Solar Power System Technology: Operation Overview & Design

Certainly there's no gainsaying the world without the invention of electricity will definitely be a brutal one. The discovery of renewable energy sources as an alternative way of providing electricity has also come with potentials with abundant energy for the world power use. Renewable energy sources has amazing potentials to cater for our daily power use as a result of constant advancement in the technologies regarding renewables.
Renewable energy is the energy from the renewable resources such as sunlight, wind, rain, waves, tides and so on. These resources are harnessed for electricity generation among other uses competing with the conventional sources and contributing to sustainable development. Major renewable types includes Bio-mass energy, the hydropower, wind and Solar energy.

Welcome to my blog this time again as I take you through one of the best and most promising renewable energy sources- Solar Energy

Solar Energy is a clean, free, non-poluting and inexhaustible form of renewable energy. The technology was firstly harnessed as solar power for heating purposes. Horace de Saussure was found in record to build the first thermal solar collector in late 1700s for water heating and food cooking. Afterwards, Henri Becquerel discovered that sun's energy could produce electric current by the phenomenon referred to as the photoelectric effect which Albert Einstein later gave an explanation to in the early 1900s which he won a Nobel prize for. The interest in solar power intensified in late 1950s leading to the development of Photovoltaic cells. These cells are made of silicon crystals which generates direct current (DC) from sunlight due to photoelectric effect. The collection of several silicon cells makes up a photovoltaic module or what we refer to as solar panel.
Today, we use solar cells for variety of applications. We have the technology in solar-powered cars, power supply for space satellites, power systems for household and for commercial purposes.

The use of Solar cells in providing energy keeps evolving in recent times and has kept growing as the world becomes more concerned about sustainability and energy use.

Solar Power System

Solar Power System is a non polluting and clean source of providing electricity that fits in a broad range of applications from residential use to industry and other commercial fields. The major components of Solar power system operation are solar panel (Photovoltaic Module), charge controller, inverter and the battery bank.

The Photovoltaic Module

The collection of several silicon cells make up a photovoltaic module responsible for the conversion of Solar irradiance to electric current. Direct current is the energy trapped by the solar panel due to photoelectric effect. This direct current is further needed to be inverted to an alternating current (AC) to suit the form of power most appliances make use of.
The photovoltaic module are majorly of two types which are the crystalline and the amorphous type.
The crystalline type of Solar panel are the monocrystalline and the polycrystalline type while the amorphous types is the thin film solar technology. The crystalline type of Solar panel has the best technology delivering better efficiency as compared to the thin film technology.
Photovoltaic module comes in different sizes (Power rating and System voltage) connected in either series and parallel to form an array as required by the system design. The video below briefly shows a parallel connection of a 150W-12V system for a 300W solar array.

Battery Bank

The battery is a medium containing numbers of cells in which the conversion process of chemical energy into electrical energy used as a source of power takes place. In the case of Solar power system, Deep cycle batteries, a type of lead-acid battery designed to be regularly discharged and recharged are employed. These batteries are suitable for solar power system as they discharge most of their capacities providing steady current for a long period of time.
Battery bank stores the direct current harvested from the solar array for use at night and during low level of Solar irradiance. You can learn more about deep cycle batteries on this previous post

Series & Parallel Connection of Batteries

Connecting batteries in either series, parallel or series-parallel depends on the system design. In a simple way, Voltage gets add up but amperage (capacity) remains the same when two or more batteries are connected in series i.e connection of positive to negative terminal in a string.

Also, amperage adds up but voltage remains the same when the connection is made parallel i.e connecting the positive terminals together and the negative terminals together.Let's take two 12V-100Ah batteries for example. Connecting this in series as shown in the image, we have a result of 24V, 100Ah pack. Also in the parallel connection image, the result gives a 12v-200Ah pack

Solar Charge Controller

Solar charge Controller is a very important component of the solar power system. It works in a very simple way but does a very important function. When we charge our mobile phone, we unplug from the power supply when the battery gets full. Okay! There, we have just prevented the battery from getting overcharged. The solar charger controller also operate in the same way, it basically monitors the battery while charging and disconnects the solar array from the battery bank when the battery gets full. It is definitely not advisable to safely use solar array for charging batteries without a charge Controller.
Solar charge Controller simply regulates the charge from the solar array and prevents the battery from overcharging. Also at night, when no charge is coming from the solar array, charge from the battery can flow backward through the solar panels, the controller here disconnects the solar array from the batteries stopping the reverse current flow.
The ability to extract maximum power from solar array is another amazing feature of Solar charge controllers. The Maximum Power Point Tracking (MPPT) technology of modern charge controllers employs the algorithm for better optimization of the solar array making them operate at the most efficient rate i.e. operating optimally at all time.

The Inverter

The inverter is a critical component in the solar power system operation which works basically to convert the direct current from the battery bank to the alternating current needed for home and industrial use. The inverter also serves as a charger i.e. it takes power from the utility supply, converts it to dc to complement the dc harvest from the solar array to charge the battery. The inverter system is the first component to be determined when designing a solar power system as the system must be chosen to be large enough to handle the total amount of load to be used at a time and it is better designed to be at least 20℅ bigger than the total power of the load

The Inverter works by by taking the constant dc from the battery and inverting it into alternating current (AC) of a pure sine wave. During the inception of inverter technology, blocky AC signals also referred to as modified sine wave were in use then but due to technology advancement, the invention of pure sine wave AC signal which most appliances are designed to work best with are now found commonly in use. A modified sine wave inverter do contain harmonic distortion which makes appliances run very hot, operating less efficient and consuming more energy as the AC output is not found pure.
If you've come across or overheard a buzz from electronic devices or a humming sound from ceiling fans while using with an inverter, there you have a modified sine wave inverter in use. Modified sine wave Inverters operates less efficiently due to harmonic producing the humming noise during operation.

Choosing a wrong choice of inverter may cost one a lot as modified sine wave Inverters are delicate to using with sensitive electronic appliances. The sine wave technology of Inverters gives a better and cleaner current as much as the conventional utility supply does. They are found relatively expensive but for a good reason you will say as well.

For better understanding of Solar-power Installation process, study the block diagram below and carefully read through the following explanation of a 3000W, 5KVA-48V system.

The solar array panels consist of 12 modules of 24V 250W solar panel, eight 12V- 200Ah batteries with a 5KVA-48V inverter system. Two solar panels each are of 24V were connected in series to make up 6pairs of 48V system, then connected in parallel across the DC cable. The DC cable which brings the final termination was connected to the charge controller. Eight batteries each of 12V-200Ah are connected in two strings of 48V i.e. Four batteries are connected serially in two strings and are paralleled to give a 48V, 400Ah battery bank.The batteries final termination i.e. the negative and positive terminal are terminated to the charge controller. The 5KVA-48V inverter system negative and positive terminal are also being connected to the final negative and positive terminal of the battery bank. The inverter output is connected to the building load through the electrical distribution board and power input from the utility was also given to the inverter which is used to charge the batteries to complement the solar array.

Solar Power system is also employed in street lighting system. Solar-powerwed street light system consist of Solar panel that collects the solar irradiance during the day and stores in the battery integrated in a metal box as shown in the image and as you may have commonly seen around. The solar panel charges the battery which powers a LED light during the night. Now, let me leave you a second with the thought of how the LED light switches ON/OFF during night and daylight. What do you think of?
Okay, let's ride on. Here, a special type of controller does the work. Intelligent and programmable charge controllers are used to detect when there is no longer energy from the sun as this time will be during that time the weather gets to go dark. The charge controller turns the LED light on using the stored energy in the battery. Also at dawn, as the controller detects light on the solar panel, it cuts off the supply from the battery and the battery gets recharged as the day gets brighter.

CONCLUSION

Solar Energy is a clean, free, non-polluting and inexhaustible form of renewable energy that can be harnessed for variety of applications..I'd leave you with the videos of an installation process . Thanks for stopping-by..! Let's all enjoy the beautiful world of Solar technology!

REFERENCES

Altenergy

Energymatters

Greenmatch

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