Solar power facts
We all know the energy of our Sun. The solar power facts speaks that this huge, endless energy can be used for all human kind on many different ways as the main renewable energy source.
The sun is virtually inexhaustible source of energy that can guarantee continuous pumping if we know how to use it. Energy that the sun shines on earth is 15 percent larger than it needs to man, but unfortunately today very small part we can use. The fact that every single hour the Sun beams on Earth energy enough to satisfy global energy needs for an entire year speaks clearly how big this source of energy is.
Utilization of solar energy
People since ancient times understood the benefits and importance of the Sun and its energy. Not coincidentally in most ancient cultures in the world supreme deity is the Sun or any of his performance. People benefits from its energy in the building of homes (for more light and heat), food processing (drying), and in war (it is known that Alexander of Macedonia always fought his battles at noon with the sun behind his army, or heat ray from Archimedes, who by directing mirrors managed to burn the sails of ships that siege Syracuse).
These days we use solar energy mostly for electricity generation, and this production of electricity from sunlight is made in two ways: indirectly, by heating a liquid or directly with photovoltaic cells.
Basic principles of direct utilization of solar energy are:
- Solar collectors – preparing hot water and space heating
- Photovoltaic cells – the direct conversion of solar energy into electricity
- Focusing solar energy – the use in large power plants
The simplest application of solar energy is with solar collectors for hot water. In this way we get electricity, but water is heated by passing through the collector itself. Panels operate on a simple principle. Consisting of pipes (or a long tube) placed in housing. Inside the housing is a vacuum, in order not to lose heat collected inside (no air, no heat transfer). For the same reason the housing is well isolated. From top collector is closed with glass in order to pass sunlight. The tubes are coated with black paint in order to better absorb solar energy, and the base of the casing with white paint or made of metal or sets of reflective material that can efficiently directing light onto the pipes. The reason for this is that collector actually uses infrared rays of the sun to heat rather than visible light. That’s way collectors can be used in winter or when it is cloudy, with reduced sunlight because infrared light passes easily through obstacles in the atmosphere.
Photovoltaic cells are semiconductor devices that directly convert sunlight energy into electricity. These cells are similar like those we can find in computer chips. When these cells are hit with sunlight, becomes reaction which triggers electrons to loose from atoms. So as they travel (flow) through the cell, they generate electricity. In the production of solar cells, a process called thermal evaporation is used.
In terms of producing electricity from sunlight, it is done with concentrated solar energy, where there are four concepts: parabolic system, Frenel’s reflectors, reflective plate system and solar tower.
In each of these systems operating principle is the same: sunlight filtering down through a system of mirrors (parabolic, flat, plate …) in a point through which passes a certain working fluid, usually molten salt or sea water. Due to the high concentration of solar rays, the liquid rapidly is heated to high temperature. Then, this liquid is used for steam, which still carries the turbine to generate electricity, similar to the thermal plants.
The problem with focusing is the large space required for the plant, but it is handled so that the power plant for example can be in the desert. In deserts also the power of solar radiation is much stronger. The big problem is the price of the mirror’s and the focusing system.
Some facts about solar energy:
- The sun produces energy for five billion years, and according to current estimates of the energy production will continue for another five billion years. Solar energy is a part of the energy produced in the Sun that reaches the earth.
- Solar energy is one of the cleanest sources of energy without having a negative impact on life and the environment.
- Solar energy is the “engine” behind almost all renewable energy sources.
Secondary sources of energy powered by solar energy, like wind power, wave power, biomass and hydro power, make the most of renewable energy sources on earth.
- At night and on cloudy days solar energy is not fully available and we need energy storage systems that are filled when the energy is available. Solar energy can be stored in different forms, but most popular are the conversion of thermal energy, storage in batteries and accumulators.
- Satellites and spacecraft use solar energy after launching as main energy source.
- Leonardo Da Vinci (1452 – 1519) planned industrial use of solar energy using a concave mirror, which directed the rays on solar water heaters. In modern times this principle is called concentrating solar. The destruction of forests in the time of Da Vinci was also big because they were main fuel for humanity.
Advantages of Solar Energy
- Solar energy is environmentally friendly, clean, and renewable without any harmful pollutants and emissions in faze of production.
- Economical because it saves our money and after initial investment the energy we get is absolutely FREE.
- Solar energy systems have a very long life, almost no maintenance and no extra costs.
Disadvantages of Solar Energy
- High installation costs
- Climate of a place and geographic location of place where you live can be a factor of advantage or disadvantage in using solar power energy.
- During night no solar energy can be produced so we need battery back up system.