Thermal Properties Of Some Selected Materials Used As Ceiling In Building

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REFERENCES

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ABSTRACT

This work investigates the thermal properties of Polyvinyl Chloride (PVC), Plaster of Paris (POP), asbestos, and cardboard commonly used as ceiling materials. The steady state method for Lee’s disc apparatus was employed to determine these thermal properties which include, thermal conductivity, thermal resistivity, thermal diffusivity, thermal absorptivity and density. The obtained results of thermal conductivity showed that, POP ceiling has the highest value of 0.1314 while card board has the least value of 0.0851 where as PVC (0.1083) and asbestos (0.1068) fall in between them. Also the results of thermal conductivity of this research ranged from (0.08510.1314w) which corresponds to the previous work of the researchers. Hence all these materials are good insulators. The thermal resistivity of these

while the P V C has the least density value of 203.59 kg/m³, where the asbestos ( 824.13kg/m³) and card board (645.81 kg/m³) densities value fall in between them. The results obtained showed based on comparison that, PVC and asbestos may be better materials for building insulation since they have better thermal efficiency. Card board among the samples used was found to have the least thermal efficiency base on the comparison where as POP falls in between them. Thus, this research may provide guide for many users of the materials.

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CHAPTER ONE

INTRODUCTION

1.1 BACKGROUND OF THE STUDY

Energy studies require the knowledge of the value of many thermophysical properties. Values of these properties for a variety of substances and materials are available [Eckert et al, 2019]. However, for new materials which appear regularly, it is important to be familiar with some basic methods of measuring these properties.

Thermal conductivity is a physical property of materials which is of great importance in physics and engineering. Unlike some physical properties, however, thermal conductivity cannot be directly measured. To determine a material thermal conductivity, intermediate quantities must be determined from which the conductivity may be ultimately calculated [Vasudeva, 2011].

Ceiling materials are overhead interior surfaces that can cover the upper limits of the room. They are not generally considered as structural element but finished surfaces concealing the underside of room structure or the floor of store above.

In Nigeria, the use of zinc made roofs without ceilings are very common, thus there is intense heat transfer to the internal environment, which may cause thermal discomfort to the inhabitants (Etuk et al., 2007). One way to reduce the thermal discomfort is by the use of radiant barrier (i.e. ceiling board) which reduce the heat flux.

However, the knowledge of thermal properties of different materials is very important in the choice of the types of materials to be used as a radiant barrier since the heat flow through any building depends on the thermal properties of the materials use in the building (Etuk et al., 2007).

The study of the thermal properties of materials will help us to know whether materials are suitable to use as Ceiling materials in our houses, school and industries.

Heat propagated in the interior spaces in buildings through roofs and walls and partly through Ceiling panels by the process of conduction and radiation (George et al., 2010). This is because the common materials used as roofing sheets are materials like zinc and aluminum which have high thermal conductivities (Michael et al, 2012).

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To reduce the intensity of this heat, there is need to use materials of tolerable thermal responses as ceiling materials in buildings.

Good insulating materials will have high value of thermal resistivity. This implies that, different type of ceiling materials will have different thermal behaviors.

Insulator is a material or devised used to inhibit or prevent the conduction of heat or electricity (Gesa et al., 2014). Proper selection of insulating materials is based on their thermal properties which include: the thermal conductivity, thermal absorptivity, thermal diffusivity, specific heat capacity (Gesa et al 2014). The primarily function of insulator in buildings are: To conserve energy, to reduce heat loss or heat gain, to maintain a temperature condition, to maintain the effective operation of equipment or chemical reaction, to assist in maintaining product at constant temperature, to prevent condensation, to create comfortable environmental condition and protect personnel. Insulation reduces heat transfer through the envelope in building. Whenever there is a temperature difference, heat flows naturally from a warmer space to a cooler space. To maintain comfort in winter (the coldest season of the year), the heat lost must be replaced by the heating system; and in summer (the warmest season of the year), the heat gained must be removed by the cooling system. Therefore, it makes sense to study the thermal properties of insulator in order to reduce gains or loss of energy in buildings and to increase comfortable condition in houses, schools and industries.

Novo et al, (2010) justified that, the thermal insulation is provided by embedding insulation materials at least on the roof areas and the vertical walls of the systems. Insulating materials are usually made in various types with different design which lead them to categorize in to good and bad insulators on their properties.

In this work, emphasis is laid on the study and comparison of thermal properties of some selected materials which include PVC (polyvinylchloride), POP (plaster of Paris), asbestos and cardboard used as ceilings in buildings. Depending on how large or small the value of their thermal properties, a particular ceiling materials may be more efficient in terms of thermal insulation than another (George et al., 2010).

Observation showed that in this present competitive world, people that are economically favored usually go for the most costly ceiling materials without any preference to the thermal insulation efficiency of such materials. It is based on this observation that this work is designed to investigate and compare the thermal properties of the most frequently used ceiling materials for efficient thermal insulation. This will determine the suitability of one ceiling material to another in order to have comfortable thermal condition in buildings.

1.2 AIM AND OBJECTIVE OF THE PROJECT

The aim of this project is, to measure the thermal properties of some material used as ceiling in building and to compare the values of each of them for thermal efficiency. These materials include PVC, POP, and ASBESTOS, CARDBOARD.

The objective of the project include,

1. To measure their thermal absorptivity

1. To measure their thermal diffusivities.

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• To measure their thermal conductivity and determine their thermal resistivity.

1. To calculate the density of each four sample.

1.3 SIGNIFICANT OF THE STUDY

Achieving the set objectives of this work will enable us to have adequate knowledge of materials which are more suitable for thermal insulation.

The results may be sufficient to tell us the efficiency of these materials. Thus, it will be important to create awareness to the general public, on which of the materials to go for, while constructing buildings in order to get maximum thermal comfort.

1.4 SCOPE AND LIMITATIONS OF THE STUDY

The research is focused on the study of thermal properties of some materials used as ceilings in buildings. The materials in consideration include P V C, POP, asbestos and cardboard. The thermal properties of interest include thermal conductivity, thermal resistivity, thermal radiation, thermal absorptivity, thermal diffusivity, specific heat capacity and density.

Due to time and financial constraints, the research will not go beyond this scope.