Design Of A Solar Photovoltaic System For Three Bedroom Flat

ABSTRACT

This is an off grid photovoltaic system designed for a three bedroom flat located in nkpolu-oroworukwo, port-harcourt, Nigeria. It is aimed at clearing doubts and fear engulfed by residential owners about photovoltaic systems in the country. The off grid photovoltaic system was design based on the electrical energy requirement of the flat. To achieve this, the power rating of common appliances which could be found in the flat were identified and multiplied by their time of operation to understand the energy demand of the house. The energy requirement of the flat was found to be 15.563kwh per day. The photovoltaic system was designed using Polysun application software. The result obtained from simulation shows that, the system will generate enough energy for operation of these appliances including in the night. The cost of the system was found to be ₦2862249 with a lifetime of at least 20 years. The cost was compared with the use of fuel generator within the same period. The payback period was found to be approximately 2.72years. This means that the cost of photovoltaic system for the flat is high but after 2.7 years, the installer of the PV system will be using energy virtually free for the remainder of the lifetime of the system.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

CHAPTER ONE

1.0      INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

• AIM OF THE PROJECT
• PURPOSE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• PROBLEM AND LIMITATION OF THE STUDY
• COMPONENTS OF PV SYSTEM AND THEIR FUNCTIONS
• SOLAR PV INSTALLATION BLOCK AND DESCRIPTION

CHAPTER TWO

LITERATURE REVIEW

• REVIEW OF THE RELATED STUDY
• ELECTRICITY CONSUMPTION IN RESIDENTIAL BUILDINGS
• SOLAR ENERGY

CHAPTER THREE

3.0     METHODOLOGY

3.1      INTRODUCTION

3.2      AREA OF STUDY

3.3      ESTIMATED ELECTRICITY CONSUMPTION OF THE HOUSE

3.4      SELECTION OF PHOTOVOLTAIC MODULE

3.5      SELECTION OF BATTERY

3.6      SELECTION OF INVERTER

CHAPTER FOUR

• ENERGY YIELD AND CONSUMPTION
• COST ESTIMATION OF THE OFF GRID PV SYSTEM
• COST ESTIMATION OF FUEL GENERATOR

CHAPTER FIVE

• CONCLUSION
• REFERENCES

APPENDIX

CHAPTER ONE

1.0                                             INTRODUCTION

1.1                            BACKGROUND OF THE STUDY

The condition of energy generation and supply in Nigeria has deteriorated to the level that it is difficult to ascertain the time it will be available to consumers. Various administrations have come up with different ways of alleviating the situation but no meaningful result is achieved till date. Recently the country has privatized power sector but the expected result is still far reach [21]. Currently, the Nigeria electricity installed capacity is 8,876MW which is mostly from fossil fuels and still grossly inadequate to meet the energy needs of more than 160 million Nigerians [17].The availability is far below the installed capacity due to many factors. In fact, the recent vandalism of gas pipelines that supply gas to power plants has caused power generation to drop to 1,580.6 megawatts in March, 2016 [16]. This has brought untold hardship on the citizens and derailed economics activities [7].

The installed capacity is not enough even when the power plants are generating at peak capacity. Only 40% of Nigeria’s population is connected to the grid and the situation is worst in the rural areas. The distribution companies out of no other alternatives resolve to the used of rationing technique and mostly supplies electricity at very low current, but still those that have access to the grid; only 30% of their needs are met [1].

The inability of energy supply to match demand has become unacceptable to many citizens. As a result, they resort to other means of energy such as burning of wood and grasses, fuel or gas used generators, for domestic and day to day running of their business without considering the effects their energy sources might caused to the environment [11]. The electricity generates by Nigeria is mostly from fossil fuels which is the reason the country was in 2012, ranked 46^th in the world for CO₂ emissions with more than 73.69 metric tons emitted in 2011 [2].

The introduction of photovoltaic technologies is a relief to the situation faced by Nigeria today. After all, the use of fossil fuel for energy generation is outdated due to its effects on climate. Apart from that, it is costly and mostly a source of conflict [22].

Photovoltaic is a technology used to convert sunlight directly to electricity. Photovoltaics are also called solar cells. When sunlight strike the surface of the cell, the energy from the light is enough to eject one electron from the shell of its host atom with a constant amount of energy. The electron removal is proportional to the intensity of micro packets of light energy usually referred to as photons [22]. Very close to the surface of the cell is a membrane called pn-junction which allows only electrons with a specific amount of energy to cross. This makes the surface of the cell facing the sun to acquire negative voltage while the other side is positive voltage [6]. If electrical cables are connected to the negative and positive sides, forming an electrical circuit, the electrons can be collected in the form of electric current (electricity) which can be used to power electric appliances. Figure 1 is the summary of how photovoltaic works.

Different cells are connected together to form a solar module. A solar module supply electricity at a particular voltage just like conventional cells. Many different solar modules connected together forms an array. The solar module can have a life time of at least 20 years [12]. Photovoltaic is currently used in many countries for electricity generation. Figure 2 from the appendix page shows the global PV installation in 2016.

Many researchers have found out that PV systems are cheap and will even get cheaper as time passes. The cost of a PV system includes the capital cost, operation and maintenance cost and installation cost. The cost depends on factors such as the size, and whether it is mounted on a roof top or on the ground [9]. The roof top PV does not require an extra space but mounting on the ground requires a separate space for the system. Figure 3 shows the projected price of photovoltaic modules.

In a comparative study conducted by [10] at university of porthartcourt, discovered that the cost of an off grid photovoltaic system is cheaper than the use of diesel for energy generation or when one embark on payment of electricity bills from the grid.

An off grid photovoltaic system generates electricity independently without grid connection. The components of the off grid photovoltaic system and their functions are seen in table 2 and the connection between the components is as seen in figure 4 from the appendix page.

1.2                                          AIM OF STUDY

The aim of this work is to design a renewable power supply that uses solar cells to convert energy from the sun into a flow of electrons by the photovoltaic effect. Solar cells produce direct current electricity from sunlight which can be used to power equipment in a three bedroom flat.

1.3                                PURPOSE OF THE STUDY

The purpose of this work is to have a steady power supply in a three bedroom flat that is independent on the mains grid system.

1.4                           SIGNIFICANCE OF THE STUDY

• Electricity produced by solar cells is clean and silent. Because they do not use fuel other than sunshine, PV systems do not release any harmful air or water pollution into the environment, deplete natural resources, or endanger animal or human health.
• Photovoltaic systems are quiet and visually unobtrusive.
• Small-scale solar plants can take advantage of unused space on rooftops of existing buildings.
• PV cells were originally developed for use in space, where repair is extremely expensive, if not impossible. PV still powers nearly every satellite circling the earth because it operates reliably for long periods of time with virtually no maintenance.
• Solar energy is a locally available renewable resource. It does not need to be imported from other regions of the country or across the world. This reduces environmental impacts associated with transportation and also reduces our dependence on imported oil. And, unlike fuels that are mined and harvested, when we use solar energy to produce electricity we do not deplete or alter the resource.
• A PV system can be constructed to any size based on energy requirements. Furthermore, the owner of a PV system can enlarge or move it if his or her energy needs change. For instance, homeowners can add modules every few years as their energy usage and financial resources grow. Ranchers can use mobile trailer-mounted pumping systems to water cattle as the cattle are rotated to different fields.

1.5                PROBLEM AND LIMITATION OF THE STUDY

• Some toxic chemicals, like cadmium and arsenic, are used in the PV production process. These environmental impacts are minor and can be easily controlled through recycling and proper disposal.
• Solar energy is somewhat more expensive to produce than conventional sources of energy due in part to the cost of manufacturing PV devices and in part to the conversion efficiencies of the equipment. As the conversion efficiencies continue to increase and the manufacturing costs continue to come down, PV will become increasingly cost competitive with conventional fuels.
• Solar power is a variable energy source, with energy production dependent on the sun. Solar facilities may produce no power at all some of the time, which could lead to an energy shortage if too much of a region’s power comes from solar power.

1.6      COMPONENTS OF PV SYSTEM AND THEIR FUNCTIONS

Components used for the photovoltaic system installation and their functions are listed in the table.1 below:

Table 1: Components of PV system and their functions

1.7      SOLAR PV INSTALLATION BLOCK AND DESCRIPTION

The stand-alone photovoltaic system is a collection of interconnected electrical components, which can generate electricity from sunlight and satisfy our daily energy requirement without worrying about any interval when the sunlight may not be available. According to Guda and Aliu (2015), Ishaq, Ibrahim and Abubakar (2013) and Pal, Das and Raju (2015) the components (see Figure 2) of such a system are:

1. Solar PV array: This is commonly refers to as solar panel. It is responsible for trapping of the solar energy as it is placed outside under the sun. They are arranged in series and parallel to meet desired output.
2. B) Charge Controller: The charge controller is use in controlling the charge (from the word charge control) in the batteries, either to prevent overcharging or discharging.
3. Inverter: This is used in converting DC to AC as power from solar PV arrays is in DC form.
4. Battery: These are used to store power for usage during the non-sunshine hour. The recommended batteries that should be used in stand-alone photovoltaic power system are deep-cycle lead-acid batteries because of their high performance (Abu-Jasser, 2010).

Balance of System Components: Components such as protective devices, blocking & bypass diodes, lightning-protection system and cable wiring constitute what is known as balance of system components (Abu- Jasser, 2010). Such components are necessary to keep the PV power system safe and reliable. In particular, selecting the correct size and type of cable will enhance the performance of the system while selecting inadequate cable size will cause voltage drop from the source to the load. In low voltage systems, such voltage drops will lead to inefficiencies.

Figure 2. Pictorial representation of Solar PV system