Solar energy as an alternative energy source: types and features of solar systems

The history of the development of solar energy

They tried to “tame” the sun back in the days of Archimedes. To this day, the legend of burning ships with the help of a huge mirror has survived - the residents of Syracuse directed a focused beam at the enemy fleet.

In the history of the development of solar energy, there are facts about the use of solar energy:

• for heating stone palaces;
• evaporation of sea water to produce salt.

Water heaters improved when Lavoisier used a lens to concentrate infrared rays. This was how iron was smelted. Later, the French began to use water heated to a state of steam for a mechanical drive to printing equipment. Scientists started talking about the prospects of solar energy after the creation of semiconductors. On their basis, the first photocells were created.

Development of non-traditional sources

Non-traditional energy sources include:

• energy of sun;
• wind energy;
• geothermal;
• energy of sea tides and waves;
• biomass;
• low-potential energy of the environment.

Their development seems possible due to the ubiquitous distribution of most species; one can also note their environmental friendliness and the absence of operating costs for the fuel component.

However, there are some negative qualities that prevent their use on an industrial scale. This is a low flux density, which forces the use of "intercepting" installations of a large area, as well as variability over time.

All this leads to the fact that such devices have a high material consumption, which means that capital investments also increase. Well, the process of obtaining energy due to some element of randomness associated with weather conditions causes a lot of trouble.

The other most important problem is the "storage" of this energy raw material, since the existing technologies for storing electricity do not allow this to be done in large quantities.However, in domestic conditions, alternative energy sources for the home are becoming increasingly popular, so let's get acquainted with the main power plants that can be installed in private ownership.

geothermal energy

Unexplored types of alternative energy sources lurk in the bowels of the globe. Mankind knows the strength and scale of natural manifestations. The power of the eruption of one volcano is incomparable with any of the man-made power plants.

Unfortunately, people still do not know how to use this gigantic energy for good, but the natural warmth of the Earth or geothermal energy attracts the attention of scientists, as it is an inexhaustible resource.

It is known that our planet annually radiates an enormous amount of internal heat, which is compensated by the radioactive decay of isotopes in the crust of the globe. There are two types of geothermal energy source.

Underground pools

These are natural pools with hot water or steam-water mixture - hydrothermal or steam-thermal sources. Resources from these sources are extracted through boreholes, then the energy is used for the needs of mankind.

Rocks

The heat from hot rocks can be used to heat water. To do this, it is pumped into horizons for further use for energy purposes.

One of the disadvantages of this type of energy is its weak concentration. However, in conditions where, when diving for every 100 meters, the temperature increases by 30-40 degrees, its economic use can be ensured.

The technology of using this energy in promising "geothermal areas" has clear advantages:

• inexhaustible reserves;
• ecological cleanliness;
• the absence of large costs for the development of sources.

Further development of civilization is impossible without the introduction of new technologies in the field of energy. On this path there are intractable tasks that humanity has yet to solve.

Nevertheless, the development of this direction plays an important role, and today there is already equipment that can significantly save resources. Traditional and alternative energy sources are an excellent alternative to them. To implement such ideas requires patience, skillful hands, as well as some skills and knowledge.

Design of a heating system on collectors

First of all, we will deal in detail with the differences in the structure and functioning of batteries and collectors.

The panel consists of several solar cells interconnected on a frame made of non-conductive energy materials.

Photovoltaic converters are quite complex structures, which are a kind of sandwich of plates with different characteristics and purposes.

In addition to solar modules and special fasteners, the system consists of the following elements:

• batteries, for energy storage;
• a controller that will monitor the degree of charge in the battery;
• inverter - to convert direct current to alternating current.

Collectors are of two types: vacuum and flat.

Vacuum collectors consist of hollow glass tubes with smaller diameter tubes inside containing an energy absorber. Smaller tubes are connected to the coolant. In the free space between them is a vacuum that retains heat.

The principle of operation of the solar collector

Flat-plate collectors consist of a frame and reinforced glass with a photoabsorbing layer.The absorber layer is connected to the tubes with the coolant.

Both of these systems consist of a heat exchange circuit and a heat accumulator (liquid tank).

From the tank, water enters the heating system using a pump. To avoid heat loss, the tank must be well insulated.

Such installations should be located on the southern slope of the roof. The angle of inclination should be 30-45 degrees. If the location of the house or the structure of the roof does not allow installing solar panels on the roof, then you can install them on special reinforced frames or on racks fixed to the wall.

The amount of solar energy released at different times of the year varies greatly. The value of the insolation coefficient for your place of residence can be found on the map of solar activity. Knowing the insolation coefficient, you can calculate the number of modules you need.

For example, you consume energy 8 kW/h, insolation is on average 2 kW/h. Solar panel power - 250 W (0.25 kW). Let's make the calculations: 8 / 2 / 0.25 \u003d 16 pieces - this is the number of panels you will need.

Biogas plants

The gas is formed as a result of the processing of waste products of poultry and animals. Recycled waste is used to fertilize the soil in household plots. The process is based on a fermentation reaction involving bacteria living in manure.

Cattle manure is considered to be the best source of biogas, although waste from birds or other livestock is also suitable.

Fermentation occurs without access to oxygen, so it is advisable to use closed containers, which are also called bioreactors.The reaction is activated if the mass is periodically mixed, for this manual labor or various electromechanical devices are used.

It will also be necessary to maintain the temperature in the installation from 30 to 50 degrees to ensure the activity of mesophilic and thermophilic bacteria and their participation in the reaction.

Construction manufacturing

The simplest biogas plant is a stirred barrel with a lid. Gas from the barrel enters the tank through a hose, a hole is made in the lid for this purpose. This design provides gas to one or two gas burners.

To obtain large-scale volumes of gas, an above-ground or underground bunker is used, which is made of reinforced concrete. It is advisable to divide the entire container into several compartments in order for the reaction to occur with a shift in time.

The container is not completely filled with mass, by about 20 percent, the rest of the space serves to accumulate gas. Two tubes are connected to the lid of the container, one is led to the consumer, and the other to the water seal - a container filled with water. This ensures gas purification and drying, high quality gas is supplied to the consumer.

Is everything so smooth?

It would seem that such a technology for power supply of a private house should have long been forced out of the market by traditional centralized methods of providing energy. Why doesn't this happen? There are several arguments that testify not in favor of alternative energy. But their significance is determined on an individual basis - for some owners of country houses, some shortcomings are relevant and others are not at all of interest.

For large country cottages, the not too high efficiency of alternative energy installations can become a problem. Naturally, local solar systems, heat pumps or geothermal installations cannot be compared with the productivity of even the oldest hydroelectric power plants, thermal power plants, and even more so nuclear power plants. However, this drawback is often minimized by installing two or even three systems, using more power. The consequence of this may be another problem - for their installation, a larger area will be required, which is not possible to allocate in all house projects.

To ensure the uninterrupted supply of the number of household appliances and the heating system familiar to a modern home, a lot of power is required. Therefore, the project should provide for such sources that can produce such power. And this requires a solid investment - the more powerful the equipment, the more expensive it is.

In addition, in some cases (for example, when using wind energy), the source may not guarantee the constancy of energy production. Therefore, it is necessary to equip all communication with storage devices. Usually, batteries and collectors are installed for this purpose, which entails all the same additional costs and the need to allocate more square meters in the house.

The principle of operation of a solar power plant at home

A solar power plant is a system consisting of panels, an inverter, a battery and a controller. The solar panel transforms radiant energy into electricity (as mentioned above). Direct current enters the controller, which distributes the current to consumers (for example, a computer or lighting).An inverter converts direct current into alternating current and powers most electrical household appliances. The battery stores energy that can be used at night.

Video description

A good example of calculations showing how many panels are needed to provide an autonomous power supply, see this video:

How solar energy is used to generate heat

Solar systems are used for water heating and home heating. They can provide heat (at the request of the owner) even when the heating season is over, and provide the house with hot water for free. The simplest device is metal panels that are installed on the roof of the house. They accumulate energy and warm water, which circulates through pipes hidden under them. The functioning of all solar systems is based on this principle, despite the fact that they may be structurally different from each other.

Solar collectors consist of:

• storage tank;
• pumping station;
• controller
• pipelines;
• fittings.

According to the type of construction, flat and vacuum collectors are distinguished. In the former, the bottom is covered with heat-insulating material, and the liquid circulates through glass pipes. Vacuum collectors are highly efficient because heat losses are kept to a minimum. This type of collector provides not only heating with solar panels of a private house - it is convenient to use it for hot water supply systems and heating pools.

The principle of operation of the solar collector

Popular manufacturers of solar panels

Most often, products of Yingli Green Energy and Suntech Power Co. are found on the shelves.HiminSolar panels (China) are also popular. Their solar panels produce electricity even in rainy weather.

The production of solar batteries has also been established by a domestic manufacturer. The following companies do this:

• Hevel LLC in Novocheboksarsk;
• "Telecom-STV" in Zelenograd;
• Sun Shines (LLC Autonomous Lighting Systems) in Moscow;
• OJSC "Ryazan Plant of Metal-Ceramic Instruments";
• CJSC "Termotron-zavod" and others.

You can always find a suitable option for the price. For example, in Moscow for solar panels for a home, the cost will vary from 21,000 to 2,000,000 rubles. The cost depends on the configuration and power of the devices.

Solar panels are not always flat - there are a number of models that focus light at one point

Battery Installation Steps

1. To install the panels, the most illuminated place is selected - most often these are the roofs and walls of buildings. In order for the device to function as efficiently as possible, the panels are mounted at a certain angle to the horizon. The level of darkness of the territory is also taken into account: surrounding objects that can create a shadow (buildings, trees, etc.)
2. Panels are installed using special fastening systems.
3. Then the modules are connected to the battery, controller and inverter, and the whole system is adjusted.

For the installation of the system, a personal project is always developed, which takes into account all the features of the situation: how the installation will be carried out solar panels on roof of the house, price and terms. Depending on the type and scope of work, all projects are calculated on an individual basis. The client accepts the work and receives a guarantee for it.

Installation of solar panels must be carried out by professionals and in compliance with safety measures.

As a result - the prospects for the development of solar technologies

If on Earth the most efficient operation of solar panels is hindered by air, which to a certain extent scatters the radiation of the Sun, then in space there is no such problem. Scientists are developing projects for giant orbiting satellites with solar panels that will operate 24 hours a day. From them, the energy will be transmitted to ground receiving devices. But this is a matter of the future, and for existing batteries, efforts are directed towards improving energy efficiency and reducing the size of devices.

geothermal energy

Unexplored types of alternative energy sources lurk in the bowels of the globe. Mankind knows the strength and scale of natural manifestations. The power of the eruption of one volcano is incomparable with any of the man-made power plants.

Unfortunately, people still do not know how to use this gigantic energy for good, but the natural warmth of the Earth or geothermal energy attracts the attention of scientists, as it is an inexhaustible resource.

It is known that our planet annually radiates an enormous amount of internal heat, which is compensated by the radioactive decay of isotopes in the crust of the globe. There are two types of geothermal energy source.

Underground pools

These are natural pools with hot water or steam-water mixture - hydrothermal or steam-thermal sources. Resources from these sources are extracted through boreholes, then the energy is used for the needs of mankind.

Rocks

The heat from hot rocks can be used to heat water. To do this, it is pumped into horizons for further use for energy purposes.

One of the disadvantages of this type of energy is its weak concentration. However, in conditions where, when diving for every 100 meters, the temperature increases by 30-40 degrees, its economic use can be ensured.

The technology of using this energy in promising "geothermal areas" has clear advantages:

• inexhaustible reserves;
• ecological cleanliness;
• the absence of large costs for the development of sources.

Further development of civilization is impossible without the introduction of new technologies in the field of energy. On this path there are intractable tasks that humanity has yet to solve.

Nevertheless, the development of this direction plays an important role, and today there is already equipment that can significantly save resources. Traditional and alternative energy sources are an excellent alternative to them. To implement such ideas requires patience, skillful hands, as well as some skills and knowledge.

Types of alternative energy

Depending on the source of energy, which, as a result of transformation, allows a person to receive electrical and thermal energy used in everyday life, alternative energy is classified into several types that determine the methods of its generation and the types of installations serving for this.

Energy of sun

Solar energy is based on the conversion of solar energy, which results in electrical and thermal energy.

The production of electrical energy is based on physical processes occurring in semiconductors under the influence of sunlight, the production of thermal energy is based on the properties of liquids and gases.

To generate electrical energy, solar power plants are completed, the basis of which are solar batteries (panels) made on the basis of silicon crystals.

The basis of thermal installations are solar collectors, in which the energy of the sun is converted into thermal energy of the coolant.

The power of such installations depends on the number and power of individual devices that are part of thermal and solar stations.

Wind energy

Wind energy is based on the conversion of the kinetic energy of air masses into electrical energy used by consumers.

The basis of wind turbines is a wind generator. Wind generators differ in technical parameters, overall dimensions and design: with a horizontal and vertical axis of rotation, different types and numbers of blades, as well as their location (land, sea, etc.).

water power

Hydropower is based on the conversion of the kinetic energy of water masses into electrical energy, which is also used by man for his own purposes.

The objects of this type include hydroelectric power plants of various capacities, installed on rivers and other water bodies. In such installations, under the influence of the natural flow of water, or by creating a dam, water acts on the blades of a turbine that generates electricity. The hydroturbine is the basis of hydroelectric power plants.

Another way to obtain electrical energy by converting the energy of water is the use of tidal energy, through the construction of tidal stations. The operation of such installations is based on the use of the kinetic energy of sea water during the tides occurring in the seas and oceans under the influence of solar system objects.

The warmth of the earth

Geothermal energy is based on the conversion of heat radiated by the earth's surface, both in places where geothermal waters are released (seismically hazardous areas), and in other regions of our planet.

For the use of geothermal waters, special installations are used, through which the internal heat of the earth is converted into thermal and electrical energy.

Using a heat pump allows you to get heat from the surface of the earth, regardless of its location. His work is based on the properties of liquids and gases, as well as the laws of thermodynamics.

biofuel

Types of biofuels differ in the ways they are obtained, their state of aggregation (liquid, solid, gaseous) and types of use. The indicator that unites all types of biofuels is that the basis for their production is organic products, through the processing of which electrical and thermal energy is obtained.

Solid types of biofuels are firewood, fuel briquettes or pellets, gaseous ones are biogas and biohydrogen, and liquid ones are bioethanol, biomethanol, biobutanol, dimethyl ether and biodiesel.

Pros and cons of solar power plants

Advantages:

• Solar energy is a renewable energy source. At the same time, it is publicly available and free of charge.
• Solar installations are quite safe to use.
• Such power plants are completely autonomous.
• They are economical and have a fast payback period. The main costs occur only for the necessary equipment and require minimal investment in the future.
• Another distinguishing feature is stability in work. There are practically no power surges at such stations.
• They are not whimsical in maintenance and are quite easy to use.
• Also, for SPP equipment, a characteristic long operating period is characteristic.

Flaws:

• As a source of energy, the solar system is very sensitive to climate, weather conditions and time of day. Such a power plant will not operate efficiently and productively at night or on a cloudy day.
• Lower productivity in latitudes with strong seasons. They are most effective in areas where the number of sunny days per year is closest to 100%.
• Very high and inaccessible cost of equipment for solar installations.
• The need for periodic cleaning of panels and surfaces from contamination. Otherwise, less radiation is absorbed and productivity drops.
• A significant increase in air temperature within the power plant.
• The need to use the terrain with a huge area.
• Further difficulties in the process of disposal of plant components, in particular photocells, after the end of their service life.

As in any industrial field, solar energy processing and conversion has its strengths and weaknesses.

It is very important that the advantages cover the disadvantages, in which case the work will be justified.

Today, most of the developments in this industry are aimed at optimizing and improving the functioning and use of existing methods and at developing new ones that are safer and more productive.

The expediency of using a solar system

Solar system - a complex for converting solar radiation energy into thermal energy, which is subsequently transferred to a heat exchanger to heat the coolant of a heating or water supply system.

The efficiency of a solar thermal installation depends on solar insolation - the amount of energy received during one day of light per 1 sq.m of a surface located at an angle of 90 ° relative to the direction of the sun's rays. The measuring value of the indicator is kWh / sq.m, the value of the parameter varies depending on the season.

The average level of solar insolation for a region with a temperate continental climate is 1000-1200 kWh/sq.m (per year). The amount of sun is the determining parameter for calculating the performance of a solar system.

The use of an alternative energy source allows you to heat the house, get hot water without traditional energy costs - exclusively through solar radiation

Installing a solar heating system is an expensive undertaking. In order for capital expenditures to justify themselves, an accurate calculation of the system and adherence to installation technology is necessary.

Example. The average value of solar insolation for Tula in the middle of summer is 4.67 kV / sq. m * day, provided that the system panel is installed at an angle of 50 °. The performance of a solar collector with an area of ​​5 sq.m is calculated as follows: 4.67 * 4 = 18.68 kW of heat per day. This volume is enough to heat 500 liters of water from a temperature of 17°C to 45°C.

As practice shows, when using a solar installation, cottage owners in the summer can completely switch from electric or gas water heating to the solar method

Speaking about the advisability of introducing new technologies, it is important to take into account the technical features of a particular solar collector. Some start with 80W/sq.m of solar energy, others start with 20W/sq.m

Even in a southern climate, using a collector system solely for heating will not pay off. If the installation is used exclusively in winter with a shortage of sun, then the cost of equipment will not be covered even for 15-20 years.

In order to use the solar complex as efficiently as possible, it must be included in the hot water supply system. Even in winter, the solar collector will allow you to "cut" energy bills for water heating up to 40-50%.

According to experts, for domestic use, the solar system pays off in about 5 years. With an increase in electricity and gas prices, the payback period of the complex will be reduced

In addition to the economic benefits, "solar heating" has additional advantages:

1. Environmental friendliness. Reduced carbon dioxide emissions. For a year, 1 sq.m of a solar collector prevents 350-730 kg of mining from entering the atmosphere.
2. Aesthetics. The space of a compact bath or kitchen can be saved from bulky boilers or gas water heaters.
3. Durability. Manufacturers claim that if the installation technology is followed, the complex will last about 25-30 years. Many companies provide a guarantee of up to 3 years.

Arguments against the use of solar energy: pronounced seasonality, dependence on the weather and high initial investment.

Numerical characteristics of solar radiation

There is such an indicator as the solar constant. Its value is 1367 watts. This is the amount of energy per 1 sq.m. planet Earth. That's just about 20-25% less energy reaches the surface of the earth due to the atmosphere. Therefore, the value of solar energy per square meter, for example, at the equator is 1020 watts. And I take into account the change of day and night, the change in the angle of the sun above the horizon, this figure decreases by about 3 times.

But where does this energy come from? Scientists first began to deal with this issue back in the 19th century, and the versions were completely different. Today, as a result of a huge number of studies, it is reliably known that the source of solar energy is the reaction of the transformation of 4 hydrogen atoms into a helium nucleus. As a result of this process, a significant amount of energy is released. For example, the energy released during the transformation of 1 gr. hydrogen is comparable to the energy that is released during the combustion of 15 tons of gasoline.

Heat pumps for home heating

Heat pumps use all available alternative energy sources. They take heat from water, air, soil. In small quantities, this heat is there even in winter, so the heat pump collects it and redirects it to heating the house.

Heat pumps also use alternative energy sources - the heat of the earth, water and air

Principle of operation

Why are heat pumps so attractive? The fact that having spent 1 kW of energy for its pumping, in the worst case, you will receive 1.5 kW of heat, and the most successful implementations can give up to 4-6 kW.And this does not contradict the law of conservation of energy in any way, because energy is spent not on obtaining heat, but not on pumping it. So no inconsistencies.

Scheme of a heat pump for the use of alternative energy sources

Heat pumps have three working circuits: two external and they are internal, as well as an evaporator, a compressor and a condenser. The scheme works like this:

• A coolant circulates in the primary circuit, which takes heat from low-potential sources. It can be lowered into water, buried in the ground, or it can take heat from the air. The highest temperature reached in this circuit is around 6°C.
• The internal circuit circulates a heating medium with a very low boiling point (typically 0°C). When heated, the refrigerant evaporates, the vapor enters the compressor, where it is compressed to high pressure. During compression, heat is released, the refrigerant vapor is heated to an average temperature of +35°C to +65°C.
• In the condenser, heat is transferred to the coolant from the third - heating - circuit. Cooling vapors are condensed, then further enter the evaporator. And then the cycle repeats.

The heating circuit is best done in the form of a warm floor. Temperatures are the best for this. The radiator system will require too many sections, which is ugly and unprofitable.

Alternative sources of thermal energy: where and how to get heat

But the biggest difficulty is the device of the first external circuit, which collects heat. Since the sources are low-potential (there is little heat at the bottom), large areas are required to collect it in sufficient quantities. There are four types of contours:

• Rings laid in water pipes with a coolant.The body of water can be anything - a river, a pond, a lake. The main condition is that it should not freeze through even in the most severe frosts. Pumps that pump heat out of the river work more efficiently; much less heat is transferred in stagnant water. Such a heat source is the easiest to implement - throw pipes, tie a load. There is only a high chance of accidental damage.

• Thermal fields with pipes buried below freezing depth. In this case, there is only one drawback - large volumes of earthworks. We have to remove the soil over a large area, and even to a solid depth.

• Use of geothermal temperatures. A number of wells of great depth are drilled, and coolant circuits are lowered into them. What is good about this option is that it requires little space, but not everywhere it is possible to drill to great depths, and drilling services cost a lot. You can, however, make a drilling rig yourself, but the work is still not easy.

• Extraction of heat from the air. This is how air conditioners with the possibility of heating work - they take heat from the "outboard" air. Even at sub-zero temperatures, such units work, though at a not very “deep” minus - up to -15 ° C. To make the work more intensive, you can use the heat from the ventilation shafts. Throw a few slings with coolant there and pump heat from there.

The main disadvantage of heat pumps is the high price of the pump itself, and the installation of heat collection fields is not cheap. In this case, you can save money by making the pump yourself and also laying the contours with your own hands, but the amount will still remain considerable. The advantage is that heating will be inexpensive and the system will operate for a long time.

Kinds

Today, various types of solar panels are gaining more and more popularity. At first glance, it may seem that all solar modules are the same: a large number of individual small solar cells are interconnected and covered with a transparent film. But, in reality, all modules differ in power, design and size. And at the moment, manufacturers have divided solar systems into two main types: silicon and film.

For domestic purposes, solar panels with silicon photocells are installed. They are the most popular on the market. Of which three types can also be distinguished - these are polycrystalline, single-crystal, they have already been described in more detail in the article, and amorphous, which we will dwell on in more detail.

Amorphous - are also made on the basis of silicon, but, in addition, they also have a flexible elastic structure. But they are not made from silicon crystals, but from silane - another name for silicon hydrogen. Of the features of amorphous modules, one can note excellent efficiency even in cloudy weather and the ability to repeat any surface. But the efficiency is much lower - only 5%.

The second type of solar panels - film, is produced on the basis of several substances.

• Cadmium - such panels were developed back in the 70s of the last century and were used in space. But today cadmium is also used in the production of industrial and domestic solar power plants.
• Modules based on semiconductor CIGS - developed from copper selenide, indium and are film panels. Indium is also widely used in the manufacture of liquid crystal monitors.
• Polymer - also used in the production of solar film modules. The thickness of one panel is about 100 nm, but the efficiency remains at the level of 5%. But from the pluses it can be noted that such systems have an affordable price and do not emit harmful substances into the atmosphere.

But also today, less bulky portable models are on the market. They are specially designed for use during outdoor activities. Often, such solar panels are used to recharge portable devices: small gadgets, mobile phones, cameras and camcorders.

Portable modules are divided into four types.

• Low-power - give a minimum charge, which is enough to recharge a mobile phone.
• Flexible - can be folded into a roll and have a small weight, due to this, and due to the great popularity among tourists and travelers.
• Fixed on a substrate - they have a much greater weight, about 7-10 kg and, accordingly, give more energy. Such modules are specially designed for use on long-distance car trips, and can also be used to partially autonomously supply energy to a country house.
• Universal - indispensable for hiking, the device has several adapters for simultaneous charging of various devices, the weight can reach 1.5 kg.

Is it suitable for an ordinary home

• For domestic use, solar energy is a promising type of energy.
• As a source of electrical energy for residential buildings, solar power stations are used, which are produced by industrial enterprises in Russia and abroad. Installations are issued various power and a complete set.
• The use of a heat pump - will provide a residential building with hot water, heat the water in the pool, heat the coolant in the heating system or the air inside the premises.
• Solar collectors - can be used in home heating and hot water systems. More efficient, in this case, vacuum tube collectors.