§25. The process of energy conversion in electrical machines. their modes of operation. Direct energy conversion Electricity conversion
An electrical product (device) that converts electrical energy with one parameter value and (or) quality indicators into electrical energy with other parameter values and (or) quality indicators. Note.… …
Electrical energy converter- 4. Electric energy converter Converter Electric power converter An electrical product (device) that converts electrical energy with the same values of parameters and (or) quality indicators into electrical energy with ... ...
electrical energy converter,- 2 electrical energy converter, electrical energy converter: An electrical device that converts electrical energy with one parameter value and / or quality indicators into electrical energy with other values ... ... Dictionary-reference book of terms of normative and technical documentation
Electrical energy converter- - an electrical product (device) that converts electrical energy with one parameter value and (or) quality indicators into electrical energy with other parameter values \u200b\u200band (or) quality indicators. GOST 18311 80 ... Commercial power industry. Dictionary-reference
Electrical energy converter- 1. An electrical product (device) that converts electrical energy with one parameter value and (or) quality indicators into electrical energy with other parameter values \u200b\u200band (or) quality indicators Used in ... ... Telecommunication dictionary
Electric energy converter (Electricity converter)- English: Electricity converter An electrical product (device) that converts electrical energy with one parameter value and (or) quality indicators into electrical energy with other parameter values \u200b\u200band (or) indicators ... ... Construction dictionary
GOST R 54130-2010: Quality of electrical energy. Terms and Definitions- Terminology GOST R 54130 2010: Quality of electrical energy. Terms and definitions original document: Amplitude die schnelle VergroRerung der Spannung 87 Term definitions from various documents: Amplitude die schnelle VergroRerung der… … Dictionary-reference book of terms of normative and technical documentation
Converters of thermal plasma energy into electrical energy. energy. There are two types P. and. e. e. magnetohydrodynamic generator and thermionic converter. Physical Encyclopedic Dictionary. Moscow: Soviet Encyclopedia. Chief Editor … Physical Encyclopedia
Converters of thermal energy of plasma (See Plasma) into electrical energy. There are 2 types P. and. e. e. Magnetohydrodynamic generator and Thermionic transducer … Great Soviet Encyclopedia
frequency converter- frequency converter An alternating current electrical energy converter that converts electrical energy with a frequency change [OST 45.55 99] EN frequency converter electric energy ... ... Technical Translator's Handbook
CONVERSION OF ELECTRIC ENERGY INTO OTHER TYPES OF ENERGY In an electrical circuit, electrical energy is simultaneously received in the source and converted into another form of energy; in the receiver. The type of receiver is chosen in accordance with the type of non-electrical energy required for practical purposes. Let us consider the principles of converting electrical energy into thermal, light and chemical; the question of converting electrical energy into mechanical energy is considered in § 10. Transformation of electrical energy into thermal energy The physical process of converting electrical 3Heprf into thermal energy is considered in § 2.2. We express the amount of released heat in terms of voltage and current. "potentials U, the charge of the displaced particles Q = h. Pa3o ° epgy of the electric field expended on the movement of Valuable particles, according to (1.5), charge W0 = UQ = Uit. manifestations of this work Observed. Therefore, the energy W3 can be considered equal to the thermal energy of the receiver: W„ = W, = Ult. r in this formula, the energy is expressed in joules. According to Ohm's law [see formula (2.6)], U = IR, then W„ \u003d I2Rt. Formula (3.10) is a mathematical expression of the Lenz-Joule law. The amount of electrical energy converted in a conductor per unit time into thermal energy is proportional to the square of the current and the electrical resistance of the conductor. I The rate of conversion of electrical energy into another form of energy in the receiver is called power receiver: Pp \u003d W „lt \u003d UI. [This formula is valid for any receiver, regardless of the type of energy that results from the conversion. [If electrical energy is completely converted into thermal energy, then the power of the receiver can be expressed through the current in (the conductor and its resistance: (3.12) V The phenomenon of conversion in conductors of electrical energy-? Pg) And into thermal energy is widely used in practice. The operation of most electrical industrial and domestic heating devices is based on this principle. The conversion of electrical energy into light Le>) "^ Principle of the conversion of electrical energy into thermal energy Nor is also the basis for the operation of electric incandescent lamps. Г> a lamp made of refractory metal At a high temperature of the lamp filament, part of the energy is emitted in the form of light energy, which in the general flow the energy emitted by the lamp is less than 10%. Conversion of electrical energy into chemical energy The battery during charging or an electrolytic van are receivers of electrical energy. The EMF of the battery El, when charging, retains the same direction as when discharging; the current in the battery changes its direction to the opposite, since it is determined not by the direction of the battery EMF, but by the EMF E of an external power source (Fig. 3.9). The EMF of the battery El charging is directed against the current and therefore called the counter-EMF. The movement of charged particles during charging is carried out as a result of the action of an electric field that is created by a power source. Are the forces of the electric field at any moment in time chemically balanced? (external) forces, therefore, the work of electric forces per unit charge can be equated to the counter-EMF El. Then the energy spent on charging, W„ = E,Q = EaIt, and the power consumption of electrical energy Pn=WJt=EaI. (3.13 (3.14) The formulas expressing the energy and power when discharging * and charging the battery are the same. However, one must not forget about the physical difference between the processes: in the first case, the battery is a source, and in the second case, a receiver of electrical energy. When converting electrical energy into thermal resistance is due to particle collisions. In the transformation of electrical energy into chemical resistance to the current, there are external forces. This explains the difference in expressions (3.11) and (3.14), which quantitatively determine the rate of conversion of electrical energy into another form of energy. The power of an electric iron 300 W at 120 V. Determine the current and resistance of the heating element Problem 3.10. A DC motor is connected to a network with a voltage of 220 V. The mechanical power on the motor shaft is 8.4 kW, the efficiency is 84%. Determine the electrical power and current of the motor. j Task 3.11 To charge the battery at a current / = 4 A, a voltage at the external terminals of the source U = 30 V, time f = 6 hours is spent. in the battery and connector-s * wires. The EMF of the battery and the charging current are assumed to be unchanged during the I “row.
Direct use of natural energy sources.
Steam engine conversion
Electricity Conversion
Energy conversion in industrial energy
As mentioned above, electricity generation is a separate industry. Currently, the largest share of electricity is produced at three types of power plants:
1. HPP (hydroelectric power plant)
2. TPP (thermal power plant)
3. NPP (nuclear power plant)
Consider the transformation of energy at these types of power plants:
hydroelectric power station
CHP
When using the thermal energy of steam in the energy conversion chain, it becomes possible to use part of the thermal energy for heating (shown by a dotted line) or for production needs.
NPP (with a single-loop reactor)
Thermal circuit.
Basic concepts
Earlier, we considered the types of energy and the possibilities of its transformation from one type to another, we will dwell in more detail on thermal energy, since it plays a very important role in the processes taking place at nuclear power plants.
As mentioned earlier, thermal energy is the energy of the chaotic movement of molecules or atoms in liquids and gases and the vibrational movement of molecules or atoms in a solid. The higher the speed of this movement, the more thermal energy the body has.
In our daily life, we all encounter the processes of transferring thermal energy from one body to another (hot tea heats a glass, a heating radiator in an apartment heats air, etc.) Based on the definition of thermal energy, we can define heat transfer.
Definition: The process of energy transfer as a result of the exchange of chaotic movement of molecules, atoms or microparticles is called heat exchange.
It is known from everyday experience that thermal energy or heat is transferred from a hotter body to a colder one, and it seems quite logical to take temperature as a measure of thermal energy, but this is a gross mistake. Body temperature is a measure of the ability to exchange heat with surrounding bodies. Knowing the temperatures of two bodies, we can only say about the direction of heat transfer. A body with a higher temperature will give off heat and cool down, and a body with a lower temperature will receive heat and heat up, however, it is impossible to determine the amount of energy transferred based on temperature alone. You don't have to look far for an example: try pouring an equal amount of boiling water into an aluminum mug and a ceramic mug. Aluminum will heat up almost instantly, almost without cooling the water, and ceramics will heat up much less and much longer, and the initial temperature of boiling water in both cases is 100 ° C. The conclusion follows: for heating different substances to the same temperature, different amounts of thermal energy are needed , each substance has its own heat capacity
Definition:The specific heat capacity of a substance is the amount of energy required to heat one kilogram of a given substance by one degree.
where: Q-energy; C - heat capacity; m - mass; dT heating;
Heat transfer methods.
As a rule, in industrial power plants, the process of converting source energy into thermal energy takes place in one place (a boiler for a thermal power plant, a reactor for a nuclear power plant), and the process of converting thermal energy into mechanical energy and then into electrical energy in another, therefore, the problem of moving thermal energy in space arises. How can heat energy be transferred from one point in space to another?
Thermal conductivity
When heating one end of a metal wire, one can notice that the temperature rises along the entire length, and the shorter the wire, the faster the opposite, not directly heated, part will heat up. By heating the wire on one side, we force the atoms and electrons at the place of heating to oscillate more strongly, the oscillating atoms and electrons involve neighboring atoms and electrons in oscillation, and the thermal energy propagates in a solid body, in our case in a metal wire. This method of transferring heat energy is called heat conduction.
Definition: Thermal conductivity is a process of heat transfer in a continuous medium through the chaotic movement of microparticles.
The amount of heat transferred due to thermal conductivity depends on the physical properties of the medium in which the heat exchange takes place. Each substance has its own coefficient of thermal conductivity l (A metal rod about a meter long, placed at one end in a fire, cannot be held in bare hands, a wooden stick of the same shape will burn more than half before it heats up to any significant extent).
The greater the temperature difference dT between the hot and cold points of the medium, the greater the amount of heat transferred per unit of time. The larger the cross-sectional area, the greater the amount of heat transferred per unit of time.
Probably everyone knows how to boil water with a fire in a wooden bowl. It is necessary to throw stones heated in the fire into the water. Heated stones are immediately wetted by water and give it their warmth. The process of heat transfer from stones to the water surrounding them is similar to thermal conductivity, but the distribution of thermal energy over the volume of water is of a different nature.
Convective heat transfer
Consider what happens in the volume of cold water when hot stones heat up part of it around them. It is known from physics that when heated, bodies expand, in other words, increase their volume, and since the mass remains constant, the density decreases. According to the law of Archimedes, a body with a density greater than the density of a liquid sinks, and with a smaller one it floats. The same
we can say about a heated liquid, having a lower density, it will begin to rise, mixing with cold layers in the upper part of the vessel, which, in turn, will begin to fall, after a while the temperature throughout the volume will become the same.
Definition:Convective heat transfer- heat transfer during mixing of more heated particles of the medium with less heated ones.
In the example above, the movement was caused by the difference in densities of the hot and cold parts of the liquid, such convection is called natural or free. If the movement is caused by the operation of a pump or fan, then convection is called forced.
Convective heat transfer occurs in gases in the same way as in liquids.
In many modern nuclear power plants, heat is removed from the reactor by forced pumping of water, gas, or liquid metal through the core. The substance that absorbs heat from a source is called a heat transfer fluid.
Heat transfer by radiation
Experiments show that heat exchange between bodies is possible even if they are in a vacuum without touching each other. In this case, the types of heat exchange described above cannot be carried out. How is the transfer of heat energy in this case?
A heated body emits electromagnetic waves, which, as you know, can propagate in an airless space, a less heated body absorbs these waves and heats up.
Definition: Heat transfer by radiation is the transfer of heat energy by means of electromagnetic waves.
In modern nuclear power plants during normal operation, heat transfer by radiation is negligibly small compared to convective.
Thermal circuit
Having considered the methods of possible heat transfer, let us return to the issue of transferring thermal energy in a nuclear power plant or thermal power plant. As is known, at operating stations, the process of converting source energy into thermal energy occurs continuously, and in the event of a heat removal termination, the installation will inevitably overheat. Therefore, along with the source, a consumer of thermal energy is needed, which will take heat and either convert it into other forms of energy or transfer it to other systems. The transfer of heat from the source to the consumer is carried out using a coolant. Based on the above, it is possible to depict the simplest thermal circuit containing an energy source, an energy consumer, and coolant paths.
https://pandia.ru/text/78/077/images/image003_160.gif" width="132" height="60">2010
UDC 621.314(075)
Reviewers: Honored Worker of Science and Technology of the Russian Federation, Professor of the Department of Operation of Power Equipment and Electrical Machines of the Saratov State Agrarian University, Doctor of Technical Sciences. ; staff of the Department of Power Supply of Ulyanovsk State Technical University (Dean of the Faculty of Energy, Professor)
Ugarov, energy: textbook. allowance / , . Ed. d.t.s. ; VolgGTU, Volgograd, 2010. - 96 p.
The methods of energy conversion and technical means - converters for their implementation are considered. The calculated ratios for a number of energy converters are given. The publication uses materials from sources given at the end of the manual, as well as materials from lectures of the authors read for students in the specialty "Power supply of industrial enterprises" and the directions "Electric power", "Electrical engineering".
It is intended for students of energy specialties studying in the specialty "Power supply of industrial enterprises" and the directions "Electric power engineering", "Electrical engineering".
Il. 32. Tab. 2. Bibliography: 21 titles.
Published by decision of the editorial and publishing council
Volgograd State Technical University
ISBN 0558-9 Ó Volgograd
state
technical
Innovative activity for the processing of hydrocarbon raw materials.
The main energy carriers - oil and gas - will be used up in the coming decades. Under various pretexts, their remnants are trying to appropriate the developed countries, which have used up their energy resources and therefore have become energy dependent on third world countries that do not belong to the so-called “golden billion”. Today, the entire energy sector of these countries is practically provided by imported oil and gas. Stocks of uranium ore suitable for processing and use in nuclear reactors may also be exhausted in the near future, after oil and gas.
In this regard, an urgent problem is to find such energy sources that are fundamentally inexhaustible and do not introduce destabilizing factors into the environment. Another urgent problem is the development and creation of installations capable of converting the energy contained in the environment, including space, into forms that would be suitable for use by mankind. Such attempts are already known: these are the energy of water flows, air, solar energy, the energy of water, the tides of the ocean, the internal heat of the Earth, etc.
2. Types of energies and principles of their transformation
2.1. Classification of types of energies
In the modern scientific conception, energy is understood as a general measure of various forms of motion of matter. For quantitative characteristics of qualitatively different forms of motion of matter and the interactions corresponding to them, various types of energy are conditionally introduced: thermal, mechanical, nuclear, electromagnetic, etc.
Distinguish between primary and secondary energies. Primary is the energy directly stored in nature: the energy of fuel, wind, heat of the Earth, etc. The energy obtained after the conversion of primary energy under special conditions, called energy, is considered secondary (for example, steam, electric, hot water, etc.). ).
Obtaining energy of the required type occurs in the process of energy production and is carried out by converting primary energy into secondary.
Almost all the energy to be used and further converted is first converted into thermal energy in industrial and heating furnaces, engines and mechanisms, household appliances (50%), boilers (10%), boilers of thermal power plants and reactors of nuclear power plants (40%). About the received thermal energy is used without further conversion into other types of energy (in industrial and heating furnaces, as well as in the form of steam, hot water, etc.). Approximately part of the received thermal energy goes to the generation of electrical energy, having undergone preliminary conversion into mechanical energy in turbine installations. Less Electric transport" href="/text/category/yelektricheskij_transport/" rel="bookmark">electric transport, various equipment of enterprises. It is noteworthy that about a sixth of the electrical energy is again converted into heat.
A scientifically substantiated classification of types of energy has been compiled. It is based on a complex criterion, including the types of matter, the forms of its movement and the types of interactions.
Types of matter: atom, electron, photon, neutrino, etc.
Forms of movement: mechanical, electrical, thermal, etc.
Types of interaction: nuclear (strong), electromagnetic, weak (with the participation of neutrinos) and gravitational (superweak).
On the basis of a complex criterion, the following types of energy can be distinguished:
1. Annihilation energy - the total energy of the system, "matter - antimatter", released in the process of their connection and annihilation (mutual annihilation) in various forms.
2. Nuclear energy - the binding energy of neutrons and protons in the nucleus, released in various forms during the fission of heavy and synthesis of light nuclei; in the latter case, it is called "thermonuclear".
3. Chemical (more logical - atomic) energy - the energy of a system of two or more substances reacting with each other. This energy is released as a result of the rearrangement of the electron shells of atoms and molecules during chemical reactions.
4. Gravistatic energy - the potential energy of the ultraweak interaction of all bodies, proportional to their masses. Of practical importance is the energy of the body, which it accumulates, overcoming the force of gravity.
5. Electrostatic energy - the potential energy of the interaction of electric charges, i.e. the energy reserve of an electrically charged body accumulated in the process of overcoming the forces of an electric field.
6. Magnetostatic energy - the potential energy of the interaction of “magnetic charges” or the energy reserve accumulated by a body capable of overcoming the force of a magnetic field in the process of moving against the direction of these forces. The source of the magnetic field can be a permanent magnet, electric current.
7. Neutrinostatic energy - the potential energy of the weak interaction of "neutrino charges" or the energy reserve accumulated in the process of overcoming the forces of the β-field - the "neutrino field." Due to the enormous penetrating power of neutrinos, it is practically impossible to accumulate energy in this way.
8. Elastic energy - the potential energy of a mechanically elastic modified body (compressed spring, gas), which is released when the load is removed, most often in the form of mechanical energy.
9. Thermal energy - part of the energy of the thermal motion of the particles of bodies, which is released in the presence of a temperature difference between the given body and the bodies of the environment.
10. Mechanical energy - the kinetic energy of freely moving bodies and individual particles.
11. Electric (electrodynamic) energy - the energy of electric current in all its forms.
12. Electromagnetic (photon) energy - the energy of the movement of photons of the electromagnetic field.
13. Meson (mesonodynamic) energy - the energy of movement of mesons (pions) - quanta of the nuclear field, through the exchange of which nucleons interact (Yukawa's theory, 1935)
14. Gravidynamic (gravitational) energy - the energy of movement of hypothetical quanta of the gravitational field - gravitons.
15. Neutrinodynamic energy - the energy of movement of all-penetrating particles of the β-field - neutrinos.
Of the 15 types of energy listed, only 10 are of practical importance so far: nuclear, chemical, elastic, gravitational, electrical, electromagnetic, electrostatic, magnetostatic, thermal, and mechanical.
Only four types are directly used: thermal (about 75%), mechanical (about 20-22%), electrical (about 3-5%) and electromagnetic (less than 1%). And so widely produced, supplied by wires, electrical energy mainly plays the role of an energy carrier.
The main source of directly usable types of energy is still the chemical energy of mineral organic fuels (coal, oil, natural gas, etc.), whose reserves, which make up a fraction of a percent of all energy reserves on Earth, are on the verge of depletion.
Since December 1942, when the first nuclear reactor was launched, nuclear and thermonuclear fuels have entered the scene as a new source of energy.
In the future, both new types of energy and new sources of energy may appear. The classification of types of energy allows you to explore and evaluate all their possible interconversions.
2.2. Transformation and conversion of types of energy
We will summarize in a matrix table all types of energies that are of practical importance, and analyze the possibilities of their mutual transformations (Fig. 2.2.1).
An analysis of various energy processes shows that two conditions must be met for the transformation of energy types:
1) ensure the proper level of energy concentration;
2) select a working body of certain properties.
Strictly speaking, during all transformations of energy, the gravitational energy of its systems - carriers should change if their position relative to the Earth's surface changes.
It follows from the matrix of energy transformations that these possibilities are very limited. The simplest, most reliable and promising ways have already been used and can only be improved in the direction of increasing the efficiency of transformations and specific energy productivity, i.e., the power of the converter.
https://pandia.ru/text/78/077/images/image011_30.jpg" width="336 height=105" height="105">E IE - natural (natural) source of energy;
And IE - artificial IE;
H E - energy storage;
PERE is an energy carrier.
Rice. 2.2.1. Matrix of possible transformations and transformation of types of energy,
of practical importance
Remained reserves in the form of direct conversion of nuclear energy into electrical and mechanical, chemical into mechanical, gravitational into mechanical. Promising is the transformation of nuclear energy into chemical and elastic energy, and gravitational energy into elastic energy by charging springs and gas cylinders in the depths of the seas.
2.3. Energy conversion is a problem of modern energy
All areas of human life and activity: cooking, industry, agriculture, transport, communications, creating comfortable conditions in homes and industrial premises - require a variety of forms of energy. The conversion of energy from primary sources often does not satisfy consumers precisely in the types of energy received and requires the need for their conversion.
Modern science knows 15 types of energies associated with the movement or different mutual arrangement of a wide variety of material bodies or particles.
Depending on the nature of the movement and the nature of the forces acting between these particles, the change in energy in systems of such particles can manifest itself in the form of mechanical work, in the flow of electric current, in the transfer of heat, in a change in the internal state of bodies, in the propagation of electromagnetic oscillations, etc. .
The fundamental law governing the transformation of energy is the law of conservation of energy. According to this law, energy cannot disappear or arise from nothing. It can only move from one type to another.
A. Einstein established the interconvertibility of energy and mass and thereby expanded the meaning of the law of conservation of energy, which is now formulated in a generalized form as the law of conservation of energy and mass. In accordance with this law, any change in the energy of a body ∆E is associated with a change in its mass ∆m by the formula:
∆E = ∆ms2,
Where With is the speed of light in vacuum, equal to 3 108 m/s.
It follows from this formula that if, as a result of any process, the mass of all bodies participating in the process decreases by 1 g, then energy equal to 9 1013 J will be released, which is equivalent to 3000 tons of conventional fuel. Most of the practically observed processes are macroscopic and the change in mass can be neglected, however, in the analysis of nuclear transformations, the law of conservation of energy and mass is necessary.
When energy is converted in any device, some part of it is lost. The efficiency of this device is usually characterized by the efficiency factor, which can be determined according to Fig. 2.3.1.
Rice. 2.3.1. Scheme for determining efficiency
According to fig. 2.3.1, efficiency can be defined as
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Losses of energy do not violate the law of conservation of energy and mean only losses for the useful effect for which the transformation of energy takes place.
The last expression shows that only a part of the primary energy, which was intended to produce a useful effect, is usefully used.
All energy losses eventually turn into heat, which is given to the environment (atmospheric air, water bodies).
One important circumstance should be noted. Since, in accordance with the law of conservation, energy does not disappear, therefore, the energy of primary energy sources used in the process of human activity is almost completely transferred in the form of thermal energy to the environment. Thus, all converted energy, including energy losses, is ultimately converted into heat. The clause "almost" means that only a very small part of the energy produced is stored for some time in the form of potential or internal energy in structures, products, products produced by man.
Heat energy conversion
Due to the fact that we use primary energy sources (gas, oil, coal) to obtain thermal energy, with the aim of its further transformation, the idea arises of using the thermal energy given away in the process of transformation to the environment.
The second law of thermodynamics, which is a universal law of nature, puts a ban on such "re-use" of thermal energy.
This law states that heat is a special form of energy transfer, and is formulated as follows: in all real processes, any form of energy can spontaneously turn into heat, but spontaneous transformation of heat into other forms of energy is impossible.
This means that any form of energy can be converted into heat without any additional bodies participating in this process, the state of which would somehow change at the end of the process. On the other hand, heat cannot be transformed into other forms of energy without leaving some changes in some of the surrounding bodies at the end of the transformation process.
Thus, if the law of conservation of energy (the first law of thermodynamics) asserts the mutual convertibility and equivalence of all types of energy, then the second law of thermodynamics notes the peculiarity of heat, its inequality in the processes of energy conversion.
It has been proven in thermodynamics that in order to continuously obtain work from heat, it is necessary to have a working body that would carry out a sequence of circular processes, i.e., such processes in which it would periodically return to its original state. In each such circular process, otherwise called a cycle, the working fluid receives a certain amount of heat Q1 from the primary energy source at a sufficiently high temperature and gives off less heat Q2 environment (water or air). Since the working fluid itself, having returned to its initial state as a result of the cycle, does not change its internal energy, then, in accordance with the first law of thermodynamics, the heat difference turns into work:
L = Q1 - Q2.
The possibility and efficiency of converting heat into other forms of energy (mechanical, electrical) is primarily determined by the temperature at which the heat Q1 can be transferred to the working body. At a thermal power plant, the working fluid is water vapor, which in a steam turbine plant receives heat from combustion products at the highest temperature of about 540 ° C.
The temperature at which heat is given off Q2, is also significant from the point of view of the efficiency of converting heat into work.
However, since the heat Q2 given to the environment, in real conditions this temperature can vary only within a narrow range.
The efficiency of converting heat into work is estimated by thermal efficiency η t, which is understood as the relation of work L received per cycle to heat Q1 received by the working fluid from the primary source of energy:
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There are three main ways to convert energy. The first of these is to obtain thermal energy by burning fuel (fossil or vegetable origin) and consuming it for direct heating of residential buildings, schools, enterprises, etc. The second method is to convert the thermal energy contained in the fuel into mechanical work, for example, when the use of oil distillation products to ensure the movement of various equipment, cars, tractors, trains, aircraft, etc. The third way is to convert the heat released during the combustion of fuel or nuclear fission into electrical energy with its subsequent consumption either for heat production or for performing mechanical work.
Electricity is also obtained by converting the energy of falling water. Electricity thus plays the role of a kind of intermediary between energy sources and its consumers (Fig. 9.1). Just as an intermediary in the market leads to higher prices, so the consumption of energy in the form of electricity leads to higher prices due to the losses in converting one type of energy to another. At the same time, the conversion of various forms of energy into electrical energy is convenient, practical, and sometimes this is the only possible way of real energy consumption. In some cases, it is simply impossible to efficiently use energy without turning it into electricity. Before the discovery of electricity, the energy of falling water (hydropower) was used to ensure the movement of mechanical devices: spinning machines, mills, sawmills, etc. After the conversion of hydropower into electrical power, the scope of application expanded significantly, and it became possible to consume it at considerable distances from the source. The fission energy of uranium nuclei, for example, cannot be directly used without converting it into electrical energy.
Fossil fuels, unlike hydro sources, have long been used only for heating and lighting, and not for the operation of various mechanisms. Firewood and coal, and often dried peat, were burned to heat residential buildings, public and industrial buildings. Coal, in addition, was used and is used for smelting metal. Coal oil, obtained by distillation of coal, was poured into lamps. Only after the invention of the steam engine in the XVIII century. the potential of this fossil fuel was truly revealed, which became a source of not only heat and light, but also the movement of various mechanisms and machines. There were locomotives, steamships with steam engines that ran on coal. At the beginning of the XX century. coal began to be burned in the furnaces of boilers of power plants for the production of electricity.
At present, fossil fuels play an extremely important role. It provides heat and light, is one of the main sources of electricity and mechanical energy to provide a huge fleet of numerous cars and various modes of transport. It should not be forgotten that fossil organic raw materials are consumed in huge quantities by the chemical industry for the production of a wide variety of useful and valuable products.
