Outline of chapters - Thesis plan

The thesis consists of eight chapters as shown in Figure 1-4 and discussed below:

Figure 1-4 Thesis structure

1.9.1 Chapter One

This is the introduction chapter titled ‘Nigerian buildings and Energy use’. To build a context behind the need for a study into energy conservation, it discusses electricity generation, distribution, transmission and consumption. The place for energy conservation and efficiency is grounded theoretically.

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Chapter 2 is the literature review titled ‘Phase Change Materials as energy conservation mechanisms in buildings’. The objective is to search for the knowledge gap within literature for PCM used for energy conservation and thermal comfort within buildings in Nigeria hot and humid, and hot and dry climate. The chapter is the theoretical framework with which PCM may be optimized for the context of the research. A brief history of the development of PCM, its various applications, thermo-physical and chemical classifications are reviewed. The development history shows the ways in which PCM are incorporated within the building applications, and ways of optimizing its thermal and energy performance.

1.9.3 Chapter Three

Chapter 3 is the ‘Methodology’ chapter and one of its objectives is to evaluate the methods of calculating the potential for energy savings with PCM. Another objective is to develop a method for collecting electricity consumption data in places suffering from power shortages. In Chapter 1, this problem is highlighted as a significant one in Nigeria. The same chapter brought to light the need to conduct a field energy auditing exercise. A method to successfully collect electricity consumption data is presented.

1.9.4 Chapter Four

Chapter 4 is the Study dealing with validating the results of the simulations predicted by the different versions of EnergyPlus for the base-case with PCM and without. The objective is to evaluate the different methods of calculating the potential for energy savings with PCM. They include Analytical (Theoretical) testing, Laboratory and Field experimentation and Computer simulation (Numerical testing). A discussion of the benefit and limitations of each method is conducted in this chapter and computer simulations are shown to be more suitable for this study.

1.9.5 Chapter Five

Chapter five: The chapter is titled ‘Disaggregating primary electricity consumption for office buildings in Nigeria’. This chapter discusses the primary field data collection exercise conducted in Nigeria. The objective is to investigate the electricity consumption within office buildings in Abuja

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The sampling issues, energy audit process, and a report of the results are presented. It also reports the results of a degree day and descriptive statistical analyses. The results provide the description and breakdown of how electricity is used into end-use aggregates.

Disaggregating electricity consumption enables the next objective. The objective is to determine the potential for energy savings within the cooling load.

1.9.6 Chapter Six

The chapter looks at‘Optimizing thermal and energy performance of buildings’. The chapter reports the bio-climatic optimization process of office buildings’ design features for electricity conservation and thermal comfort in Nigerian office buildings. The variables examined are bio-climatic design variables such as orientation, glazing, shading, airtightness and insulation. This is achieved using building energy modelling and simulation software, DesignBuilder and an internal EnergyPlus simulation engine as discussed in Chapter 2 and later in this chapter.

The above process is conducted to achieve another objective; to create a base-case for testing the performance of PCMs. The bio-climatic optimization process is required because testing PCM systems on a poorly designed building might give erroneously superior results simply because there is so much room for energy savings. Testing PCM systems on a thermally optimized base-case building on the other hand will provide reasonable results.

1.9.7 Chapter Seven

The chapter is titled ‘PCM performance in office buildings’. One of the objectives is to create an optimized model for a PCM system for office buildings in warm climates. The bio-climatic model presented in Chapter 6 is used to analyse the effect of varying thermo-physical properties of the PCM system on electricity consumption and thermal comfort. in the form of a parametric analysis process using building energy calculation software, EnergyPlus.

1.9.8 Chapter Eight

The other objective is to evaluate the potential effect of incorporating PCMs in the building fabric on thermal comfort and energy consumption. The performance in

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operational mode of the PCM is analysed using degree day and descriptive statistics.

The result is a PCM model for use in office buildings in Nigeria.

1.10 Conclusion

It is estimated that buildings contribute as much as one third of total global annual greenhouse gas emissions, primarily through the use of fossil fuel during their operational phase and consumes up to 40% of all energy in Nigeria, similar to global trends (Adeleke, 2010). In addition, Nigeria suffers from an energy crisis which manifests in power outages despite being highly endowed with natural energy resources (Ibitoyea & Adenikinju, 2007). Due to the power outages, the built environment has adapted to interrupted electricity supply by installing back-up power generators fuelled mostly by diesel and petrol.

Energy conservation and efficiency practices and technologies are required to ensure rationalized consumption of energy in Nigeria (Sambo, 2008). This is desirous due to wasteful and inefficient use of electricity in residential, offices buildings, and industries as reported by Uyigue et al.(2009).

Energy consumption in office buildings is one of the highest compared to the

consumption of other building types. Energy in office buildings is mainly consumed for thermal comfort, lighting and operating office equipment purposes (Santamouris and Dascalaki, 2002).

The aim of this investigation is therefore to evaluate the potential of incorporating PCM systems in composite hot humid/ hot dry climates in order to conserve energy in office buildings within the context of an overburdened and failing central power utility in Nigeria.

A quantitative research strategy using cross-sectional method of data collection is employed to achieve the objectives of the study which are:

1. To build a context behind the need for a study into energy conservation in Nigeria

2. To search for the knowledge gap within literature for PCM used for energy conservation and thermal comfort within warm-humid climates

3. To validate the computer software’s and user’s ability to simulate PCMs in buildings

4. To develop a method for collecting electricity consumption data in places suffering from power shortages

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5. To investigate the electricity consumption within office buildings in Nigeria 6. To determine the potential for energy savings within the cooling load 7. To create a base-case for testing the performance of PCMs

8. To optimized model for a PCM system for office buildings in warm climates 9. Evaluate the potential effect of incorporating PCMs in the building fabric on

thermal comfort and energy consumption

Apart from PCMs, bioclimatic design principles are adopted to save energy because buildings are designed based on natural ventilation, local climate and materials, and using renewable and clean technologies (Khalifa and Abbas, 2009).

Chapter 2 is the literature review titled ‘Phase Change Materials as energy conservation mechanisms in buildings’. It is centred on a description of Phase Change Materials (PCMs) properties and their application in the built environment as an energy conservation mechanism.

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