V last years scientists are especially interested in alternative energy sources. Oil and gas will sooner or later run out, so we have to think about how we will survive in this situation now. Wind turbines are actively used in Europe, someone is trying to extract energy from the ocean, and we will talk about solar energy. After all, the star that we see in the sky almost every day can help us save and improve the ecological situation. The value of the sun for the Earth can hardly be overestimated - it gives warmth, light and allows all life on the planet to function. So why not find another use for it?

A bit of history

In the middle of the 19th century, physicist Alexander Edmond Becquerel discovered the photovoltaic effect. And by the end of the century, Charles Fritts had created the first device capable of converting solar energy into electricity. For this, selenium was used, covered with a thin layer of gold. The effect was weak, but it is this invention that is often associated with the beginning of the era of solar energy. Some scholars disagree with this formulation. They call the world famous scientist Albert Einstein the founder of the era of solar energy. In 1921 he received the Nobel Prize for explaining the laws of the external photoelectric effect.

It would seem that solar energy is a promising development path. But there are many obstacles for it to enter every home - mainly economic and environmental. What constitutes the cost of solar panels, what harm they can cause to the environment and what other ways of obtaining energy exist, we will find out below.

Accumulation methods

The most urgent task associated with the domestication of the sun's energy is not only its receipt, but also its accumulation. And this is what is most difficult. Currently, scientists have developed only 3 ways to fully tame solar energy.

The first is based on the use of a parabolic mirror and is a bit like playing with a magnifying glass, which is familiar to everyone from childhood. Light passes through the lens, gathering at one point. If you put a piece of paper in this place, it will light up, since the temperature of the crossed rays of the sun is incredibly high. A parabolic mirror is a concave disc that resembles a shallow bowl. This mirror, unlike a magnifying glass, does not transmit, but reflects sunlight, collecting it at one point, which is usually directed at a black pipe filled with water. This color is used because it absorbs light best. The water in the pipe heats up under the influence of sunlight and can be used to generate electricity or to heat small houses.

Flat heater

This method uses a completely different system. The solar receiver looks like a multi-layer structure. The principle of its operation looks like this.

Passing through glass, the rays hit darkened metal, which is known to absorb light better. Solar radiation turns into and heats the water that is under the iron plate. Then everything happens as in the first method. The heated water can be used either for space heating or for generating electricity. True, the effectiveness of this method is not high enough to be used everywhere.

As a rule, the solar energy obtained in this way is heat. To obtain electricity, the third method is much more often used.

Solar cells

We are most familiar with this method of obtaining energy. It involves the use of various batteries or solar panels that can be found on the roofs of many modern homes. This method is more complicated than those previously described, but it is much more promising. It is he who enables the sun into electricity on an industrial scale.

Special panels designed to trap the rays are made from enriched silicon crystals. Sunlight, falling on them, knocks the electron out of orbit. In its place, another immediately strives, thus a continuous moving chain is obtained, which creates a current. If necessary, it is immediately used to provide devices or is accumulated in the form of electricity in special batteries.

The popularity of this method is justified by the fact that it allows you to get more than 120 watts from just one square meter of solar panels. At the same time, the panels have a relatively small thickness, which allows them to be placed almost anywhere.

Types of silicon panels

There are several types of solar panels. The first ones are made using monocrystalline silicon. Their efficiency is approximately 15%. These are the most expensive.

The efficiency of elements made of polycrystalline silicon reaches 11%. They cost less, since the material for them is obtained using a simplified technology. The third type is the most economical and has the lowest efficiency. These are panels made of amorphous silicon, that is, non-crystalline. In addition to low efficiency, they have another significant drawback - fragility.

Some manufacturers use both sides of the solar panel - the rear and the front - to increase efficiency. This allows you to capture light in large volumes and increases the amount of energy received by 15-20%.

Domestic manufacturers

Solar energy on Earth is becoming more widespread. Even in our country, they are interested in studying this industry. Despite the fact that the development of alternative energy is not very active in Russia, certain successes have been achieved. Currently, several organizations are engaged in the creation of panels for obtaining solar energy - mainly scientific institutes of various fields and factories for the production of electrical equipment.

1. NPF "Kvark".
2. JSC "Kovrov Mechanical Plant".
3. All-Russian Research Institute for the Electrification of Agriculture.
4. NPO mechanical engineering.
5. JSC VIEN.
6. JSC "Ryazan plant of cermet devices".
7. OJSC Pravdinsky Experimental Plant of Power Sources "Pozit".

This is only a small part of the enterprises taking Active participation in developing alternative

Impact on the environment

The rejection of coal and oil sources of energy is associated not only with the fact that these resources will sooner or later run out. The fact is that they greatly harm the environment - they pollute the soil, air and water, contribute to the development of diseases in people and reduce immunity. That is why alternative energy sources must be environmentally safe.

Silicon, which is used for the production of solar cells, is itself safe as it is a natural material. But after cleaning it, waste remains. They can harm humans and the environment if used improperly.

In addition, in an area completely covered with solar panels, natural light can be disrupted. This will lead to changes in the existing ecosystem. But overall, the environmental impact of solar conversion devices is minimal.

Profitability

The biggest costs are associated with the high cost of raw materials. As we have already found out, special panels are created using silicon. Despite the fact that this mineral is widespread in nature, great problems are associated with its extraction. The fact is that silicon, which makes up more than a quarter of the mass of the earth's crust, is not suitable for the production of solar cells. For these purposes, only the purest material obtained by an industrial method is suitable. Unfortunately, it is extremely problematic to obtain the purest silicon from sand.

In terms of price, this resource is comparable to uranium used at nuclear power plants. That is why the cost of solar panels currently remains at a fairly high level.

Modern technologies

The first attempts to tame solar energy appeared a long time ago. Since then, many scientists have been actively searching for the most efficient equipment. It should not only be cost effective, but also compact. Its efficiency should strive for maximum.

The first steps towards the ideal device for generating and converting solar energy were taken with the invention of silicon batteries. Of course, the price is quite high, but the panels can be placed on the roofs and walls of houses, where they will not interfere with anyone. And the effectiveness of such batteries is undeniable.

But The best way to increase the popularity of solar energy - to make it cheaper. German scientists have already proposed replacing silicon with synthetic fibers that can be integrated into fabrics or other materials. The efficiency of such a solar battery is not very high. But a shirt interspersed with synthetic fibers can at least provide electricity to a smartphone or player. Work is also actively carried out in the field of nanotechnology. Probably, they will allow the sun to become the most popular source of energy in this century. Specialists of Scates AS from Norway have already announced that nanotechnology will reduce the cost of solar panels by half.

Solar energy for home

Many people probably dream of housing that will provide for itself: there is no dependence on centralized heating, difficulties with paying bills and harm to the environment. Already, in many countries, housing is being actively built that consumes only energy obtained from alternative sources. A striking example- the so-called solar house.

During the construction process, it will require more investments than the traditional one. But on the other hand, after several years of operation, all costs will pay off - you will not have to pay for heating, hot water and electricity. In a solar home, all these communications are tied to special photovoltaic panels placed on the roof. Moreover, the energy resources obtained in this way are not only spent on current needs, but also accumulate for use at night and in cloudy weather.

Currently, the construction of such houses is carried out not only in countries close to the equator, where it is easiest to obtain solar energy. They are also being built in Canada, Finland and Sweden.

Advantages and disadvantages

The development of technologies for the widespread use of solar energy could be more active. But there are certain reasons why this is still not a priority. As we said above, during the production of panels, substances harmful to the environment are produced. In addition, the finished equipment contains gallium, arsenic, cadmium and lead.

The need to recycle photovoltaic panels also raises many questions. After 50 years of operation, they will become unusable and will have to be destroyed somehow. Will this not cause colossal harm to nature? It should also be borne in mind that solar energy is a fickle resource, the efficiency of which depends on the time of day and weather. And this is a significant drawback.

But, of course, there are pluses. Solar energy can be mined almost anywhere on Earth, and the equipment for generating and converting it can be small enough to fit on the back of a smartphone. More importantly, it is a renewable resource, that is, the amount of solar energy will remain unchanged for at least another thousand years.

Perspectives

The development of technologies in the field of solar energy should lead to a decrease in the cost of creating elements. Glass panels are already appearing that can be installed on windows. Advances in nanotechnology have made it possible to invent a paint that can be sprayed onto solar panels and can replace the silicon layer. If the cost of solar energy really drops several times, its popularity will also grow many times over.

The creation of small panels for individual use will allow people to use solar energy in any conditions - at home, in the car or even outside the city. Thanks to their distribution, the load on centralized power grids will decrease, since people will be able to charge small electronics on their own.

Shell experts believe that by 2040, about half of the world's energy will be generated from renewable resources. Already, in Germany, the consumption of solar energy is actively growing, and the capacity of the batteries is more than 35 Gigawatts. Japan is also actively developing this industry. These two countries are the leaders in the consumption of solar energy in the world. The United States is likely to join them soon.

Other alternative energy sources

Scientists never stop puzzling over what else can be used to generate electricity or heat. Here are some examples of the most promising alternative energy sources.

Windmills can now be found in almost any country. Even on the streets of many Russian cities, lanterns are installed that provide themselves with electricity from wind energy. Surely their prime cost is higher than average, but over time they will compensate this difference.

A long time ago, a technology was invented that allows you to get energy using the difference in water temperatures on the surface of the ocean and at depth. China is actively going to develop this direction. In the coming years, off the coast of the Middle Kingdom, they are going to build the largest power plant using this technology. There are other ways to use the sea. For example, Australia is planning to create a power plant that generates energy from the force of currents.

There are many others or heat. But against the background of many other options, solar energy is indeed a promising direction in the development of science.

The sun is one of the renewable alternative energy sources. Today, alternative heat sources are widely used in the agricultural sector and in the household needs of the population.

Harnessing the sun's energy on earth plays important role In human life. With the help of its heat, the sun, as a source of energy, heats the entire surface of our planet. Thanks to its thermal power, winds blow, seas, rivers, lakes are heated, all life on earth exists.

Renewable heat sources, people began to use many years ago, when modern technologies did not exist yet. The sun is the most affordable heat energy supplier on earth today.

Applications of solar energy

Every year the use of solar energy is gaining more and more popularity. A few years ago, it was used to heat water for country houses, summer showers, and now renewable heat sources are used to generate electricity and hot water supply for residential buildings and industrial facilities.

Today, renewable heat sources are used in the following areas:

• in the agricultural sector, for the purpose of supplying electricity and heating greenhouses, hangars and other buildings;
• for power supply of sports facilities and medical institutions;
• in the aviation and space industry;
• in the lighting of streets, parks, as well as other urban objects;
• for the electrification of settlements;
• for heating, power supply and hot water supply of residential buildings;
• for household needs.

Application features

The light that the sun emits on the earth is converted into thermal energy with the help of passive as well as active systems. Passive systems include buildings, in the construction of which such building materials are used that most efficiently absorb the energy of solar radiation. In turn, active systems include collectors that convert solar radiation into energy, as well as solar cells that convert it into electricity. Let's take a closer look at how to properly use renewable heat sources.

Passive systems

These systems include solar buildings. These are buildings built taking into account all the features of the local climatic zone. For their construction, such materials are used that make it possible to maximize the use of all thermal energy for heating, cooling, lighting residential and industrial premises. These include the following building technologies and materials: insulation, wooden floors, light-absorbing surfaces, and the building's orientation to the south.

Such solar systems make it possible to maximize the use of solar energy, moreover, they quickly recoup the costs of their construction by reducing energy costs. They are environmentally friendly and also allow you to create energy independence. It is because of this that the use of such technologies is very promising.

Active systems

This group includes collectors, accumulators, pumps, pipelines for heat supply and hot water supply in everyday life. The first ones are installed directly on the roofs of houses, and the rest are placed in basements in order to use them for hot water supply and heating.

Solar photovoltaic cells

In order to more effectively realize all solar energy, such solar energy sources as photocells, or, as they are also called, solar cells, are used. On their surface, they have semiconductors, which, when exposed to the rays of the sun, begin to move, and thereby generate an electric current. This principle of generating current does not contain any chemical reactions, which allows the photocells to work for a long time.

Photovoltaic converters such as solar energy sources are easy to use because they are lightweight, easy to maintain, and very efficient in using solar power.

Today, solar panels, as a source of energy from the sun on earth, are used to generate hot water supply, heating and to generate electricity in warm countries such as Turkey, Egypt and Asia. In our region, the solar energy source is used to supply electricity to autonomous power supply systems, low-power electronics and aircraft drives.

Solar collectors

The use of solar energy by collectors is that they convert radiation into heat. They are divided into the following main groups:

• Flat solar collectors. They are the most common. It is convenient to use them for domestic heating needs, as well as for heating water for hot water supply;
• Vacuum collectors. They are used for domestic needs when high temperature water is needed. They consist of several glass tubes, passing through which the rays of the sun heat them, and they, in turn, give off heat to the water;
• Air solar collectors. They are used for air heating, air mass recovery and drying plants;
• Integrated manifolds. Most simple models... They are used for preheating water, for example, for gas boilers. In everyday life, the heated water is collected in a special tank - accumulators and is then used for various needs.

The use of solar energy by collectors is carried out by storing it in so-called modules. They are installed on the roof of buildings and consist of glass tubes and plates, which, in order to absorb more volume sunlight, painted black.

Solar collectors are used to heat water for hot water supply and heating residential buildings.

Benefits of solar installations

• they are completely free and inexhaustible;
• have complete safety in use;
• autonomous;
• economical, since the expenditure of funds is carried out only for the purchase of equipment for installations;
• their use guarantees the absence of voltage surges, as well as stability in the power supply;
• durable;
• easy to use and maintain.

The use of solar energy with the help of such installations is gaining popularity every year. Solar panels make it possible to save a lot of money on heating and hot water supply, moreover, they are environmentally friendly and do not harm human health.

Today, the issue of providing mankind with energy resources is quite acute. Everyone knows that scientists have long been struggling to find alternative sources. It is sad that in recent years, at the household level, there has been no clear breakthrough in this industry. Our people are not available solar technology... Humanity has found many unconventional ways to obtain energy: geothermal stations, wave and tidal power plants, hydroelectric power plants, wind turbines, hydrogen and space energy, biofuels, and even a thunderstorm. This is an incomplete list of the finds of mankind.

Second place in alternative energy

The second place after wind turbines, in terms of the combination of advantages and disadvantages, was taken by the energy of the sun. An endless source that always remained before our eyes, although we have not yet learned how to use it effectively. In practice, silicon batteries are capable of demonstrating no more than 22% efficiency. They will show an efficiency of 75-80%, but they are used only as heating elements. Flat vacuum manifolds are more demanding on the conditions of use, the vacuum is more difficult to hold in such a large system, which is sensitive to body deformations.

Although we are most interested in the use of this source in heating. Many people do not mind heating their home using natural energy, and not at the expense of their wallet. Here the most unpleasant thing awaits us. The cost is so high that the alternative is no longer tempting.

Therefore, I propose to look at this problem from the side familiar to our person. Namely, to see how you can warm up without spending exorbitant amounts. It is difficult now to understand who first came up with the idea of ​​using beer in this way, but air collectors from beer cans are now being constructed in America, Europe, and indeed all over the world. They are equipped with a thermostat, microcontroller and additional pressurization. In your performance, it will be of the right size and much less cost. Although, if you drink beer on purpose, then I'm not sure about the latter.

DIY panels

Devices from aluminum cans

You don't need to be an experienced craftsman to create your first battery. You can still catch the energy of the sun. To do this, you will need a certain number of beer cans, several square meters of chipboard, approximately the same amount of insulation and silicone glue.

The ends of the cans are carefully opened along the collar. If desired, clean the outer surface for better adhesion and glue the pipes of the required length. After that, they are glued in rows into a box, the dimensions of which will tell the master the imagination and are painted black. Preferably heat-resistant paint.

All internal surfaces are insulated. We advise you to use extruded polystyrene foam, subsequently painted with black paint. And experiment with insulation. The pipes themselves, as a result, should be arranged vertically, and the upper and lower ends should be connected to each other, like battery registers.

DIY aluminum cans collector

Above and below, they make supply pipes, air intake, which will need to be brought into your home. Put a small cooler on the inlet, and a slightly modernized car thermostat or use another thermoregulation method on the hot outlet. Practice proves that it can be a good help for your heating system. The main thing is a high-quality, sealed assembly and location of the battery. From the front, cover the box with glass, or better with polycarbonate. According to the calculations of specialists, 15 square meters of collectors are needed to heat a house of 100 square meters. Such a wonderful alternative will be significantly inferior to industrial designs, but still ...

Parabolo - concentric mirror concentrator

In Europe, they are used, limited to only the perforated surface of aluminum alloys.

The cost of such heaters is high due to large sizes and expensive materials. Therefore, it is not worth considering homemade flat heat exchangers. The next option will interest suburban residents. Its difference is radical in almost everything. In fact, it is a parabolic-concentric mirror concentrator of the sun's energy. But the main benefit lies in the materials used. A concentrator is a mirror curved in one plane that concentrates the sun's rays at a certain point. Three tricks apply here.

Mirror material, reflective surface size and heat accumulator. A frightening curved mirror turns out to be made of mirror film. The mirror film is glued to the concave surface in the form of a groove. The basis for the mirror is to choose the same notorious polystyrene foam.

And as load-bearing structures, they will act various materials: from wood to metal. The required number of mirror segments is produced, which are attached to the supporting frames.

In a sense, the whole structure resembles a children's swing, where mirrors act instead of a seat, and a pipeline is located on the axis - a heat exchanger. Since this is a suburban solution, the dimensions here can be impressive.

Solar concentrator from a satellite dish

Water sun traps

A number of such devices are located along the movement of the sun. The mirror focuses in one line, from where the coolant will take power. The coolant will be ordinary water, which runs through thin-walled pipes running in several rows. Use stainless steel or regular thin-walled steel pipes of the correct diameter. With such a serious approach, this system cannot do without a dimensional heat accumulator.

There are ready-made solutions here, but a flight of imagination is welcome. For example, a “pool” for several cubes, made of polystyrene and wooden supports. The inner surface is lined with a dense greenhouse film. And the strength of the sides is expected to hold several cubes of water. A roof covering this mini-pool, in the shape of a pyramid, is also made of similar materials.

Such simplicity of design, coupled with uncomplicated materials, provide high maintainability. And replacement of worn-out parts. The cost will also vary significantly. It is better to place such a heat storage in an open space, this will provide easy access if necessary.

The mirror on the supporting structure must be able to be rotated vertically. In this case, the concentrator monitors the luminary all year round. The pipeline is included in the general heating system to save money.

Solar vacuum collector

Further, the rates begin to rise. Unfortunately, we are talking about the price. Their cost is quite high, although the efficiency is also quite high. It is impossible to make it yourself, because the production uses high-strength borosilicate glass with a low metal content.

A barium getter is used to control the vacuum. If the tightness is not broken, then the tube has a silvery color, if it turns white, then the integrity is broken. Vacuum collectors are less dependent on weather conditions than others, since the heat channel is separated from the atmosphere by vacuum. And the vacuum, as you know, is an excellent heat insulator. In bad weather, they absorb infrared radiation that passes through the clouds. Another plus in favor of this technology.

Types of vacuum collectors

There are several of them, some of them of a more successful design, but they are more expensive. The most successful is a collector with a feather tube and a direct-flow heat channel. The principle of the device is approximately the same in all cases. The flask is an elongated, thin thermos with a vacuum between its walls. A highly absorbent coating is applied to the inner glass, and a heat pipe with a coolant is placed inside.

Heat carriers are fundamentally different. In one case, it is an easily evaporating liquid, heat transfer occurs through evaporation and condensation. With a straight-through channel, the coolant flows through each of the heat pipes, transferring and releasing energy. The main disadvantage is the high price and difficulty in repair. In case of repair of some vacuum collectors, the coolant will have to be drained from the solar system. The difference in efficiency depending on the manufacturer is quite significant and can even be doubled.

With vacuum tubes, it is easier to assemble the system, since the main element is ready. It remains to ensure the contact of the copper absorber with the coolant of the entire system, and place the batteries from the vacuum tubes in a safe casing in an illuminated place. Of course, it is better to entrust the assembly and installation of a large system to specialists. A solar system with such elements often overheats and boils and needs some control over it. If your main heating has a large displacement and there will be no overheating, try assembling the auxiliary module yourself.

Homemade vacuum tubes

Silicon-based mining

The absorption classics are silicon-based batteries.

We divide them into three types:

• based on mono elements
• based on poly-elements
• amorphous, they are also film. They also include panels based on cadmium telluride, based on copper-indium selenide and polymer panels.

There are pros and cons here. The plus is that at the output we get electricity, the use of which is very wide. Polycrystalline panels have an average efficiency of 12-18% and are cheaper to manufacture. Monopanels, on the contrary, are more expensive and have a higher efficiency - 18-22%. Amorphous panels have the lowest efficiency of 5-6% but show a number of advantages. Optical absorption is 15-20 times higher than that of poly and single crystals. The thickness is less than 1 micron. Has good performance in cloudy weather, high flexibility. Polymer batteries are used where elasticity and environmental friendliness are of the greatest importance. In addition to the panels, charging systems, voltage transformations, and power distributors will be required. These are inverters, batteries, controllers. Silicon cells are sensitive to dirt, and when high temperatures a cooling system may be required, although modern designs provide for this.

More recently, Australian scientists have managed to set a record of 35% efficiency, a fundamentally new development in this area. Although the French claim to develop modules with an efficiency of 46%, by Soitec, CEA-Leti and the Fraunhofer Institute. But mere mortals will not see this for a long time. In addition, silicon batteries also have disadvantages. In America, the use of such panels began in the sixties, but our craftsmen seem to be making similarities from cheap analogs from the east for a long time. It's still too valuable a way to save money for common man... Although, it is very attractive to get a certain autonomy in the power supply.

There are also innovations in the automotive, aviation, and shipbuilding industries. Exhibition, single or experimental specimens exist, but so far, it remains a luxury. Sometimes, well-forgotten old things arise from the past, for example, lighting with the help of light wells. The method is familiar since the days of the gray pyramids.

Some want to bring the idea of ​​solar roads to life. There were transparent elements and an aircraft capable of flying around the earth on a light sail. Germany has set a record for the amount of energy received per day, and in India, an entire airfield has switched to feeding on natural resources. Surely the day is near when technology will allow us to take from the sun exactly as much as we need.

Solar energy gives life to all life on Earth. Under its influence, water evaporates from the seas and oceans, turning into water droplets, forming fogs and clouds. As a result, this moisture falls back to the Earth, creating a constant circulation. Therefore, we constantly observe snow, rain, frost or dew. The huge heating system created by the sun allows the most optimal distribution of heat over the Earth's surface. In order to correctly understand and use these processes, it is necessary to imagine the source of the sun's energy and what determines its influence on our planet.

Types of solar energy

The main type of energy released by the Sun is considered to be radiant energy, which has a direct impact on all the most important processes occurring on Earth. If we compare other terrestrial energy sources with it, then their reserves are infinitely small and do not allow solving all problems.

Of all the stars, the Sun is closest to the Earth. By its structure, it is a gaseous sphere, many times larger than the diameter and volume of our planet. Since the dimensions of the gas sphere are rather arbitrary, then the solar disk visible from the Earth is considered its boundaries.

Source and physical properties of solar energy

All processes occurring on the Sun can be observed only on its surface. However, the main reactions take place in its inner part. In fact, it is a giant nuclear power plant with a pressure of about 100 billion atmospheres. Here, under the conditions of complex nuclear reactions, hydrogen is converted into helium. It is these reactions that form the main source of energy for the sun. The internal temperature averages about 16 million degrees.

The gas raging inside the Sun is not only extremely hot, but also extremely heavy, with a density many times higher than the average solar density. At the same time, X-rays are generated, which, as they approach the Earth, increase their wavelength and decrease the frequency of oscillations. Thus, they gradually become visible and ultraviolet light.

With distance from the center, the nature of the radiant energy changes, influencing the temperature. At first, it gradually decreases to 150 thousand degrees. From the Earth, only the outer solar shell, the so-called photosphere, is clearly visible. Its thickness is about 300 km, and the temperature of the upper layer drops to 5700 degrees.

Above the photosphere is the solar atmosphere, which consists of two parts. The lower layer is called the chromosphere, and the upper layer, which has no boundaries, is the solar corona. Here gases are heated up to several million degrees under the influence of shock waves of monstrous force.

Solar radiation is absorbed by the land surface, the oceans (covering about 71% of the earth's surface) and the atmosphere. The absorption of solar energy through atmospheric convection, evaporation and condensation of water vapor, drives the water cycle and drives the winds. The sun's rays absorbed by the ocean and land maintain an average temperature at the Earth's surface, which is now 14 ° C. Through the photosynthesis of plants, solar energy can be converted into chemical energy, which is stored in the form of food, wood and biomass, which is eventually converted into fossil fuels.

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Prospects for use

Solar energy is a source of wind energy, water, heat of the seas, biomass, as well as the cause of the formation of peat, lignite and coal, oil and natural gas for thousands of years, but this indirect energy and accumulated over thousands and millions of years. The energy of the Sun can be used directly as a source of electricity and heat. To do this, it is necessary to create devices that concentrate the energy of the Sun in small areas and in small volumes.

The total amount of solar energy absorbed by the atmosphere, land and ocean surface is approximately 3,850,000 exajoules (EJ) per year. In one hour, this gives more energy than the whole world used in the whole 2002. Photosynthesis takes about 3,000 EJ per year for biomass production. The amount of solar energy that reaches the surface of the earth is so large that in a year it will approximately double all the energy that can potentially be generated from all non-renewable sources: coal, oil, uranium ores.

The amount of solar energy that a person can potentially use is different from the amount of energy that is near the earth's surface. Factors such as day and night cycles, cloudiness and available land surface reduce the amount of energy available for use.

Geographical location affects the energy potential, since the areas closer to the equator receive more solar radiation. However, the use of photovoltaic devices, which can change their orientation in accordance with the position of the Sun in the sky, can significantly increase the potential of solar energy in areas far from the equator.

The availability of land significantly affects the potential for energy production, since solar panels can only be installed on lands that are suitable for this and not used for other purposes. For example, a suitable place to install roof panels is steel.

Solar systems are divided into active and passive, depending on how they absorb, process and distribute solar energy.

Active solar technology uses photovoltaics, concentrated solar energy (English), solar collectors, pumps and fans to turn solar radiation into a useful energy output. Passive solar technologies include the use of materials with favorable thermal characteristics, the design of rooms with natural air circulation and the favorable positioning of buildings in relation to the position of the Sun. Active solar technologies increase energy supply, while passive solar technologies reduce the need for additional energy sources.

At this time, heating devices are working that accumulate the energy of the Sun, as well as prototypes of electric motors and cars that use the energy of the Sun.

Solar energy is believed to be no more than 1% of the total energy used by the end of the century. Back in 1870, a solar desalination plant was built in Chile sea ​​water, which produced up to 30 tons of fresh water per day and worked for over 40 years. Thanks to the use of heterojunctions, the efficiency of solar cells already reaches 25%. The production of solar cells in the form of a long polycrystalline silicon strip has been established, which have an efficiency of more than 10%.

Thermal energy

Technologies that use solar thermal energy can be used to heat water, heat rooms, cool rooms and generate process heat.

As of 2007, the total installed capacity solar systems for water heating was approximately 154 thermal GW. China is the world leader in this area, having installed 70 GW of thermal power as of 2006 and plans to reach 210 GW of thermal power by 2020. Israel and Cyprus are the world leaders in the use of solar water heating systems per capita with 90% of households that have installed them. In the USA, Canada and Australia, solar water heaters are used primarily for heating swimming pools, with an installed capacity of about 18 GW in 2005.

Heating, cooling and ventilation

Cooking

Solar ovens use sunlight for cooking, drying and pasteurization. They can be divided into three broad categories: box cookers, panel cookers and reflector cookers. The simplest solar oven is a box, which was first built by Horace Benedict de Saussure in 1767. A simple box oven consists of an insulated container with a transparent lid. It can be used effectively in partially cloudy skies and typically reaches temperatures of 90-150 ° C. The panel oven uses a reflective panel to direct the sun's rays onto an insulated container and reach temperatures comparable to that of a box oven. Reflective ovens use different reflector geometries (dish, trough, Fresnel mirrors) to focus the beams on the container. These ovens reach temperatures of 315 ° C, but require a direct beam and must be rearranged along with the changing position of the sun.

Process heat

Water treatment

Solar desalination can be used to turn salty or brackish water into drinking water. For the first time, an example of such a transformation was recorded by Arab alchemists of the 16th century. For the first time, a large-scale project from solar desalination was built in 1872 in the Chilean mining town of Las Salinas. The plant, which had a solar collector area of ​​4,700 m2, could produce up to 22,700 liters of drinking water and remained in operation for 40 years. Individual still designs include single-slope, double-slope (greenhouse or type), vertical, conical, inverted absorber, multi-wick, and multiple effect. ... These desalination plants can operate in passive, active and hybrid modes. Double-slope Kazan is the most cost-effective for decentralized domestic needs, while active multiple effect units are more suitable for large-scale projects.

Solar energy can be used in average rates for wastewater treatment without the use of chemicals and energy costs. Another environmental benefit is that algae live in such ponds and consume carbon dioxide during photosynthesis, although they can produce toxic substances that make the water unusable.

Power generation

Solar energy works by converting sunlight into electricity. This can happen either directly, using photovoltaics, or indirectly, using concentrated solar energy systems. (English) in which lenses and mirrors collect sunlight from a large area into a thin beam, and a tracking mechanism tracks the position of the sun. Photovoltaics converts light into electrical current using the photoelectric effect.

It is assumed that solar energy will become the largest source of electricity by 2050, in which photovoltaics and concentrated solar energy will account for 16 and 11% of global electricity production, respectively.

Commercial concentrated solar power plants first appeared in the 1980s. After 1985 installation of this type of SEGS (English) in the Mojave Desert (California) 354 MW has become the largest solar power plant in the world. Among other solar power plants of this type, the Solnova solar power plant (English)(150 MW) and SPP Andasol (English)(100 MW), both in Spain. Among the largest power plants on photovoltaic (English): Agua Caliente Solar Project (250 MW) in the USA, and Charanka Solar Park (221 MW) in India. Projects over 1 GW are under development, but most PV installations, up to 5 kW, are small and rooftop. As of 2013, solar energy accounted for less than 1% of the world's electricity.

Architecture and urban planning

The presence of sunlight has influenced the design of buildings from the very beginning of architectural history. Advanced solar architecture and urban planning techniques were first introduced by the ancient Greeks and Chinese, who oriented their homes south to provide light and warmth.

Agriculture and crop production

see also

Notes (edit)

1. Smil (1991), p. 240
2. Radiation and light mode
3. Natural Forcing of the Climate System. Intergovernmental Panel on Climate Change. Retrieved September 29, 2007.
4. Somerville, Richard. Historical Overview of Climate Change Science (PDF). Intergovernmental Panel on Climate Change. Retrieved September 29, 2007.
5. Vermass, Wim. An Introduction to Photosynthesis and Its Applications. Arizona State University. Retrieved September 29, 2007.
6. Smil (2006), p. 12
7. http://www.nature.com/nature/journal/v443/n7107/full/443019a.html
8. Powering the Planet: Chemical challenges in solar energy utilization (PDF). Retrieved August 7, 2008.
9. Energy conversion by organisms photosynthetic. Food and Agriculture Organization of the United Nations. Retrieved May 25, 2008.
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12. ... Renewable and Appropriate Energy Laboratory. Retrieved December 6, 2012.
13. Total Primary Energy Consumption. Energy Information Administration. Retrieved June 30, 2013.
14. Total Electricity Consumption Net. Energy Information Administration. Retrieved June 30, 2013.
15. Energy and the challenge of sustainability (PDF). UN Development Program and World Energy Council(September 2000). Retrieved January 17, 2017.