HARNESSING PASSIVE COOLING STRATEGIES TO ENHANCE THERMAL COMFORT IN THE DESIGN OF PROPOSED SCHOOL OF ENVIRONMENTAL STUDIES ABDUGUSAU POLYTECHNIC, ZAMFARA STATE, NIGERIA.

ABTSRACT

Passive design responds to local climate and site conditions in order to maximise the comfort and health of building users while minimising energy use. The key to designing a passive building is to take best advantage of the local climate. Passive cooling refers to any technologies or design features adopted to reduce the temperature of buildings without the need for power consumption. Consequently, Buildings consume large amount of energy in order to achieve thermal comfort for users. To achieve the goal of thermal comfort in buildings, passive cooling is one of the suggested practices emphasized to be adopted in many buildings around the world of which educational facilities have been a major target as an opportunity of achieving thermal comfort. When it comes to educational facilities, end users who are usually students, lecturers and other occupants spend almost 50% of the entire day within the buildings. To add on 50%, occupancy is predominantly during day time when environmental conditions are adverse to human survival hence creating thermal discomfort which in turn leads to low productivity and occupancy dissatisfaction. Many educational facilities mostly in Africa have been built relying on natural climatic conditions for occupancy comfort throughout the year which has brought about discrepancies amongst users. Whilst passive cooling can provide thermal comfort in some climates, a gap of thermal comfort improvement strategies in buildings still exits to enhance suitable thermal condition in buildings thus avoiding occupant dissatisfaction, low productivity and overall building performance. The aim of this study is to test the usefulness of applying selected passive cooling strategies to improve thermal comfort of buildings in hot dry climate of Gusau for the design of School of Environmental Studies Abdugusau Polytechnic, Nigeria. The methodology adopted were case studies and simulation whereby, three 3 case studies buildings of the same usage type were selected and eight passive cooling strategies were applied. Simulation software – namely ECOTECT – was used to assess the performance of the building. Solar shading performance was also assessed using Sun Cast Analysis, as a part of the ECOTECT software. Result from the simulation indicated that the Mean Radiant Temperature can be reduced and thermal comfort percent can be improved by applying passive cooling strategies. Mechanical ventilation without cooling registered a negligible improvement in occupancy thermal comfort while on application of scheduled cooling thermal comfort improved between slightly warm and slightly cool with a 15% improvement in comfort hours. Also, in respect to indoor temperature, upper rooms are the worse where the temperature reach up to 39°C on peak day hours beside the temperature drop to uncomfortable level during night, the situation is different on ground flat when simulation indicated better performance on ground floor even though the recorded temperature still above the comfort level but not as high as those recorded on top floor. Also the simulation showed that temperature at peak hour (between13:00 and 17:00 O’clock) up to 40°C which is almost 12°C above comfort range. This means that it is impossible to achieve comfort temperature with passive cooling however passive cooling improve significantly temperature within the building. This study can help architects and related stake holders to exploit passive instruments to reduce interior temperature and energy consumption of a building during the design process.

 

 

 

Table of Contents

Declaration …………………………………………………………………………………………………………… ii

Certification ………………………………………………………………………………………………………….iii

Acknowledgement ………………………………………………………………………………………………… iv

Dedication …………………………………………………………………………………………………………….. v

ABTSRACT …………………………………………………………………………………………………………. vi

LIST OF FIGURES …………………………………………………………………………………………….xiii

LIST OF TABLES ………………………………………………………………………………………………. xv

LIST OF PLATES ……………………………………………………………………………………………… xvi

Abbreviations ……………………………………………………………………………………………………. xvii

1.0 INTRODUCTION ………………………………………………….. Error! Bookmark not defined.

Background of Study ………………………………………………………………………………….. xvi

Problem Statement ……………………………………………………………………………………….. 3

Aim and Objectives ………………………………………………………………………………………. 3

Research Questions ………………………………………………………………………………………. 4

Scope of the Study ………………………………………………………………………………………… 5

Justification of the Study ………………………………………………………………………………. 5

2.0 LITERATURE REVIEW ………………………………………………………………………………… 6

Introduction …………………………………………………………………………………………………. 6

       The Definitions of Thermal comfort ………………………………………………………………. 7

2.3.1 Physical factors …………………………………………………………………………………………….. 10

2.3.2 Environmental factors ……………………………………………………………………………………. 11

2.3.2Thermal Comfort Calculation ………………………………………………………………………… 15

2.3.3 Comfort Zone ……………………………………………………………………………………………….18

2.3.4 Bioclimatic Charts ………………………………………………………………………………………… 22

2.3.5Thermal Comfort Scales ………………………………………………………………………………… 24

2.4       Passive Cooling of buildings ………………………………………………………………………… 30

2.4.2Solar and heat protection techniques ……………………………………………………………….. 33

2.4.3 Heat modulation or amortization technique (Modify heat gains) …………………………. 41

2.4.4 Heat dissipation technique (Remove internal heat) ……………………………………………. 41

2.4.5Natural cooling; Evaporative Cooling ……………………………………………………………… 46

3.0 RESEARCH METHODOLOGY ……………………………………………………………………. 48

3.1 Introduction …………………………………………………………………………………………………… 48

3.2 Research Design. ……………………………………………………………………………………………. 48

3.3 Population of Study ……………………………………………………………………………………….. 50

3.4 Sampling ……………………………………………………………………………………………………….. 50

3.5 Instrument of Data Collection ………………………………………………………………………… 51

3.6 Procedure for Data Collection ………………………………………………………………………… 52

3.6.1 Simulation of the case ……………………………………………………………………………………. 53

3.6.2 Variables of Study ………………………………………………………………………………………… 54

3.7 Data Analysis …………………………………………………………………………………………………. 54

4.0 FINDINGS …………………………………………………………………………………………………….. 55

4.1       Introduction ……………………………………………………………………………………………….. 55

4.2      Case Study One: Nuhu Bamalli Polytechnic School of Environmental Studies,

Zaria …………………………………………………………………………………………………………………… 55

Background ………………………………………………………………………………………………………….. 55

4.2.1Site Planning and Landscaping ………………………………………………………………………. 56

4.2.2Structure and Materials …………………………………………………………………………………. 57

4.2.3 Application of Passive Cooling Strategies ………………………………………………………..57

4.2.4 Summary case ………………………………………………………………………………………………. 61

4.3     CASE STUDY TWO: SCHOOL OF ENVIRONMENTAL STUDIES HASSAN

USMAN POLYTECHNIC KATSINA ………………………………………………………………….. 63

4.3.1Background …………………………………………………………………………………………………. 63

4.3.2Site Planning and Landscaping ………………………………………………………………………. 63

4.3.3Structure and Materials …………………………………………………………………………………. 64

4.3.4Application of Passive cooling Strategies ………………………………………………………… 64

4.3.5Summary case ………………………………………………………………………………………………. 67

4.4      CASE STUDY THREE: SCHOOL OF ENVIRONMENTAL STUDIES ABDU

GUSAU POLYTECHNIC TALATA MAFARA …………………………………………………… 69

4.4.1Background …………………………………………………………………………………………………. 69

4.4.2Site Planning and Landscaping ………………………………………………………………………. 70

4.4.3Application of Passive cooling strategies …………………………………………………………. 70

4.4.4Summary case ………………………………………………………………………………………………. 73

4.5      COMPARATIVE ANALYSIS OF RESULTS/FINDINGS ……………………………. 75

5.0 SIMULATION AND FINDINGS …………………………………………………………………… 77

5.1 SIMULATION OF A CASE STUDY………………………………………………………………. 77

5.2       SIMULATION SOFTWARE ………………………………………………………………………. 78

5.3       ROOM TEMPERATURE OF DIFFERENT AREAS WITHIN THE BUILDING

          78

5.3.1Solar Heat Protection …………………………………………………………………………………….. 79

5.3.2Internal Zone Temperature …………………………………………………………………………….. 80

5.4       FINDINGS FROM CASE STUDIES AND SIMULATION…………………………… 82

6.0 THE SITE ……………………………………………………………………………………………………… 83

6.1       Introduction ……………………………………………………………………………………………….. 83

6.1.1 General Climatic Data ……………………………………………………………………………………83

6.1.2 Precipitation …………………………………………………………………………………………………. 85

6-2Temperatures …………………………………………………………………………………………………… 85

6.1.3Wind speed ………………………………………………………………………………………………….. 86

6.2       Study Area (Profile) ……………………………………………………………………………………. 86

6.3       Site Selection Criteria and Features …………………………………………………………….. 87

6.4        Site Location ………………………………………………………………………………………………. 87

6.5       Site Analysis ……………………………………………………………………………………………….. 88

6.5.2Topography …………………………………………………………………………………………………. 88

6.5.3Vegetation …………………………………………………………………………………………………… 89

6.5.4Services ………………………………………………………………………………………………………. 89

6.5.5Climate ……………………………………………………………………………………………………….. 90

7.0 DESIGN REPORT ………………………………………………………………………………………… 92

7.1 Design Brief …………………………………………………………………………………………………… 92

7.2       Concept Development …………………………………………………………………………………. 93

7.2.1 Architectural Concept ……………………………………………………………………………………. 93

7.2.2Facade Concept ……………………………………………………………………………………………. 93

7.3       Floor Plans …………………………………………………………………………………………………. 94

7.3.1Site plan ………………………………………………………………………………………………………. 94

7.3.2Ground floor plan …………………………………………………………………………………………. 95

7.3.3First floor plan ……………………………………………………………………………………………… 95

7.3.4Second floor plan ………………………………………………………………………………………….. 96

7.4       Schedule of Accommodation ……………………………………………………………………….. 97

7.5      Passive Cooling Strategies Applied in the Proposed Design of School of

environmental design …………………………………………………………………………………………… 99

7.6      Internal Zone Temperature ……………………………………………………………………….. 102

8.0CONCLUSION AND RECOMMENDATIONS ……………………………………………. 104

8.1 Conclusion …………………………………………………………………………………………………… 104

8.2       Contribution to Knowledge ……………………………………………………………………….. 104

8.3        Recommendations …………………………………………………………………………………….. 105

8.4       Areas of Further Research ………………………………………………………………………… 105

REFERENCES ………………………………………………………………………………………………….. 107

APPENDICES …………………………………………………………………………………………………… 114

1 1.0. INTRODUCTION  Background of Study

The chief goal of building is to provide a healthy and comfortable shelter. Thermal comfort improves concentration, workmanship and enthusiasm (Samuel, Nagendrab, & Maiya, 2013). enhancing productivity and quality (Srinavin & Mohamed, 2003) whereas a poor thermal environment results in sickness (Balaras, Dascalaki, & Gaglia, 2007) and (Wolkoff & Kjaergaard, 2007). Conventionally thermal comfort is achieved by energy intensive mechanical air conditioners. They are associated with sick building syndrome in many cases (Seppanen & Fisk, 2002).

It is important for architects to appreciate the manner in which energy is used in buildings as well as the fuel type employed for its generation. This is particularly important because it will help in identifying ways in which we could attempt to reduce our dependency on fossilfuel, and thus consider new forms of renewable technologies. (Tukur, 2013).

Passive cooling is a building design approach that focuses on heat gain control and heat dissipation in a building in order to improve the indoor thermal comfort with low or nil energy consumption (Samuel, Nagendrab, & Maiya, 2013). Passive cooling systems are energy-efficient and eco-friendly techniques used to improve the thermal comfort with nil or little power consumption. They work either by removing heat from the building to a natural heat sink or by preventing heat from entering the living space from external heat sources.

(Chafe,Tukur,& Sagada,2016).

In Nigeria, most buildings rarely take passive architecture and energy efficiency into consideration due to ignorance, poverty, lack of awareness and/or improper policy on building regulations by Government, use of mechanical devices to achieve thermal comfort in buildings is not only capital intensive but also generate greenhouse gases, air and noise pollution amongst others (Nwofe, 2014).

Wong and Li, (2007) states that, with the global emergence of energy shortages, climatic changes and sick building syndromes associated with the common usage of air-conditioning, authorities worldwide have recognized the necessity in finding strategies that can cultivate a more sustainable design with satisfactory indoor thermal comfort. This has led to the growing interest in passive cooling strategies that take advantage of natural ventilation which has the potential to reduce first costs and operating costs for commercial buildings while maintaining ventilation rates consistent with acceptable indoor air quality. One of the main objectives of designing a building is to provide a comfort condition for the building’s occupants, while at the same time minimizing the building’s energy consumption. (Chafe, et al., 2016). This research deals with the regulation of thermal comfort and building indoor temperature in school of environmental studies.

According to American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE Standards, 2004), thermal comfort is that condition of mind which expresses satisfaction with the thermal environment. Because there are large variations, both physiologically and psychologically, from person to person, it is difficult to satisfy everyone in a space. The environmental conditions required for comfort are not the same for everyone.

                                                                            Problem Statement

Buildings consume large amounts of energy in order to achieve thermal comfort for users. Thermal Discomfort affects the quality of teaching and learning in schools. To achieve the goal of thermal comfort in buildings, passive cooling is one of the suggested practices emphasized to be adopted in many buildings around the world of which educational facilities have been a major target as an opportunity of achieving thermal comfort.

In educational facilities, end users who are usually students, lecturers and other occupants spend almost 50% of the entire day within the buildings (Ibrahim, Baharun, Abdul Mannan, & Abang Adenan, 2013). Furthermore, occupancy is predominantly during day time when environmental conditions are adverse to human survival hence creating thermal discomfort which in turn leads to low productivity and occupancy dissatisfaction.

Whilst passive cooling can provide thermal comfort in some climates, a gap of thermal comfort improvement strategies in buildings still exists to enhance suitable thermal condition in buildings thus avoiding occupant dissatisfaction, low productivity and overall building performance. The research seeks to study the passive cooling strategies that suit the hot dry climate of Talata Mafara and also to find out the effect of each strategy applied in the design of School of Environmental Studies AbduGusau Polytechnic, Zamfara State Nigeria.

                                                                            Aim and Objectives

The aim of the research is to evaluate the effect of passive cooling strategies for achieving indoor thermal comfort in Design of School of Environment Studies building for AbduGusau

Polytechnic Talata Mafara.

The aim of this work has been achieved through the following objectives:

1. Identify various passive cooling strategies that enhance thermal comfort suitable in hot dry climate of Talata Mafara.
2. To use of computer simulation software to find out the improvements that can be achieved by modifying building components and design elements that enhance thermal comfort for the geographical conditions of Talata Mafara.

• To design a proposed school of environmental studies building that will provide a suitable environment for users’ comfort.

                                                                            Research Questions

The main research questions of this study are:

1. What are the appropriate passive cooling strategies which enhance thermal comfort that are suitable in the hot dry climate of Mafara? ii. What are the possible improvement in indoor temperature and comfort that can be achieved by applying passive cooling strategies?

iii. How can passive cooling be improved through design processes that will provide thermal comfort in the design of school of environmental studies in

Mafara?

                                                                             Scope of the Study

The research is limited to improving passive cooling in delivering indoor thermal comfort in school of environmental studies, specifically, in  hot-dry climate of Mafara. This research  focused on evaluating the effect of each strategy on specific factor of thermal comfort. It  highlighted the theoretical framework necessary to achieve environmentally-friendly indoor environment. This was coupled with the assessment of existing principles and the

consideration of the study area climate. It is also within the scope of this research to highlight the concept of designing for thermal comfort. Finally, the research will develop a theoretical  as well as design solutions for enhancing thermal comfort in hot-dry climate of Mafara.

                                                                      Justification of the Study

There were several researches about overall passive cooling strategies for buildings and there are various researches about simulations focusing on various particular passive cooling.

However, there is a lack of such studies in terms of Mafara climate and built environment. The research will help to get better understanding about the interactive relationship between the buildings’ envelop shape and the surrounding environment.

HARNESSING PASSIVE COOLING STRATEGIES TO ENHANCE THERMAL COMFORT IN THE DESIGN OF PROPOSED SCHOOL OF ENVIRONMENTAL STUDIES ABDUGUSAU POLYTECHNIC, ZAMFARA STATE, NIGERIA.

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