THE PURPOSE. Conducting a comparative analysis of the problems of efficient power supply torural consumers. Offering solution stop roblems by using multi-fuelmicrothermal power plants based on the Stirlingengine for ruralareas. Justification and description of prospects for the use of multi-fuelmicro-thermal power plants based on the Stirlingengine for ruralareas. METHODS. Methods of computer simulation of thermodynamic processes of multi fuel micro-thermal power plants based on an engine based on an engine with external heat supply are used. A computer simulation method has been developed that allows constructing a PV diagram and processes of changes in the pressure and volume of the working fluid depending on the position of the working piston and the displacer. Mathematical methods of analysis and description of the thermodynamic cycle of an engine with external heat supply are used. RESULTS. Выполнен анализ достижений и уровня современных достижений в области микро электростанций. Установлено направление развития научных исследований по разработке двигателя с внешним подводом тепла. Приведены некоторые результаты исследований по эффективности работы двигателя с внешним подводом теплоты. CONCLUSIONS . Одним из решений проблемы эффективного электроснабжения сельских потребителей может быть внедрения микро тепловых электростанций. Их использование позволит снизить стоимость электроэнергии и обеспечить ее бесперебойную поставку. Основой микро тепловой электростанции является двигатель с внешним подводом теплоты, работающий по принципу Стирлинга.

THE PURPOSE. Improving the accuracy of forecast calculations of demand for energy resources is an urgent task, especially in the light of the Digital Energy of the Russian Federation program. Prediction is also required for he at supply systems. The complexity of the analysis is the lack of confirmation of the similarity properties of energy systems and complexes for buildings with similar functionality. On the example of buildings of secondary educational institutions located i n the territory of Moscow, the assumption of heteromorphism of thermal systems is proved. METHODS. In the work, an assumption was made that there were no significant changes in the data on the heat consumption of the energy facilities of schools, which was confirmed by the absence of changes in the average annual heat consumption and jumps in the monthly heat consumption diagrams. The amount of heat energy consumption measured and transferred to the IS is influenced by a number of additional factors: accura cy drift of heat energy metering devices; aging and overgrowing of the internal surfaces of the building's heating network equipment; physical aging and deterioration of the building envelope and deterioration of their thermal insulation performance. When compiling predicted energy consumption, this means that it is permissible to use not only statistical data about the analyzed object itself, but also about a variety of objects similar to those analyzed in structure and functionality. RESULTS. A set of input factors is proposed that makes it possible to accurately determine the predicted demand for thermal energy for buildings of secondary educational institutions. The possibility and similar accuracy of the results of forecasting the demand for thermal ene rgy is shown both through the use of multivariate regression analysis and artificial neural networks. CONCLUSION. ЭBased on the combined use of various mathematical approaches, it is proposed to use the methodology for forecasting energy demand by energy complexes and systems as a mechanism for determining the correctness of the transmitted meter readings.

THE PURPOSE. The aim of the work is to find a method for mathematical modeling and analysis of inhomogeneous physical fields and the influence of internal structures on these fields. Solutions are sought in areas in which there are subdomains with already known behavior (“embedded” areas and embedded solutions). The goal is to find a modeling method that does not require a change in existing software and is associated only with the modification of the right-hand sides of the equations under consideration. METHODS. The proposed method of mathematical modeling is characterized by the use of characteristic functions for specifying the geometric location and shape of embedded areas, for specifying systems of embedded areas (for example, spherical fillings or turbulent vortices) without specifying them as geometric objects, for modifying the calculated differential equation within the embedded areas. RESULTS. A theorem is formulated and proved (in the form of a statement) that formalizes the essence of the proposed method and gives an algorithm for its application. This algorithm consists in a) representation of the differential equation of the problem in another analytical form; in this form, a term is added to the original differential equation (to its right-hand side), in the presence of which this equation gives a predetermined ("built-in") solution in the necessary regions and b) a representation of the desired solution (using the characteristic function) in the form in which this solution takes the form of either the desired function (in the main area) or the specified functions (in the embedded areas). Examples of calculations from two physical and technical areas - thermal conductivity and hydrodynamics are presented. The result of the work is also the calculation of a turbulent flow in a pipe, in which a system of ball vortices, the speed and direction of rotation of these vortices are specified. CONCLUSION. The proposed method makes it possible to simulate complex physical processes, including turbulence, has been tested, is quite simple and indispensable in cases where embedded structures can be specified only by software.

PURPUSE. This article describes the possibility of burning natural gas from different fields in a stationary power gas turbine General Electric 6FA. METHODS. Currently, gas turbine technologies are one of the most stably developing areas related to the modernization of generating equipment. At present, modernization of power plants is underway both with gas turbine units and with units in the combined-cycle power unit in the Republic of Tatarstan. The conducted studies allow us to evaluate the effect of the component composition of the fuel on the performance of a gas turbine. Comparative studies make it possible to evaluate changes in the energy characteristics of a gas turbine operating as part of a combined cycle gas turbine unit. RESULTS. The study shows that changes in the fuel composition have an impact on the energy characteristics of a gas turbine plant (efficiency, air consumption). Work with a deviation of the Wobbe index is not permissible. The deviation of the Wobbe index for the city of Zainsk is 5.29%, therefore, when installing a gas turbine it is necessary to change the setting of the fuel system. For synthesis gas, the deviation of the Wobbe index was 22.23%, the use of this fuel is unacceptable without changing the design and setting of the fuel system, since the throughput of the fuel system is not designed for a flow rate of 27.8 kg/s. The smallest values of the amount of CO₂, NO, O₂ in the composition of the combustion products are achieved on the fuel gas of the city of Kazan. CONCLUSION. The use of synthesis gas as the only fuel is undesirable when operating a gas turbine in a combinedcycle unit, since the calorific value of the flue gases when operating on synthesis gas is minimal and amounts to 94.3 MW, which will affect the operation of the steam turbine.

THE PURPOSE. Perform a review of information sources on the state of small-capacity thermal power in Russia when the unit capacity of steam turbine, gas turbine and gas piston units is less than 25 MW. Evaluate the information sources of the authors of publications that provide statistics for small-scale energy facilities. Make an assessment of the state of small-scale energy in Russia based on a specific list of objects maintained by the authors over the past 25 years. Consider the manufacturers and characteristics of different types of aggregates, as well as the schemes for integrating aggregates into the thermal schemes of existing sources. METHODS. Statistical indicators of small-scale energy facilities presented in tabular form in Excel are determined based on the built-in functions of this program. RESULTS. The production and characteristics of modern units based on steam turbines are considered. Practical schemes for integrating counter-pressure steam turbo generators into the thermal schemes of existing heat sources are presented. Russian and foreign manufacturers and characteristics of electric units based on gas turbines and internal combustion engines operating on the Otto cycle are considered. Thermal diagrams of gas-turbine and gas-piston units producing both electric and thermal energy are given. A statistical analysis of the list of small-scale cogeneration and power plants of simple cycle compiled by the authors is performed. The number of stations of different types, their distribution by total capacity, regions, industries, and years of commissioning are determined. CONCLUSION. It is shown that gas-turbine and gas-piston installations with a total capacity of up to 80% play a decisive role in the structure of small thermal energy. Quantitative indicators - the total number of stations of small-scale power facilities is about 1500 units and the total electric capacity is more than 18 GW allow us to get an idea of the significant role of small-scale heat power in Russia. Quantitative indicators for solar and wind power plants in the country are also considered.

THE PURPOSE. To analyze the materials of heat supply schemes for large cities of Russia, to consider the impact of an increase in the number of boiler houses in cities when planning the development and modernization of heat supply sources. To develop a methodology for choosing the structure of thermal generation in cities, which is distinguished by the use of an additional criterion for energy efficiency and a system of taken into account restrictions on the energy balances of the region. The weakening of attention to the overall energy efficiency of the aggregates of heat generation sources is shown, an additional reserve for increasing the energy efficiency of heat supply of cities is identified. METHODS. When solving this problem, methods of comparative analysis of the heat supply schemes of large cities of the Russian Federation over the past 7-10 years is used. RESULTS. The article describes the relevance of the topic, created a methodological base aimed at increasing the energy efficiency of heat supply systems in the city. A criterion is proposed that takes into account the different efficiency of sources and structural effects that are realized when choosing the composition of working heat sources for the prospective of urban development. The basic provisions, the relations used, the features of the developed methodology are given. A conclusion is drawn on the appropriateness and effectiveness of these proposals when testing this method. CONCLUSION. The developed method for choosing the structure of thermal generation was tested in the analysis of schemes of large cities of the Russian Federation. Efficiency on the example of the districts of Nizhny Novgorod ranged from 16.5 million to 180.0 million rubles per year.

THE PURPOSE. Of this work is to estimate parameters for a sufficiently comlete thermal decomposition of tarry products of the fixed-bed gasification of wood fuel. METHODS. To this end, mathematical models are used in different statements: the decomposition of the tar is considered in the approximations of one- and two-reaction kinetic scheme; to assess the influence of the bed height and temperature, the convection-diffusionreaction equation with a given temperature distribution along the length of the reaction zone is used; the temperature of the gasification process is estimated from experimental data and thermodynamic calculations. Along with the numerical model of the decomposition of the tar, a simplified analytical expression (for large Peclet numbers) is applied, the limits of its applicability are determined. RESULTS. Of calculations show that the efficiency of the airblown gasification of wood is determined by the temperature level of the oxidation stage: in the range of modes in which the optimal values of efficiency are achieved, the conversion of tarry products does not proceed sufficiently completely due to kinetic limitations; an increase in the specific consumption of the oxidizer leads to a decrease in efficiency due to stoichiometric reasons. CONCLUSION. Physicochemical limitations do not allow reaching the limiting values of gasification efficiency, shifting the optimal modes towards increasing the specific air consumption; a decrease in the yield of tar requires, first of all, changes in the thermal modes of gasification (for example, external heating or an increase in the oxygen concentration).

THE PURPOSE. Consider a stationary diffusion problem when a pure liquid evaporates from a flat surface of evaporation into a laminar boundary layer of a forced gas flow (in the absence of deepening of the evaporation surface and wave formation on it) at the number. In the classical model of the diffusion problem of the flow of mass from a flat surface into the laminar boundary layer, only the additional slowing down effect arising in this case is taken into account. However, the resulting solution does not correspond to the general case of evaporation, since in this case the mass transfer can significantly depend on the thermal conditions of the problem, conjugate in phases; in criterion form, this circumstance is expressed by the appearance of an additional parameter [1-3]. Note that this parameter is related to the value of the derivative of the relative concentration along the transverse coordinate on the evaporation surface. In the course of the proposed solution, the temperature of the evaporation surface and, accordingly, the value of this parameter were taken constant. METHODS. When solving the problem, we used approximate numerical methods for integrating the diffusion equation (Euler's method, integro-differential equation method, and also the method of successive approximations). In this case, the retarding effect of the vapor flow from the surface of the phase transition was assumed to be relatively insignificant in our case (which corresponded to the experimental data used in [1-3]. RESULTS. The article analyzes the well-known classical solution of the diffusion equation according to the Hartnett - Eckert model and notes that the result obtained in this case does not correspond to the general case of evaporation, when the mass transfer in the gas phase also depends on the complex. Based on the solution obtained in our work, we come to the conclusion that the effect of this parameter manifests itself in an increase in the thickness of the diffusion boundary layer. In addition, this effect is also associated with the value of the longitudinal coordinate, being more noticeable at its small values. CONCLUSION. The indicated evaporation pattern can be physically explained by a relatively larger amount of evaporated substance than in the “standard” case (since values, in turn, are associated with higher values of the evaporation surface temperature). It can also be assumed that in the region of the gas flow immediately adjacent to the evaporation surface, these factors manifest themselves in a similar way in the case of turbulent flows.

THE PURPOSE. Transformer oil is widely used in high-voltage electrical equipment and acts as a dielectric and also as a cooling medium. It consists of a complex mixture of hydrocarbon compositions with various impurity compounds. During the operation of oil -filled electrical equipment under the influence of the technological operating conditions of high -voltage devices, aging of both transformer oil and solid insulation occurs. In this case, the dielectric properties deteriorate, which can damage the transformer equipme nt. METHODS. To increase the service life of oil-filled electrical equipment, an antioxidant additive is introduced into the transformer oil at the stage of its manufacture, which is most often used as ionol, the concentration of which must be constantly controlled by various instrumental methods. To determine the antioxidant additive in transformer oil, a sample preparation system is used based on liquid-phase extraction with selective solvents, which are used as aliphatic alcohols of various physical and chemical nature. RESULTS. It has been established that ethyl alcohol, which is widely used in the sample preparation system for liquid extraction of ionol, contains a significant amount of water, which has a negative effect on the process of ionol extracti on from transformer oil. In addition, the composition of ethyl alcohol contains impurity substances that can have a negative effect on the process of liquid-phase extraction of ionol from transformer oil. The generalized data on the physicochemical properties of extractants used to extract ionol from transformer oil are presented. CONLUSION. It has been shown that butanol is the most promising organic solvent for the extraction of ionol, which has a higher boiling point compared to ethyl alcohol and contains a small amount of water. It was found that the selectivity of the chromatographic separation of butanol components with an elevated column temperature increases. At the same time, the separation efficiency increases as the number of theoretical plates per meter of chromatographic column increases. As the temperature of the capillary column increases, the symmetry of the chromatographic peaks of the separated components also increases.

THE PURPOSE. The process of o n-line calculation of electricity losses in three phase distribution electric networks (DEN) with a voltage of a 0,4 kV, where monitoring of electricity losses (commercial accounting) is carried out by an automated information measuring system of electrici ty monitoring and accounting (AIMS EMA) is considered. The problem of operative detecting of unauthorized power take -offs in the DEN under condition of unknown values of parameters of the network equivalent circuit, i.e. resistances of its interpersonal sections, which can change significantly over time because of external climatic factors (temperature, humidity, etc.) is being solved. METHODS. The procedure of the proposed calculation can be implemented by the available means of AIMS EMA. It is based on simultaneous measurements for the same observation interval of effective values of current and voltage, active and reactive powers at the beginning of the DEN and at each subscriber. In the course of periodic measurements of these mode parameters, the initial data used in the proposed calculation are formed. RESULTS. The analysis of the known methods of solving this problem is carried out, their disadvantages are shown and the new methodology, which is based on a preliminary operative calculation of reliable values of the resistances of interpersonal sections, provided that unauthorized power take -offs are possible in DEN is presented. While solving, the conditions of equality of resistances of the phase and neutral wires within the interpersonal section of th e DEN are used. The proposed method makes available the implementation of the operative calculation of technical losses in DEN and the identification of the commercial losses (unauthorized power take -offs) in it, as well as a detailed analysis of subscribe r data in order to detect the location (coordinate) and the amount of unaccounted electricity. CONCLUSIONS. The proposed methodology can be used in existing AIMS EMA without the introduction of additional measuring means (functions).

Considerer the influence of a change in the height of the height of the finning of bimetallic finned tubes of a single-row bundle on the thermal, overall and metal-capacity characteristics in the mode of free air convection at different angles of inclination (γ = 0, 15, 30, 45, 60 and 90°) to the horizontal plane. The investigated tubes have the following characteristics: the material of the supporting tube was carbon steel (outer diameter d_out = 25 mm, wall thickness δ = 2 mm), the material of the rolling finned shell was aluminum alloy AD1M. Geometric parameters of the fins: d×d₀×h×s×Δ×φ× l = 56,0×26,8×14,6×2,5× 0,5×19,3×300 mm (type I). The studies were carried out by the method of complete thermal modeling on a specially designed experimental stand. Then the fins were ground by grinding with the formation of new types of tubes (II–VI), which were assembled into a single-row bundle with a constant relative transverse pitch σ₁ = S₁ / d = 1,14 = const. The article describes the criterion dependences for heat transfer of a finned single-row bundle of tubes with different finning heights at different angles of inclination to the horizontal plane, as well as a graphical dependenc e of the correction factor for the angle of inclination of bundle (γ = 0–90°) were obtained. It has been established that an increase in the angle of inclination and the height of the finning of tubes of a single -row bundle is generally accompanied by a decrease in heat transfer. In terms of overall and metal-capacity characteristics, the most effective is a single-row bundle at various angles of inclination to the horizontal plane with a tube finning height 2,0 mm.

THE PURPOSE. The task of analysis and monitoring of the functioning of electromechanical converters in transient and static modes is relevant at the design and operation stages. Software products for recording and processing measurement information, as well as for performing the necessary technical calculations, such as LabView, MatLab Simulink and others, offer great opportunities for solving the task and allow obtaining reliable results. METHODS. The study of electromechanical DC converters with built-in tachogenerators carried out, the measurement and fixing of the output coordinates of which is provided by experimental sets of various configuration with subsequent processing of the results of functional monitoring using application programs. RESULTS. The developed experimental sets differ in the composition and cost of hardware, the need to use one or another software support, the form of presenting the results of monitoring the functioning of research objects and the accuracy of the results. CONCLUSION. The present study aimed at a comparative analysis of two experimental sets. These sets allow obtaining mathematical models of electromechanical DC converters necessary for the implementation of the monitoring method of the function ing. The analysis performed from the point of view of material costs for hardware and software, the processing time of the experimental results and the correspondence of the obtained results to the required accuracy of the formation of mathematical models.