Life on the planet is impossible without energy. The physical law of conservation of energy says that energy cannot arise from nothing and does not disappear without a trace. It can be obtained from natural resources such as coal, natural gas or uranium, and converted into forms that are convenient for us, such as heat or light. In the world around us, we can find various forms of energy storage, but the most important for a person is the energy that the sun's rays give - solar energy.

Solar energy refers to renewable energy sources, that is, it is restored without human participation, in a natural way. It is one of the environmentally friendly energy sources that does not pollute the environment. Application possibilities solar energy are practically unlimited and scientists around the world are working on developing systems that expand the possibilities of use solar energy.

One square meter of the Sun emits 62,900 kW of energy. This roughly corresponds to the power of 1 million electric lamps. Such a figure is impressive - the Sun gives the Earth 80 thousand billion kWh every second, that is, several times more than all the power plants in the world. The challenge facing modern science is to learn how to use the energy of the Sun most fully and effectively, as the safest. Scientists believe that the widespread use of solar energy- this is the future of humanity.

The world's reserves of discovered deposits of coal and gas, at such rates of their use as today, should be depleted in the next 100 years. It is estimated that the reserves of fossil fuels in yet unexplored deposits would be sufficient for 2-3 centuries. But at the same time, our descendants would be deprived of these energy carriers, and the products of their combustion would cause colossal damage to the environment.

Atomic energy has a huge potential. However, the Chernobyl accident in April 1986 showed what serious consequences the use of nuclear energy can entail. The public around the world has recognized that the use of atomic energy for peaceful purposes it is economically justified, but the strictest security measures should be observed when using it.

Therefore, the cleanest, safest source of energy is the Sun!

Solar energy can be converted into useful energy through the use of active and passive solar energy systems.

Passive solar energy systems.

The most primitive way of passive use solar energy- it is painted in dark color container for water. Dark color, accumulating solar energy, turns it into heat - the water heats up.

However, there are more progressive methods of passive use. solar energy... Construction technologies have been developed that, when designing buildings, taking into account climatic conditions, selecting building materials make the most of solar energy for heating or cooling, lighting of buildings. With this design, the building structure itself is a collector that accumulates solar energy.

So, in 100 AD Pliny the Younger built a small house in the north of Italy. In one of the rooms the windows are made of mica. It turned out that this room was warmer than the others and required less firewood to heat it. In this case, mica acted as an insulator that retains heat.

Modern building structures take into account the geographical location of buildings. Thus, a large number of south-facing windows are provided in the northern regions in order to receive more sunlight and heat, and the number of windows on the east and west side is limited to limit the supply of sunlight in summer. In such buildings, window orientation and arrangement, heat load and thermal insulation form a single design system in the design.

Such buildings are environmentally friendly, energy independent and comfortable. There is a lot of natural light in the rooms, the connection with nature is more fully felt, and in addition, electricity is significantly saved. Heat in such buildings is retained thanks to selected heat-insulating materials for walls, ceilings and floors. These first "solar" buildings gained immense popularity in America after World War II. Subsequently, due to the decline in oil prices, interest in the design of such buildings faded somewhat. However, now, due to the global environmental crisis, there has been an increase in attention to environmental projects with renewable energy systems has increased again.

Active solar energy systems

At the heart of active systems of use solar energy solar collectors are used. Collector absorbing solar energy, converts it into heat, which heats buildings through the coolant, heats water, can convert it into electrical energy, etc. Solar collectors can be used in all processes in industry, agriculture, household needs where heat is used.

Collector types

solar air collector

it simplest view solar collectors. Its design is extremely simple and resembles the effect of an ordinary greenhouse, which is found in any summer cottage. Do a little experiment. On a sunny winter day, put any object on the windowsill so that the sun's rays fall on it and after a while, put your palm on it. You will feel that the item has become warm. And outside the window maybe - 20! It is on this principle that the work of a solar air collector is based.

The main element of the collector is a heat-insulated plate made of any material that conducts heat well. The plate is dark colored. The sun's rays pass through the transparent surface, heat the plate, and then transfer the heat into the room with a stream of air. The air is passed through by natural convention or by a fan, which improves heat transfer.

However, the disadvantage of this system is that additional costs are required for the operation of the fan. These collectors work for daylight hours, therefore they cannot replace the main heating source. However, if the collector is installed in the main source of heating or ventilation, its efficiency increases disproportionately. Solar air collectors can also be used for desalination of sea water, which reduces its cost to 40 eurocents per cubic meter.

Solar collectors can be flat or vacuum.

flat solar collector

The collector consists of a solar energy absorbing element, a coating (glass with a reduced metal content), a pipeline and a thermal insulating layer. The transparent coating protects the case from adverse climatic conditions. Inside the housing, the solar energy absorber (absorber) panel is connected to a coolant that circulates through the pipes. The pipeline can be both in the form of a lattice and in the form of a serpentine. The coolant moves along them from the inlet to the outlet, gradually heating up. The absorber panel is made of metal that conducts heat well (aluminum, copper).

The collector captures heat, converting it into thermal energy... Such collectors can be installed in the roof or located on the roof of the building, or they can be located separately. This will give the site a modern look.

Vacuum solar collector

Vacuum collectors can be used all year round. The main element of the collectors are vacuum tubes. Each of them consists of two glass tubes. The pipes are made of borosilicate glass, with the inner lined with a special coating that absorbs heat with minimal reflection. Air is pumped out of the space between the tubes. A barium getter is used to maintain the vacuum. In good condition, the vacuum tube is silvery. If it looks white, then the vacuum has disappeared and the tube needs to be replaced.

The vacuum collector consists of a set of vacuum tubes (10-30) and transfers heat to the storage tank through an anti-freeze liquid (heat carrier). The efficiency of vacuum collectors is high:

- in cloudy weather, because vacuum tubes can absorb the energy of infrared rays that pass through clouds

- can work at subzero temperatures.

Solar panels.

A solar battery is a set of modules that receive and convert solar energy, including thermal ones. But this term has traditionally been assigned to phytoelectric converters. Therefore, when we say "solar battery" we mean a phytoelectric device that converts solar energy into electrical energy.

Solar panels are capable of generating electrical energy continuously or storing it for further use. For the first time, photovoltaic batteries were used in space satellites.

The advantage of solar panels is maximum design simplicity, simple installation, minimum maintenance requirements, long term exploitation. Installation does not require additional space. The only condition is not to shade them for a long time and remove dust from the work surface. Modern solar panels are capable of maintaining efficiency for decades! It is hard to find a system that is so safe, effective and so long lasting! They generate energy throughout the day, even in cloudy weather.

Solar panels have their drawbacks in application:

- sensitivity to dirt. (If the battery is positioned at a 45 degree angle, it will be cleaned by rain or snow, thus no additional maintenance is required)

- sensitivity to high temperature. (Yes, when heated to 100 - 125 degrees, the solar battery may even turn off and a cooling system may be required. The ventilation system will consume a small fraction of the energy generated by the battery. Modern designs of solar panels provide for a hot air outflow system.)

- high price. (Taking into account the long service life of solar panels, it will not only recoup the costs of purchasing it, but also save money on electricity consumption, save tons of traditional fuels, while being environmentally friendly)

The use of solar energy systems in construction.

In modern architecture, more and more often they plan to build houses with built-in rechargeable solar energy sources. Solar panels are installed on the roofs of buildings or on special supports. These buildings use a quiet, reliable and safe source of energy - the sun. Solar energy is used for lighting, space heating, air cooling, ventilation, and electricity generation.

We present several innovative architectural projects using solar systems.

The façade of this building is constructed of glass, iron, aluminum with built-in solar energy accumulators. The energy produced is enough to not only provide the residents of the house with autonomous hot water supply and electricity, but also to illuminate the street for 2.5 km throughout the year.

This home was designed by a group of American students. The project was submitted to the competition "Design, construction of houses and operation of solar panels." Terms of the competition: to present an architectural project of a residential building with its economic efficiency, energy saving and attractiveness. The authors of the project have proven that their project is affordable, attractive to the consumer, combines excellent design and maximum efficiency. (translated from the site www.solardecathlon.gov)

The use of solar energy systems in the world.

Systems of use solar energy perfect and environmentally friendly. All over the world there is a huge demand for them. All over the world, people are beginning to abandon the use of traditional fuels due to the rise in gas and oil prices. So, in Germany in 2004. 47% of homes had solar collectors to heat their water.

In many countries of the world, state programs for the development of the use of solar energy... In Germany, this is the program "100,000 solar roofs", in the United States a similar program "Million solar roofs". In 1996. architects from Germany, Austria, Great Britain, Greece and other countries have developed a European Charter on solar energy in construction and architecture. In Asia, China is leading, where, on the basis of modern technologies, solar collector systems are being introduced into the construction of buildings and the use of solar energy in industry.

A fact that says a lot: one of the conditions for joining the European Union is an increase in the share of alternative sources in the country's energy system. In 2000. there were 60 million square kilometers of solar collectors operating in the world; by 2010, the area had increased to 300 million square kilometers.

Experts point out that the systems market solar energy on the territory of Russia, Ukraine and Belarus is just being formed. Solar systems have never been produced on a large scale, because raw materials were so cheap that expensive equipment for solar systems was not in demand ... The production of collectors in Russia, for example, has been almost completely stopped.

In connection with the rise in prices for traditional energy sources, there has been a revival of interest in the use of solar systems. In a number of regions of these countries, experiencing a shortage of energy resources, local programs for the use of solar systems are being adopted, but solar systems are practically not familiar to the wide consumer market.

The main reason for the slow development of the market for the sale and use of solar systems is, firstly, their high initial cost, and secondly, the lack of information about the capabilities of solar systems, advanced technologies for their use, about the developers and manufacturers of solar systems. All this cannot make it possible to correctly assess the effectiveness of the use of systems operating on solar energy.

It should be borne in mind that a solar collector is not a final product. To obtain the final product - heat, electricity, hot water - it is necessary to go from design, installation to the launch of solar systems. The limited experience of using solar collectors shows that this work is not more difficult than installing traditional heating, but the economic efficiency is much higher.

In Belarus, Russia, Ukraine, there are many firms engaged in the design and installation of heating equipment, but traditional energy sources have priority today. Development of economic processes, world experience in using systems solar energy shows that the future belongs to alternative energy sources. For the near future, it can be noted that solar systems are a new, practically unoccupied position in our market.

The energy of the sun is just a stream of photons. And at the same time it is one of the fundamental factors that ensure the very existence of life in our biosphere. Therefore, it is quite natural that sunlight is actively used by humans not only in the climatic aspect, but also as an alternative source of energy.

Where is solar energy used

The scope of application of the sun's energy is very extensive, and every year it becomes more and more. So, more recently, a summer cottage shower with a solar heater was perceived as something extraordinary, and the possibility of using sunlight for household power grids seemed fantastic. Today, you will not surprise anyone not only with an autonomous solar station, but also with mobile chargers powered by solar batteries and even small appliances (for example, clocks) that operate on the photovoltaic effect.

In general, the use of solar energy is in great demand in areas such as:

Agriculture;
Power supply of sanatoriums and boarding houses;
Space industry;
Conservation activities and ecotourism;
Electrification of remote and hard-to-reach regions;
Street, garden and decorative lighting;
Sphere of housing and communal services (hot water supply, adjoining lighting);
Mobile technology (solar-powered gadgets and charging modules).

Previously, the energy of the sun was used mainly in the space industry (power supply of satellites, stations, etc.) and in industry, but over time, alternative energy began to actively develop in everyday life. Some of the first objects to be equipped with solar installations were southern boarding houses and sanatoriums, especially located in secluded areas.

Solar installations and their advantages

The successful application of the first solar modules proved that the energy of the sun's rays has a lot of advantages over traditional sources. Previously, the main advantages of solar plants were only called environmental friendliness and inexhaustibility (as well as free) of sunlight.

But in fact, the list of advantages is much wider:

Autonomy, since no external power communications are required;
Stability of power supply, due to the specificity of the solar current is not subject to voltage surges;
Profitability, since funds are spent only once, when installing the unit;
Solid service life (over 20 years);
All-season use, solar installations work effectively even in frost and cloudy weather (with a slight decrease in efficiency);
Simplicity and ease of service, as only occasionally needs to be cleaned front sides panels from dirt.

The only drawback is the dependence on the sun and the fact that such installations do not work at night. But this problem is solved by connecting special batteries, in which the energy of sunlight generated during the day is accumulated.

Photoenergy

Photovoltaic energy is one of two ways to use the sun's radiation. It is a direct current generated by sunlight. This transformation takes place in the so-called photocells, which, in fact, are a two-layer structure of two semiconductors of different types. The lower semiconductor is p-type (with a lack of electrons), the upper one is n-type with an excess of electrons.

The electrons of the n-conductor absorb the energy of the rays of the sun falling on them and leave their orbits, and the energy impulse is sufficient for them to pass into the zone of the p-conductor. In this case, a directed electron flow is formed, called a photocurrent. In other words, the entire structure works as a kind of electrodes, in which electricity is generated under the influence of the sun.

Silicon is used for the production of such photocells. This is explained by the fact that silicon, firstly, is widespread, and secondly, its industrial processing does not require large expenditures.

Silicon photocells are:

Monocrystalline. They are made of single crystals and have a uniform structure with a slightly higher efficiency (about 20%), but they are more expensive.
Polycrystalline. They have an uneven structure due to the use of polycrystals and a slightly lower efficiency (15-18%), but much cheaper than monovariants.
Thin-film. They are made by spraying amorphous silicon onto a thin-film substrate. They are distinguished by a flexible structure and the lowest production cost, however, they have twice the size compared to their crystalline counterparts of the same power.

The fields of application of each type of cells are very extensive and are determined by their operational characteristics.

Solar collectors

Solar collectors are also used as solar energy converters, but their principle of operation is completely different. They convert the incident light not into electrical energy, but into thermal energy by heating the liquid heat carrier. They are used either for hot water supply or for heating houses. The main element of any collector is an absorber, which is also a heat sink. The absorber is either a flat plate or a tubular evacuated system, inside which a coolant circulates (this is either simple water or antifreeze). Moreover, the absorber must be painted black with a special paint to increase the absorption coefficients.

It is by the type of absorbers that collectors are divided into flat and vacuum ones. For flat ones, the heat sink is made in the form of a metal plate, to which a metal coil with a coolant is soldered from below. A vacuum absorber is made of several glass tubes interconnected at the ends. The tubes are made double, a vacuum is created between the walls, and a rod with a coolant is placed inside. All rods communicate with each other by means of special connectors at the pipe joints.

Both types of absorbers are housed in a durable lightweight housing (usually made of aluminum or shock-resistant plastics) and are reliably insulated from the walls. The front side of the case is covered with transparent impact-resistant glass with maximum transparency for photons. This ensures better absorption of solar energy.

Features of functioning

The principle of operation of both types of collectors is the same. Heating up in the manifold to high temperatures, the coolant flows through the connecting hoses to the heat exchange tank, which is filled with water. It passes through the tank along a serpentine tube, giving off its heat to the water. The cooled coolant leaves the tank and is fed back to the collector. In fact, this is a kind of "solar" boiler ", only instead of a heating coil, a coil in the tank is used, and instead of an electrical network - sunlight.

Structural differences also determine the difference in the use of vacuum and flat-plate collectors. The use of solar radiation with the help of vacuum models is possible all year round, including in winter and in the off-season. Flat options work better in the summer. However, they are cheaper and simpler than vacuum ones, therefore they are optimally suited for seasonal purposes.

Solar energy in cities (eco houses)

Solar energy is actively used not only for private houses, but also for urban buildings. How a person uses solar energy in megacities is not difficult to guess. It is also used for heating and hot water supply of buildings, and often entire neighborhoods.

V last years the concept of eco-houses fully operating on alternative energy sources is being actively developed and implemented. They use combined systems to efficiently obtain solar, wind and thermal energy from the earth. Often, such houses not only fully cover their energy needs, but also transfer the surplus to urban networks. Moreover, quite recently, projects of such eco-buildings have appeared in Russia.

Solar stations and their types

In the southern regions with high insolation, not just individual solar plants are being built, but entire stations that generate energy on an industrial scale. The amount of solar energy they generate is very large and many countries with suitable climates have already begun to gradually convert the entire energy system to such an alternative. According to the principle, the work of the station is divided into photothermal and photovoltaic. The former work according to the collector method and supply heated water to the houses for hot water supply, while the latter generate electricity directly.

There are several types of solar stations:

Tower. Allows to obtain superheated steam supplied to generators. A tower with a water reservoir is based in the center of the station, heliostats (mirror) are placed around it, which focus the rays on the reservoir. These are quite effective stations, their main drawback is the difficulty of precise positioning of the mirrors.
Poppet. Consist of a solar receiver and a reflector. Reflector - a dish-shaped mirror that concentrates radiation on the receiver. Such concentrators of solar energy are located at a short distance from the receiver, and their number is determined by the required power of the installation.
Parabolic. Tubes with a coolant (usually oil) are placed at the focus of a long parabolic mirror. The heated oil gives off heat to the water, which boils and rotates the generators.
Balloons. In fact, these are the most efficient and mobile solar stations on Earth. Their main element is a photovoltaic balloon filled with water vapor. It rises high into the atmosphere (usually above the clouds). The heated steam from the ball is fed to the turbine through a flexible steam line, at the outlet from it it condenses and the water is pumped back into the ball. Once in the ball, the water evaporates and the cycle continues.
On photo batteries. These are solar-powered installations that are already familiar to everyone, which are used for private houses. They provide electricity and water heating in the required volumes.

Today, various kinds of solar power plants (including combined ones, combining several types) are playing an increasing role in the power generation of many countries. And some states are restructuring their energy sector in such a way that in a few years they will almost completely switch to alternative systems.

People can no longer imagine life without electricity, and every year the need for energy is growing more and more, while the reserves of energy resources such as oil, gas, coal are rapidly decreasing. Humanity is left with no other options than the use of alternative energy sources. One of the ways to generate electricity is to convert solar energy using photovoltaic cells. People learned that it is possible to use the energy of the sun for a relatively long time, but they began to actively develop only in the last 20 years. In recent years, continuous research, the use of the latest materials and creative design solutions have significantly increased the performance of solar cells. Many believe that in the future, humanity will be able to abandon traditional methods of generating electricity in favor of solar energy and get it using solar power plants.

Solar energy

Solar energy is one of the sources of generating electricity in a non-traditional way, therefore it belongs to alternative energy sources. Solar energy uses solar radiation and converts it into electricity or other forms of energy. Solar energy is not only an environmentally friendly source of energy; when converting solar energy, no harmful by-products are released, but also the energy of the sun is a self-renewing source of alternative energy.

How solar energy works

It is not difficult to theoretically calculate how much energy can be obtained from the flow of solar energy, it has long been known that after passing the distance from the Sun to the Earth and falling on a surface of 1 m2 at an angle of 90 °, the solar flux at the entrance to the atmosphere carries an energy charge equal to 1367 W / m², this is the so-called solar constant. This is ideal under ideal conditions, which, as we know, is practically impossible to achieve. Thus, after passing through the atmosphere, the maximum flux that can be obtained at the equator will be 1020 W / m2, but the average daily value that we can obtain will be 3 times less due to the change of day and night and the change in the angle of incidence of the solar flux. And in temperate latitudes, the change of seasons is added to the change of day and night, and with it a change in the duration of daylight hours, therefore, in temperate latitudes, the amount of energy received will be reduced by 2 times.

Development and distribution of solar energy

As we all know, in the past few years, the development of solar energy has been gaining momentum every year, but let's try to trace the dynamics of development. Back in 1985, the world's solar capacity was only 0.021 GW. In 2005, they already amounted to 1,656 GW. 2005 is considered a turning point in the development of solar energy; it was from this year that people began to take an active interest in the research and development of solar-powered electrical systems. Further, the dynamics leaves no doubt (2008 - 15.5 GW, 2009 - 22.8 GW, 2010 - 40 GW, 2011 - 70 GW, 2012 - 108 GW, 2013 - 150 GW, 2014 - 203 GW). The palm in the use of solar energy is held by the countries of the European Union and the United States; more than 100 thousand people each are employed in the production and operational sphere in the United States and Germany alone. Also, Italy, Spain and, of course, China can boast of their achievements in the development of solar energy, which, if not the leader in the operation of solar cells, is how the manufacturer of solar cells increases the rate of production from year to year.

Advantages and Disadvantages of Using Solar Energy

Advantages: 1) environmental friendliness - does not pollute the environment; 2) availability - photovoltaic cells are available for sale not only for industrial use, but also for creating private mini solar power plants; 3) the inexhaustibility and self-renewability of the energy source; 4) constantly decreasing cost of electricity production.
Disadvantages: 1) the impact on performance of weather conditions and time of day; 2) to save energy, it is necessary to accumulate energy; 3) lower productivity in temperate latitudes due to the change of seasons; 4) significant heating of the air above the solar power plant; 5) the need to periodically clean the surface of the photocells from contamination, and this is problematic due to the huge areas occupied by the installation of photocells; 6) you can also say about the relatively high cost of equipment, although every year the cost is decreasing, while there is no need to talk about cheap solar energy.

Prospects for the development of solar energy

Today, a great future is predicted for the development of solar energy, every year more and more new solar power plants are being built, which amaze with their scale and technical solutions. Also, scientific research aimed at increasing the efficiency of photovoltaic cells does not stop. Scientists have calculated that if the land of planet Earth is covered by 0.07%, with the efficiency of solar cells in 10%, then the energy will be enough for more than 100% of all the needs of mankind. Today, photocells with an efficiency of 30% are already in use. According to research data, it is known that the ambitions of scientists promise to bring it to 85%.

Solar power plants

Solar power plants are structures whose task is to convert streams of solar energy into electrical energy. The sizes of solar power plants can be different, ranging from private mini power plants with several solar panels to huge ones, covering an area of over 10 km².

What are solar power plants

Quite a long time has passed since the construction of the first solar power plants, during which many projects have been implemented and many interesting design solutions have been applied. It is customary to divide all solar power plants into several types:
1. Solar power plants of the tower type.
2. Solar power plants, where solar cells are photovoltaic cells.
3. Disc solar power plants.
4. Parabolic solar power plants.
5. Solar power plants of the solar-vacuum type.
6. Solar power plants of the mixed type.

Tower solar power plants

A very common type of power plant design. It is a tall tower structure at the top, which houses a reservoir, painted black with water to better attract reflected sunlight. Around the tower are large mirrors in a circle with an area of over 2 m², they are all connected to a single control system that monitors the change in the angle of inclination of the mirrors so that they always reflect sunlight and direct it directly to the water tank located at the top of the tower. Thus, the reflected sunlight heats the water, which forms steam, and then this steam is pumped to the turbine generator where electricity is generated. The heating temperature of the tank can be up to 700 ° C. The height of the tower depends on the size and power of the solar power plant and, as a rule, starts from 15 m, and the height of the largest today is 140 m. This type of solar power plants is very common and is preferred by many countries for its high efficiency of 20%.

Photovoltaic solar power plants

Photovoltaic cells (solar panels) are used to convert solar flux into electricity. This type of power plant has become very popular due to the possibility of using solar panels in small blocks, which makes it possible to use solar panels to provide electricity to both private houses and large industrial facilities. Moreover, the efficiency is growing every year and today there are already photocells with an efficiency of 30%.

Parabolic solar power plants

This type of solar power plant looks like huge satellite dishes, the inside of which is covered with mirror plates. The principle by which the energy conversion takes place is similar to tower stations with a slight difference, the parabolic shape of the mirrors makes the sun's rays, reflecting from the entire surface of the mirror, concentrate in the center, where the receiver is located with a liquid that heats up, forming steam, which in its queue is the driving force for small generators.

Tray solar power plants

The principle of operation and the method of generating electricity is identical to tower and parabolic solar power plants. The only difference is the design features. On a stationary structure, a bit like a giant metal tree, on which are hung round flat mirrors that concentrate solar energy on the receiver.

Solar power plants of solar-vacuum type

This is very unusual way use of solar energy and temperature differences. The structure of the power plant consists of a glass-roofed parcel of land in a circular shape with a tower in the center. The tower is hollow inside, at its base there are several turbines that rotate due to the air flow due to the temperature difference. Through the glass roof, the sun heats the ground and the air inside the room, and the building communicates with the outside environment by a pipe, and since the air temperature outside the room is much lower, an air draft is created, which increases with an increase in the temperature difference. Thus, the turbines generate more electricity at night than during the day.

Mixed solar power plants

This is when in solar power plants of a certain type, for example, solar collectors are used as auxiliary elements to provide objects with hot water and heat, or it is possible to use sections of photocells at the same time in a tower-type power plant.

Solar energy is developing at a high rate, people are finally seriously thinking about alternative energy sources in order to prevent the inevitably impending energy crisis and environmental catastrophe. Although the leaders in solar energy are still the United States and the European Union, all other world powers are gradually beginning to adopt and use the experience and technologies for the production and use of solar power plants. There is no doubt that sooner or later solar energy will become the main source of energy on Earth.

Solar energy- this is light, heat and life on our planet, and also solar energy is the main alternative source, which is several orders of magnitude higher than the entire existing energy potential of the Earth, and it is able to fully meet all of its energy needs.

As the Sun is an endless source of heat and light (conventionally), so the energy of solar radiation has been supporting life on Earth for more than one million years. The Sun has the ability to provide all vital processes due to its composition. In percentage terms, it mainly consists of two elements: hydrogen (73%) and helium (25%). More details about the formation and life cycle of the Sun can be found, for example, in Wikipedia.

The thermonuclear fusion reactions that take place on the sun burn hydrogen, converting it into helium. The colossal energy of the sun's rays released during such processes is radiated into space. By the way, scientists are trying to repeat these reactions on earth (reaction of controlled thermonuclear fusion, international TOKAMAK project).

All organisms that use the energy of sunlight provide their vital processes with its help - sunlight is necessary for the initial stage of the photosynthesis process. With its participation, the synthesis of substances such as oxygen and hydrocarbons occurs.

The amount of hydrogen in the sun is gradually decreasing, and sooner or later the time will come when its supply in the sun will be depleted. However, due to a large number hydrogen, this will not happen, at least for the next 5 billion years.

Every second in the core of the Sun, about 4 million tons of matter are converted into radiant energy, resulting in the generation of solar radiation and a stream of solar neutrinos.

The main influx of energy from the Sun, which reaches the Earth's atmosphere, is in the spectral range of 0.1-4 microns. In the range of 0.3 1.5-2 microns, the Earth's atmosphere is almost transparent to solar radiation. Ultraviolet waves (wavelengths shorter than 0.3 microns) are absorbed by the ozone layer, which is located at altitudes of 20-60 km. X-rays and gamma rays hardly reach the Earth's surface.

The concentration of solar energy is characterized by a value of 1367 W / m2, called the solar constant. It is such a flow that passes through a perpendicular area of 1 m2 in size, if it is placed at the entrance to the upper layer of the Earth's atmosphere. When this flow reaches sea level, energy losses reduce it to 1000 W / m2 at the equator. But the change of day and night reduces it by another 3 times. For temperate latitudes, taking into account the winter period, it is half of the quantitative indicator of the maximum flow at the equator.

Averaged over time and over the Earth's surface, this flux is 341 W / m 2. Calculated for the full surface, or 1.74x10 17 W calculated for the full surface of the Earth. Thus, the Earth on the surface will receive 4.176x10 15 kWh of energy per day, most of which is returned to space in the form of radiation.

According to the IEA for 2015, the world energy production was 19,099 Mtoe (the equivalent of a megaton of oil). In terms of the usual kilowatt-hours, this figure will be 6.07x10 11 kWh per day.

The sun gives the earth 8,000 times more energy than is necessary for all of humanity. It is obvious that the prospects for the use of this type of energy are very wide. With its participation, wind power is developing (wind occurs due to temperature differences), photovoltaic converters are used and pumped storage stations are being built. There is widespread use of solar panels.

The potential for solar energy applications is very high.

Advantages and Disadvantages of Using Solar Energy

Benefits of using solar energy led to the fact that today we see its use in the most different types human activity.

The main advantages are:

The inexhaustible energy of the sun in the next 4 billion years;
The availability of this type of energy - it is with it that farmers, owners of private houses, and giant factories work with it safely and efficiently;
Free and ecological cleanliness of the generated energy;
Prospects for the development of this energy source, which is becoming more and more relevant due to the rise in prices for other types of energy;
Because the number of equipment put into operation annually and its reliability is growing, the cost of the generated kilowatt hour of solar energy is decreasing.

The conditional disadvantages of solar energy include:

The main disadvantage of solar energy is the direct dependence of the amount of received light and heat on the influence of factors such as weather, season or day. The logical consequence in this case is the need to store energy, which increases the cost of the system;
For the production of equipment items for this purpose, rare and, therefore, expensive items are used.

Prospects for the development of solar energy

Today, technologies that use the energy of sunlight are finding more and more widespread applications. The most common are solar panels. Photovoltaic cells are successfully installed on different kinds transport - from electric vehicles to airplanes. The Japanese practice installing them on trains.

With a successful operation, one of the European solar power plants provides all the needs of the Vatican. The largest solar-powered plant in California (photos give an idea of the scale) is already providing the state with its round-the-clock work.

The introduction of such technologies is facing resistance from the leaders of the hydrocarbon industry - after all, alternative energy sources may soon oust their representatives from the leading positions.

If we talk about direct conversion, then the most common are such devices for converting solar energy as heat pipes (solar collectors) and solar photovoltaic cells.

Solar plant economics

When considering the possibility of installing a solar power plant, the main focus is on the environmental and economic aspects. They sound like this:

What is the cost of a solar installation?
What is the payback period?
Will the unit generate enough electricity?

It is advisable to consider small power plants with a capacity of up to 50 kW. Installations of higher power are used mainly at industrial facilities.

Will a home solar power plant generate enough electricity?

To answer the third question, before starting the design of the solar installation, it determines the energy consumption profile of the house. It can be recorded by installing an electricity meter at the facility with the function of saving the current parameters: mains voltage, current consumption, current power consumption, frequency. After a month, you can evaluate your consumption profile with average, maximum and minimum values of the parameters.

If there is no such device, then the energy consumption profile can be estimated as follows: you will need to record all devices that can be used in the house and simulate possible options their daily use. Then, armed with a calculator, you can calculate your daily electricity consumption and peak power values.

The region where the building is located plays a significant role. The energy reaching the Earth's surface, depending on the region, can vary from more than 5 kWh / m2 / day to 1.5 kWh / m2 / day or less.

If the maximum consumption is during daylight hours, then in order to ensure the sufficiency of the generated electricity, it is necessary to divide the maximum power consumption by the power of one solar panel. The type and characteristics of the panels are known from the manufacturers catalogs. It should be borne in mind that the characteristics of solar panels are given at their maximum illumination - a correction for the regional coefficient is required. Winter period when batteries are covered with snow is not counted.

This calculation does not take into account the following feature: During the day, the installation will always generate excess energy, and at night, for obvious reasons, the generation will be equal to 0.

On the one hand, storage batteries increase the overall cost of the system, on the other hand, they can reduce the number of solar panels by storing energy during periods of less power consumption.

To calculate the AKB bank, you need to answer the following questions:

Is the system supposed to be completely autonomous?
If the system is not autonomous, then what is the maximum possible period of power outages.

The maximum consumption in kWh is multiplied by the number of hours without the main source (it must be borne in mind that at the time the sun is turned off it may not be there). Based on these data, you can calculate the capacity of the battery bank. Discharging the battery to 0 reduces their service life, therefore, the coefficient of the maximum discharge indicator is introduced into the calculation, for example, it can be 50, 40 or 30%. The lower the maximum discharge rate, the more battery will be required.

Solar power installation cost

The main components of the system equipment are distributed by cost in the following percentage ratio (conditionally):

Inverter and control system - 15-40%;
Solar panels and MPPT controllers - 20-40%;
Bank AKB - 30%.

The cost of solar panels and batteries will be identical for systems of all manufacturers, significant differences are only in the cost of the inverter equipment with a control system and an MPPT controller.

The price difference reaches more than 200%, depending on the manufacturer. This is due not only to the "brand", but also to the capabilities of the system, for example, ease of management, the ability to remotely access, maximum load and resistance to 2x-3x overloads, the ability to partially disconnect the load, etc.

Each final technical solution will be slightly different from the others due to the fact that all people use different household appliances in different time days. There is no ideal combination of equipment, even for a given power.

As an approximate cost of a functional solar installation in a country house, taking into account the reservation of part of the capacity, one can roughly focus on the figures of 700-1800 USD / kW, depending on the manufacturer of the equipment.

Payback period of a solar generation installation

If the owners conditionally leave for the dacha only for the weekend, and at the same time there are no consumers in the house who work every day, then, most likely, the system will pay off for at least 10-15 years, at current electricity tariffs.

With permanent residence, the payback period will be reduced to 6-10 years.

The positive side of the coin is that the owner of such a house receives a stable source of power supply and does not depend on power line breaks or power drops. Everyone is sitting without light, and you are with light, security systems are functioning, there is no need to manually open the garage, etc.

It can be assumed that the development of private electric transport will shorten the payback period of a solar installation for households. The owner of such a car will "refuel" it from his own roof for free.

The payback period depends on the completeness of electricity use. If the structure uses 100% of the generation and is connected to the central power supply network, then in general there is no need to install a battery bank. The estimated full payback period for such an installation will be 3-5 years, and even shorter in hot regions.

An additional benefit is generated due to the fact that during the day the owner DO NOT PAY at the day rate, and at night PAYING at night.

Such quickly recouped objects can be any energy-consuming production with an empty flat roof, shopping and entertainment and sports centers and parking lots at them, refrigeration complexes, etc.

Surprisingly, such solutions, which can significantly reduce operating costs, are still not used by property owners.

For the foreseeable future, with the development of solar energy, an increasing number of building owners will use clean energy instead of hydrocarbons.

Our Sun is a huge glowing ball of gas, inside which complex processes take place and, as a result, energy is continuously released. The energy of the Sun is the source of life on our planet. The sun heats the atmosphere and surface of the Earth. Thanks to solar energy, winds blow, the water cycle in nature is carried out, the seas and oceans are heated, plants develop, animals have food. It is thanks to solar radiation that fossil fuels exist on Earth. Solar energy can be converted into heat or cold, propulsion and electricity.

The sun evaporates water from the oceans, seas, from the earth's surface. It converts this moisture into water droplets, forming clouds and fogs, and then causes it to fall back to Earth in the form of rain, snow, dew or frost, thus creating a gigantic cycle of moisture in the atmosphere.

Solar energy is the source of the general circulation of the atmosphere and the circulation of water in the oceans. It seems to create a gigantic system of water and air heating of our planet, redistributing heat over the earth's surface.

Sunlight, falling on plants, causes the process of photosynthesis in it, determines the growth and development of plants; getting on the soil, it turns into heat, heats it, forms the soil climate, thereby giving vitality to the seeds of plants in the soil, microorganisms and living things inhabiting it, which without this heat would be in a state of suspended animation (hibernation).

The sun emits a huge amount of energy - approximately 1.1x10 20 kWh per second. A kilowatt hour is the amount of energy required to operate a 100 watt incandescent light bulb for 10 hours. The outer layers of the Earth's atmosphere intercept approximately one millionth of the energy emitted by the Sun, or approximately 1,500 quadrillion (1.5 x 10 18) kWh annually. However, only 47% of all energy, or approximately 700 quadrillion (7 x 10 17) kWh, reaches the Earth's surface. The remaining 30% of solar energy is reflected back into space, about 23% evaporate water, 1% of the energy comes from waves and currents, and 0.01% from the formation of photosynthesis in nature.

Solar energy research

Why does the sun shine and not cool down for billions of years? What "fuel" gives it energy? Scientists have been looking for answers to this question for centuries, and only at the beginning of the 20th century was the correct solution found. It is now known that, like other stars, it shines due to thermonuclear reactions taking place in its depths.

If the nuclei of atoms of light elements merge into the nucleus of an atom of a heavier element, then the mass of the new one will be less than the total mass of those from which it was formed. The rest of the mass is converted into energy, which is carried away by the particles released during the reaction. This energy is almost completely converted into heat. Such a reaction of synthesis of atomic nuclei can occur only at very high pressure and temperatures over 10 million degrees. Therefore, it is called thermonuclear.

The main substance that makes up the sun is hydrogen, it accounts for about 71% of the entire mass of the star. Almost 27% belongs to helium, and the remaining 2% belongs to heavier elements such as carbon, nitrogen, oxygen and metals. The main "fuel" of the sun is hydrogen. From four hydrogen atoms, as a result of a chain of transformations, one helium atom is formed. And from each gram of hydrogen participating in the reaction, 6x10 11 Joules of energy are released! On Earth, this amount of energy would be enough to heat 1000 m 3 of water from 0є C to the boiling point.

Solar energy potential

The sun provides us with 10,000 times more free energy than is actually used around the world. In the global commercial market alone, just under 85 trillion (8.5 x 10 13) kWh of energy is bought and sold per year. Since it is impossible to trace the entire process as a whole, it is impossible to say with certainty how much non-commercial energy people consume (for example, how much wood and fertilizer is collected and burned, how much water is used to produce mechanical or electrical energy). Some experts believe that such non-commercial energy accounts for one fifth of all energy used. But even if this is the case, then the total energy consumed by humanity during the year is only about one seven thousandth of the solar energy that falls on the Earth's surface during the same period.

In developed countries such as the United States, energy consumption is approximately 25 trillion (2.5 x 10 13) kWh per year, which equates to more than 260 kWh per person per day. This indicator is the equivalent of more than one hundred 100W incandescent light bulbs operating daily throughout the day. The average US citizen uses 33 times more energy than an Indian, 13 times more than a Chinese, two and a half times more than a Japanese, and twice as much as a Swede.