Solar technology taps directly into the sun to produce solar energy which is converted into solar electricity using photovoltaic (PV) cell. Solar electricity has been gaining ground as a source of electricity. Most likely you have solar powered calculators, streetlights or solar panels on rooftops for powering household appliances like TV, computer, light, fan, handset, etc. it has also used to power rural and agricultural appliances. The same solar power can also be used to generate large amount of electricity.Photovoltaic (PV) cells convert sunlight to electricity. But more electricity is produce when the sunlight is very strong striking the PV cells directly. The PV cells consist of two or more layers of semi-conductor, most commonly silicon. When the silicon is exposed to light, so multiple PV cells are connected together and sealed behind glass to form a module known as SOLAR PANEL. Modules range in power output from about 10 watts to 300 watts. PV allows you to produce electricity, without noise, air pollution and fuel. Most PV has a life span of 25-50years SOLAR PANELS TYPES.There are three main types of solar panels in commercial production, all with some advantages and disadvantages. All these are base on silicon semiconductors and they are arranged in other of their efficiency.1. MONOCRYSTALLINE SILICON CELLSMonocrystalline silicon cell is made from a single large crystal, cut from ingots. Most efficient but also slightly costlier than the other technologies and better in low light. It is the most efficient of photovoltaic (PV) technologies, with efficiencies of 5%, meaning you will get more electricity from it. The manufacturing process Monocrystalline silicon cells are more complicated
2. MULTICRYSTALINE SILICON CELLSThis is made from an ingot of melted and recrystalling silicon, which is then saw cut into very thin water and assemble into complete cells. The manufacturer process is simpler thereby making multicrystalline cell cheaper than that of monocrystalline. Multicrystalline cells are slightly efficient with average efficiencies of 12% creating a granular texture.
3. AMORPHOUS SILICON CELL.Amorphous silicon cell- thin film, the silicon is spread directly on large plates, usually of something like stainless steel. It is Cheaper to produce, but often much less efficiencies of 6%, which needs larger panels for the same power output. The production method is quite different. Their low cost makes it ideally suited for many applications where high efficiency is not required, but low cost is considered.COMPONENT OF SOLAR ELECTRICITY GENERATOR OR GENERATORThere are six (6) basic components of solar electricity generator. They are1. Solar panels2. Charge controller3. Deep solar cycle batteries4. Ac/Dc inverter5. Thunder insulator wire6. Loads
PHOTOVOLTAIC (PV) SOLAR PANELSSolar panels are the source of electricity for a solar power generator. The solar panel or PV directly converts sunlight into DC (direct current) electricity.PV panels are rated in watts based on the maximum power of electricity one can generate under an ideal sun and temperature condition. The rate output of PV panels is use to determine the number of panels one will need to meet the electricity needs. Multiple panels combined together are called array.PV array can be mounted at a fixed angle of preferable angles 45% facing east, or they can be mounted on a tracking devices that follows the sun, allowing them to capture the most sunlight over the course of a day. PV modules are durable, long lasting, and environmentally friendly and cost efficient on the long-run. Because of their durability, PV systems can be designed to meet any electrical requirement, no after how large or how small. It also can be connected to an electricity distribution system (grid-connected), or they can stand alone (off-grid). Most carry a warranty of 25 years and if properly maintained can attain a life span of 50 years. They can withstand severe weather such as extreme heat, hail stone snow and cold.
CHARGE CONTROLLER/VOLTAGE REGULATORCharge controller is use in Combination with a battery, and it just what its name implies. It controls the charge the battery is receiving. The charge controller is placed between the solar module and the battery. With out a charge controller, the battery will be over-charge, and this can damage the battery which may lead to out brake of fire.Charge controller includes maximum and low voltage power point tracking. This feature optimizes the solar photo voltaic arrays energy production and also prevents the batteries from over-dischargingINVERTERSInverter converts direct current (DC)-e.g. 12V, 24V and 48V to Alternating Current (AC) - e.g. 220V. The inverter has to match with the wattage output of the solar panels. Inverter supply better quality power than the power utility company and works well with most appliances. Inverters are rated in watts by their continuous voltage output and comes in different power voltage specification e.g. 150watts 300watts, 800watts, 1200watts etc.The size of inverter chosen is dependent on the total cumulative power to be consumed and this requires elementary arithmetic. Take for instance you want power few appliances like a 14” TV, a radio, a DVD and a light at once, add up all their wattage, therefore buy an inverter that can supply at least 79 watts continuously. To power a whole house full of appliances and lights requires more planning and would require a mid size inverter (e.g. 1.5kva to 7.5kva) or a bigger one. Obviously not all appliances will be switched on at the same time. The bottom line is that the type of inverter you choose is determined by the quality of electricity in wattage your appliances will consumeAPPLIENCES SPECIFIED POWERRadio 5wLight (compact fluorescent) 14wDVD 20w14” colour TV 40wTotal daily power requirement 79w
TYPES OF INVERTER.MODIFIED OR SQUARE SINE WAVE INVERTERA modified sine wave inverter is cheaper and can power most household appliances and tools, but some loads will be damaged by it (e.g. laser printers or some cordless power tools) it presents some challenges by giving humming sound when some types of load is used by with it e.g. A microwave.
PURE SINE INVERTERPure sine wave has much more “flow” to them. You could say that their power has been smoothed out; you need pure wave inverter if you hope to power large appliances. For the purest, best form of power, you will require a pure sine wave inverter.BATTERIES FOR SOLAR ENERGY SYSTEMLike other renewable energy system, solar energy system uses a lead-acid deep cycle battery. This type of battery is different from the conventional car battery, lead-acid deep cycle batteries last longer but also cost more than a conventional battery. The major difference between lead-acid battery and other batteries is that they have solid lead plates. In conventional batteries, the plate is made of sponge-like material. BATTERY SIZE TO YOUR SYSTEMBe sure you have a battery properly sized to your system. If you size your battery too small, they may discharge too often, and this leads to replacing them more often, when you size your system very well and maintain it, it may last to 10 to 15yrsSOLAR ENERGY BATTERY MAINTAINANCEThe good cycle battery can last long if you take good care of it, some of the base steps to ensure the good working condition of your battery are1. Fully charge your battery before use.2. Be sure to fully tighten the connectors and properly wire all the cables.3. Fasten vent caps tightly and checked from time to time.4. Batteries should be wiped free of all corrosion, dust and dirt frequentlyDEPTH OF DISCHARGEDepth of discharge is a measure of how much energy has been taken from a battery. With the lead-acid deep cycle battery used in a solar electric system, there is more tolerance for discharging. You can discharge the battery of a solar energy system 50%to 80% with no damage to the battery; this makes it very different from a car battery.AC/DC BREAKER/ INVERTER DISCONNECTThe AC breaker panel is the devise where all the house electric wiring meet with the supplier of electricity, whether grid (PHCN) or power generator. It is mounted on the wall and you can find it at the stairway, balcony, basement, or garage, etc of your home. The solar electricity will use AC breaker to route electricity to the house. it allows you to change over from solar electricity to grid electricity and vice versa.TOOLS NEEDED1. Pairs of Hand gloves2. Eye Google3. Set of Screw drivers4. Cutter: for cutting of wires5. Set of Pliers:6. Copper plate:7. Spanner:8. Digital Voltmeter: for reading voltage of your solar panel and battery voltage and current9. Compass: for navigation (use to know where the sun is facing or where it rises)10. Salt and charcoalCOMPASSMagnetic compass is an instrument that is use to determine the position of placement of a solar panel. The aim of this is for the PV to get as much sunlight to generate electricity. The PB should be installed at an angle 45 facing east.INSTALLATION
PV ARREYSPV arrays for stand alone system are installed many unique and innovate ways, however, there are common issues involved in any installation, whether the array is fixed or tracking, mounted at ground level, or on a pole or building. The array orientation and tilt angle consideration are discussed in the section.CONTROL CENTREElectronics controllers, converters, or inverters are often installed in the control centre along with switches, fuses, etc. electric components must be able to withstand expected temperature extremes in both operating and non-operating state. Any printed circuit boards in these units should be coated or sealed to protect the electronics from humidity and dust. Certified electrical service about the type of the box needed for a specific application.High temperature will shorten the life of electric equipment. Try to mount the boxes in a shaded area and/or provide air circulation, particularly for inverters. Dust can be problem in a well-vented enclosure. Some boxes have filters at the air access points. Screen the inlets of the electrical boxes to prevent spider’s wasps, lizard and other insects from setting up residence. Finding wasps in the electrical box may not affect performance, but it will certainly make maintenance more exciting.
BATTERYEARTHINGA good earthing will provide a well-defined, low –resistance path from the stand-alone PV system to earth ground. This part is expected to carry fault current if system malfunctioning occur so the ground wire must be as large as the largest conductor in the system. TWO TYPES OF EARTHING ARE NEEDED IN PV SYSTEMS System earthing and equipment earthing. For the system earthing, one of the current carrying conductors, usually the negative, is earthed with salt and charcoal at a single point. This establishes the maximum voltage with respect to ground and also serves to discharge surge currents induced by lighting. Any exposed metal that might be touched by personnel should be earthed. This includes equipment boxes and array frames. This will limit the risk of electrical shock should a fault occur.A PV array can attract lightening, especially if located at a high elevation relative to the surrounding terrain. In particular, water pumping systems may draw lighting because of the excellent ground path provided by the well casing. Current surge can be caused by near strikes occur more frequently and the severity of possible damage depends on the distance from the strike to the array. Commercially available surge protection devices (movistor and silicon oxide varistors) are reasonably prices and their use is recommended. They are normally installed in the array output and at the DC input to any electronic device. If an inverter used, installing the wiring in earth, buried metallic conduit will decrease susceptibility to lightening
BASIC ELECTRONICSSERIES AND PARALLEL SOURCESERIES CONNECTIONSource of electric current such as batteries and solar panels can also be connected in various ways. They can be arranged in series by connecting a terminal (+ve positive) of one source to the negative terminal (+ve negative) of the next source. For example of battery A is connected to the negative terminals of the battery A, and the positive terminal of battery B to the negative terminal C the ABC are in series. The load is then place between the positive terminals of battery A. this increases the voltage but the current remains constant.When sources of electric current are connected in series, their total voltage is equal to the sum of their individual voltages. For example, three 12-volt batteries connected in series gives a total voltage of 12v + 12V + 12V= 36V. if the load is 9 ohms, then the batteries send a current of 36 / 9= 4 Amp through the load which is the current supplied the individual battery.
PARRALLEL CONNECTIONSource of electricity current such as batteries and solar panels can be connected in parallel. They are arrange in parallel. They are arranged in parallel by connecting the +ve (positive) terminal of one source is connected to the positive terminal terminal of the next source. Then the negative terminal of the battery A is connected to positive is connected positive terminal of battery B. likewise if negative terminal of battery A is connected to negative terminal of battery B, then the two batteries are connected in parallel. Load is placed between the positive terminal B and negative terminal B, this will increase their current, but the voltage remains constant i.e. the individual voltage. When source of electric current are connected in parallel, their total current is equal to the sum of their individual current of 70A + 70A + 70A =210A. But the voltage will remain the same (i.e. 12V).
If you need more electricity to power your appliances, your PVs and batteries will have to be connected in parallel. But if you need more voltage battery, the higher voltage will force an electric current through the low voltage battery and damage it.
