.12: Heat transfer mechanisms of the human body. ...................................14

Fig. 2.13: The various ways by which bodies lose and gain heat. .......................14

Fig. 2.14: Factors influencing human thermal comfort. ........................................15

Fig. 2.15: Air velocity or movement through a building. .......................................16

Fig. 2.16: Solar radiation absorption into a habitable space. ..............................16

Fig. 2.17: A swimming pool at Signal Garden Hotel in Kitui, a place to cool down the body with the relatively high air and radiant temperature in Kitui. .............17

Fig. 2.18: The Vitruvian Model of Environment. ......................................................18

Fig. 2.19: Basic bioclimatic design strategies for the hot tropics. ........................18

Fig. 2.21: Courtyard pools cool through evaporation. .........................................19

Fig. 2.20: Diversion of cool breezes. ........................................................................19

Fig. 2.22: Plan of IBM Plaza, Kuala Lumpur, Malaysia has service spaces on the west facade to protect the central spaces from heat gains. .............................20

Fig. 2.23: Ventilated space between the roof and the ceiling. ...........................21

Fig. 2.24: Ideal sun-path orientation........................................................................21

Fig. 2.25: Effect of large outlet than inlet. ...............................................................22

Fig. 2.26: Louvre windows offer variable ventilation path. ...................................22

Fig. 2.27: The stack effect; hot air rises due to buoyancy, and its low pressure sucks in fresh air from outside. .................................................................................23

Fig. 2.28: The wind catch (malkaf). .........................................................................23

Fig. 2.29: Different wing walls of better and worse effectiveness; apertures on same wall. ..................................................................................................................23

Fig. 2.31: Trees and shrubs to funnel breezes. ........................................................24

Fig. 2.30: Different wing walls of better and worse effectiveness; apertures on adjacent walls. ..........................................................................................................24

Fig. 2.32: The exterior appearance of the malkaf (wind catcher). .....................28

Fig. 2.1: A typical Akamba traditional house (Musonge). ....................................08

Fig. 2.2: North American Indians’ dwellings in various climatic regions. .............08

Fig. 2.3: Old commercial buildings in Kitui Town CBD. ..........................................09

Fig. 2.4: Bonus Mall in Kitui Town CBD. .....................................................................09

Fig. 2.5: A panoramic view of the Bus Park in Kitui Town CBD. ............................09

Fig. 2.6: Wooded savanna in Kitui. ..........................................................................10

Fig. 2.7: Grassland savanna experienced in some parts of the country. ...........10

Fig. 2.8: Kenya climatic zone. ..................................................................................10

Fig. 2.9: Olgyay’s bioclimatic chart showing the hot conditions partially within the comfort zone while the cold conditions fall outside the comfort zone. Air movement is significant during the hot conditions. Radiation required during the cold conditions. High thermal mass cooling and natural ventilation is required. .....................................................................................................................12

Fig. 2.10: A typical Olgyay’s bioclimatic chart used to determine thermal comfort. ......................................................................................................................13

ix

Fig. 4.1: Location of Kitui Town within Kitui County, Kenya. ..................................36

Fig. 4.2: Kitui Town CBD as highlighted. ..................................................................36

Fig. 4.3: Old commercial buildings in Kitui Town CBD (as shown in both images A & B). ............................................................................................................................37

Fig. 4.4: A mosque in Mjini Settlement; one of the buildings that stands out and defines the settlement. .............................................................................................37

Fig. 4.5: Muli Mall in Kitui Town CBD. ........................................................................38

Fig. 4.6: Bonus Mall in Kitui Town CBD. .....................................................................38

Fig. 4.7: Mulleys Shopping Centre in Kitui Town CBD. ............................................38

Fig. 4.8: The Kitui County Assembly, which is along the Kibwezi - Kitui - Mwingi Road (Road B7). ........................................................................................................38

Fig. 4.9: Concrete blocks and coarse aggregates for concrete. .......................39

Fig. 4.10: An aerial view of part of Mjini Settlement (the Noor Mosque and Madrassa area) showing use of corrugated iron sheets. Galvanised iron sheets have been preferred on the recent construction works done in the area of study. ..........................................................................................................................39

Fig. 4.11: Residential units in Kitui Township Area. Fired bricks have been used for walling on most low-rise residential units. Galvanised iron sheets are used on the recent construction works done. ............................................................................40

Fig. 4.12: Wrought iron used for the palisade fence and gate at the Huduma Centre in Kitui. ...........................................................................................................40

Fig. 4.13: A typical Akamba traditional homestead (Musyi). ...............................41

CHAPTER FOUR

Fig. 4.14: A typical Akamba traditional homestead layout. ................................41

Fig. 4.15: The typical Akamba traditional house (Kisukuu). ..................................42

Fig. 4.16: A typical cone-on-cylinder type Akamba traditional house (Musonge). .................................................................................................................42

Fig. 4.17: Sections of the typical Akamba traditional houses; Musonge (left) & Kisukuu (right). ............................................................................................................42

Fig. 4.18: A typical Akamba traditional house layout. ..........................................42

Fig. 4.19: A typical section of the bee-hive type Akamba traditional house (Kisukuu). ....................................................................................................................42

Fig. 4.20: The free standing Akamba traditional unit (Musonge) that the author found within the study area. ....................................................................................43

Fig. 4.21: A section of the free standing Akamba traditional unit (Musonge) that the author found within the study area. ................................................................43

Fig. 4.22: A plan of the free standing Akamba traditional unit (Musonge). .......43

Fig. 4.23: The location of the free standing traditional unit in the homestead as highlighted in red. .....................................................................................................43

Fig. 4.24: A Swahili courtyard house in Mjini Settlement. ......................................44

Fig. 4.25: Noor Mosque and Madrassa in Mjini Settlement; a settlement occupied by the Swahili majority of whom are Muslims. .......................................................44

Fig. 4.26: A satellite image showing Mjini Settlement as highlighted; it is located within Kitui Township. .................................................................................................44

Fig. 4.27: An old Swahili house, Mzee Yusuf’s (partly demolished as he’s doing an on-site incremental upgrading of the house). ......................................................45

Fig. 4.28: A Swahili courtyard house in Mjini Settlement which the author studied as a case. ...................................................................................................................45

Fig. 4.29: Contemporary dwelling units; a bungalow and an apartment block. ..........................................................................................................................46

Fig. 4.30: A satellite image showing moderately dense high end modern residential area within the suburb of Kitui Township Area, referred to as ‘Site Area’. ..........................................................................................................................46

Fig. 4.31: A satellite image showing dense and compact contemporary estates within Kitui Township; Mosquito (left)and Kunda-Kindu (right) Settlements. There are several high-rise units within the settlements...................................................46

Fig. 4.32: Semi-detached contemporary houses in ‘Site Area’.. .........................47

CHAPTER THREEFig. 3.1: The author recording information obtained from the field by sketching. ...................................................................................................................31

Fig. 3.2: Nikon D3100 camera used to take photographs in the field.................32

Fig. 3.3: A 5m tape measure used to take measurements in the field. ..............32

Fig. 3.4: HOBO data loggers used to collect empirical climatic data................32

Fig. 3.5: One of the interviewees, Mzee Yusuf (right); a village elder in Mjini Settlement, with his friend. .......................................................................................33

Fig. 3.6: The author engaged in a focused group discussion with some members of the community......................................................................................................33

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Fig. 4.33: A contemporary house owned by the Kitui County Government for some of its staff. .........................................................................................................47

Fig. 5.1: An aerial view of Mosquito Settlement (left), Mjini Settlement (centre) and part of the CBD (right). .....................................................................................50

Fig. 5.2: A panoramic view of the Bus Park in Kitui Town CBD. ............................50

Fig. 5.3: Kalundu Dam which lies within Majengo Settlement (A swahili settlement 1 km from the Town’s CBD). .....................................................................................50

Fig. 5.4: An Akamba traditional house (Musonge); 01 on the map. ...................51

Fig. 5.5: A Contemporary house; 02 on the map. .................................................51

Fig. 5.6: A Swahili courtyard house; 03 on the map. .............................................51

Fig. 5.7: Contemporary houses; 04 on the map. ...................................................51

Fig. 5.8: Kitui Township satellite image. ...................................................................51

Fig. 5.9: An Akamba traditional house (Musonge). ..............................................52

Fig. 5.10: A satellite image showing Bi. Mwikali’s compound with her house highlighted. ................................................................................................................52

Fig. 5.11: Plan of the Musonge. ................................................................................53

Fig. 5.12: Grass thatch for roofing. ...........................................................................53

Fig. 5.14: A section of the Musonge. .......................................................................53

Fig. 5.13: Lattice & internal wall. ..............................................................................53

Fig. 5.15: Floor. ............................................................................................................54

Fig. 5.16: Fenestrations (A & B). ................................................................................54

Fig. 5.17: Fenestration. ..............................................................................................54

Fig. 5.18: Outdoor space. ........................................................................................54

Fig. 5.19: Plan highlighting in red the location of the data logger in Bi Mwikali’s house.. ........................................................................................................................55

Fig. 5.20: A contemporary house, Bw. Katabu’s house. .......................................57

Fig. 5.21: A satellite image showing Bw. Katabu’s house as highlighted. ..........57

Fig. 5.22: Plan of Bw. Katabu’s house. ....................................................................58

Fig. 5.23: Floor, ceiling, wall finishes, internal doors................................................58

CHAPTER FOUR

CHAPTER FIVE

Fig. 5.24: Fenestrations (A & B). ................................................................................59

Fig. 5.25: Back outdoor space & fenestrations on it. ............................................59

Fig. 5.27: Front outdoor space. ................................................................................59

Fig. 5.26: Front door. ..................................................................................................59

Fig. 5.28: Plan highlighting in red the location of the data logger in Bw. Katabu’s house. .........................................................................................................................60

Fig. 5.29: A Swahili courtyard house, Bw. Khatibu’s house. ..................................62

Fig. 5.30: A satellite image showing Bw. Khatibu’s house as highlighted. ..........62

Fig. 5.31: Compact Courtyard of Bw. Khatibu’s house.........................................63

Fig. 5.33: Plan of Bw. Khatibu’s house. ....................................................................63

Fig. 5.32: Internal walls do not allow for cross-ventilation. ....................................63

Fig. 5.34: Thick walling & fenestration. ....................................................................64

Fig. 5.36: Corrugated iron sheets used for roofing.................................................64

Fig. 5.37: Floor surface. .............................................................................................64

Fig. 5.35: Ceiling, floor & walling. .............................................................................64

Fig. 5.38: Fenestrations; windows. ............................................................................65

Fig. 5.39: Fenestrations; doors. .................................................................................65

Fig. 5.40: Fenestrations on the rear facade. ..........................................................65

Fig. 5.41: Plan highlighting in red the location of the data logger in Bw. Khatibu’s house. .........................................................................................................................66

Fig. 5.42: Contemporary housing units. ..................................................................68

Fig. 5.43: A satellite image showing Mama Arianna’s house as highlighted. ....68

Fig. 5.44: Plan of Mama Arianna’s house. ..............................................................69

Fig. 5.45: Roof eaves , permanent ventilation & fenestration..............................69

Fig. 5.46: Floor, wall & ceiling materials. ..................................................................69

Fig. 5.47: Fenestrations & permanent vents (Front). ..............................................70

Fig. 5.49: Fenestrations (Back) & recessed Kitchen verandah. ............................70

Fig. 5.51: Outdoor spaces (Front; A and back; B). ................................................70

Fig. 5.48: Fenestrations (Front) & recessed entry porch. .......................................70

Fig. 5.50: Fenestrations (Back)..................................................................................70

Fig. 5.52: Plan highlighting in red the location of the data logger in Mama Arianna’s house.........................................................................................................71

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CHAPTER SIX

Fig. 5.53: Plan highlighting in red the location of the external data logger at the kitchen verandah of Mama Arianna’s house. ......................................................73

CHAPTER FIVE

Fig. 6.1: A swahili courtyard dwelling unit, Bw. Khatibu’s house. .........................81

Fig. 6.2: Semi-detached contemporary dwelling units, Mama Arianna’s house is the furthest left...........................................................................................................81

Fig. 6.3: Internal wall in Bi. Mwikali’s house. ............................................................82

Fig. 6.4: Courtyard of Bw. Khatibu’s house. ............................................................82

Fig. 6.5: A building at the B.A.T. Grounds in Kitui. Fired bricks and mortar used for the walling. ................................................................................................................83

Fig. 6.6: Daily temperature fluctuations for different construction methods......83

Fig. 6.7: Permanent ventilation space as part of the fenestration as highlighted in red and another permanent vent above the fenestration. ............................84

Fig. 6.8: Mama Arianna’s front outdoors. ...............................................................84

Fig. 6.9: Narrow & single banked layout plan enhances cross-ventilation. .......85

Fig. 6.10: Stabilised earth bricks used in the walling construction. ......................85

Fig. 6.11: Glass louvres deflecting air flow. .............................................................86

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LIST OF TABLES & GRAPHS

GRAPHSTABLESTable 2.1: Climatic Data of Kitui. .............................................................................11

Table 2.2: Mean monthly relative humidity of Kitui................................................12

Table 2.3: Mean monthly temperature of Kitui. .....................................................12

Table 2.4: Time-lag figures for common materials. ................................................20

Table 2.5: Density and resistivity of some common building materials. ..............25

Table 2.6: Absorptivities and emissivities of various surfaces................................26

Table 2.7: Thermo-physical properties of various building materials. ..................27

Table 5.1: Average conditions in Bi Mwikali’s house. ............................................55

Table 5.2: Internal temperature conditions of Bi. Mwikali’s house in comparison with the maximum, minimum and average of the external temperature conditions...................................................................................................................56

Table 5.3: Average conditions in Bw. Katabu’s house. .........................................60

Table 5.4: Internal temperature conditions of Bw. Katabu’s house in comparison with the maximum, minimum and average of the external temperature conditions...................................................................................................................61

Table 5.5: Average conditions in Bw. Khatibu’s house. ........................................66

Table 5.6: Internal temperature conditions of Bw. Khatibu’s house in comparison with the maximum, minimum and average of the external temperature conditions...................................................................................................................67

Table 5.7: Average conditions in Mama Arianna’s house. ..................................71

Table 5.8: Internal temperature conditions of Mama Arianna’s house in comparison with the maximum, minimum and average of the external temperature conditions. ..........................................................................................72

Table 5.9: Average external conditions. .................................................................73

Table 5.10: Comparative analysis of the houses investigated in the study. .......74

Table 5.11: Internal temperature conditions of the houses under study in comparison with the maximum, minimum and average of the external temperature conditions during the data logging period of 7 days, from 1000Hrs 28/09/2016 to 1000Hrs 05/10/2016. ..........................................................................79

Graph 2.1: Mean monthly rainfall. ..........................................................................11

Graph 2.2: Mean monthly temperature conditions (Min. & Max.). ....................11

Graph 2.3: Mean monthly relative humidity (a.m. & p.m.). .................................11

Graph 5.1: Conditions in Bi. Mwikalis House. ..........................................................55

Graph 5.2: Comparison of external conditions and internal conditions in Bi. Mwikalis House. ..........................................................................................................56

Graph 5.3: Conditions in Bw. Katabu’s House. ......................................................60

Graph 5.4: Comparison of external conditions and internal conditions in Bw. Katabu’s House. ........................................................................................................61

Graph 5.5: Conditions in Bw. Khatibu’s House. ......................................................66

Graph 5.6: Comparison of external conditions and internal conditions in Bw. Khatibu’s House. ........................................................................................................67

Graph 5.7: Conditions in Mama Arianna’s House. ................................................71

Graph 5.8: Comparison of external conditions and internal conditions in Mama Arianna’s House. .......................................................................................................72

Graph 5.9: External conditions. ...............................................................................73

Graph 5.10: Internal temperature conditions of the houses under study in comparison with the external temperature conditions. ......................................78

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Kitui is a town in Kenya, 180 km East of Nairobi and 105 km East of Machakos, and is the

headquarters of Kitui County. The local people are mostly of the Akamba ethnicity with a

notable population of the Swahili. Kitui Town has different house typologies varying from

the Akamba traditional houses, Swahili houses to the contemporary houses and buildings

all of which have different design approaches, yet existing in the same savanna climate

in which Kitui Town lies resulting to different human thermal comfort levels within these

structures.

The growing need for shelter has resulted to putting up of contemporary houses that have

little regards to no climatic context considerations at all. This study sought to examine

the thermal comfort levels in the house typologies in Kitui Township Area and analyse the

bioclimatic design strategies utilised in these house typologies to provide for human thermal

comfort and ultimately establish the most appropriate bioclimatic design strategies for

human thermal comfort to be used in design of contemporary buildings.

The author used the case study method in this study. The data needed for this study was

collected through photographs, sketches & measured drawings, scientific studies using

data loggers, interviews, administration of questionnaires and literature review. The author

found that the Akamba traditional house had better thermal performance compared

to one of the contemporary houses as the latter was double banked, the entire block

oriented along the north-south axis and having the fenestrations on the east and west

façades, the internal walls not allowing for ventilation as permanent vents had not been

provided for and its outdoor spaces being hard landscaped.

The author concluded that in order to achieve human thermal comfort, the following

design approaches have to be applied to minimise heat gains and maximise on natural

cooling: having moderately dense & compact site planning; have courtyards & single

banked rooms; use servant spaces as thermal buffer spaces; use heavy structures & locally

available materials; orient buildings along the east-west axis & optimise on wind; have

openings on north & south façades; and providing well landscaped outdoor spaces.

ABSTRACT

INTRODUCTION

1


Introduction 01

1.1 Background of StudyKitui Town’s local people are mostly of the Akamba ethnicity; Kitui also has a notable

population of the Swahili who occupy two settlements; Mjini & Majengo Settlements.

The town residents have different house typologies varying from the Akamba traditional

houses, Swahili houses to the contemporary houses. Fig. 1.1 to Fig. 1.4 shows these different

house typologies. All of these typologies have different bioclimatic design approaches

to some level, yet they all exist in the same savanna climate in which Kitui Town lies. This

variety results to different human thermal comfort levels within the structures.

Thermal comfort comparative analysis studies have been carried out in different locations

and most recently by Nzuki, S. (2014), who conducted a comparative analysis of traditional

and contemporary buildings in Magadi Township which lies in the semi-arid climate. It is

alongside these studies that the author sought to build on, but in Kitui Township Area.

Man was faced with the challenge of designing for climate as soon as he left the areas that

didn’t need shelter from climate, the less hospitable shelter of the cave. The architect’s

design problem is to produce an internal environment, which will not place undue stress

upon the body’s heat-compensation mechanism.

Fig. 1.1: An Akamba traditional house (Musonge).Source: Author, 2016.

Fig. 1.2: A Swahili house.Source: Author, 2016.

Fig. 1.3: A contemporary house.Source: Author, 2016.

Fig. 1.4: Contemporary housing units.Source: Author, 2016.


Introduction 02

1.2 Problem StatementMost of our modern solutions to climatic problems often do not work, and buildings are

made bearable by means of ingenious mechanical devices whose cost sometimes

exceeds that of the building shell. Fig. 1.5 shows a building in Kitui that partly uses these

mechanical devices. The comfort created by these devices is still problematic as the over-

controlled and uniform environment may lead to unforeseen dangers, as man may not

be so much controlling the environment as escaping it. The poor thermal performance of

many of these buildings despite use of mechanical equipment suggests that we cannot

ignore the physical environment, and that we underestimate its continued effect on our

buildings and cities.

Kitui lies within the savanna climatic zone and Olgyay, V. (1963) has established that for

such climates characterised by excessive heat and glaring sun requires that the shelter be

designed to reduce heat impacts and provide shade. The bioclimatic design strategies

for the savanna climate include: use of thick walls (adobe) with good insulation value and

the capacity to delay heat impacts for long hours thus reducing the daily heat peaks;

have small fenestrations; building orientation to extend on an east-west axis; design for

good ventilation & air movement; use of insulated lightweight roofs with ceilings on the

underside; and packing of buildings together which leaves least surface exposed to the

scorching heat & shades the courtyards, providing cooling wells & establishing ‘introvert’

dwelling units looking inward away from the hostile environment. Moreover, the closeness

yields protection through mass. Fig. 1.6 shows a Swahili house within Kitui Town that has

observed some of these bioclimatic design strategies.

It is based on these and much more bioclimatic design strategies discussed in Chapter two

that the author used to analyse how the houses in Kitui utilised these strategies, examined

the thermal comfort of users in these houses and established the most appropriate

strategies to be used in the area of study; as some of the buildings in Kitui respond well to

the savanna climate while others do not.

Fig. 1.5: Mulleys Shopping Centre in Kitui Town CBD.Source: Author, 2016.

Fig. 1.6: A Swahili courtyard house in Kitui Town, Mjini Settlement.Source: Author 2016.


Introduction 03

1.3 Research Objectives

Fig. 1.7: The Vitruvian Model of Environment.Source: Selective Environment; Hawkes, D. et al, 2012; Author modified 2016.

i. What are the thermal comfort levels in the house typologies in Kitui Township

Area?

ii. What are the bioclimatic design strategies utilised in the house typologies in Kitui

Township Area to provide for human thermal comfort?

iii. What are the most appropriate bioclimatic design strategies for human thermal

comfort to be used in design of contemporary buildings in Kitui?

i. To examine the thermal comfort levels in the house typologies in Kitui Township

Area.

ii. To analyse the bioclimatic design strategies utilised in the house typologies in

Kitui Township Area to provide for human thermal comfort.

iii. To establish the most appropriate bioclimatic design strategies for human

thermal comfort to be used in design of contemporary buildings in Kitui.

1.4 Research Questions


Introduction 04

1.5 Justification of StudyThere has been a growing trend of buildings being put up in our towns and cities with little

to no regard of the climate considerations in which they are located; for example Fig. 1.8

shows a building put up in Nairobi that has ignored several bioclimatic design strategies

for the climate, the highlands climate. Therefore, this prompts scholars to conduct studies

on the appropriate bioclimatic design strategies for different climatic zones. This is a wide

scope, but this particular research is limited to Kitui Township Area, which lies in the savanna

climate.

Kitui being one of the regions in which buildings are being put up with little to no regard

of the local climate considerations, this research sought to analyse the environmental

suitability of the house typologies in Kitui, with regards to thermal performance and

bioclimatic strategies utilised; and with the findings, establish the appropriate bioclimatic

design strategies for human thermal comfort for Kitui, which lies in the Savanna climate.

1.6 Significance of StudyThis research thesis seeks to establish the appropriate bioclimatic design strategies that

should be used more so in the design of the contemporary buildings to achieve a good

internal environment & thermal comfort for Kitui, which lies in the savanna climate. The

findings from this study will therefore be of significance to the designers, on the design of

buildings in Kitui, to achieve a good internal environment & thermal comfort; for example

Fig. 1.9 shows a section of the Eastgate Building in Harare, a building that has achieved a

good internal environment by responding to the climate design-wise.

Fig. 1.8: View Park Towers in Nairobi, Kenya. A non-responsive building to the local climate.Source: Google images, 2016.

Fig. 1.9: A Section of the Eastgate Building in Harare, Zimbabwe. An environmentally responsive building.Source: Selective Environment; Hawkes, D. et al, 2012; Author modified 2016.


Introduction 05

1.7 Research Scope & LimitationsThis research is mainly limited

geographically to Kitui Township Area,

which experiences the savanna climate.

Earlier studies have been carried out

on the bioclimatic design strategies for

different climates in different locations.

Thermal comfort comparative analysis

studies have also been carried out for

different climates in different locations.

This study, therefore, sought to establish the

appropriate bioclimatic design strategies

for Kitui, which lies in the savanna climate,

to provide for human thermal comfort for

the modern age.

This research thesis is focused on the house

typologies in Kitui Township Area; the

Traditional Akamba house, Swahili house

and contemporary houses.

During the study, the limitations were

financial and time constraints that

limited the amount of data collected.

Another limitation was on the region’s

climatic data that was available from the

meteorological station, which was up to

the year 1979; there was no recent data.

Fig. 1.10: A satellite image showing the Kitui Township Area and locations of the selected cases for this study.Source: Ministry of Lands, Housing & Urban Development, Kenya, 2015; Author modified 2016.


Introduction 06

1.8 Research OrganisationChapter one is an introductory chapter that states the background of study, problem

statement, research objectives, research questions, justification of study, significance of

study, research scope & limitations and research organisation.

Chapter two critically reviews earlier studies done and published literature from relevant

areas of study. The author critically reviewed various published material and summarised

the information. The main areas of focus include the factors that influence human thermal

comfort and the bioclimatic design strategies for human thermal comfort appropriate for

the Savanna climate in which Kitui Town lies. This chapter enabled the author to establish

variables that were used to measure a design’s response to climate in the fieldwork.

Chapter three reviews the research methods. This chapter reviews the research purpose,

research strategy, time horizon, population, element & population frame, sampling

method, data collection methods, data analysis and data presentation.

Chapter four entails a review on the architecture in Kitui Township. This chapter entails a

review of the architectural development of Kitui; common building materials used; and

the settlement patterns, homestead layouts, typologies, form, technology & materials of

the house typologies in Kitui Township Area. This chapter is a preamble of chapter five.

Chapter five entails the research findings. Information obtained from the field and the

documentation of the same done comprehensively in this chapter. The selected cases

have been expounded on, and further with a tabular comparative analysis done to find

out which case has the best user thermal comfort with the appropriate bioclimatic design

strategies for Kitui Town, which lies in the savanna climate.

Chapter six gives the conclusions and recommendations. A small section of this chapter

recommends on future research based on this study.

Documents

Thermal Comfort Comparative Analysis of Houses in Kituiarchitecture.uonbi.ac.ke/sites/default/files/cae/builtenviron... · i “...Although I believe that the appearance of a building