Solar Energy and how it works

What is solar energy?

The sun generates or radiates large amounts of energy every second of time. More energy is generated by the sun than what the world consumes in a year. Solar energy is what make life on earth possible for humans, animals and plants. Solar energy is a free renewable energy with the sun as it’s source.

What Is Solar Energy Earth And Sun
How does the sun generate solar energy

How does the sun generate solar energy?

At its core, the sun receives its energy from within itself. Hydrogen and helium atoms in a plasma form, is what the sun consist of.  Generating energy, the sun uses a process called nuclear fusion. The process of nuclear fusion takes place where high temperatures and pressure from the sun’s core allow for nuclei to separate from their electrons. A helium atom is formed due to hydrogen nuclei which fuse together. Therefore, radiant energy gets released from this process.

How long does solar energy take to reach earth?

Thousands of years can pass before the radiant energy at the sun’s core finally reaches the solar surface. Also, the radiant energy which are released, can take up to eight minutes to reach the earth at the speed of light. This is about 299,338 kilometres per second. But does all the solar energy from the sun reach earth? Unfortunate, most of the solar energy is radiated into empty space, therefore, only a small fraction of all the sun’s energy reaches the earth. To give you an idea of the amount of energy, it would be something like 1 part of 2 billion. However, the small amount of radiant energy we receive on earth, is still an enormous amount.

Distance For Sun Solar Rays To Travel To Earth
Sun Provides Solar Light And Solar Heat To Earth

How much solar energy is provided to the earth?

More solar energy is released by the sun in a single hour than China or America can consume in a year. Large amounts of solar energy reaching the earth, are reflected against the atmosphere away from the earth, into space. About 60% of the remaining solar energy is consumed by the ocean and earth. The remaining solar energy gets consumed by clouds and in the atmosphere.  

Does the sun only provide solar energy?

The sun is the source of many different energy forms to the earth.  Solar energy allows many other entities to have energy such as water cycles. Therefore, we can generate energy from moving water sources. Also, wind formations and energy is also made possible due to solar energy.  Therefore, we can use wind turbines to generate kinetic energy for useable electricity. Flora or plants also make use of solar energy in the form of photosynthesis. Fossil fuels used to generate electricity, petrol and diesel, were also once a receiver of solar energy.

Solar Energy Usages

How do we use solar energy?

People have been obtaining methods to capture solar energy and also have been using solar energy for centuries. From heating themselves from the cold, drying clothes and heating water, solar energy is the oldest form of energy. Using glass which eventually advanced to magnifying glasses, was used to obtain solar energy and assist people to quickly start a fire. Over a hundred years ago, researches made use of a solar collector which produced steam to power an engine. Solar water heating became a solution in the early 1900’s. Today, it is common to find the advanced solar water heaters on most roofs of homes and businesses.

Ways to capture and use solar energy

Solar collectors

A solar collector is an excellent device to capture solar energy through sunlight and transform it into energy. The time of day, seasons and depending on weather conditions, would determine how effective the solar collectors would be. If it is a sunny day, which is most of the days in our sunny South Africa, the more effective solar collectors would be. If you park your car and leave it in the sun while you go shopping, the car would act as a solar collector. The sun’s light reaches the car and all the insides of the car’s equipment absorbs the solar energy. Energy which is absorbed, is transformed into thermal energy which is stuck inside of the car.

Solar Collector Solar Hot Water Geyser Flat Panel
Solar Space Heating Diagram

Solar building heating

Solar building heating is when the solar energy gets used to heat a space inside of a home or building. There are two types of solar building heating. Passive solar building heating and active solar building heating. Also, hybrid systems are both passive and active.

Passive solar heating

The design of a passive solar heating system is when the building and its materials are designed in a specific manner to obtain passive solar heating. Basically, the building is one big solar collector. Sunlight shines through the windows of the building, therefore, the floors and walls are heated inside of the building. Although, the light can easily get into the building but, when the light is transformed into thermal energy, it is trapped inside of the building. Also, no equipment or machinery are used to transport heat through the building. Passive solar heated building is quieter building to work at as there is no additional noises from machinery to produce heat.

Passive Solar Building Heat Diagram
Active And Passive Solar Heating Diagram

Active solar heating

Active solar heating is used in buildings which uses mechanical equipment and additional sources of energy to collect and transfer thermal energy. Such a system can consist of dark metal plates inside frames with glass enclosures, which is mounted to a roof to collect solar energy from the sun. The dark coloured metal plates are used to collect and absorb radiant energy. These collectors have special fluids which get heated up by the collector. A solar pump is used to transport the heated fluid into the building for heating the air or the water inside. It is a best practice to install a solar collector as high as possible unto a roof of a building or house. This is because, the solar collector would get the most exposure directly from the sun. When installing a solar collector, ensure that trees or other structures won’t obstruct the solar energy or sunlight from reaching the solar collector. Solar thermal energy or heat can be stored in a larger tank filled with liquid.

Solar water heating

Solar energy can be used to heat water, therefore allowing people to have hot water generated from solar energy. To heat water using an electrical geyser, which allows you to take a shower or bath, contributes to a large amount of your electrical utility bills at the end of each month. Installing a solar hot water geyser, can drastically reduce your electrical costs on heating water. Solar geysers or solar hot water heaters, works almost in the same way as solar building heating. South Africa is in the southern hemisphere. So, in the southern hemisphere, solar geyser collectors should face true north and in the northern hemisphere, solar geyser collectors should face true south. Therefore, solar hot water geysers can obtain as much as possible solar energy from the sun. When the solar energy process to heat the water is completed, the hot water is stored inside a tank. The storage tank is connected to buildings plumbing system which allows hot water availability through faucets and it works just like a normal electrical geyser would. The hot water is piped to faucets throughout a house, just as it would be with an ordinary water heater.

Solar Hot Water Geyser Heater Diagram

Solar or radiant energy to electricity

Solar energy is commonly used to generate usable electricity. Thermal energy systems and photovoltaic systems are used to generate electricity from solar energy.

Photovoltaic Systems

Photovoltaic Systems

Photovoltaic originates from the word photo, in other words, light and volt which entities to measure electricity. Photovoltaic cells are commonly known as solar PV cells or solar cells. Scientist are working on the advancements of solar cells to improve its efficiencies every day as the demand for solar cell systems increase. Solar cells are found in many types of devices. Solar calculators, solar toys and solar lights just to mention a few. Solar cells are made from wafers of silicon. Silicon is one of the elements found in sand. The silicon wafer’s top has a small quantity of phosphorous added to it.  Therefore, providing the wafer with a larger quantity of negatively charged electrons. This is also known as a n-type silicon because it is negative and give up its electrons. At the bottom of the wafer, a little amount of boron is added which allow electrons to attract to it. This is known as a p-type silicon as it is positive. When all chemicals are inside of the silicon wafer, electrons flow from the negative n-type silicon to the positive p-type silicon. Therefore, an electrical field is created between the layers at the p-type and n-type junction. The p-type silicon has a negative charge because it gained electrons from the n-type. On the other hand, the n-type has a positive charge because it lost electrons.

What happens if the Photovoltaic system is in the sun?

When the Photovoltaic system or PV cells are in direct sunlight, the radiant energy releases the electrons inside the solar cell. When a circuit is created by the connected wafer sides, energy from electrons are transferred from atom to atom from the n-type through wire to the p-type. Therefore, the solar cell is generating electricity. Basically, this is the transfer or electricity based on the movement of electrons.  If you place a light as a load on the wire forming the circuit, the electricity flow will light up the load or the bulb. Conversion of sunlight into usable electricity happens immediately. There are no moving parts in this system, therefore,  PV systems  can last for years.

Photovoltaic PV Systems Generating Electricity Sunlight
Solar PV System Sizes

How large are PV systems?

Photovoltaic systems can be used in small calculators, in homes to power appliances or can be used in large power plants which can provide electricity for suburbs of homes. Most complete residential PV installations are about 6kW in size. A power plant solar PV scales can reach amounts of 4MW in many cases. However, this is not always the case as most photovoltaic installations vary in size due to space requirements and costs. Solar researchers are working hard to provide more advanced PV cells which can be flexible and also thinner without sacrificing efficiencies. Solar researchers also developed solar cells which can be implemented inside windows or thin film solar panels that can attach to the external side of a building. Nowadays, there are also solar paint available. Solar technology will just get better and progress as time passes.  See our range of solar panels offered today. 

See the following useful links

Get solar energy for your home today!