DESIGN AND INSTALLATION OF 200 WATT SOLAR POWER SYSTEM
ABSTRACT
The 200 Watt solar system was determined by load assessment, solar panel number determination, battery requirement and then inverter sizing. A complete solar panel rated at 200w was however purchased, together with 2 no. 150A solar battery, 1500W inverter and also 10A charge controller. These were assembled together with necessary protective gadgets like cut out switches; to give the 200W expected. The solar panel was mounted outside the building to allow for maximum collection of sun energy. It is expected that the system will help the department meet up with its office duties even when central power is not available.
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
The solar inverter is a critical component in a solar power system. It performs the conversion of the variable DC output of the Photovoltaic (PV) module(s) into a clean sinusoidal 50 or 60 Hz AC current that is then applied directly to the commercial electrical grid or to a local, off-grid electrical network. A solar cell (also called photovoltaic cell) is the smallest solid-state device that converts the energy of sunlight directly into electricity through the photovoltaic effect. A Photovoltaic (PV) module is an assembly of cells in series or parallel to enlarge or increase voltage and/or current. A Panel is an assembly of modules on a structure. An Array is an assembly of panels at a site. Typically, communications capability is included so users can monitor the inverter and report on power and operating conditions, provide firmware updates and control the inverter grid connection.
At the heart of the inverter is a real-time microcontroller. The controller executes the very precise algorithms required to invert the DC voltage generated by the solar module into AC. This controller is programmed to perform the control loops necessary for all the power management functions necessary including DC/DC and DC/AC. The controller also maximizes the power output from the PV through complex algorithms called maximum power point tracking (MPPT). The PV maximum output power is dependent on the operating conditions and varies from moment to moment due to temperature, shading, soilage, cloud cover, and time of day so adjusting for this maximum power point is a continuous process. For systems with battery energy storage, the controller can control the charging as well as switch over to battery power once the sun sets or cloud cover reduces the PV output power. (Aditee P. Bapat et al 2013).
The general objective of the system is to provide efficiency, steadiness in the use of power appliances, by ensuring continuous availability of power supply even in the absence of mains. Uninterruptability of the system made it possible to eliminate all suspense from mains outage during the execution of an important and urgent assignment as may be required. For better production of the system, the system was operated at a fully charged condition of the battery.
The project was rated 200W of 220V and 50Hz. It was expected that at this condition, it was favourable to carry load of the stipulated power. Loads of low power factors are not helpful since they produce spikes. Overloading is not potent to provide zero change over time and the inverter had LEDs which indicates mains failure and battery discharge and system fault.
1.2 Statement of the Problem
If there is one factor that has perpetually maintained the status of Nigeria as a less developed country, it is its electricity sector. Till date, many households and businesses cannot be guaranteed of 24 hours supply of electricity from the public grid. At this stage of Nigeria’s social and economic development, the country cannot deliver adequate energy to the citizens despite huge financial resources that have been expended in the sector. Rather, Nigerians have continued to rely on electricity generators for their power supply, fuel marketers are taking significant portion of households’ and businesses’ incomes to supply power, noise pollution from regular humming generators have become integral part of living for many Nigerians with imaginable consequences on their health. Because of these problems, there is a need to design and construct the solar panel inverter which will complement the electricity supply from the public grid. It is less noisy and does not have any consequence(s) on human health. (Lookman Oshodi 2014).
1.3 Aim and Objectives
1.3.1 Aim
The aim of this project is to design and construct a 200Watt solar power system.
1.3.2 Objectives
The objectives of this project are;
1. To provide efficiency, steadiness in the use of power appliances, by ensuring continuous availability of power supply even in the absence of mains.
2. To eliminate all suspense from mains outage during the execution of an important and urgent assignment as may be required.
3. To design a simple and rugged technology; this will utilize the appropriate use of home or local electrical appliances.
1.4 Significance of the Study
The solar inverter is the second most important (and second most expensive) component of a solar PV system. It’s important because it converts the raw Direct Current (DC) solar power that is produced by your solar panels into Alternating Current (AC) power that comes out of the wall sockets. Inverters also have technology that maximizes the power output of that DC energy.
The use of solar power has many advantages. First, the energy from the sun is free and readily accessible in most parts of the world. Moreover, the sun will keep shining until the world's end. Also, silicon from which most photovoltaic cells are made is an abundant and nontoxic element (the second most abundant material in the earth's crust).
Second, the whole energy conversion process is environmentally friendly. It produces no noise, harmful emissions or polluting gases. The burning of natural resources for energy can create smoke, cause acid rain and pollute water and air. Carbon dioxide, CO2, a leading greenhouse gas, is also produced in the case of burning fuels. Solar power uses only the power of the sun as its fuel. It creates no harmful by-product and contributes actively to the reduction of global warming.
1.5 SCOPE OF STUDY
This solar power source makes it possible to provide a clean reliable supply of alternative electricity free of sags or surges which could be found in the line voltage frequency (50Hz). This project design aims at creating a 200 watts power source which can be utilized as a regular power source by remote rural industries and private individuals at home or in the office. This project involves the design and construction of a 200Watt Solar PV (photovoltaic) system which involves a solar panel, car battery and an inverter. Furthermore, as a consumer is generating his or her own electricity they also will benefit from a reduction in their electricity bills. This solar power source makes it possible to provide a clean reliable supply of alternative electricity free of sags or surges which could be found in the line voltage frequency.
The solar power system (SPS) system achieved this by direct current from solar panel and by rectifying the standard main supply, using the direct current to charge the batteries and to provide clean alternative power by passing the energy a filter system. It has zero change over time and LEDs which indicates mains fail and battery discharge level and it provides 100% protection against line noise, spikes surges and audio frequency interference.
1.7 Definition of Terms
Inverters
The inverter takes DC power from the charged battery bank and converts it to AC power for the typical household lights and appliances. Once the number of watt-hours required for a day is determined, the peak loads need to be ascertained to properly size the inverter. This is the number of watts used based on all appliances and loads that will be running at one time. A water pump and washing machine motor is an example of what may be the peak load requirements. A 1/2 HP (horse power) pump and washing machine will use about 1875 (adjusted) watts per hour. If this represents the total peak loads, an inverter that will be able to supply at least 1875 watts of continuous power from the battery bank; say one in the 200 watt range will be needed. It's a good idea to start out the system with the size of inverter you plan to grow into, as upgrading to newer, larger models is costly. (Pure Energies 2014) There are two basic types of inverters.
Central Inverters
Central inverters are well-tested and reliable systems that have been around for decades. These are the most common types of inverters. With central inverters, every solar panel is wired in a “string” to the inverter box. The conversion from DC to AC occurs at one central location, such as a garage. Because the solar panels are wired in “series,” each panel’s power output depends on all of the panels working. For example, In a string of Christmas tree lights. If one bulb goes out, the whole string of lights go out until the bad bulb is replaced. So, if shade from a tree covers one panel, it can seriously diminish the power produced by the whole solar system until the shade clears. This is why an accurate shade analysis is so important.
Micro Inverters
Micro inverters are relatively new to solar. Instead of converting the DC to AC power at a central location, micro inverters are installed right under each solar panel. The main advantage to micro inverters is the ability for each solar panel to transmit power into the house. In other words, each panel produces its own solar power and keeps producing out solar watts regardless of what happening to the panel beside it. The down side of micro inverters is that they can be more expensive and take more labour cost to replace each inverter. Also, because they are so new, micro inverter reliability is unproven outside of lab testing. (Pure Energies 2014).
The BOS (Balance of System)
There are many other less well known and less expensive parts to a solar system. Installers typically wrap these up into “The BOS” or “Balance of System.” The balance of system includes components such as wiring, emergency DC disconnects, system monitoring hardware, the frames or “racking” that holds your panels to the roof and at the right angle, nuts, bolts, roof “flashing” to prevent leaks, and more. (Pure Energies 2014).
Solar Panels
Solar Panels can be used for charging your batteries. They provide a good solution for those that want to be self-sufficient and go on long camping missions through remote areas. They are available in various voltage and power ratings. More than one solar panel can be used in parallel to combine their power output. Solar panels joined in parallel work most efficiently if they are the same. If they are the same, you can design it so that they both generate power at their optimal operating points. Mixing different panels together gives a compromised operating point. It will work but the panels will not operate as efficiently.
Solar Panel Poly or Mono
Silicon solar panels have two basic construction methods – polycrystalline or monocrystalline. There are slight differences between poly and mono cells. Mono are slightly more expensive, require more energy to make, and are slightly more efficient. Poly are slightly cheaper, use less energy to make so are better for the environment, are slightly less efficient but have a slightly better temperature coefficient. That means at elevated temperatures the poly cells become more efficient. The differences are only slight. It is largely irrelevant. A solar panel with good efficiency and good temperature coefficient is to be used whether it is poly or mono, it does not matter.
Inverter unit: This unit converts a DC voltage into AC voltage with the help of the inverter unit.
Automatic Control Unit: This provides all the required control needed to meet up the objective of the whole system.
Battery Unit: This is a secondary cell unit, capable of storing enough DC voltage from either sun or AC main, of which is later converted to AC voltage.
